FIELD

The present invention relates to systems and processes for manufacturing high temperature components. More particularly, the present invention relates to systems and processes for the formation of cooling structures in components at least partially formed from the three-dimensional (3D) printing of a ceramic fiber composite material.

BACKGROUND

Gas turbines comprise a casing or cylinder for housing a compressor section, a combustion section, and a turbine section. A supply of air is compressed in the compressor section and directed into the combustion section. The compressed air enters the combustion inlet and is mixed with fuel. The air/fuel mixture is then combusted to produce high temperature and high pressure gas. This working gas then travels past the combustor transition and into the turbine section of the turbine.

Generally, the turbine section comprises rows of vanes which direct the working gas to the airfoil portions of the turbine blades. The working gas travels through the turbine section, causing the turbine blades to rotate, thereby turning the rotor. The rotor is also attached to the compressor section, thereby turning the compressor and also an electrical generator for producing electricity. High efficiency of a combustion turbine is achieved by heating the gas flowing through the combustion section to as high a temperature as is practical. The hot gas, however, may degrade various metal turbine components, such as the combustor, transition ducts, vanes, ring segments, and turbine blades that it passes when flowing through the turbine.

For this reason, strategies have been developed to protect turbine components from extreme temperatures, such as the development and selection of high temperature materials adapted to withstand these extreme temperatures and cooling strategies to keep the components adequately cooled during operation. State of the art superalloys with additional protective coatings are commonly used for hot gas path components of gas turbines. In view of the substantial and longstanding development in the area of superalloys, however, it figures to be extremely difficult to further increase the temperature capability of superalloys.

For this reason, ceramic matrix composite (CMC) materials have been developed and increasingly utilized. These materials offer a high temperature resistance, e.g., up to or greater than 1200° C. Typically, CMC materials include a ceramic or a ceramic matrix material, either of which hosts a plurality of reinforcing fibers. The fibers may have a predetermined orientation to provide the CMC materials with additional mechanical strength. Generally, (fiber reinforced) ceramic matrix composites are manufactured by the infiltration of a matrix slurry (e.g., alumina, mullite, silicon-containing polymers, molten silicon) into a fiber preform. While oxide and non- oxide CMC materials can be operated at high temperatures, they can only do so for limited time periods in a combustion environment without being cooled since external surfaces are exposed to gas path combustion gases that are substantially hotter than 1200° C. For this reason, cooling strategies are often employed for components formed entirely or substantially from CMC materials.

By way of example, a plurality of radially extending cooling passages (channels) and holes are often drilled within an interior of a CMC component body in a predefined pattern. Cooling air may be flowed through the cooling passages to carry away heat from the body and to and through film cooling holes to provide a blanket layer of air on an exterior surface the component. Drilling the holes through the body of the CMC component, however, significantly limits the geometries and configurations available for the cooling channels.

SUMMARY

In accordance with an aspect of the present invention, there are disclosed systems and processes for the customized formation of cooling structures, including passages and/or holes, in a component formed at least partially via three dimensional (3D) printing a ceramic matrix composite (CMC) material,. Aspects of the present invention further allow for the formation of at least a portion of the component contemporaneously with the formation of cooling structures therein. In one aspect, a ceramic fiber composite (e.g., a fiber coextruded with a matrix slurry) is deposited (3D printed) on a substrate in a predetermined pattern to define at least an outer wall of a component as one or more cooling channels and/or cooling holes are formed. By way of example, the systems and processes described herein may utilize a CMC component having no cooling structures and formed from a conventional layup process as a base substrate, and then 3D print a ceramic fiber composite to form an outer wall on the base substrate along with cooling structures (channels/holes) for a near wall cooling design. In other embodiments, the entire component (substrate (body) and cooling channels / holes) is formed by 3D printing a ceramic fiber composite.

In accordance with another aspect, the ceramic fiber composite is deposited about one or more sleeves to form a respective cooling channel in the deposited ceramic fiber composite as at least a portion (e.g., outer or near wall) of the structure is also being formed (from the ceramic fiber composite). The sleeves define a desired dimension of a cooling passage in the structure. In addition, the sleeves provide high structural integrity while withstanding the high cooling air pressures that would be expected to flow there through. Further, in certain embodiments, interlaminar cracks that typically form between layers/plies of conventional CMC materials and resulting interlaminar failure of the associated structure can be significantly reduced due to the elimination of plies and the 3D printing of a ceramic fiber composite. Still further, the improved structural integrity is located where the component is most likely to be exposed to high temperature damage, namely at an exterior (outer) wall of the component which is in contact with the hot gas of the turbine engine.

In accordance with another aspect, the systems and processes described herein enable the 3D printing of ceramic fiber composites into components having complex shapes, dimensions, thicknesses with complex cooling designs formed therein. These cooling designs may not be otherwise obtainable by conventional drilling techniques due to the preference toward linearity in such processes. In addition, the systems and processes described herein may enable the printing of ceramic fiber composites on complex 3D surfaces, such as gas turbine components. Further, the systems and processes described herein may allow for the formation of near wall cooling channels while allowing increased control of the near (outer) wall thickness and material selection. In this way, the systems and processes described herein allow for the manufacture of components otherwise not yet considered at the present time. For example, components having distinct ceramic materials, fibers, and porosities within the same component with wall thicknesses and cooling channels / holes of any suitable dimension / orientation are now much more accessible,

In accordance with an aspect of the present invention, there is provided a process for forming cooling channels within a ceramic matrix composite component, the process comprising: introducing a ceramic material into a solid fiber material to produce a ceramic fiber composite; and depositing the ceramic fiber composite in a

predetermined pattern to form at least a portion of an outer wall the ceramic matrix composite component having a plurality of internal cooling channels formed therein.

In accordance with yet another aspect, there is provided a component

comprising a body having a least a portion of an outer wall formed from a three- dimensionally printed pattern of a ceramic fiber composite, wherein the 3D printed pattern defines a plurality of cooling channels therein.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following description in view of the drawings that show:

FIG. 1 is a schematic view of a 3D printing system for manufacturing a

component from a ceramic matrix composite in accordance with an aspect of the present invention;

FIG. 2 is a cross-section of a fiber material comprising an uptake enhancement structure in accordance with an aspect of the present invention;

FIG. 3 is a schematic showing further components for a 3D printing system in accordance with an aspect of the present invention;

FIG. 4 illustrates a fiber material loaded with two ceramic materials in distinct portions thereof in accordance with an aspect of the present invention.

FIG. 5 illustrates a fiber material having a first and a second ceramic coating layer in accordance with an aspect of the present invention;

FIG. 6 is a schematic showing further components for a 3D printing system in accordance with an aspect of the present invention; FIG. 7 is a schematic showing still further components for a 3D printing system in accordance with an aspect of the present invention;

FIG. 8 illustrates a cutting mechanism associated with a dispensing head in accordance with an aspect of the present invention;

FIG. 9 illustrates a stationary vane formed by a system in accordance with an aspect of the present invention;

FIG. 10 illustrates a dispensing head having a laser source attached thereto in accordance with an aspect of the present invention.

