Aluminum alloy member and method for forming surface protective film of aluminum alloy

摘要

PROBLEM TO BE SOLVED: To provide an aluminum alloy member having a protective film that is formed on a surface of an aluminum alloy and has excellent corrosion resistance to a fluorine radical and a fluorine ion and little gas emission even under a high temperature condition.SOLUTION: An aluminum alloy member has a protective film 4 composed of an amorphous alumite layer 2 and a crystallized alumite layer 3 laminated in this order on the surface of an aluminum alloy 1. A method for forming a surface protective film of an aluminum alloy includes a crystallized alumite processing step for anode oxydation of the surface of the aluminum alloy 1 using spark discharge to form the crystallized alumite layer 3 and an amorphous alumite processing step for anode oxydation of the surface of the aluminum alloy 1 on which the crystallized alumite layer 3 is formed, without using spark discharge, to form the amorphous alumite layer 2.