GRAETZ JASON (US)
ADJORLOLO ALAIN A (US)
SU1353727A1 | 1987-11-23 | |||
JP2012005999A | 2012-01-12 |
CLAIMS What is claimed is: 1. A crystalline titanium and magnesium compound, having an X-ray diffraction (XRD) pattern having interplanar spacing (d-spacing) values at about 5.94, 3.10, 2.97, 2.10, 1.98, 1.82, and 1.74 ± 0.1 angstroms. 2. The crystalline titanium and magnesium compound of claim 1, further having an XRD having additional interplanar spacing (d-spacing) values at about 1.62, 1.57, 1.55, 1.48, 1.44, 1.34, 1.28, 1.21, 1.18, 1.15, 1.13, 1.08, 1.03 ± 0.1 angstroms. 3. The crystalline titanium and magnesium compound of claim 1 or 2, further having a cubic symmetry and a lattice parameter from about 10.225 angstroms to about 10.325 angstroms. 4. The crystalline titanium and magnesium compound of any of claims 1-3, further having an XRD pattern, produced with an x-ray wavelength of 1.54 angstroms (Cu k alpha), having peaks at 14.89°, 28.78°, 30.09°, 43.10°, 45.85°, 50.20°, and 52.66° ± 0.25 q. 5. The crystalline titanium and magnesium compound of claim 4, further having XRD peaks, produced with an x-ray wavelength of 1.54 angstroms (Cu k alpha), at 56.63°, 58.90°, 59.65°, 62.59°, 64.75°, 70.31°, 73.71°, 79.02°, 81.63°, 84.20°, 86.23°, 91.34°, and 96.59° ± 0.25 2q. 6. The crystalline titanium and magnesium compound of any of claims 1-5, wherein titanium is present at about 15 at% to about 25 at% and magnesium is present at about 1 at% to about 8 at%. 7. The crystalline titanium and magnesium compound of claim 6, further comprising oxygen and fluorine. 8. The crystalline titanium and magnesium compound of claim 7, wherein the oxygen is present at about 30 at% to about 45 at% and the fluorine is present at about 30 at% to about 40 at%. 9. The crystalline titanium and magnesium compound of claim 8, wherein titanium is present at about 25 at%, magnesium is present at about 5 at%, oxygen is present at about 35 at%, and fluorine is present at about 35 at%. 10. A protective coating comprising the crystalline titanium and magnesium compound of any of claims 1-9. 11. The protective coating of claim 10, further comprising titanium dioxide. 12. The protective coating of claim 10 or 11, having a thickness of about 500 nm to about 10 mm. 13. A method of preparing a crystalline titanium and magnesium compound, having an X-ray diffraction (XRD) pattern having interplanar spacing (d-spacing) values at about 5.94, 3.10, 2.97, 2.10, 1.98, 1.82, and 1.74 ± 0.1 angstroms, comprising: preparing a solution comprising: a titanium compound at a concentration of about 0.1 M to about 0.4 M, boric acid at a concentration of about 0.3 M to about 1 M, sodium tetraborate at a concentration of about greater than 0 M to about 0.0065 M, and a magnesium compound at a concentration of about 0.01 M to about 0.1 M. 14. The method of claim 13, wherein the titanium compound comprises ammonium hexafluorotitanate and the magnesium compound comprises one or more of magnesium acetate, magnesium sulfate, magnesium chloride, or magnesium nitrate. 15. The method of claim 14, wherein preparing the solution comprises: dissolving the boric acid, the sodium tetraborate, and the magnesium compound in water to form a first solution; dissolving the titanium compound in water to form a second solution; and pouring the second solution into the first solution. 16. A method, comprising: preparing a solution comprising a titanium compound at a concentration of about 0.1 M to about 0.4 M, boric acid at a concentration of about 0.3 M to about 1 M, sodium tetraborate at a concentration of about greater than 0 M to about 0.0065 M, and a magnesium compound at a concentration of about 0.01 M to a 0.1 M to form a titanium/magnesium solution. 17. The method of claim 16, further comprising: reacting a metal surface with the titanium/magnesium solution; and drying the metal surface with the titanium/magnesium solution to form a titanium/magnesium protective coating on the metal surface. 18. The method of claim 17, wherein reacting the metal surface with the titanium/magnesium solution comprises immersing the metal surface in the titanium/magnesium solution. 19. The method of claim 17 or 18, further comprising applying a primer and/or a paint on the titanium/magnesium protective coating. 20. The method of any of claims 17-19, wherein the metal surface comprises aluminum or an aluminum alloy substrate selected from 2024-T3 aluminum alloy, 6061 aluminum alloy, or 7075 aluminum alloy. |