FIGS. 1 1 -12 illustrate steps in a 3D printing process of a ceramic fiber composite in accordance with an aspect of the present invention;

FIG. 13 illustrates the printing and cutting of a ceramic fiber composite in a predetermined pattern in accordance with an aspect of the present invention;

FIG. 14 illustrates the printing and cutting of a ceramic fiber composite in a predetermined pattern in accordance with another aspect of the present invention;

FIG. 15 illustrates a printing pattern in accordance with an aspect of the present invention.

FIG. 16 illustrates a component of a ceramic matrix composite material having a defect therein.

FIG. 17 illustrates the repair of the defect of FIG. 16 via application of a ceramic fiber composite in accordance with aspects of the present invention.

FIG. 18 illustrates a robotic arm having a dispensing head associated therewith in accordance with an aspect of the present invention.

FIG. 19 illustrates a component (airfoil) comprising internal cooling channels in accordance with an aspect of the present invention.

FIG. 20 illustrates a cross-section taken at line A-A of FIG. 19 in accordance with an aspect of the present invention.

FIG. 21 illustrates a cooling hole in accordance with an aspect of the present invention.

FIG. 22 illustrates a cross-section of an outer wall having cooling channels formed therein on a conventional layup ceramic matrix composite (CMC) material in accordance with an aspect of the present invention. FIG. 23 illustrates a laterally extending cooling channel in a 3D printed

component in accordance with an aspect of the present invention.

FIG. 24 illustrates a sleeve defining a cooling channel within an outer wall formed by 3D printing a ceramic fiber composite in accordance with an aspect of the present invention.

FIG. 25 illustrates another view of a plurality of sleeves defining cooling channels in accordance with another aspect of the present invention

FIG. 26 illustrates the braiding of a ceramic fiber composite about sleeves defining cooling channels in accordance with another aspect of the present invention.

FIG. 27 illustrates a cross-section of a double-walled component having cooling channels formed therein in accordance with an aspect of the present invention.

FIG. 28 illustrates a cross-section of a component having internal cooling channels and a thermal barrier coating (TBC) thereon in accordance with an aspect of the present invention.

FIG. 29 illustrates the 3D printing of a ceramic fiber composite to define an engineered surface for the improved attachment of a TBC thereto in accordance with an aspect of the present invention.

FIG. 30 illustrates the deposition of a TBC on the engineered surface in accordance with an aspect of the present invention.

DETAILED DESCRIPTION

The below description first describes in detail systems and processes for the three dimensional (3D) printing of a ceramic fiber composite material. In one aspect, the below-described systems and processes 3D print a ceramic fiber composite to manufacture all or a portion of a CMC (ceramic matrix composite) component, such as hot gas path turbine component. In accordance with another aspect, the 3D printing systems and processes described below may further be utilized for the formation of cooling structures (e.g., passages and/or holes) within the same component as all or a portion of it is being formed by 3D printing. In still other aspects, the 3D printing systems and processes may be utilized to build an outer wall having cooling structures formed therein on an existing component formed by another process (other than the described 3D printing process), such as a conventional layup process. In further aspects, the 3D printing systems and processes described below may be utilized to form an engineered surface on the outer wall of a component (having cooling structures formed therein) for improved attachment of a thermal barrier coating (TBC) to the component to provide multiple high temperature resistance strategies in the same component.

Turning now to FIG. 1 , FIG. 1 illustrates a system 10 for printing a ceramic fiber composite 24, 48 to form a component, cooling structures (passages and/or holes), and/or engineered surfaces as set forth herein. The system 10 comprises a source 12 of a first solid fiber material 14 (or fiber material 14), a source 16 of a first ceramic material 18, a first injector 20 in fluid communication with the source 16 of the first ceramic material 18 configured to introduce an amount of the first ceramic material 18 into the first solid fiber material 14 to form a first ceramic fiber composite 24; and a first dispensing head 22 configured to deposit the first ceramic fiber composite 24 therefrom in a predetermined pattern onto a working surface 25. By way of example, the working surface 25 may be a substrate, a layer of ceramic material, or a previously deposited layer of a ceramic fiber composite. As used herein, the term "ceramic fiber composite" is understood to refer to a material formed from a combination, e.g., extrusion, of a ceramic or ceramic matrix material with a solid fiber material.

The source 12 of first solid fiber material 14 may be in any form, such as a spool (with fibers wound about a mandrel) or the like, which conveys an amount of the first ceramic fiber material 14 for the system 10 as needed. In addition, the first solid fiber material 14 may comprise any suitable fiber material which provides a degree of added strength for the ceramic fiber composite. The first solid fiber material 14 also has a desired thickness and a longitudinal length (L), which may extend through at least a portion of the system 10.

In an embodiment, the first solid fiber material 14 comprises a ceramic material. Without limitation, exemplary ceramic materials include alumina, mullite,

aluminosilicate, yttria alumina garnet, silicon carbide, silicon nitride, silicon carbon nitride, molydisicilicide, zirconium oxide, titanium oxide, combinations thereof, and the like. In an embodiment, the first solid fiber material 14 comprises an oxide material. In another embodiment, the first solid fiber material 14 comprises a non-oxide material. In a particular embodiment, the first solid fiber material 14 may comprise ceramic fibers sold under the trademark Nextel, such as Nextel 610, and 720 fibers. In addition, the first solid fiber material 14 may be in any suitable form, such as a straight filament, a bundle or a roving of multiple fibers, a braid, or a rope. In still other embodiments, the fiber material may comprise non-ceramic materials, including but not limited to carbon, glass, polymeric, metal, or any other suitable fiber materials.

In an embodiment, the first solid fiber material 14 is delivered from the fiber source 12 such that a longitudinal section (L) of the fiber is repeatedly exposed (e.g., within a loading region 15) to the first injector 20 as one of the first solid fiber material 14 and the first injector 20 is advanced past the other. As needed, an amount of a first ceramic material 18 may be introduced into the first solid fiber material 14 by the first injector 20, or alternatively by any other suitable method or device. In this way, the first ceramic material 18 may be absorbed by and/or coated on the first solid fiber material 14 along all or a portion of its longitudinal length to provide a first ceramic fiber composite 24. The amount of first ceramic material 18 introduced may be any suitable amount, such as from about 1 to about 500 μΙ_ per millimeter of length (L) of the associated fiber material, e.g., first solid fiber material. As used herein, the term "about" refers to an amount that is ± 5 % of the stated amount.

Alternatively, the ceramic material 18 may be introduced into the first solid fiber material 14 by any other suitable process and in any suitable form, such as a slurry or the like, to form the first ceramic fiber composite 24. In certain embodiments, the amount of ceramic material introduced to the first ceramic solid fiber composite may be a predetermined volume (vol.) % of the first solid fiber material 14, such as from 1 to 75 vol. %, and in a particular embodiment, from 20 to 50 vol. %.

