BACKGROUND

[00011 Electronic devices, such as laptops and mobile phones, include various components located within a metal alloy housing. Such a metal alloy housing is made of a metal alloy substrate, whic should have a good metallic lustre and should be able to withstand wear and tear from regular use and exposure to the natural environment. Housing for such electronic devices should have a good surface finish.

BRIEF DESCRIPTION OF DRAWINGS

[00011 Figure 1 is a flowchart showing an example of a process for producing a coated metal alloy substrate.

[0002J Figure 2 is a partial cross-sectionai diagram showing an example of a coated metal substrate.

[Q0Q3j Figure 3 is a flowchart showing an example of a process for producing a coated metal aiioy substrate.

[00041 Figure 4 is a partial cross-sectional diagram showing an example of a coated metal substrate.

[0005J Figure 5 is a flowchart showing an example of a process for producing a coated metal alloy substrate.

[0006] Figure 6 is a partial cross-sectionai diagram showing an example of a coated metal substrate.

[00071 Figure 7 shows an example housing for a laptop. DETAILED DESCRIPTION

[0008] Before the process for producing a coated metal alloy substrate, the coated metal alloy substrate and the electronic device having a housing are disclosed and described, it is to be understood that this disclosure Is not limited to the particular process details and materials disclosed herein because such process details and materials may vary somewhat it is also to be understood that the terminology used herein is used for the purpose of describing particular examples. The terms are not intended to be limiting because the scope of the present disclosure is intended to be limited by the appended claims and equivalents thereof.

[0009] it is noted that, as used in this specification and the appended ciaims, the singular forms ‘ ^: a \ “an” and “the ⁸ include plural referents unless the context clearly dictates otherwise.

[0010] if a standard test is mentioned herein, unless otherwise stated, the version of the test to be referred to is the most recent at the time of filing this patent application,

[0011] As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a iiit!e above” or “a little below” the endpoint. The degree of flexibility of this term can be dictated by the particular variable and would be within the knowledge of those skilled in the art to determine based on experience and the associated description herein.

[0012] Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format, it is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to inciude the numerical values explicitly recited as the limits of the range and also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of "about 1 wt % to about 5 wt. %” should be interpreted to include the explicitly recited values of about 1 wt % to about 5 wt % and also Include individual values and subranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3.5, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc. This same principle applies to ranges reciting a single numerical value. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.

{00131 As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individualiy identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list based on their presentation in a common group without indications to the contrary.

{0014j As used herein, the term “3D surface profile” may refer to the spatial dimensions (e.g. three-dimension spatial data in x, y and z coordinates) of the surface features on the metal a!ioy substrate.

[0015j Surface features are defined herein as any deviations (e.g. peaks and valleys) fro a reference line (which may also be referred to as a mean line) that is traverse to the metal aiioy substrate surface.

[00181 As used herein, the surface roughness parameter Ra, is the arithmetic mean average of the height of surface features, measured from the reference line. Ra may be calculated using the formula: wherein L is the evaluation length and Z is the height of surface features. In some examples, the Ra is calculated on a 100 p x 100 pm scale. The Ra may be determined using any suitable profiiometer, for example, using atomic force microscopy.

{00171 As used herein, the surface roughness parameter Rq, is the root mean square average of the height of surface features, measured from the reference line Rq may be calculated using the formula; wherein L is the evaluation iengfh and Z is the height of surface features in some examples, the Rq is calculated on a 100 pm x 100 pm scale. Rq may otherwise be referred to as the room mean squared or RMS. The R may be determined using any suitable profilometer, for example, using atomic force microscopy.

[00183 As used herein, “structured light” refers to a projection of a pattern of light. Structured light may be in the pattern of grids, stripes or horizontal bars.

[0019| As used herein, the term “3D printer” refers to any printing apparatus that prints at least one layer according to 3D spatial coordinates to form a 3D part.

[00201 As used herein, the term “printing” refers to any process that uses a printing apparatus. This term may be taken to exclude electroplating and spray-painting processes.

[00213 As used herein, the term ^!! 3D inkjet printing” refers to a 3D printing process using a printing apparatus wherein a stream of fluid droplets are jetted onto a substrate (e.g. the metal alloy substrate) to form the coating layer. Inkjet printing may be thermal or piezeoelectric.

[0022J As used herein, the term “binder jetting” refers to a type of printing process wherein a binder is selectively deposited onto at least one powder layer. The binder may fuse the powder together to form the coating layer. The binder may be deposited using an inkjet printhead or an inkjet nozzle.

[0023| As used herein, the term “stereolithography’' (SLA) refers to a printing process that comprises depositing photocurable material and exposing the photocurab!e material to U V to form the coating layer.

[00243 As used herein, the term “digital light processing" refers to a printing process that comprises depositing a material, and exposing the material to a digital light projector to form the coating layer.

[00253 As use herein, the term “fused deposition modelling” refers to a printing process that selectively deposits melted thermoplastic material to form the coating layer. The thermoplastic material may come in filament form. [00281 As used herein, the term "selective laser sintering" refers to a printing process that uses a laser to sinter or fuse powder material to form the coating layer.

J0027J As used herein, the term “polyjet printing" refers to a printing process that jets liquid droplets onto the substrate; the liquid droplets are then cured to form the printed coating layer. The liquid droplets may be a photopolymer which are then cured using UV light. The term poiyjet printing may be used interchangeably with material jetting.

[0028J As used herein, the term ''deposited” when used to refer to the location or position of a layer includes the term “disposed” or “coated”.

[00291 As used herein, the term “engraving” when used to refer to the formation of a chamfered edge includes the term “etching" or “cutting"

[0030J As used herein, the term 'polishing’ refers to any process which serves to level the surface features of the metal alloy substrate surface by removal of at least a portion of the metal alloy substrate surface. Polishing may include chemical polishing, electrochemical polishing, mechanical polishing or a combination thereof. Polishing does not occur when using a printing process or engraving process described herein.