The XRD peaks were compared to patterns of over 400,000 compounds in several XRD databases without finding a match. Based on this, the XRD pattern appears to characterize a novel crystalline titanium and magnesium compound. Although the exact composition and atomic positions are unknown, the XRD pattern may correspond to a structure with a cubic symmetry with a lattice parameter of about a = 10.275 Å ± 0.05 Å. Identical patterns were obtained using Mg(CH 3 COO) 2 , MgSO 4 , MgCl 2 , or Mg(NO 3 ) 2 , indicating that the various anions are not present in the crystal structure. Similarly, the same pattern was obtained when using dipotassium titanium hexafluoride (K 2 TiF 6 ) or (NH 4 ) 2 TiF 6 , indicating that the cations are not present in the crystal structure. Thermal stabilities show that the crystalline phase decomposes with gentle heating at 150°C (substantially decomposed) and 250°C (completely decomposed). Thermal stabilities may be measured by any technique known in the art, such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), or accelerating rate calorimetry (ARC). Thermal stabilities may also be measured using a temperature treatment (ramp or soak) and XRD (in situ or ex situ) to identify a phase change. Concurrent disappearance of all the peaks with heating indicates that the XRD pattern very likely belongs to a single phase. The low decomposition temperature of 250°C indicates that the phase likely contains hydroxide anions, molecularly bound water, or possibly molecularly bound HF. FIGS.5A-5D are scanning electron micrographs of example titanium/magnesium coatings. FIG.5A shows a region near a scratch 510 that was intentionally made to fracture the coating. The edge of the scratch 510 is just visible from the bottom of the micrograph. Debris from the scratch is seen on the coating. FIG.5B shows a close up of a fractured and spalled-off region 520, showing the coating in cross section. The coating is continuous and dense with no clear crystal faceting. This indicates that the crystalline size is likely small, e.g., less than or equal to 1 mm. The coating also appears well adhered to the substrate because remnants of the coating remain in the fractured and spalled-off region 520, which indicates cohesive failure within the coating as opposed to adhesive failure at the coating/substrate interface. FIGS.5C and 5D show plan views of the coatings. Small defects and fine cracks are visible. Example 1. Two coated panels were made using the following procedure. First, 18.594 g of H 3 BO 3 , 1.249 g Na 2 B 4 O 7 •10 H 2 O, and 1.206 g of MgSO 4 were dissolved in 399.95 g of deionized (DI) water in a 1000 mL beaker with magnetic stirring. Next, 19.811 g of (NH 4 ) 2 TiF 6 was dissolved in 100.027 g DI water in a 250 mL beaker with magnetic stirring. The titanium solution was poured into the boric acid solution and stirred for 15 seconds. Approximately half of the combined coating solution was poured into each of two 5” x 7” trays. Two aluminum alloy 2024 panels were attached using double-back tape to two fixtures designed for holding 4” x 6” panels facedown approximately 0.5 inch above the bottom of the trays. The faces to be coated on the aluminum panels were wiped with isopropyl alcohol. The fixtures were placed into the trays containing the coating solution. The fixtures were sloshed back and forth for about 2 to 3 minutes, and checked by lifting out to ensure that the aluminum surface to be coated was completely wet by the coating solution (e.g., water-break- free surface) and was free of any trapped air bubbles. The trays were covered to reduce evaporation and left at room temperature overnight. After 17 hours, the fixtures with the aluminum panels were lifted out of the trays. The coated surfaces were rinsed under running DI water for about 5 minutes and wiped gently with wet Kimwipes TM . The panels were pried off of the double-back tape. The backside of the panels were rinsed with DI water and scrubbed with a maroon Scotch-Brite TM pad. The panels were blown free of water with compressed nitrogen and allowed to dry in air. Example 2. Following coating, 2024-T3 aluminum alloy samples were tested for corrosion protection in a bulk electrolyte consisting of 0.1 M sodium chloride (NaCl) solution buffered with borate at pH 6.4. Standard electrochemical impedance spectroscopy (EIS) techniques were used to determine the polarization resistance. The polarization resistance is a measure of the corrosion protection, with higher polarization resistance corresponding to improved corrosion protection. The polarization resistances of several coatings as a function of time in the corrosive 0.1 M NaCl solution are shown in Figure 6. For reference, a coating made with a commercial chromate-based conversion coating product (Alodine® 