In an embodiment, the first solid fiber material 14 may comprise an uptake enhancement feature 26 associated therewith to facilitate uptake of the first ceramic material 18. In an embodiment, referring to FIG. 2, the uptake enhancement feature 26 may comprise a physical structure which facilitates uptake of the first ceramic material 18 (or other material) into the first solid fiber material 14. For example, the uptake enhancement feature 26 may comprise a member selected from the group consisting of tubes, whiskers, flyfeet, and scoops associated with the first solid fiber material 14. In the embodiment shown, there is illustrated a longitudinal portion of the first solid fiber material 14 having scoops 28 integrated therewith for enhancing uptake of the first ceramic material 18, or any other suitable material. The uptake enhancement feature 26 may be associated with a surface of the first solid fiber material 14, or may be incorporated within the first solid fiber material 14 by any suitable method. In a certain embodiment, the first solid fiber material 14 may be manufactured with the uptake enhancement feature 26 incorporated therein.

The source 16 of the first ceramic material 18 may comprise any suitable housing, such as a vessel or a syringe with a plunger, for containing a quantity of the first ceramic material 18. Similar to the first solid fiber material 14, the first ceramic material 18 may comprise an oxide material or a non-oxide material. In an

embodiment, the first ceramic material 18 comprises an oxide material, such as zirconium oxide, titanium oxide, aluminum oxide, mullite, combinations thereof, and the like. In another embodiment, the first ceramic material 18 comprises a non-oxide material, such as a carbide material (e.g., a SiC material). In yet another embodiment, the first ceramic material 18 may comprise a ceramic-polymer mixture. In yet another embodiment, the ceramic material 18 may comprise a silicon-containing polymer, which may also comprise an oxide or non-oxide material. In certain embodiments, the first ceramic material 18 may comprise a mixture of two or more ceramic materials.

Additionally, in some embodiments, the first solid fiber material 14 and the first ceramic material 18 may be of the same oxide or non-oxide material (e.g., oxide/oxide or non- oxide/non-oxide) or different materials of the same type (e.g. oxide1/oxide2, non- oxide1/non-oxide2). In other embodiments, the first solid fiber material 14 and the first ceramic material 18 may be of different types (e.g., oxide/non-oxide).

In accordance with an aspect, the first injector 20 is in fluid communication with the source 16 of the first ceramic material 18 such that the first injector 20 introduces the first ceramic material 18 to the first solid fiber material 14 in a loading region 15 thereof. The amount of first ceramic material 18 delivered to the first solid fiber material 14 is without limitation and may, for example, be an amount which fully saturates the first solid fiber material 14 as portions of the first solid fiber material 14 travel past the first injector 20. In an embodiment, the amount of the first ceramic material 18 delivered to the first solid fiber material 14 by the first injector 20 may be from 1 to 500 μΙ_ per millimeter of length (L) of the fiber material, e.g., first solid fiber material 14. Further, in an embodiment, the first ceramic material 18 has a solids fraction of from about 1 to about 90 wt %.

The skilled artisan would also readily appreciate that the amount of ceramic material 18 introduced to the first solid fiber material 14 may be dependent on properties of the first solid fiber material 14 and the first ceramic material 18, such as density, fiber thickness, viscosity, and the like. The first injector 20 may comprise any suitable structure that will allow for the active or passive introduction of a ceramic material, e.g., a first ceramic material 18, into an associated fiber material, e.g., first solid fiber material 14. In an embodiment, the first injector 20 comprises one or more nozzles 29, each of which may have any suitable outlet diameter and outlet shape suitable for the particular application. Further, in an embodiment, the first injector 20 may comprise a syringe comprising a suitable housing for storing an amount of a ceramic material therein, at least one nozzle 29 (see e.g., FIGS. 1 , 3 and 8), and a plunger for directing the ceramic material out of the syringe through the nozzle 29. The first injector 20 may further comprise any suitable valves, lines, pumps, controllers, sensors, or other components associated therewith as are necessary or desired for operation thereof.

In accordance with an aspect, the first injector 20 may be disposed at any suitable angle relative to a longitudinal length (L) of the first solid fiber material 14 in order to introduce the first ceramic material 18 into the first solid fiber material 14 in the loading region 15 thereof to provide the ceramic fiber composite 24. In an embodiment, the angle is normal to the longitudinal length (L) of the first solid fiber material 14 as shown in FIG. 1 , although it is understood that the present disclosure is not so limited. In other embodiments, the first injector 20 may be oriented at an angle other than 90 degrees relative to the longitudinal length (L) of the first solid fiber material 14.

The above embodiment describes a single ceramic material being introduced to the first solid fiber material 14. It is also understood, however, that the present invention is not so limited. In other embodiments, the system 10 may include one or more additional ceramic sources in communication with first injector 20 and optionally one or more additional injectors for introducing the additional ceramic material(s) into the first solid fiber material 14. Referring to FIG. 3, for example, there is shown a source 30 of a second ceramic material 32 in fluid communication with a second injector 34, which may also include one or more nozzles 29 through which the second ceramic material 32 can exit. In this embodiment, the second injector 34 may configured to introduce a selected amount of the second ceramic material 32 into the first solid fiber material 14 in a loading region 15 thereof. The loading region 15 may progress up (toward the fiber source) as the first ceramic fiber composite 24 is deposited by the system 10. The first ceramic fiber composite 24 (though now loaded instead or also with a second ceramic material vs. a first ceramic material) may be deposited from the first dispensing head 22 onto the working surface 25. For ease of illustration, all of the components of FIG. 1 are not shown as being included in FIG. 3; however, it is understood that the components of FIG. 1 may also be present in the embodiment shown in FIG. 3, as well in the other figures showing further components of the system 10.

In an embodiment, as shown in FIG. 4, the second ceramic material 32 may be introduced to the first solid fiber material 14 such that a first longitudinal portion 36 of the first solid fiber material 14 has the first ceramic material 18 and a second (distinct) longitudinal portion 38 of the first solid fiber material 14 includes the second ceramic material 32. A line is shown dividing the two portions; however, it is understood that the separation of the two ceramic materials may not be so distinct, and that there may be some mixing of materials at or near the intersection of the two materials. Alternatively, a first length of the fiber material 14 could be provided with the first ceramic material 18, the first length cut (as will be described below), and a second length of the fiber material 14 could be provided with the second ceramic material 32. In this way, the first solid fiber material 18 and resulting ceramic matrix composite may be provided with more than one type of ceramic material, such as ceramic materials having differing porosities. This may be useful, for example, when higher temperature fibers are more desirable in a portion of the component vs. another portion. Aspects of the present invention thus provide numerous design options in the formation of ceramic fiber composite materials and components therefrom.

In still other embodiments, as shown in FIG. 5, the second ceramic material 32 may be added to the first solid fiber material 14 in a same region 15 of the first solid fiber material 14 such that the first ceramic material 18 forms a first ceramic layer 40 on the fiber material 14 and the second ceramic material 32 forms a second ceramic layer 42 over the first ceramic layer 40. FIG. 5 is a cross-sectional view of a portion of a fiber (fiber material 14) having a first ceramic layer 40 and a second ceramic layer 42 thereover. In this embodiment, the second ceramic material 32 may be different from that of the first ceramic material 18 in terms of composition, porosity, or the like. In this way, in certain embodiments, the first solid fiber material 14 may be provided with the beneficial properties of two distinct ceramic materials.