[00311 As used herein, the term ‘chemical polishing’ refers to any chemical process which removes at least a portion of the coating layer to level the surface features of the metal alloy substrate surface. Chemical polishing may include treating the metal alloy substrate with acid solution, for example, treating the metal alloy substrate with hydrochloric add, nitric acid, phosphoric acid, sulfuric acid and combinations thereof.

[00321 As used herein, the term ’carried out’ when used to refer to a process may be used interchangeably with ‘performed’.

[00331 As used herein, the term ‘micro-arc oxidation’ (MAO) refers to an electrochemical surface treatment process for generating oxide coatings on metals, Micro-arc oxidation may otherwise be referred to as plasma electrolytic oxidation or PEG.

[00343 As used herein, the term “CNG” refers to computer numerical control, which may be referred to simply as “numerical control". A CNC process involves automated control of d machining ioois, wherein the machine tools may follow pre-coded programmed instructions.

[O035J As used herein, “diamond cut process” or “diamond cutting process’ ⁵ refers to any machine process which uses diamond as a cutting tool.

[00361 As used herein, the term “chamfered edge" refers to an edge of a substrate that has resulted from engraving or cutting,

[00371 As used herein, the term “comprises” has an open meaning, which allows other, unspecified features to be present. This term embraces, but is not limited to, the semi- closed ter “consisting essentially of and the osed term "consisting of’. Unless the context indicates otherwise, the term “comprises” may be replaced with either “consisting essentially of or “consists of,

[00381 Unless otherwise stated, any feature described herein can be combined with any other feature described herein.

[00393 When coating metal alloy substrates, including metal alloy substrates that are insert-molded with plastic substrates, the present inventors have found difficulties in obtaining good surface uniformity. Typically polishing is required to achieve a degree of surface uniformity. However, polishing can cause damage to the coated substrate, thereby increasing the risk of corrosion and the tendency to fail in salt fog tests, Chemical polishing, for example, may also cause impurity contamination and/or bubble formation on the substrate surface. Polishing steps may aiso require the application of additional coating layers to address the reduction in, for example, corrosion resistance. The present inventors have found that good surface uniformity, smoothness to the touch and/or corrosion resistance may be achieved on metal ailoy substrates by first, 3D scanning a surface to determine the 3D surface profiie the metal ailoy substrate, followed by printing at least one coating layer on the metal alloy surface. In this process, the printing step is adjusted according to the 3D surface profile of the metal alloy substrate. The coated metal alloy substrate resulting from this process may have good aesthetic properties, a glossy surface finish and good corrosion resistance with a relatively thin overall coating layer, which is lightweight Furthermore, the process described herein may avoid polishing treatments ) thereby resulting in a more efficient process. Process for p oducing a coated metal alloy substrate

[0040J !n some examples, there is provided a process for producing a coated metal alloy substrate for an electronic device, comprising: scanning a metal alloy substrate to determine the 3D surface profile of at least a portion of the metal alloy substrate; and printing at least one coating layer on at least a portion of the metal alloy substrate, wherein the printing is adjusted according to the 3D surface profile of the metal alloy substrate.

Metal aiioy substrate

[0041| The metal alloy substrate may comprise a metal selected from aluminium, magnesium, lithium, titanium, niobium, zinc, stainless steel and alloys thereof. For example, the metal alloy substrate may comprise a metal alloy selected from an aluminium alloy, a magnesium alloy, a lithium alloy, a titanium alloy and stainless steel. These metals may be light-weight and can provide a durable housing. In an example, the metal alloy substrate comprises a magnesium alloy. The metal alloy may comprise a content of metal of at least about 75 wt %. For example, when the metal alloy is a magnesium alloy, the magnesium alloy may comprise at least about 80 wt. % magnesium, or at least 85 wt. % magnesium, or at least about 90 wt. % of magnesium, based on the total weight of the metal alloy.

[00421 The magnesium alloy may further comprise aluminium, zinc, manganese, silicon, copper, a rare earth metal or zirconium. The aluminium content may be about 2,5 wt. % to about 13.0 wt. %. When the magnesium alloy comprises aluminium, then at least one of manganese, zirconium, or silicon is also present. Examples of magnesium alloys include AZ31S, AZ61, AZ60, AZ8G, A 60, AZ91D, LZ91, LZ14, ALZ881 alloys according to the American Society for Testing Materials standards.

[00431 * ⁿ one example, the metal alloy comprises at least one of the following list including, At: about 0.02 wt.% to about 9.7 wt,%, Zn: 0.02 wi.% to about 1,4 wt.%, Mn: about 0,02 wt.% to about 0.5 wt.%, a component selected from Si: about 0.02 w$,% to about 0.1 wt.%, Fe; about 0.004 wt.% to about 0,05 wt.%, Cai about 0.0013 wt.% to about 0.04 wt.%, Ni; about 0.001 wt.% to about 0.005 wt.%, Cu: about 0.008 wt.% to about 0.05 wt/%, Li: about 9.0 wt.% to about 14.3 wt.%, Zr; up to about 0,002 wt.%. or combinations thereof, ail based on the total weight of the metal alloy, and the balance being Mg and inevitable impurities.

[O044J In some examples, the metal alloy substrate is an insert molded metal substrate comprising a further materiai, such as pSastic(s) or a plastic insert, in some examples, the insert molded metal substrate may be formed by using the metal substrate as a mold. This metal mold may have a section into which a material, such as plastic, is injected to form a plastic insert. Plastics used for insert molded metal substrates may b selected from poSybutylene terephtha!ate (PBT), polyphenylene sulfide (PPS), polyamide (nylon), polyphthaiamide (PPA), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK), polycarbonate (PC) and acrylonitrile butadiene styrene with polycarbonate (ABS/PC) with about 15 to about 50 wt.% glass fibre fiiler. The portion of the insert molded metal alloy substrate between the meta! ailoy and the further materiai, such as plastic, is referred to herein as “the junction”. The present inventors found that the process according to the methods described herein can iead to a smoother coated surface at the junction,

[00453 The metal alloy substrate is suitable for an electronic device in some examples, the electronic device is selected from a computer, a laptop, a tablet, a workstation, a ceil phone, a portable networking device, a portable gaming device and a portable GPS.

