Metal material having formed thereon chromium oxide passive film and method for producing the same, and parts contacting with fluid and system for supplying fluid and exhausting gas

摘要

The object of the present invention is to form a chromium-oxide film excellent in corrosion resistance without containing an oxide film of other metal onto the optional metallic material. The chromium-oxide passivation film excellent in corrosion resistance without containing the oxide film of other metal can be formed inexpensively and in a short time, and a fluid supplying system for supplying fluid hard in corrosivity in safety is able to be provided. This invention comprises a step of forming the passivation film consisting of a chromium oxide by giving heat treatment in an oxidizing atmosphere after coating chromium on metallic material of which surface roughness (Ra) of a coat surface is not more than 1.5 mum