In other embodiments, one or more ceramic materials may be mixed by a suitable mixing device and introduced into the first solid fiber material 14 by the first injector 20, the second injector 34, or a like device. In this way also, novel materials may further be created, such as a fiber material being combined with a ceramic blend having desired properties from each of a plurality of distinct ceramic materials, or having new properties altogether.

In accordance with another aspect, the system 10 allows for more than one type of fiber material to be deposited therefrom. To accomplish this, in an embodiment (and referring now to FIG. 6), the system 10 may further include a source 44 of a second solid fiber material 46, a second injector 34 in communication with the source 30 of a second ceramic material 32 (as previously described herein), the second injector 34 configured for introducing the second ceramic material 32 into the second solid fiber material 46 in a loading region 15 thereof to produce a second ceramic fiber composite 48. In addition, the system 10 may further describe a second dispensing head 50 for dispensing the second ceramic fiber composite 48 onto the working surface 25 (which may be a substrate, a previously laid down layer of a ceramic material, first ceramic fiber composite 24, second ceramic fiber composite 48, or the like) in a predetermined pattern. Again, for ease of illustration, the other components described herein for system 10 are not shown in FIG. 6, but it is understood that they may be included therein.

Further, for ease of discussion, the source 44 of second solid fiber material 46, the second solid fiber material 46, the second ceramic fiber composite 48, the source of second ceramic material 30, the second ceramic material 32, the second injector 34, and the second dispensing head 50 may be the same or similar in structure or composition as described above for the corresponding first ones of each like component (12, 14, 16, 18, 20, 22, 24). It is understood in the interest of brevity that the possible embodiments for each composition will not be re-explained for the second of these elements. It is further understood that each component may be of the same

structure/type as that of its corresponding first component, or may be different in kind. By way of example only, the second solid fiber material 46 may be different from the first solid fiber material 14. Still further, it is further understood that the present invention is not so limited to first and second ones of the above components. In certain embodiments, still further fiber or ceramic materials (and corresponding components for the same) may be provided.

In accordance with another aspect, when the first ceramic fiber composite 24 or the second ceramic fiber composite 48 are printed (deposited), the first ceramic fiber composite 24 and the second ceramic fiber composite 48 may be deposited on or incorporated into an existing working surface 25 that comprises a ceramic material (note: the term "ceramic" is understood herein to include a ceramic or ceramic matrix material). In an embodiment, the working surface 25 comprises a ceramic material without fibers incorporated therein. In certain aspects, the system 10 may further include a structure for dispensing the ceramic material without fibers in a predetermined pattern. The ceramic fiber composite(s) may then be added onto/into the deposited ceramic only material. In this way, aspects of the present invention may not only print a ceramic fiber composite, but also add a fiber material to a ceramic material to build a component in contrast to known systems and processes, wherein a ceramic material is incorporated into a fiber material, typically a fiber layup or preform.

Referring now to FIG. 7, to provide a ceramic material to the working surface 25, the system 10 may further include a ceramic only dispensing head 52 in fluid communication with a source 54 of a ceramic material 56. As with dispensing heads 22, 50, the dispensing head 52 may include at least an inlet and an outlet, such as a nozzle 31 , for dispensing of the ceramic material 56 therefrom. In addition, the source 54 of ceramic material 56 may be the same as the source of ceramic material (16 or 30) for the fiber materials (14 or 46) or may comprise an independent source of a different ceramic material as shown. In an embodiment, the ceramic material 56 may comprise either or both of the first ceramic material 18 and the second ceramic material 32.

As will be discussed below, in certain embodiments, the ceramic only dispensing head 52 may deposit the ceramic material 56 in a predetermined pattern in one or more layers on the working surface 25. Thereafter, an amount of a first or second ceramic fiber composite (24 or 48) may be deposited on the ceramic material 56 (or vice-versa). Further thereafter, an additional layer of a ceramic material 56 or a ceramic fiber composite (24 or 48) may be deposited on the previously deposited layer(s) in a predetermined pattern. These steps may be repeated in any desired order until the component is formed. It is appreciated that any desired number of fiber dispensing heads or ceramic only dispensing heads may be provided in the system 10, or as modules to be added/removed from existing systems.

In accordance with another aspect, as mentioned, the dispensing heads (22, 50, or 52) deposit the ceramic fiber composites or the ceramic material in a predetermined pattern. To accomplish this, a motor or other drive mechanism 58 may be associated with each dispensing head (22, 50, or 52) to allow for deposition of the associated material on the working surface 25 in any coordinate position at a point in time. In an embodiment, the working surface 25 is configured to move with respect to one or more of the dispensing heads (22, 50, and/or 52). In another embodiment, one or more the dispensing heads (22, 50, and/or 52) may be configured to move with respect to the working surface 25. In certain embodiments, as shown in FIG. 18, the drive mechanism 58 comprises a robotic arm 75, and any one or more of the dispensing heads described herein (22, 50, or 52) may be associated with the robotic arm 75 such that the associated dispensing heads have a freedom of movement in any desired direction (e.g., rotationally and in any or all of an x, y, or z direction (FIG. 12). Without limitation, the robotic arm 75 may comprise a 5-axis or a 6-axis robotic arm as are known in the art.

In addition, the system 10 may further comprise one or more controllers (e.g., controller 60) in electrical (wired or wireless) in communication with the drive

mechanism 58 to facilitate the amounts, concentrations, order, location of, and extent of deposition of the materials, as well as the operation of any pumps, values, or the like, positions of the working surface 25 and/or dispensing heads (22, 50, or 52), or other parameter(s). For purposes of illustration, FIG. 7 shows a controller 60 in electrical communication with a drive mechanism 58 for controlling a position of the ceramic only dispensing head 52, although it is understood the remaining dispensing heads (22, 50) may have the same or a distinct drive mechanism 58 and/or controller 60 associated therewith.

The controller 60 may comprise a general or special purpose computer programmed with or software/hardware to carry out an intended function as described herein. As used herein, the term "computer" may include a processor, a

microcontroller, a microcomputer, a programmable logic controller (PLC), a discrete logic circuit, an application specific integrated circuit, or any suitable programmable circuit or controlling device. The memory may include a computer-readable medium or a storage device, e.g., floppy disk, a compact disc read only memory (CD-ROM), or the like. In an embodiment, the controller 60 executes computer readable instructions for performing any aspect of the methods or for controlling any aspect of the systems or process steps described herein. As such, the controller 60 may be configured to execute computer readable instructions to monitor and/or adjust parameters such as: timing of deposition steps, the amounts, concentrations, order, location of, and extent of deposition of materials; the operation of pumps, valves, or the like; positions of the working surface and/or dispensing heads, or any other parameter(s). If necessary, the systems and processes described herein may employ one or more sensors for monitoring a desired parameter. Correspondingly, the controller 60 may comprise one or more inputs for receiving information from the one or more sensors.

In accordance with another aspect, when the first ceramic fiber composite 24, the second ceramic fiber composite 48, and/or fiber material alone is deposited onto the working surface 25, any of these components (which include a fiber material) may need to be cut, such as at an edge of the predetermined pattern in which it is deposited. To accomplish this, as shown in FIG. 8, the system 10 may further include a cutting mechanism 62 to cut the fiber material (e.g., first or second ceramic fiber composite 24, 48) at a point of time after deposition of the fiber material from its associated dispensing head (22 or 50). In certain embodiments, the cutting mechanism 62 may be associated with a particular (fiber) dispensing head (22 or 50) so as to be able to cut the ceramic fiber composite (24 or 48) close to the outlet of the nozzle 29 where it is deposited so as to leave little slack after cutting.