Seaming the metal alloy substrate

[00463 in some examples, the scanning is carried out using a 3D scanner. The 3D scanner may comprise a radiation source and a sensor in some examples, the 3D scanner emits light, ultrasound rays, infrared rays or x-rays, for example, using the radiation source. In some examples, the 3D scanner may detect and/or measure reflected light and/or reflected radiation to determine the 3D surface profile of the metal alloy substrate, for example, using the sensor.

[00473 in some examples, the 3D scanner may be a 3D fight scanner or a 3D laser scanner. In some examples, the 3D light scanner may be a structured-light scanner, in some examples, the laser scanner may be a triangulation-based laser scanner. In some examples, the laser scanner may be a time of flight scanner. s [0048] in some examples, the 3D surface profile may be determined by measuring the deformation of light, for example, using a structured-light scanner.

[0049] In some examples, the 3D surface profile may be determined by calculating the angle of reflected light at the sensor, for example, using a triangulation based laser scanner

[0050] In some examples, the 3D surface profile may be determined by measuring the time taken for light to reach the sensor, for example, using a time of flight laser scanner

[0051] in some examples, the 3D scanner and/or sensor comprises a camera, which may take 2D images of the metal alloy substrate. In some examples, the scanning comprises capturing at least iOQ 2D images of the metal alloy substrate from different angles. In some examples, at least 952D images, or at least 902D images, or at least 85 2D images, or at least 802D images, or at least 75 2D images, or at feast 70 2D images, or at feast 85 2D images, or at feast 60 2D images, or at feast 552D images, or at least 50 2D images, or at least 45 2D images, or at feast 40 2D images, or at least 35 2D images or at least 30 2D images, or at least 252D images, or at least 202D images, or at least 15 2D images, or at least 10 2D images, or at least 5 2D images are captured of the metai alioy substrate from different angles. In these examples, the 3D scanner may use the captured 2D images to determine the 3D surface profile of the metal alloy substrate, for example, by mosaicing the 2D images in some examples, the 3D scanner comprises two or more cameras

[0052] in some examples, the scanner determines the 3D surface profile and outputs the 3D surface profile in a computer-readable file or CAD fife, for example, wherein the file is in a DXF, a DWG, an OBJ, a STL or a PLY file format.

Printing

[0053] in some examples, the printing may be adjusted according to the 3D surface profile of the metal alloy substrate. In some examples, the printing is adjusted according to a computer readable file or CAD file, for example, a CAD file in a DXF, a DWG, an OBJ, a STL or a PLY file format. 0054J In some examples, the printing may be carried out using a 3D printer In some examples, the printing may be selected from thermal 3D inkjet printing, piezeoelectric 3D inkjet printing, binder jetting, stereolithography (SLA), digital fight processing (DLP), fused deposition modelling (FDM), selective laser sintering (SIS) and poiyjet printing in some examples, at least a portion of the at least one coating layer is jetted on to at least a portion of the metal alloy substrate using at least one inkjet nozzle or an inkjet printhead, for example, using multiple inkjet nozzles or inkjet printheads.

[00551 The printing occurs on at least a portion of the metal alloy substrate. In some examples, the at least a portion comprises at least about 5%, or at ieast about 10%, or at least about 20%, or at least about 30%, or at least about 40%, or at least about 45%, or at least about 50%, or at least about 60%, or at ieast about 70%, or at least about 80%, or at least about 90%, or at least about 95%, or at Ieast about 99% of the metal alloy substrate. In some examples, the printing occurs on at least a portion of an insert-moulded alloy metal substrate. In some examples, the printing may occur on at ieast a portion of the metal alloy substrate that comprises a further material (e.g, a plastic insert) in some examples, the printing may occur on at ieast a portion of the metal alloy substrate that comprises a junction between the metal alloy and a further material (e.g. a plastic insert).

[00581 In some examples, after printing a coating layer, the coating layer may be heated or UV~cured. In some examples, the coating layer may be heated to a temperature between about 60 X to about 120 X, or from about 65 X to about 110 °C, or about 75 C to about 100 X, about 85 X to about 90 , In some examples, after printing a coating layer, the coating layer may be heated, for example, to a temperature greater than about 70 X, or greater than about 75 X, or greater than about 80 X. in some examples, after printing a coating layer, the coating layer may be UV-cured, for example, by exposure to UV light.

[00573 * ⁿ some examples, the at ieast one coating layer is selected from: a primer coating layer, a base coating layer and a top coating layer.

[0058] The primer coating layer may comprise at ieast one of a polyurethane or a filler selected from carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, a synthetic pigment, a metallic powder, aluminium oxide, carbon nanotubes (CNTs), graphene, graphite, or an organic powder or a combination thereof . The primer may comprise a polyurethane and a tier In an example, the primer coating layer is a polyester polyurethane.

[00591 The primer coating layer may have a thickness of less than about 25 pm, or less than about 20 pm, or less than about 15 pm, or less than about 12,5 pm, or less than about 10 pm, or less than about 8 pm, or less than about 5 pm. The thickness of the primer coating layer can be measured after it has been printed using, for example, a micrometre screw gauge or scanning electron microscope (SEM).

[00601 to some examples, the base coating layer may comprise polyurethane-containing pigments. The base coating layer may further comprise at least one of carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminium oxide, an organic powder, an inorganic powder, graphene, graphite, plastic beads, a colour pigment or a dye. The organic powder may, for example, be an acrylic, a polyurethane, a polyamide, a polyester or an epoxide. In some examples, the base coating layer may further comprise a component selected from barium sulfate, talc, a dye and a colour pigment in one example, the base coating layer comprises a colour pigment or a dye. In some examples, the base coating layer may further comprise a heat resistant material, such as a silica aerogel. The base coating layer can comprise a heat resistant material and a component as described above.

