Method of manufacturing an electrical resistance heating means

摘要

An electrical resistance heating element is made from an electrical resistance material having the following composition in weight percent: - Group A: - aluminium 3-8 - yttrium, zirconium, hafnium and/or 0-0.45 - one or more rare earth elements - Group B: - chromium 12-30 - iron and/or nickel and/or cobalt balance - The electrical resistance material is arranged in an atmosphere having a potential for oxidation such as to permit oxidation of the constituent(s) from Group A and to inhibit oxidation of the constituents from Group B. The resistance material is then heated in the atmosphere to a temperature in the range from 800 DEG C. to a temperature below its melting point so as to oxidize the constituent(s) of Group A at the surface and to form a surface layer consisting essentially of continuous unified oxide of the constituent(s) of Group A.