The cutting mechanism 62 may comprise any suitable component effective to cut the desired material at a desired time and location. In an embodiment, the cutting mechanism 62 comprises a device that cuts the fiber material mechanically. Without limitation, as shown in FIG. 8, the cutting mechanism 62 may comprise two opposable arms 64, one or both housing a cutting tool 66, such as a cutting (razor) blade, which acts to cut the ceramic fiber composite upon closure of the arms 64 with respect to one another (with the fiber material therebetween). Alternatively, the cutting mechanism 62 may comprise any other structure configured to cut the ceramic fiber composite (24 or 48) or fiber material deposited from an associated dispensing head (22 or 50) at a predetermined time and position along a length of the ceramic fiber composite (24 or 48) or fiber material. The cutting mechanism 62 may also include a laser-based approach. For example, as shown in FIG. 10, the cutting mechanism 62 may also comprise a laser source 65, which may be (but not necessarily) associated with a particular dispensing head (22 or 50), and which is configured to deliver a suitable amount of energy 67 for cutting the ceramic fiber composite (24 or 48) at a desired position.

In particular embodiments, activation of the cutting mechanism 62 may be automated, and thus programmed to cut the associated fiber material (e.g., ceramic fiber composite 24 or 48) when the associated dispensing head or working surface 25 reaches a desired location/position or at a predetermined point in time. The cutting mechanism 62 may itself have a controller/microprocessor (of the type described above for controller 60) for automating these functions, or alternatively may be in electrical communication with an external controller, e.g., controller 60, for control of the operation thereof.

The apparatuses and products described herein may be suitable for

manufacturing any suitable ceramic matrix composite structure. The structure may be a newly manufactured component or a repair or addition to an existing component. In an aspect of the invention, the apparatuses and processes described herein are suitable for the manufacture of components having a complex 3D shape, e.g. , an airfoil, shape. Thus, in an embodiment, the structure formed by the systems and processes described herein may comprise a gas turbine component. In certain embodiments, the gas turbine component may comprise a rotating component, such as a blade. In other embodiments, the gas turbine component may comprise a stationary component, such as a vane. By way of example, FIG. 9 illustrates a component 70, e.g., a stationary vane 71 , having an airfoil portion 72 of a ceramic fiber composite formed by any of the processes and systems described herein. As shown, the airfoil portion 72 may be disposed between an inner and outer platform 74, 76, and secured to each by any suitable method or structure to provide the stationary vane 71 .

In other embodiments, the systems and processes may be configured for 3D printing the material to repair/augment an existing component, such as any of the gas turbine components described herein. By way of example, FIG. 16 illustrates a portion of an existing component 200 formed from a typical ceramic matrix composite 202. In this embodiment, as is typical for high strength components, the ceramic matrix composite 202 may comprise a fibrous layup or weave 204 into which a ceramic or ceramic matrix material is impregnated. For ease of illustration, the ceramic material is considered to be removed from FIGS. 16-17.

When the component 200 is damaged through operation and include one or more defects 206 formed therein, it of course may be desirable to repair the defect(s) 206 to restore it to a desirable operating condition. In the case of the weave 204 shown in FIG. 16, however, it is well-appreciated that restoration of the original weave structure may be completely impossible as the weave structure cannot be recreated at the location of the defect(s) 206. Currently known systems and methods thus do not provide an adequate method of repairing ceramic matrix composite structures where the weave structure has been compromised. Aspects of the present invention, however, provide a system and method for providing localized ceramic-reinforced fibers where necessary to repair the defect. As shown in FIG. 17, where the defect(s) 206 lie in the fibrous weave 204, a ceramic solid fiber composite, e.g., first ceramic fiber composite 24, can be printed within the area of the defect(s) 206 via any system or process described herein so as to reestablish a fiber reinforced ceramic (repair 208) with a comparable, if not stronger, ceramic (solid) fiber composite at the location of the defect(s) 206.

The operation of the systems as described herein, and the components therein, will be briefly described in the below paragraphs. It is however understood that the processes for operating the systems described herein and manufacturing component(s) therefrom is not so limited to the below description. Accordingly, the processes may include any additional or alternative steps that would be appreciated from the disclosure of the components described herein. Further, any component(s) or process step(s) described herein with respect to one embodiment may be combined with component(s) or process step(s) of any other embodiment described herein.

Referring now to FIGS. 1 1 -12, there are shown exemplary steps in a process for forming a ceramic matrix composite component in accordance with an aspect of the present invention. As shown in FIG. 1 1 , an amount of a ceramic material 56 is first delivered from the ceramic only dispensing head 52 onto a substrate 102 to form a first (cross-sectional) layer 104 thereon (working surface 25). The substrate 102 may comprise any suitable structure. In certain embodiments, the substrate 102 may comprise a platform for a blade or vane, a substrate intended to be removed upon completion of the component, or alternatively may be an initial cross-section of the structure or component to be formed. In an embodiment, a ceramic material 56 may be deposited on the substrate 102 by the ceramic only dispensing head 52 in a

predetermined pattern to form the first layer 104.

Next, as shown in FIG. 12, an additional ceramic layer may be deposited from dispensing head 52, or a layer of a ceramic fiber composite (24 or 48) may be deposited from an associated dispensing head (22 or 50) onto the first layer 104 to form the next cross-sectional layer 106 and an updated working surface 25. Alternatively, one or more ceramic fiber composite layers may be first deposited on the substrate 102, and thereafter layer(s) of a ceramic material, e.g., ceramic material 56, may be deposited thereon.

To accomplish the deposition of the ceramic fiber composite, as was shown in FIGS. 1 and 3, a suitable amount of a fiber material, e.g., first solid fiber material 14, may be deposited from its corresponding fiber material source, e.g., source 16. An amount of a ceramic material (e.g., first and/or second ceramic materials 18, 32) may be introduced onto/into the fiber material 14 from a corresponding injector (e.g., injector 20 or 34). The resulting ceramic fiber composite (24 or 48) may be fed to a

corresponding dispensing head (22 or 50).

To deposit the ceramic fiber composite(s) (24 or 48) onto the working surface 25 in the predetermined pattern, the associated dispensing head (22 or 50) may deposit the desired material and be moved with respect to the working surface 25 in any direction as shown in FIG. 1 1 , or alternatively, the working surface 25 may be caused to move in any of the direction with respect to the associated dispensing head (22 or 50). In any case, the ceramic fiber composite (24 or 48) may be deposited from its

associated dispensing head (22 or 50) so as to deposit the ceramic fiber composite (24 or 48) onto the working surface 25 in a predetermined pattern to form the next cross- sectional layer 106.