[00611 in some examples, the base coating layer has a thickness of less than about 25 pm, or less than about 20 p , or less than about 15 p , or less than about 12.5 p , or less than about 10 pm, or less than about 8 p , or less than about 5 pm. The thickness of the primer coating layer can be measured after it has been printed using, for example, a micrometre screw gauge or scanning electron microscope (SEM).

[0062j to some examples, the top coating layer Is a heat-sensitive or UV-curable resin. The top coating layer may comprise at least one of a polyacrylic resin, a polyurethane resin or polymer, a urethane acrylate resin, an acrylic acrylate resin or an epoxy acrylate resin, or a combination thereof.

[0063J to some examples, the top coating layer has a thickness of less than about 25 pm, or less than about 20 pm, or less than about 15 pm, or less than about 12.5 pm, or less than about 10 pm, or less than about 8 p , or less than about 5 pm. The thickness of the primer coating layer can be measured after it has been printed using, for example, a micrometre screw gauge or scanning electron microscope (SEM).

[0064J In some examples the primer coating layer is thicker than the base coating layer or the based coating layer.

[00651 ^ some examples, more than one coating layer is printed on at least a portion of the metal alloy substrate. For example, two layers, three layers, four layers, five layers, six layers, seven layers or more than seven layers may be printed on at teas a portion of the metai alloy substrate one on top of the other, in such processes, scanning is performed before printing each coating layer to determine the 3D surface profile of at least a portion of the metai alloy substrate. In some examples, more than one coating layer is printed on at least a portion of the metal alloy substrate. In some examples, the printed coating iayer comprises a first coating layer (e.g. primer coating), a second coating layer (e.g. base coating iayer) and a third coating layer (e,g. a top coating layer).

[00661 For example, the process for producing a metal alloy substrate for an electronic device may comprise: (i) scanning a metal alloy substrate to determine the 3D surface profile of at least a portion of the metal alloy substrate; (si) printing a first coating layer (e.g. a primer layer) on at least a portion of the metal alloy substrate to form a first-coated metai alloy substrate, wherein the printing is adjusted according to the 3D surface profile of the metal alloy substrate, (Hi) scanning the first-coated metal alloy substrate to determine the 3D surface profile of at least a portion of the first-coated metal allo substrate, and (iv) printing a second coating Iayer (e.g. a base coating layer) on at least a portion of the first- coated metai alloy substrate, wherein the printing is adjusted according to the 3D surface profile of the first-coated metai alloy substrate, and optionally (v) scanning the second- coated metal alloy substrate to determine the 3D surface profile of at least a portion of the first-coated metal ailoy substrate, and (vi) printing a third coating iayer (e.g. a top coating iayer) on at feast a portion of the second-coated metai ailoy substrate, wherein the printing is adjusted according to the 3D surface profile of the second-coated metai aiioy substrate, and so on.

[00671 in some examples, printing at feast one coating iayer on at least a portion of the metal aiioy substrate produces a metai alloy substrate with at least one printed coating Iayer on at least portion of the metai aiioy substrate. Polishing treatment

[0068J !n some examples, the process does not comprise a polishing treatment after printing the at least one coating layer. In some examples, the present inventors found that a polishing treatment was not necessary since the printed coating layers formed by the process described herein had a good surface finish. The present inventors found that by not polishing the coated metal al!oy substrate, damage to the metal alloy substrate surface may be prevented, thereby increasing corrosion resistance. The present inventors found that by not polishing the coated metal alloy substrate, the amount of coating applied to the metal alloy substrate surface may be reduce compared to other coating processes.

Pre-treating the metal alloy substrate before scanning the metal alloy substrate

[0069J in some examples, the metal alloy substrate Is treated with micro-arc oxidation or preliminary passivated before scanning the metal alloy substrate.

100701 in some examples, the metal alloy substrate is treated with micro-arc oxidation before scanning the metal alloy substrate. Micro-arc oxidation (MAO) is an electrochemical oxidation process that can, for example, generate an oxidized layer on the metal alloy substrate.

[00711 MAO involves creating micro-discharges on a surface of the metal alloy immersed in an electrolyte to produce a crystalline oxide coating. The resulting micro-arc oxide layer may be ductile and have a relatively high hardness. Unlike anodizing processes, MAO employs a high potential such that discharges occur. The resulting plasma can modify the structure of the oxide layer. MAO is a chemical conversion process that causes oxidation of the underlying metal alloy material, instead of an oxide layer being disposed on to a surface of the metai alioy. This may lead to a metal surface with enhanced wear and corrosion resistance and may prolong the component lifetime. In comparison to an oxide layer produced by a deposition process, a micro-arc oxide layer may have a higher adhesion to the underlying metal alloy The electrolytic solution for MAO may comprise an electrolyte selected from sodium silicate, sodium phosphate, potassium fluoride, potassium hydroxide, sodium hydroxide, fluorozirconate, sodium hexametaphosphate, sodium fluoride aluminium oxide, silicon dioxide, ferric ammonium oxalate, a salt of phosphoric acid, polyethylene oxide a!kylphenoiic ether and a combination thereof.

[00723 The oxidised layer may have a thickness of from about 3 p to about 15 pm, such as from about 5 pm to about 12 pm, or from about 7 p to about 10 p . The thickness of the oxidised layer can be measured using, for example, a micrometre screw gauge or scanning electron microscope (SEM).

[00731 ^ some examples, the etai alloy substrate is preliminary passivated before scanning the metal alloy substrate. Preliminary passivation is a process which comprises depositing an inorganic layer on the metal alloy substrate. The inorganic layer may comprise a salt selected from a molybdate salt, a vanadate salt, a phosphate salt, a chromate salt, a stannate salt and a manganese sail In one example, the inorganic layer comprises a phosphate salt. The inorganic layer may contain oxidic salts that can provide the first surface with a dark grey appearance, in one example, the inorganic layer may be non-transparent.

[0074] The inorganic layer may have a thickness of from about 0.5 pm to about 5 pm, such as from about 1 pm to about 4 p , or about 2 pm to about 3 p . The thickness of the Inorganic layer can be measured using, for example, a micrometre screw gauge or scanning electron microscope (SEM).

