Claims
- 1. A method of making an electrode consisting essentially of the steps of:
- (a) applying to an electroconductive nickel-containing substrate a coating solution of at least one metal oxide precursor compound and an etchant capable of etching the surface of the substrate or any previously applied coating,
- (b) heating the coated substrate to remove volatiles from the so-coated substrate to cause the metal of the precursor compounds and those etched from the substrate or previous coating to be concentrated and recoated on the substrate or previously applied coating, and
- (c) further heating the coated substrate, in the presence of oxygen, air or an oxidizing agent, to a temperature sufficient to oxidize the metal.
- 2. The method of claim 1 wherein the metal oxide precursor compounds are selected from the group of metal chlorides, nitrates, sulphates, or phosphates.
- 3. The method of claim 1 wherein the metal precursor compounds comprise at least one metal compound from the group of Ru, Rh, Pd, Os, Ir, or Pt, and at least one from the group of Ni, Co, Fe, Cu, W, V, Mn, Mo, Nb, Ta, Ti, Zr, Cd, Cr, B, Sn, La, and Si.
- 4. The method of claim 1 wherein the metal of at least one of the metal precursor compounds is that of the substrate.
- 5. The method of claim 1 wherein the etchant is from the group of hydrochloric acid, sulphuric acid, nitric acid, phosphoric acid, a peroxide, and hydrazine hydrosulphate.
- 6. The method of claim 1 wherein the etchant is hydrogen peroxide.
- 7. The method of claim 1 wherein the etchant is a mixture of an acid and a peroxide.
- 8. The method of claim 1 wherein the etchant is a mixture of hydrochloric acid and hydrogen peroxide.
- 9. The method of claim 1 wherein the coating procedure is repeated at least once.
- 10. The method of claim 1 wherein the coating procedure is repeated a plurality of times.
- 11. The method of claim 1 wherein the temperature at which the oxidation of the metal is carried out is in the range of from about 300.degree. to about 600.degree. C.
- 12. The method of claim 1 wherein the heating of the substrate takes place for a period of time of about 5 to about 60 minutes.
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 174,749, filed Mar. 29, 1988, now abandoned.
This is a continuation-in-part application of Ser. No. 134,269 filed Dec. 17, 1987, now U.S. Pat. No. 4,871,703 which is a continuation-in-part of Ser. No. 068,773 filed June 26, 1987, now U.S. Pat. No. 4,760,041, which is a continuation of application Ser. No. 848,516 filed Apr. 7, 1986 (now abandoned) which is a continuation of application Ser. No. 499,626 filed May 31, 1983 (now abandoned).
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4213843 |
Sato et al. |
Jul 1980 |
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4465580 |
Kasuya |
Aug 1984 |
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4760041 |
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Jul 1988 |
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0090435 |
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Continuations (2)
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Number |
Date |
Country |
Parent |
174749 |
Mar 1988 |
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Parent |
499626 |
May 1983 |
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Continuation in Parts (3)
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Number |
Date |
Country |
Parent |
134269 |
Dec 1987 |
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Parent |
68773 |
Jun 1987 |
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Parent |
848516 |
Apr 1986 |
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