Patent ID: 6333072
Filing Date: 2001-12-25
Classification: C23C

Abstract:
A process for forming an adherent metal oxide coating, with the ability to withstand severe flow boiling conditions of about 200,000 BTU/hr.multidot.ft.sup.2 heat flux, on a metallic surface consisting essentially of the steps in this order:(a) providing an oxide mixture consisting of at least one reactive metal oxide selected from the group consisting of iron oxides, nickel oxides, zinc oxides and ferrite compounds, having an average particle diameter of from about 1 to about 10 .mu.m and an average surface area of from about 0.5 to about 5 m.sup.2 /gram;(b) ball milling said oxide mixture in a non-aqueous solvent for at least 24 hours and then drying said oxide mixture to form a dry powder mixture;(c) combining diluted phosphoric acid with said dry powder mixture to form a coating mixture;(d) applying said coating mixture to said metallic surface and,(e) heating said metallic surface to form an adherent metal oxide coating on said metallic surface, wherein said phosphoric acid is added in an amount sufficient to produce a porosity of about 20 to about 50% in said adherent metal oxide coating.