[Q075J In some examples, the metal alloy substrate is treated with micro-arc oxidation and preliminary passivated before scanning the metal alloy substrate in these examples, micro-arc oxidation and passivation are carried out in a stepwise manner.

[00763 in some examples, the metai alloy substrate is not further treated with micro-arc oxidation or preliminary passivated after printing the at least one coating layer.

Engraving the coated metai alloy substrate

[0O773 in some examples, the coated metal alloy substrate may be engraved to form at least one chamfered edge after printing the at least one coating layer. [0078] The coated metal alloy substrate may be engraved by a laser-cutting process or a Computer Numerical Control (CNC) diamond cut process. The CNC diamond cut process may use a water-based cutting fluid.

[0079] The chamfered edge formed by the engraving may be an exposed non-oxl dized surface of the metal alloy substrate. The non-oxidszed surface of the substrate exposed in this way is an uncoated surface of the substrate that has not undergone substantial oxidation. The engraving process removes a part ef the metal alloy substrate, including, for example, any oxidized layers to expose a shiny surface of the underlying substrate. The engraving process may remove a part of the at least one printed coating iayer to expose a shiny surface of the underlying substrate

[0080] Engraving the metal alloy substrate to form at least one chamfered edge may be carried out to form a predefined pattern or shape. The engraving process may allow the formation of patterns that will provide a surface of the chamfered edge with a texture or finish that is different to the texture or finish of th metai alloy substrate that has not been engraved. The surface of the metal alloy substrate that has not been engraved may be referred to as the nan-chamfered surface.

[0081] Using an engraving process, parts of the metai alloy substrate may be cut away and each resulting chamfered edge may form an edge, a sidewali, a logo, a gap for a click pad, a gap for a fingerprint scanner,

[0082] in some examples, a passivation iayer is applied to the at least one chamfered edge, and an electrophoretic deposition iayer is applied to the passivation iayer.

[0083] in some examples, a sealing layer is applied to the at feast one chamfered edge and an electrophoretic deposition Iayer is applied to the sealing layer.

[0084] in some examples, a passivation iayer is applied to the at least one chamfered edge, a sealing layer is applied to the passivation layer and an electrophoretic deposition layer is applied to the sealing Iayer.

[0085] The application of a passivation Iayer and an electrophoretic deposition layer may protect and retain the attractive and shiny appearance of the underlying metallic substrate, which may be a chamfered edge. The application of a passivation layer and an electrophoretic deposition layer may also enhance corrosion resistance of the metal alloy substrate. These properties may be additionally enhanced by the application of a sealing layer between the passivation layer and the electrophoretic deposition layer.

Passivation layer

[00863 The passivation layer may be sprayed, rollered, dipped, or brushed onto the metal alloy surface.

[00871 The passivation layer may be transparent. The passivation layer may comprise a chelating agent and a metal ion or chelated metal complex thereof, or a mixture of the chelating agent, the metal ion and the chelated metal complex. The chelated metal complex comprises a ligand coordinated to the metal ion. The ligand is the chelating agent.

[0088| The chelating agent may be selected from ethy!enediaminetetraacetic acid (EDTA), ethy!enediamine (EN), nitrilotriacetic acid (NTA), diethyienetriaminepenfa(methylenephosphonic acid) (DTPPH), 1-hydroxyethane-1,i- diphosphonic add (HEDP) nitriSotiis(methyienephosphonic add) (NTMP), and phosphoric add. in one example, the chelating agent is DTPPH.

[00891 The metal ion may be selected from an aluminium ion, a nickel ion, a chromium ion, a tin ion, an indium ion, and a zinc ion. in one example, the metal ion is selected from an aluminium ion, a nickel ion and a zinc ion.

[0090J in one example, the chelated metal complex may comprise DTPPH chelated to an aluminium ion. In another example, the chelated metal complex may comprise DTPPH chelated to a nickel ion. In a further example, the chelated metal complex may comprise DTPPH chelated to a zinc ion.

[00911 The passivation layer may have a thickness of from about 30 n to about 3 pm, such as from about 200 nm to about 2 p , or from about 500 nm to about 1 pm. The thickness of the passivation iayer can be measured after it has been applied using, for example, a micrometre screw gauge or scanning electron microscope (SEM). Electrophoretic deposition layer

[00921 The electrophoretic deposition layer may comprise an electrophoretic polymer selected from polyacrylic polymer, polyacrylamide-acrylic copolymer and epoxy-containing polymer,

[00931 The electrophoretic deposition layer may be transparent In one example, the electrophoretic deposition layer is colourless. In another example, the electrophoretic polymer layer may comprise a colorant,

[00941 ^ “colorant” may be a material that imparts a colour to the electrophoretic deposition layer. As used herein, “colorant” includes pigments and dyes, such as those that Impart colours, such as black, magenta, cyan, yellow and white to an electrophoretic deposition layer. The pigment particles may be dispersed throughout the electrophoretic deposition layer. The pigment may be selected from carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, pearl pigment, metallic powder, aluminium oxide, dye, graphene, graphite, pigment colorants, magnetic particles and an inorganic powder. Although the present description primarily exemplifies the use of pigment colorants, the term “pigment” can be used more generally to describe pigment colorants and also other pigments such as organometailics, ferrites and ceramics in one example, the pigment is a dye. The dye may be dispersed throughout the electrophoretic deposition layer.

