| 摘要 |
PURPOSE:To increase the surface hardness of a metal surface and to improve the wear resistance by subjecting the metal surface to chromizing and nitriding in arbitrary order. CONSTITUTION:A metal surface is chromized as usual and nitrided in an ammonia atmosphere or the like, or the metal surface is heated in an ammonia atmosphere or the like to form an alpha-phase contg. nitrogen as a supersatd. solid soln. and it is chromized at ordinary temp. By the nitriding and chromizing, chromium nitride having about 1,200Hv is formed and a metal surface having improved wear resistance is obtd. this method is suitable for the surface hardening of a boiler tube, a machine structure, metal powder, etc., requiring high hardness.
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