| 摘要 |
A method of furnishing the surface of ferroalloys with resistance to hot corrosive gases containing halogens or compounds thereof or to general oxidation which comprises the steps of heating in an oxidizing atmosphere at a temperature of 1,000 DEG to 1,400 DEG C for a suitable number of hours articles prepared from a metal consisting of 10 to 25 percent of chromium, 2 to 5 percent of aluminum, less than 0.04 percent of carbon, 0.005 to 0.05 percent of nitrogen, 0.1 to 0.6 percent of titanium, 0.01 to 0.5 percent of zirconium, iron as the remainder and further containing ordinary impurities, in which constitution ratio of Ti% + Zr% to N% ranges from 10 to 60, so as to diffuse by migration in the surface layer of the base body of the article part of oxidizable elements contained therein, thereby forming an oxide layer mainly consisting of alpha Al2O3 on said surface.
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