[00953 The colorant can be any colorant compatible with the electrophoretic polymer and useful for providing an e!ectrophoretic deposition layer. For example, the colorant may be present as pigment particles, or may comprise a resin and a pigment. The pigments can be any of those standardly used in the art. In some examples, the colorant is selected from a cyan pigment, a magenta pigment, a yellow pigment and a black pigment. For example, pigments by Hoecbst including Permanent Yellow DHG, Permanent Yellow GR, Permanent Yellow G, Permanent Yellow NCG-71, Permanent Yellow GG, Hansa Yellow RA, Hansa Brilliant Yellow 5GX-02, Hansa Yellow X, NOVAPERM® YELLOW HR, NOVAPERM® YELLOW FGL, Hansa Brilliant Yellow 10GX, Permanent Yellow G3R-01, HOSTAPERM© YELLOW H4G, HOSTAPERM® YELLOW H3G, HOSTAPERM® ORANGE GR, HOSTAPERM® SCARLET GO, Permanent Rubine F6B; pigments by Sun Chemical including L74-1357 Yellow, L75-1331 Yellow, L75-2337 Yellow; pigments by Heubach including DALAMAR® YELLOW YT-858-D; pigments by Ciba-Geigy including CROMOPHTHAL® YELLOW 3 G, CROMOPHTHAL® YELLOW GR. CROMOPHTHAL© YELLOW 8 G. IRGAZINE® YELLOW 5GT. IRGAUTE® RUB IN E 4BL, MONASTRAL® MAGENTA, MONASTRAL® SCARLET, MONASTRAL® VIOLET MONASTRAL® RED, MONASTRAL® VIOLET; pigments by BASF including LUMOGEN® LIGHT YELLOW, PALIOGEN® ORANGE, HELIOGEN® BLUE L 690 IF, HELIOGEN® BLUE TBD 7010, HELIOGEN® BLUE K 7090, HELIOGEN® BLUE L 710 IF, HELIOGEN® BLUE L 6470, HEUOGEN® GREEN K 8683, HELIOGEN® GREEN L 9140; pigments by Mobay including QU5NDQ® MAGENTA, INDOFAST® BRILLIANT SCARLET, QUINDO® RED 6700, QUINDO® RED 6713, INDOFAST® VIOLET; pigments by Cabot including Maroon B STERLING® NS BLACK, STERLING® NSX 76, MOGUL® L; pigments by DuPont including TIPURE® R-1Q1; and pigments by Paul Uhiich including UHL!CH® BK 8200. If the pigment is a white pigment particle, the pigment particle may be selected from TiOs, calcium carbonate, zinc oxide, and mixtures thereof. In some examples, the white pigment particle may comprise an aiumina-TiOi pigment. In some examples the colorant may be Pacific Blue dye.

[00961 The colorant or pigment may be present in the electrophoretic deposition layer in an amount of from about 0 1 wt.% to about 15 wt.%, based on the total weight of the electrophoretic deposition layer. For example, the colorant or pigment may he present in the electrophoretic deposition layer in an amount from about 0.5 wt.% to about 13 wt.%, or from about 1 wt.% to about 12 wt.%, or from about 1,5 wt.% to about 10 wt.%, or from about 2 wt.% to about 9 wt.%, or from about 2.5 wt.% to about 8 wt.%, or from about 3 wt.% to about 7 wt.%, or from about 3.5 wt.% to about 6 wt.%, or from about 4 wt.% to about 5 wt.%, based on the total weight of the electrophoretic deposition layer, in some examples, the colorant or pigment particle may be present in the electrophoretic deposition layer in an amount of at least 5.5 wt.% based on the total weight of the electrophoretic deposition layer, for example at least 4.5 wt.% based on the total weight of the electrophoretic deposition layer.

[00971 In one example of an electrophoretic deposition layer comprising a colorant, the electrophoretic deposition layer comprises, based on the total weight of the electrophoretic deposition layer, 10 wt.% polyacrylic copolymer resin, 0.1 wt.% Pacific Biue dye, 0.3 wt.% of an anionic compound, such as sodium dodecylbenzene and 89.6 wt% do-ionized water.

[0098] in one example of a transparent electrophoretic deposition iayer, the electrophoretic deposition Iayer comprises, based on the total weight of the electrophoretic deposition layer, 10 wt.% polyacrylic copolymer resin, 0,3 wt.% of an anionic compound, such as sodium dodecylbenzene and 896 wt.% de-ionized water.

[00991 The electrophoretic deposition Iayer may have a thickness of from about 5 pm to about 60 p , for example from about 10 p to about 55 pm, or from about 15 pm to about 50 p , or from about 20 pm to about 45 , or from about 25 p to about 40 m, or from about 30 pm to about 35 pm.

[00100] The thickness of the electrophoretic deposition iayer can be measured after it has been applied using, for example, a micrometre screw gauge or scanning electron microscope (SEIV!),

[00101] To carry out the electrophoretic deposition, the etai alloy substrate is made an electrode of an electrochemical cell. The electrochemical cell also has an inert electrode as the counter eiectrode and an electrolyte comprising an electrophoretic polymer. A potential difference is applied across the electrodes of the electrochemical ceil to deposit the electrophoretic polymer over the coating layer. The electrolyte may have a concentration of from about 1 wt.% to about 25 wt.%, such as from about 5 wt.% to about 20 wt.%, or from about 10 wt.% to about 15 wt.% of the electrophoretic polymer. The polymer, in general, has ionizable groups. When the polymer Is a negatively charged material, then it wiii be deposited on the positively charged electrode (anode). When the polymer is a positively charged material, then it will be deposited on the negatively charged electrode (cathode).

Sealing Layer

[00102] in some examples, the sealing layer comprises a metai compound and a surfactant. In some examples, the metal compound may comprise a cation selected from aluminium, nickel or cerium. In some examples, the metai compound may comprise an anion selected from fluoride or acetate in some examples, the metal compound is selected from aluminium fluoride, nickel fluoride, cerium fluoride, cerium acetate, aluminium acetate, nickel acetate or a combination thereof. In some examples, the metal compound may be present in an amount from about 0.5 wi% to about 5 0 wt%, or from about 1.5 wt% to about 4,0 w?%, or from about 2.5 wt% to about 2.0 wt% by weight of the sealing layer.

