Prevention of corrosion in metals

• US 3,936,583 A
• Filed: 10/25/1973
• Issued: 02/03/1976
• Est. Priority Date: 10/26/1972
• Status: Expired due to Term

• Current Assignee: The secretary of state for defence in her Britannic Majesty's Government of the United Kingdom of Great Britain And Northern Ireland
• Original Assignee: Secretary of State For Defence In Her Britannic Majesty's Government of The UK of GT Britain and Northern Ireland
• Inventors: Rhoades-Brown, John Ernest, Lloyd, Geoffrey Oliver, Saunders, Stuart Richard John
• Primary Examiner(s): Pitlick, Harris A.
• Application Number:
  US05/409,592
• Time in Patent Office: 831 Days
• Field of Search: 148/6.15 R, 148/6.14 R, 148/6, 117/127, 427/435
• US Class Current: 428/450
• CPC Class Codes: C21D 1/70 while heating or quenching
• CPC Class Codes: C23C 22/02 using non-aqueous solutions

Abstract

A method of protecting an article having at least a surface layer of an alloy of iron and/or nickel which contains at least 1 per cent of chromium, against high temperature oxidation, by contacting the article with a solution or a suspension of a borate and/or a phosphate in a volatile polar organic solvent so that, after removal of the solvent, a film weighing at least 3 μ g / cm² of the borate and/or phosphate material is deposited on the surface of the article.

Claims

1. A process for the protection of the surface of an article, said surface being an iron or nickel alloy which contains at least 1 per cent by weight of chromium, against high temperature oxidation comprising contacting the same article with a solution or a suspension of a material selected from the group consisting of borax, sodium metaborate, zinc borate and boric acid, in a volatile polar organic solvent, whereby, after removal of the solvent, a film weighing at least 3 μ

g/cm² of the said material is deposited on the surface of the article.

2. A process according to claim 1 wherein the chromium is present in the alloy in the range 3 to 30 per cent by weight.

3. A process according to claim 1 wherein the borate is borax.

4. A process according to claim 1 wherein the polar organic solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, t-butyl alcohol, acetone, methyl ethyl ketone, 1,4 dioxane and ethylene glycol.

5. A process according to claim 1 wherein the solution or suspension of a borate contains additionally silica or tetraethylorthosilicate.

6. An iron or nickel alloy treated by the process of claim 1.

7. A process for retarding the production of a scale by oxidation at a temperature of 600°

C or above on an iron or nickel alloy containing at least 1 per cent by weight of chromium which comprises coating the surface of the alloy with a material selected from the group consisting of borax, sodium metaborate, zinc borate and boric acid, in a polar solvent and removing the solvent to leave a film weighing at least 3 μ

g/cm² of the borate on the surface of the alloy.