600) is shown. The initial resistance is about 600 kOhm-cm 2 , and then decreases to about 25 kOhms-cm 2 in about 1 day. A coating made with NaCl added to the solution instead of MgCl 2 is also shown. This coating has an initial resistance of about 300 kOhm-cm 2 , which decreases to about 100 kOhms- cm 2 and remains at 100 kOhms-cm 2 up to at least 1 day. A coating in accordance with an example of the present disclosure was made using MgCl 2 . The coating solution contained 1.489 g H 3 BO 3 , 0.036 g of MgCl 2 , and 1.584 g of (NH 4 ) 2 TiF 6 dissolved in 39.977 g of deionized water. The (NH 4 ) 2 TiF 6 was added last and stirred for 2 min. Two 1” x 1” 2024 aluminum coupons were coated by immersing the coupons face down in the coating solution for 16 hours. The initial resistance was about 200 kOhms-cm 2 . This resistance decreased to 80 kOhms-cm 2 in 4 days. The maintained high resistance illustrates the better durability for corrosion protection for coatings with the novel crystalline titanium/magnesium phase. A coating in accordance with an example of the present disclosure was made using Mg(CH 3 COO) 2 . The coating solution contained 9.318 g H 3 BO 3 , 0.539 g of Mg(CH 3 COO) 2 , and 9.940 g of (NH 4 ) 2 TiF 6 dissolved in 250.12 g of deionized water. The (NH 4 ) 2 TiF 6 was added last and stirred for 2 minutes. One 1” x 1” 2024 aluminum coupon was coated by immersing the coupon face down in about 20 mL of the coating solution for 16 hours. The initial resistance was about 100 kOhms-cm 2 . This resistance increased to greater than 200 kOhms-cm 2 before decreasing to about 100 kOhms-cm 2 in 4 days. A coating in accordance with an example of the present disclosure was made using MgSO 4 . The coating solution contained 9.298 g H 3 BO 3 , 0.601 g of MgSO 4 , and 9.298 g of (NH 4 ) 2 TiF 6 dissolved in 250 g of deionized water. The (NH 4 ) 2 TiF 6 was added last and stirred for 4 minutes. One 1” x 1” 2024 aluminum coupon was coated by immersing the coupon face down in about 20 mL of the coating solution for 16 hours. The initial resistance was 300 kOhms-cm 2 . This resistance increased to 3,000 kOhms-cm 2 (3 MOhms-cm 2 ) before beginning to decrease. A coating in accordance with an example of the present disclosure was made using 0.02 M MgSO 4 and 0.0065 M Na 2 B 4 O 7 •10 H 2 O at high pH. The coating solution contained 2.979 g H 3 BO 3 , 0.203 g of Na 2 B 4 O 7 •10 H 2 O, 0.198 g of MgSO 4 , and 3.154 g of (NH 4 ) 2 TiF 6 dissolved in 80.012 g of deionized water. The (NH 4 ) 2 TiF 6 was added last and stirred for 2.5 minutes. Four 1” x 1” 2024 aluminum coupons were coated by immersing the coupons face down each in about 20 mL of the coating solution for 16 hours. This coating solution was designated “high pH” because of the added Na 2 B 4 O 7 •10 H 2 O, which raised the pH slightly from about pH = 3 – 4 to about pH = 4. The initial resistance was 160 kOhms-cm 2 . This resistance increased to 400 kOhms-cm 2 and was maintained between 200 kOhms-cm 2 and 400 kOhms-cm 2 for at least 10 days. Example 3. In order to be able to reuse the coating solution multiple times, a coating solution was prepared containing 0.375 g H 3 BO 3 , 0.096 g of MgSO 4 , and 1.579 g of (NH 4 ) 2 TiF 6 dissolved in 40.003 g of deionized water. The (NH 4 ) 2 TiF 6 was added last and stirred for 4 minutes. Two 1” x 1” 2024 aluminum coupons were coated by immersing the coupon face down each in about 20 mL of the coating solution for 16 hours. After this initial run of using the coating solution, the same coating solution was used repeatedly for an additional 5 runs (6 in total) over 10 calendar days. Coatings were obtained from each run, with the sixth run coating having a resistance of 120 kOhms-cm 2 . Further, the disclosure comprises examples according to the following clauses: Clause 1. A crystalline titanium and magnesium compound, having an X-ray diffraction (XRD) pattern having interplanar spacing (d-spacing) values at about 5.94, 3.10, 2.97, 2.10, 1.98, 1.82, and 1.74 ± 0.1 angstroms. Clause 2. The crystalline titanium and magnesium compound of Clause 1, further having an XRD having additional interplanar spacing (d-spacing) values at about 1.62, 1.57, 1.55, 1.48, 1.44, 1.34, 1.28, 1.21, 1.18, 1.15, 1.13, 1.08, 1.03 ± 0.1 angstroms. Clause 3. The crystalline titanium and magnesium compound of Clause 1 or 2, further having a cubic symmetry and a lattice parameter from about 10.225 angstroms to about 10.325 angstroms. Clause 4. The crystalline titanium and magnesium compound of any of Clauses 1-3, further having an XRD pattern, produced with an x-ray wavelength of 1.54 angstroms (Cu k alpha), having