| 摘要 |
PURPOSE:To improve the oxidation resistance and corrosion resistance of a heat resistant metallic article by heating the article in a packing agent contg. powder contg. a rare earth element, powder of an inert carrier and a halide so as to diffuse the rare earth element in the surface layer of the article. CONSTITUTION:An article contg. one or more among Al, Si and Cr is buried in a packing agent prepd. by blending powder contg. a rare earth element or powder of misch metal with powder of an inert carrier such as alumina and a halide such as NH4Cl. The article is subjected to packing treatment at about 700-900 deg.C in a nonoxidizing atmosphere such as H2 for about 0.5-2.0hr. The article is then taken out, and diffusion treatment is carried out at about 900- 1,000 deg.C in a nonoxidizing atmosphere for about 0.5-4.0hr. By this method the rare earth element can be diffused only in the surface layer of the article.
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