ALLOY SURFACE ACTIVATION BY IMMERSION IN AQUEOUS ACID SOLUTION

摘要

A process for surface activation or depassivation of an article, in particular an alloy, by immersion of the alloy in an aqueous acid solution. The surface activation methods of the present invention can be performed during a relatively short period of time and achieve reductions in production costs and provide environmental friendliness as compared to prior art processes. In a further embodiment, after surface activation, the article is immersed in a second liquid that prevents re-formation of a passivating oxide layer on the surface of the article. In a further embodiment the surface-activated alloys are subjected to surface engineering by a process that infuses carbon or nitrogen through the surface at a temperature sufficiently low to suppress precipitation of carbides or nitrides.

主权项

1. A process for preventing oxidation of a surface of an alloy article, comprising the steps of:
activating at least one surface portion of an alloy article; and contacting the at least one surface portion of the article with a liquid comprising one or more of an alcohol, an aqueous acid, a fatty acid, an oil, and water prior to formation of a passivating layer on the at least one surface portion.