[00103] in some examples, the surfactant may be selected from alcohol sulfates, alkyl benzene sulfonates, sodium caseinate, sodium polyacrylate, sodium polyoxyethylene alkyl ether carboxy!ate, and sodium dodecyi sulfate. The surfactant may be present in an amount from about 0.1 wt% to about 2 wt%, or about 0.5 wt% to about 1 5 wt% by weight of the sealing layer

[00104] In some examples, after applying the sealing layer, the sealing layer is heated. In some examples, the sealing layer is heated to a temperature from about 25 °C to about 100 °C. In some examples, the sealing layer is heated to a temperature greater than about 25 °€, or greater than 30 °C, or greater than about 40 °C, or greater than about 50 °C, or greater than about 80 °C, or greater than about 70 °C, or greater than about 80 °C, or greater than about 90 °C.

[00105] in some examples, the sealing layer may have a thickness of from about 1 p to about 3 pm. The thickness of the layer can be measured after it has been applied using, for example, a micrometre screw gauge or scanning electron microscope (SEM).

Coated metat aHo substrate

[00106] in some examples, there is provided a coated metal alloy substrate for an electronic device, comprising: a metal alloy substrate: and at least one printed coating layer on at least a portion of the metal alloy substrate in some examples, the at least one printed coating layer printed on at least a portion of the metal alloy substrate is based on a 3D surface profile of the metal alloy substrate. In some examples, the coated metal alloy substrate is formed according to the process described herein. |00107] in some examples, the at least one printed coating layer has an average thickness less than about 100 pm, or less than about 75 pm or less than about 50 p , or less than about 25 pm, or less than about 10 pm, or less than about 5 pm. In some examples, more than one printed coated layer may be printed on at least a portion of the metai aiioy substrate, for example, two layers, three layers, four layers, five layers, six layers, seven layers or more than seven layers may be printed on at least a portion of the metal alloy substrate on top of one another, in some examples, a primer coating layer, a base coating layer and a top coating layer are printed on at least a portion of the metai alloy substrate in some examples, the total thickness of ail the printed coating layers (e.g. the primer coating layer, the base coating layer and the top coating layer) is less than about 100 pm, or less than about 75 pm or less than about 50 pm, or less than about 25 pm, or less than about 10 pm. The thickness of the coating layer(s) can be measured after all layers have been printed using for example, a micrometre screw gauge or scanning electron microscope (SEM). The average thickness refers to the mean thickness. The present inventors found that by using the process described herein, a thin total coating may provide good corrosion resistance,

[00108] in some examples, the printed coating layer has a surface roughness parameter Ra of less than about 12 pm, or less than about 1 pm, or less than about 0.9 pm, or less than about 0.7 pm.

[00109] in some examples, the printed coating layer has a surface roughness parameter Rq of less than about 1.5 p , or less than about 1.2 p , or less than 1 pm, or less than about 0.8 pm,

[00110] In some examples, the coated metal alloy substrate has an ISO 1302 roughness grade of M8 or less, or N7 or less, or N6 or less.

[00111] in some examples, the coated metal alloy substrate demonstrates corrosion resistance for at least 96 hours in a salt-fog test in accordance with ASTM B t 17,

Electronic device [00112] The electronic device of the present disclosure may be a computer, a laptop, a tablet, a workstation, a ceiS phone, a portable networking device, a portable gaming device and a portable GPS.

[00113] Th electronic device has an electrical circuit, such as a motherboard or display circuitry. The housing may be external to the electrical circuit

Housing in some examples there is provided a coated metal alloy substrate having a housing, wherein the housing comprises a coated metal alloy substrate, and the coated metal alloy substrate comprises a metal alloy substrate; and at ieast one printed coating layer on at least a portion of the metal alloy substrate. In some examples, the at least one printed coating layer printed on at least a portion of the metal alloy substrate is based on a 3D surface profile of the metai alloy substrate. In some examples, the coated metal alloy substrate is fanned according to the process described herein. The housing may comprise a coated metal alloy substrate as described herein,

[00114] The electronic device has an electrical circuit, such as a motherboard or display circuitry. The housing may be external to the electrical circuit.

[00115] The housing comprises a coated metal alloy substrate disclosed herein. The metal alloy substrate can be light-weight and may provide a durable housing. The housing of the present disclosure may have cosmetic features that are visually appealing to a user, such as an attractive surface finish. The housing according to the present disclosure may have chamfered surfaces that are glossy or have a natural metallic lustre. The glossy surface and/or metallic lustre can be determined by visual examination.

[00116] The housing may provide an exterior part of the electronic device, such as a cover or a casing of the electronic device. The housing may include a support structure for an electronic component of the electronic device. The housing may include a battery cover area, a battery door, a vent or combinations thereof,

[00117] The housing may provide a substantial part of the cover or the casing of the electronic device. The term “substantial part” in this context refers to at least about 50 %, such as at least about 60 %, at least about 70 %, at least about 80 % or at least about 90 %, of the total weight of the cover or the casing. The housing may provide the entire cover or casing of the electronic device.

[00118] The housing can be a cover, such as a lid, the casing or both the cover and the casing of the electronic device. The casing may for a bottom or lower part of the cover of the electronic device. For example, the housing is the casing of a laptop, a tabiet or a cell phone.

[00118] The chamfered edge may provide an edge or peripheral area in the housing for a touchpad, a fingerprint scanner, a trackball, a pointing stick, or a button, such as a mouse button or a keyboard buton. Non-chamfered surfaces of the coated metal alloy substrate may provide a bezel for a display screen, a casing, or wrist rest for a keyboard,

[00120] Examples of housings of the present disclosure are shown in Figures 2, 4 and 6 which are partial cross sections through the housing. The housing cross-section shown in Figure 2 shows the metal alloy substrate (1 ), an oxidised iayer or inorganic iayer (2) and a printed coating iayer (3). The housing cross-section shown in Figure 4 shows the etal alioy substrate (1), an oxidised layer or inorganic layer (2) and a printed primer coating iayer (3a), a printed base coating layer (3b), and a printed top coating layer (3c), The housing cross-section in Figure 6 shows a coated metal alloy substrate (1 ) an oxidised iayer or passivation layer (2), a printed primer coating layer (3a), a printed base coating iayer (3b), a printed top coating layer (3c), a chamfered edge (4), a passivation layer (5) and an electrophoretic deposition layer (6). Figure 7 shows an example of the housing of the present disclosure. The housing is a casing (7) for the keyboard of a iaptop. The metal alloy substrate is coated with at least one printed coating Iayer (8), which provides a wrist- rest and cover for the iaptop. Chamfered edges form further surfaces such as (9), (10) and (11). Both the chamfered and non-chamfered surfaces have an attractive appearance and provide a pleasant tactile surface. The non-chamfered surface is found to be smooth to the touch and have a good surface finish, Aiong with a high metaiiic lustre, the surfaces are corrosion resistant and have a durable coating.