Thereafter, an additional ceramic only layer or an additional ceramic fiber composite layer may be deposited on the next cross-sectional layer 106 to form a yet further cross-sectional layer. It is appreciated that this process may be repeated several times until the desired structure is formed. Still further, the combination of ceramic materials, fiber materials, ceramic fiber composites, and order of printing (deposition) of components may be quite large in number and is without limitation herein. In certain embodiments, the fiber material (14 or 46) may even be deposited on the working surface 25 without loading of a ceramic material therein.

As noted above, when a fiber material as described herein (ceramic fiber composite or fiber material without ceramic material) is deposited, it may be desirable to cut the fiber material at a point in its path of deposition. Referring again to FIGS. 8 and 10, the deposited ceramic fiber composite (24 or 48) may be cut at a desired position along a longitudinal length thereof by the cutting mechanism 62, which may be mechanical or laser-based. For example, as shown in FIG. 13, the ceramic fiber composite (e.g., first ceramic fiber composite 24) may be cut upon reaching an edge of the component to be formed as indicated by the solid lines 105. The solid lines 105 refer to locations where a cut may be made. The arrows in this instance refer to the direction of deposition of the material. Spacing between deposited tracks is illustrated in FIG. 13 to better show the path of deposition; however, it is appreciated that the spacing between tracks is not necessary or may not be desired. Typically, an overlap is desired of approximately 10-20 % of the roving diameter when the fiber material is in the form of a roving.

In accordance with another aspect, as shown in FIG. 14, the systems and processes described herein may allow for turning of the fiber material (e.g., ceramic fiber composite 24) as indicated by reference numeral 107 without cutting of the material. In certain embodiments, the fiber material is not cut until deposition of the subject cross-sectional layer is complete as is indicated by solid line 105. The skilled artisan would readily appreciate whether turning of the fibers would be suitable for a particular application may be dependent on fiber thickness, fiber stiffness, the length of the deposition path, degree of turn, and the like. Moreover, to reiterate, spacing between deposited tracks is illustrated in FIG. 14 to better show the path of deposition; however, it is appreciated that the spacing between tracks (or turns) is not necessary or may not be desired.

When ceramic fiber composites are printed as described herein, the cutting step allows complex geometries to be formed as the component's shape is not limited to an existing preform fiber shape. In accordance with another aspect, the deposition of the materials described herein can be provided in any desired order layer by layer until the component having a final desired composition, shape, and size is formed. Nothing in this disclosure is intended to limit the order of deposition of layers herein, each of which may comprise any of the material(s) described herein.

It is further contemplated that the deposited materials need not all be

printed/deposited in the same direction and pattern. In accordance with another aspect, it is contemplated that a "weave-like" structure may be formed by depositing a first layer of the loaded ceramic material in a first x, y, or z direction, and thereafter 3D printing a second layer over the first layer in a second x, y, or z direction distinct from the first direction. For example, as shown in FIG. 15, a first layer 120 of a fiber loaded ceramic material (24 or 48) may be printed in at least a first direction 122 and a second layer 124 of the fiber loaded ceramic material (24 or 48) may be printed over the first layer 120 in at least a second direction 126, e.g. transverse to the first direction 122.

In the manufacture of a typical ceramic matrix composite material, a fiber preform is utilized which includes a weave structure, wherein fibers extending in one direction are loomed over and under fibers extending in another direction (e.g., transversely) to add strength to the overall material. In an aspect, the 3D printing of ceramic fiber composite material(s) as described herein improves upon these conventional

techniques. As mentioned above, the weaving process may, in fact, significantly weaken the mechanical strength of the fibers. In contrast, the systems and processes described herein allow fibers to be oriented in different directions in the same material yet eliminate processing steps that weaken the fibers as in typical weaving processes.

In accordance with another aspect, once all the desired layers are deposited to form the component 70 as described in any of the systems and processes described herein, the component 70 may be sintered or otherwise heated to a desired

temperature. The sintering, for example, may take place by the application of energy, such as the application of heat, for any suitable duration at any desired temperature. In an embodiment, the component 70 (upon printing of all the layers) is sintered at a temperature of at least about 500°C, and in particular embodiment from 500°C to 1200°C - either isothermally or with a temperature gradient.

In accordance with an aspect, any existing system configured for the free form extrusion of ceramic materials can be modified with the components described herein to provide a system which deposits a ceramic fiber composite. Further, although aspects of the present invention have been explained in the context of manufacturing or repairing gas turbine components, as easily understood by those skilled in the art, the instant manufacturing concepts may be applied to other suitable fields and components.

In accordance with an aspect of the present invention, since the systems and processes described herein dispense a ceramic solid fiber composite on a layer-by- layer basis to form the component, not only can complex geometries and compositions be formed (heretofore not possible), but specific features can be incorporated into the finished product as desired. By way of example, as the component is being formed, a plurality of cooling channels and/or cooling holes may be formed within an interior of the component (which may be a turbine blade, a vane, or the like). In particular

embodiments, a plurality of cooling channels are formed in an outer wall of the component completed/formed to provide near wall cooling strategies.

By way of example and referring to FIG. 19, there is shown an exemplary component 300 formed by the processes described herein with internal cooling structures. The component 300 comprises a body (airfoil) 302 having an airfoil shape 304, a leading edge 306, and a trailing edge 308. A pressure side wall 310 and a suction side wall 312 extend therebetween. Within the body 302, there is shown a plurality of cooling channels 314. In the embodiment shown, the cooling channels 314 extend radially through an interior of the body 302 to define radially extending cooling channels 315, although the present invention is not so limited to a radially extending orientation. In a particular embodiment, the cooling channels 314 are also oriented in a serpentine configuration such that air flows upward and downward through the airfoil 302 during operation.

Referring now to FIG. 20, there is shown a cross-section of the airfoil 302 shown in FIG. 19 taken at line A-A, wherein the airfoil 302 comprises an outer wall 316 defining an outer perimeter thereof that encompasses a cavity 318 extending through the component 300. In an embodiment, the outer wall 316 further includes a plurality of internal cooling holes 320 extend laterally across the body 302 and fluidly connecting the cavity 318 with the radially extending channels 314. Further, the outer wall 316 may include a plurality of exit cooling holes 322 which fluidly connects the cooling channels 314 with an exterior of the component 300. In operation, cooling air may flow into each cooling channel 314 from the bottom of the channel 314 and through the internal cooling holes 320 to the cavity 318. In addition, cooling air may flow through the cooling channels 314 to produce near wall cooling of the outer wall 316. In certain

embodiments, the heated air is then discharged through the exit cooling holes 322 to produce a layer of film air on an external wall surface of the component 300 for added thermal protection. In certain embodiments, an outlet 324 is also provided at the trailing edge 308 for exit of heated cooling air therefrom.

The cooling channels 314 and cooling holes 320, 322 may be formed in the outer wall 316 in any suitable pattern. In addition, the cooling channels 314 and cooling holes 320, 322 may comprise any suitable dimension, such as having a desired bore size and cross-sectional shape. In addition, any suitable number of cooling channels 314 and corresponding holes 320, 322 may be provided in the component. In certain

embodiments, each of the cooling channels 314 and cooling holes 320, 322 are defined by a 3D printing process as described herein. For example, in an embodiment, a ceramic fiber composite 24, 48 is deposited from its associated dispensing head 22, 50 so as to deposit the ceramic fiber composite 24, 48 in a predetermined pattern to form a plurality of successive cross-sectional layers which define the outer wall 316. As all or a portion of the outer wall 316 of the component 300 is formed, the cooling channels 314 and cooling holes 320, 322 may be defined by pausing the printing of the ceramic fiber composite 24, 48 such that no material is printed in a defined area during 3D printing of selected layers.

