초록 ▼

A ceramic coating is formed on a conductive article by immersing a first anodic electrode, including the conductive article, in an electrolyte comprising an aqueous solution of alkali metal hydroxide and an alkali metal silicate, providing a second cathodic electrode in contact with the electrolyte,

A ceramic coating is formed on a conductive article by immersing a first anodic electrode, including the conductive article, in an electrolyte comprising an aqueous solution of alkali metal hydroxide and an alkali metal silicate, providing a second cathodic electrode in contact with the electrolyte, and passing an alternating current from a resonant power source through the first electrode and to the second electrode while maintaining the angle φ between the current and the voltage at zero degree, while maintaining the voltage within a predetermined range. The resulting ceramic coated article comprises a coating which includes a metal, silicon, and oxygen, wherein the silicon concentration increases in the direction from the article surface toward an outer surface of the ceramic coating surface layer.

대표청구항 ▼

1. A method for forming a ceramic coating on an electrically conductive article, the method comprising:immersing a first electrode comprising said electrically conductive article in an electrolyte comprising an aqueous solution of a metal hydroxide and a metal silicate; providing a second electrode

1. A method for forming a ceramic coating on an electrically conductive article, the method comprising:immersing a first electrode comprising said electrically conductive article in an electrolyte comprising an aqueous solution of a metal hydroxide and a metal silicate; providing a second electrode comprising one of the vessel containing the electrolyte or an electrode immersed in the electrolyte; passing an alternating current from a resonant power source through the first electrode as an anode and to the second electrode as a cathode while maintaining the angle φ between the current and the voltage at zero degrees, and while maintaining the voltage between the first and second electrodes within a predetermined range. 2. The method for forming a ceramic coating on an electrically conductive article according to claim 1, wherein said predetermined voltage range is between about 220-1,000V.3. The method for forming a ceramic coating on an electrically conductive article according to claim 2, wherein said aqueous solution of a metal hydroxide and a metal silicate comprises about 0.5-5 g/liter of alkali metal hydroxide and 1-500 g/liter sodium silicate.4. The method for forming a ceramic coating on an electrically conductive article according to claim 1, further comprising adding mixed complexes to the electrolyte.5. The method for forming a ceramic coating on an electrically conductive article according to claim 4, wherein said mixed complexes include at least one metal selected from the group consisting of Cu, Zn, Cd, Cr, Fe, Ti, and Co to serve as central atoms in the mixed complexes.6. The method for forming a ceramic coating on an electrically conductive article according to claim 4, further comprising adding at least one phosphate to the electrolyte.7. The method for forming a ceramic coating on an electrically conductive article according to claim 6, wherein said at least one phosphate comprises an ammonium phosphate.8. The method for forming a ceramic coating on an electrically conductive article according to claim 1, wherein said step of passing an alternating current from a resonant power source further comprises:changing said angle φ during said step of passing an alternating current by changing at least one of a transformer secondary winding inductance and an additional inductance in a resonant circuit or by changing a capacitance in the resonant circuit. 9. The method for forming a ceramic coating on an electrically conductive article according to claim 8, wherein said electrolyte comprises salts of metals selected from the group consisting of B, Al, Ge, Sn, Pb, As, Sb, Bi, Sc, Te, P, Ti, V, Nb, Ta, Cr, Mo, W, Mn and Fe.10. The method for forming a ceramic coating on an electrically conductive article according to claim 8, further comprising adding at least one pigmenting substance to the electrolyte.