EXAMPLES [00121] The following illustrates examples of the process for producing a coated metal alloy substrate, the coated metal alloy substrate, the electronic device having a housing and other aspects described herein. Thus, these examples should not be considered as limitations of the present disclosure, but are merely in place to each how to make examples of the present disclosure.

Example 1

[00122] A keyboard casing for a laptop was manufactured from an insert-molded magnesium alloy substrate comprising the magnesium alloy AZ31B. AZ31N comprises, based on the weight of the total alloy: Ai: 2.5-3.5 wt%, Zn: 0.6-1.4 wt.%, Mn: 0.2 wt.%, Si:0-1 wt.%, Cu: 0.05 wt.%, Ca: 0.04 wt.%, Fe; 0.005 wt.%, HI 0005 wt.% and the remainder being Mg and inevitable impurities. The magnesium alloy has been formed by insert-molding the metal alloy substrate with a polyphenylene sulfide. The surface was degreased and cleaned using ultrasonic cleaning.

[00123] An oxidized surface layer was first formed on the magnesium alloy substrate by micro-arc oxidation.

[001 4] The metai alloy substrate was then scanned using a HP structured light scanner Pro S3 with a dual camera. The 3D light scanner has a scan size of 60-500 nm, a resolution up to ,005mm and a scanning time of less than 10 seconds. The structured Sight scanner generated a 3D surface profile of the metal alloy substrate surface using Artec Studio 14. A primer coating layer was then printed on the metal alloy substrate according to the 3D surface profile of the metai ailoy substrate surface using a Jet Fusion 4200 printer with Siemens’ Digital Enterprise software and heated to 70 ^,: C for 30 minutes. The printer primer coating layer used was a polyester polyurethane, impsrite 300®. The printer primer coating layer had a smooth surface {Ra < 1 ,0 p ) and no polishing treatment was performed.

[00125] The primer coated metal alloy substrate was further scanned using the scanning process, and a base coating layer was printed on the primer-coating layer according to the 3D surface profile of the primer-coated metal alloy substrate surface. The base coating was applied and cured as described above for the primer coating iayer. 1001263 The base coating layer was a polyurethane, Lesonal Basecoat SB. The printed base coating layer had a thickness of 15 pm. The base coating layer had a smooth surface fRa < 0.8 pm) and no polishing treatment was performed.

[00127] The base coated metal alloy substrate was further scanned using the scanning process, and a top coating layer was then printed on the base coating layer according to the 3D surface profile of the metal alloy substrate surface. The top coating was applied as described above for the primer coating layer and cured at 55 ^' C for 15 minutes followed by UV exposure at 1,200 mJ/cm ^a for 30 seconds.

[00128] The printed top coating layer was a urethane acrylate resin, EBECRYL@230. The printed top coat layer had a thickness of 18 pm. The top coating layer ha a smooth surface (Ra < 0.5 pm) and no polishing treatment was performed.

[001 8] The coated metal alloy substrate was found to have good surface uniformity and was smooth to the touch. The coated metal alloy substrate was found to also have a glossy surface finish as determined by visual determination. The coated metal aiioy substrate was found to have good corrosion resistance.

Example 2

[00130] Chamfered edges were engraved into the coated metal alloy substrate of Example 1 using a CNC cutting process. This process uses a diamond cutting procedure, using a lathe, to remove a thin Mg alloy layer to expose a non-oxidised surface of the coated metal alloy substrate. This cuts an opening in the casing for a touchpad. The machine used was a Brother Speedio S500 21 (machine dimensions 61.4” x 87.4” x 98.3”). The dimensions of the touchpad were between G.3-2mm in width.

[00131] The exposed chamfered edge was coated with a solution comprising a chelated metal complex wherein the chelating agent is DTTPH and the etai ion is zinc. The solution was dried and formed a transparent passivation layer which comprises DTTPH and zinc. The transparent passivation layer protects the underlying metallic surface of the substrate and prevents it from undergoing atmospheric oxidation.

[00132] To the passivation layer was applied a yellow-coloured electrophoretic deposition layer. The yellow-coloured electrophoretic deposition layer comprised 10 wt. % polyacrylic polymer, 5 wt. % pigment yellow 191, 0.5 wt. % sodium polyacrylate, and 0.3 wt, % glutaraldehyde, based on the total weight of the electrophoretic deposition layer. The substrate was then heated at 170 °C for 45 minutes. |00133] Further chamfered edges were then cut into a second area of the coated metal alloy substrate using a CNC cutting process to cut an opening in the casing for a fingerprint scanner.

[00134] To the second chamfered edge was applied a transparent passivation layer, as described for the first chamfered edge.

[00135] Using electrophoretic deposition, a red-coioured electrophoretic layer was applied to the transparent passivation layer. The electrophoretic deposition layer comprised 10 wt. % polyacrylic polymer, 5 wt. % Pigment Red 168 IV1F, 05 wt. % sodium po!yacrylate, and 0,3 wt. % glutaraSdehyde, based on the total weight of the electrophoretic deposition layer. The substrate was then heated at 170 for 45 minutes.

[00136] The resultant substrate had two chamfered edges, both of which were coloured. The laptop housing had a yellow-coloured touchpad and a red-coloured fingerprint scanner.

[00137] The coated metal alloy substrate was found to exhibit the properties of the metal alloy substrate according to Example 1, but the engraved chamfered edges also were found to have good corrosion resistance. The chamfered edges were found to have good metallic lustre providing a product with more than 95 gloss units.