When provided, it is appreciated that a plurality of the cooling holes 320, 322 are provided in spaced relation to one another in a radial direction through the component 300. As such, the cooling holes 320, 322 may be manufactured so as be enclosed yet not collapse on themselves. To accomplish this, as each layer (whether a ceramic material, ceramic solid fiber composite 24, 48 or other material) is deposited, the subject cooling holes 320, 322 may be enclosed by repeatedly offsetting one layer of the previously ceramic fiber composite 24, 48 relative to the previously deposited layer of the ceramic fiber composite 24, 48. For example, as shown in FIG. 21 , with each deposition of ceramic fiber composite 24, an extent 326 of the most recently deposited layer 328 extends laterally over a previously deposited layer 330 until the subject cooling hole 320, 322 is closed. In other embodiments, the ceramic fiber composite 24, 48 may be printed about a fugitive material or temporary spacer(s) positioned in the desired location(s) of the cooling channel 314 or cooling holes 320, 322. Once printed, the fugitive material or spacer(s) may be removed to reveal the desired cooling channel 314 or cooling holes 320, 322 as described herein. In certain embodiments, the body 302 of the desired component 300 with cooling channels 314 and/or cooling holes 320, 322 formed therein (FIG. 20) is entirely 3D printed with the ceramic fiber composite 24, 48. In other embodiments, as shown in FIG. 22, at least a portion 332 of the body 302 (e.g. , outer wall 316) is formed via 3D printing a ceramic fiber composite 24, 48 as described herein while another portion 335 of the body 302 comprises a conventional ceramic matrix composite (CMC) layup 334 as is known in the art. In this way, aspects of the present invention allow for printing an outer wall 316 on an existing CMC component, wherein the outer wall 316 includes the cooling channels 314. In certain embodiments, as shown in FIG. 22, the outer wall 316 may further include exit cooling holes 322. In further embodiments, the conventional CMC layup 334 and the outer wall 316 may further include each include internal cooling holes 320 which lead from the cooling channels 314 to the cavity 318 as described herein. In addition, if so, the internal cooling holes within the CMC layup 334 may be provided therein by any suitable method such as by drilling or otherwise may be formed therein upon manufacture.

The previous description discussed cooling channels 314 whose longest dimension extends radially through the component 300 and optionally cooling holes 320, 322; however, it is understood that the present invention is not so limited. A significant advantage of the systems and processes described herein is that the 3D printing of the ceramic fiber composite allows for the formation of cooling channels in any desired configuration with or without the aid of fungible materials, spacers, and the like. In further embodiments, as shown in FIG. 23, the body 302 of the component 300 may comprise one or more cooling channels 314 whose longest dimension instead extends laterally though the body 302 of the component. In particular, the longest dimension of the channels 314 may extend perpendicular / angled relative to the radial direction of the component 300 (e.g., a blade or vane) so as to define laterally extending cooling channels 336. In certain embodiments, the body 302 comprises a plurality of laterally extending cooling channels 336 formed therein. In certain embodiments, the channels 336 are formed by the absence of printing in the area of the desired channel repeatedly offsetting one layer of the ceramic fiber composite relative to the previously deposited layer of the ceramic fiber composite to close the channel 336 as was described above for cooling holes 320, 322. It is appreciated that any number of the channels 336 (extending laterally) may be provided in the component, each of which may start/exit at different radial positions along the component 300. When channels 336 are provided in the component 300, in some embodiments, the channels 336 comprise an outlet 338 disposed at a trailing edge 308 of the body 302 so as to enable exit of the cooling air from the component. In addition, it is appreciated that the channels 336 may be in fluid communication with a source of cooling air, such as via pathways 340 (within the material of the body 302) that lead from the channels 336 to the cavity 318.

In accordance with another aspect, any of the cooling channels as described herein may be defined in the outer wall 316 of the component 300 in any desired orientation by positioning one or more sleeves 342 having a bore 344 in the outer wall 316 in a desired position. Each sleeve 342 thus has a desired dimension (e.g., length, bore diameter) and position corresponding to a desired dimension and position of a cooling channel in the outer wall 316. As shown in FIG. 24, for example, the sleeve 342 may be deposited in a desired position on an existing substrate 334 (e.g., one formed by the 3D printing process described herein or a conventional CMC layup). Thereafter, the ceramic fiber composite 24, 48 may be 3D printed about the sleeve 342 as described herein so as to encompass the sleeve 342 with a ceramic fiber composite 24 and complete formation of the outer wall 316 of the component 300. In an embodiment, the bore 24 is not fully encompassed by the outer wall 316 and is exposed to an exterior of the outer wall 316 such as cooling air may travel through the sleeve 342 and exit to the surrounding environment (exterior of the component). The sleeve 342 of FIG. 24 is shown as being substantially laterally positioned (perpendicular to a radial (longest dimension) dimension of the component) in the outer wall 316 to define a laterally extending cooling channel (e.g., channel 336); however, it is understood that the present invention is not so limited. In other embodiments, the sleeve 342 may instead or also be positioned in substantially a radial direction within outer wall 316 to define a radially extending cooling channel 314 as described herein. Alternatively, the sleeve 342, given its flexibility, may be positioned in any other suitable orientation. Each sleeve 342 is formed from a material suitable for the intended operation of the component. In certain embodiments, the sleeve 342 is formed from a ceramic material or any other suitable material that will maintain its structural integrity at the operating temperature(s) of the associated turbine engine in which the component having the sleeve 342 is used / intended to be used. In certain embodiments, the sleeves 342 are also flexible so that it may be curved and also more easily oriented in its desired final position. Given its structural integrity, the cooling channels 314 (defined by the sleeves 342) can withstand the pressures associated with the cooling air flowing there through and high operating temperatures without deforming or outright failure of the channel 314. In certain embodiments, the sleeves 342 comprise a fibrous material, such as a braided fibrous material, having a bore 344 therein. In a particular

embodiment, the sleeves 342 comprise a braided sleeve of 3M™ Nextel™ fibers (e.g., Nextel 440™ alumina-boria-silica fibers) which maintain their mechanical strength at temperatures up to 2500°F, and even up to 3000°F for short durations.

In accordance with another aspect, the sleeves 342 comprise a plurality of rigid sleeves 346 which are able to maintain a desired shape and mechanical stability when exposed to an associated operating environment. In addition, the rigid sleeves 346 may provide a degree of through thickness reinforcement to the CMC component 300. As shown in FIG. 25, a plurality of channels, e.g., channels 314, are defined by a plurality of corresponding rigid sleeves 346 in spaced relationship to another within the outer wall 316. The rigid sleeves may comprise any suitable material configured to withstand the intended operating temperatures of the associated component and may be provided in any suitable orientation, such as a radial and/or lateral direction. In the embodiment shown, the sleeves 346 are disposed on a conventional CMC layup 334 in a desired position. To fix the rigid sleeves 346 in the desired position, the ceramic fiber composite 24, 48 may be deposited from its associated dispensing head 22, 50 in a predetermined pattern to form a plurality of successive cross-sectional layers which define the outer wall 316 and encompass the rigid sleeves 346.

