METHOD FOR REMOVING DIFFUSED FILM FROM NICKEL BASE ALLOY

摘要

PROBLEM TO BE SOLVED: To provide a method for removing a diffused film contg. Al from the surface part of an Ni base alloy. ;SOLUTION: The outer parts of the film existing on the diffused inner parts of the film are mechanically removed and, thereafter, Al is decreased from the diffused inner parts exposed on the surface. Such decrease is executed by exposing the inner parts to a reducing gas contg. about 6wt.% or over of gaseous halogen. The reducing gas is a mixture composed of, for example, about ≤20wt.% gaseous hydrogen halide (for example, gaseous hydrogen fluoride) and the balance gaseous hydrogen. The exposure temp. is about ≥1600°F and the exposure time is preferably about 2 to 10 hours at about 1600 to 2000°F.;COPYRIGHT: (C)1998,JPO