peaks at 14.89°, 28.78°, 30.09°, 43.10°, 45.85°, 50.20°, and 52.66° ± 0.25 q. Clause 5. The crystalline titanium and magnesium compound of Clause 4, further having XRD peaks, produced with an x-ray wavelength of 1.54 angstroms (Cu k alpha), at 56.63°, 58.90°, 59.65°, 62.59°, 64.75°, 70.31°, 73.71°, 79.02°, 81.63°, 84.20°, 86.23°, 91.34°, and 96.59° ± 0.25 2q. Clause 6. The crystalline titanium and magnesium compound of any of Clauses 1-5, wherein titanium is present at about 15 at% to about 25 at% and magnesium is present at about 1 at% to about 8 at%. Clause 7. The crystalline titanium and magnesium compound of Clause 6, further comprising oxygen and fluorine. Clause 8. The crystalline titanium and magnesium compound of Clause 7, wherein the oxygen is present at about 30 at% to about 45 at% and the fluorine is present at about 30 at% to about 40 at%. Clause 9. The crystalline titanium and magnesium compound of Clause 8, wherein titanium is present at about 25 at%, magnesium is present at about 5 at%, oxygen is present at about 35 at%, and fluorine is present at about 35 at%. Clause 10. A protective coating comprising the crystalline titanium and magnesium compound of any of Clauses 1-9. Clause 11. The protective coating of Clause 10, further comprising titanium dioxide. Clause 12. The protective coating of Clause 10 or 11, having a thickness of about 500 nm to about 10 mm. Clause 13.A method of preparing a crystalline titanium and magnesium compound, having an X- ray diffraction (XRD) pattern having interplanar spacing (d-spacing) values at about 5.94, 3.10, 2.97, 2.10, 1.98, 1.82, and 1.74 ± 0.1 angstroms, comprising: preparing a solution comprising: a titanium compound at a concentration of about 0.1 M to about 0.4 M, boric acid at a concentration of about 0.3 M to about 1 M, sodium tetraborate at a concentration of about greater than 0 M to about 0.0065 M, and a magnesium compound at a concentration of about 0.01 M to about 0.1 M. Clause 14. The method of Clause 13, wherein the titanium compound comprises ammonium hexafluorotitanate and the magnesium compound comprises one or more of magnesium acetate, magnesium sulfate, magnesium chloride, or magnesium nitrate. Clause 15. The method of Clause 14, wherein preparing the solution comprises: dissolving the boric acid, the sodium tetraborate, and the magnesium compound in water to form a first solution; dissolving the titanium compound in water to form a second solution; and pouring the second solution into the first solution. Clause 16. A method, comprising: preparing a solution comprising a titanium compound at a concentration of about 0.1 M to about 0.4 M, boric acid at a concentration of about 0.3 M to about 1 M, sodium tetraborate at a concentration of about greater than 0 M to about 0.0065 M, and a magnesium compound at a concentration of about 0.01 M to a 0.1 M to form a titanium/magnesium solution. Clause 17. The method of Clause 16, further comprising: reacting a metal surface with the titanium/magnesium solution; and drying the metal surface with the titanium/magnesium solution to form a titanium/magnesium protective coating on the metal surface. Clause 18. The method of Clause 17, wherein reacting the metal surface with the titanium/magnesium solution comprises immersing the metal surface in the titanium/magnesium solution. Clause 19. The method of Clause 17 or 18, further comprising applying a primer and/or a paint on the titanium/magnesium protective coating. Clause 20. The method of any of Clauses 17-19, wherein the metal surface comprises aluminum or an aluminum alloy substrate selected from 2024-T3 aluminum alloy, 6061 aluminum alloy, or 7075 aluminum alloy. When introducing elements of the present invention or exemplary aspects or example(s) thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there can be additional elements other than the listed elements. Although this invention has been described with respect to specific examples, the details of these examples are not to be construed as limitations. Different aspects, examples and features are defined in detail herein. Each aspect, example or feature so defined can be combined with any other aspect(s), example(s) or feature(s) (preferred, advantageous or otherwise) unless clearly indicated to the contrary. Examples described above illustrate but do not limit the invention. It should also be understood that numerous modifications and variations are possible in accordance with the principles of the present disclosure. Accordingly, the scope of the invention is defined only by the following claims.
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