In a particular embodiment, the ceramic fiber composite 24, 48 may be deposited from its associated dispensing head 22, 50 so as to form a braided reinforcement 348 for each rigid sleeve 346. Thereafter, the ceramic fiber composite 24, 48 may be woven about the rigid sleeves 346 in multiple paths as the ceramic fiber composite 24, 48 is deposited so as to encompass the rigid sleeves 346. In one embodiment, this done by depositing the ceramic fiber composite 24, 48 over a first rigid sleeve 346 and then under a subsequent rigid sleeve 346, and so on, as is shown in FIG. 26. For ease of viewing two paths are shown, however, it is understood that several passes may be required to provide the final product with the desired material density. After the ceramic fiber composite 24, 48 (and any other materials) are fully deposited, the outer wall 316 may be sintered via the application of heat, for any suitable duration at any desired temperature, e.g., at a temperature of at least about 500°C, and in particular

embodiment from 500°C to 1200°C as set forth herein. In an embodiment, the rigid sleeves 346 are oriented and maintained in a radial position (longest dimension of the component).

In accordance with another aspect, the above embodiments illustrated single wall (outer wall 316) structures for the component 300; however, in other embodiments, the components 300 described herein may include a double walled structure 400. The double walled structure 400 allows for thinner walls in the component which aids in cooling, as well as for backside cooling of each wall. As shown in FIG. 27, the component 300 is shown as comprising an inner wall 402 and an outer wall 404 spaced by a gap 406 between the outer wall 404 and the inner wall 402 in at least a portion of the double walled structure 400. In certain embodiments, the gap 406 comprises a radially extending cooling channel 314 as described herein. Each of the inner wall 402 and the outer wall 404 may be formed by the 3D processes of a ceramic fiber

composite 24, 48 described herein or by a conventional layup process. The cooling channel 314 may be of any suitable thickness which allows for passage of a cooling gas there through. In addition, the cooling channel 314 may be sized so as to sufficiently provide the double-walled structure with a load bearing capability, including bending forces.

In certain embodiments, as is also shown in FIG. 27, the double walled structure 400 may comprise a plurality of cooling pins 408 which extend laterally between the inner wall 402 and the outer wall 404 across the gap 406, and allow for cross flow or conductive cooling between the outer wall 404 and the inner wall 402. The pins 408 may be formed from any suitable material, such as a ceramic matrix composite or ceramic material. Further, the pins 408 may be of any suitable thickness and

dimension. In certain embodiments, the pins 408 comprise a bore extending there through. In certain embodiments, the pins 408 are positioned as the inner wall 402 and outer wall 404 are formed by depositing a ceramic fiber composite 24, 48 as described herein. In other embodiments, the pins 408 may be inserted during a conventional layup process.

In still further embodiments, any of the embodiments of the components 300 described herein may further include a thermal barrier coating (TBC) for additional thermal protection. For example, as shown in FIG. 28, an outer wall 316 of component 300 comprises a TBC 350 on an outer surface thereof. The TBC 350 may comprise any suitable material which provides an increased temperature resistance to the body 302 when applied to a surface thereof. The TBC may further comprise a degree of porosity suitable for the desired application. In an embodiment, the TBC 350 comprises a stabilized zirconia material. For example, the TBC 350 may comprise an yttria- stabilized zirconia (YSZ), which includes zirconium oxide (Zr0 ₂ ) with a predetermined concentration of yttrium oxide (Y2O3), . In another embodiment, the TBC 350 may comprise a magnesia stabilized zirconia, ceria stabilized zirconia, aluminum silicate, or the like.

In another embodiment, the TBC 350 may comprise a pyrochlore structure. In an embodiment, the pyrochlore structure has the empirical formula A2B2O7 or in general terms A _v B _x O _z where v = 2, x = 2 and z = 7. Deviations from this stoichiometric composition for v, x and z may occur as a result of vacancies or minor, deliberate or undeliberate doping. In the formula A _v B _x O _z where v = 2, x = 2 and z = 7, gadolinium (Gd) is typically used for A, and hafnium and/or zirconium (Hf, Zr) are typically used for B. In this case too, minor deviations from this stoichiometry may occur. When Hf and Zr are used as B (e.g., Gdv(Hf _x Zr _y )Oz), x + y = 2. In other embodiments, B = Zr or Hf individually, and the pyrochlore structure may comprise one of gadolinium zirconate (Gd ₂ Zr ₂ 0 ₇ ) or gadolinium hafnate (Gd ₂ Hf ₂ 0 ₇ ). In still other embodiments, the TBC 350 may comprise a bilayer 8YSZ/59 weight percent gadolinium stabilized zirconia (8YSZ/59GZO) coating, a bilayer 8YSZ/30-50 weight percent yttria stabilized zirconia ("30-50 YSZ") coating, or the like.

In yet another embodiment, the TBC 350 may comprise a dimensionally stable, abradable, ceramic insulating material comprising a plurality of hollow ceramic particles dispersed in the. The hollow particles may be of any suitable dimension, and in one embodiment may be from 1 -100 micron in diameter. The TBC 350 may be applied by any suitable process, such as a thermal spray process, a slurry-based coating deposition process, or a vapor deposition process as is known in the art.

In accordance with another aspect, the outer wall 316 having channels 314 and/or cooling holes 320, 322 formed therein may comprise an engineered surface 352 which facilitates adherence of the TBC 350 to the outer wall 316. For a description of engineered surfaces for use herein and processes for making the same, see related application PCT/US2017/021795, the entirety of which is incorporated by reference herein. In an embodiment, the ceramic fiber composite 24, 48 is printed on the outer wall 316 in a predetermined pattern 354. In an embodiment, the predetermined pattern 354 comprises a plurality of spaced apart segments 356, such as in a grid pattern 358 as shown in FIG. 29. Once the grid pattern 358 has been formed and the material sintered, the TBC 350 may be applied thereover and within channels 360 formed by the grid pattern 358 as shown in FIGS. 29-30. The resulting structure comprises a TBC 350 which is further anchored by the engineered surface 352. The engineered surface 352 aids in preventing spallation and separation of the TBC 350 from the CMC outer wall 316 under the extreme conditions to which the component 300 may be subjected.

In some instances, a bond coat (not shown) as is known in the art may be utilized to improve adhesion of the TBC layer 350 to its underlying surface. The material for the bond coat layer may comprise any suitable material. For example, an exemplary bond coat layer may comprise an MCrAIY material, where M denotes nickel, cobalt, iron, or mixtures thereof, Cr denotes chromium, Al denotes aluminum, and Y denotes yttrium. In other embodiments, the bond coat layer may comprise alumina, yttrium aluminum garnet (YAG), or other suitable ceramic-based material, e.g., a rare earth oxide and/or rare earth garnet material. The bond coat may also be applied by any known process, such as via a thermal spraying or a slurry-based deposition process.

While various embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions may be made without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.