| 摘要 |
<p>The steel is first coated with a porous layer (I) of metallic chromium, and is then exposed at high temp. to an atmos. contg. halide, so a chromium halide is formed which provides Cr diffusing into the steel substrate to form a continuous, non-porous and protective layer (Ia) of a Cr-C-Fe alloy bonded to the steel by diffusion. The Cr(I) is pref. applied to the steel substrate physically, esp. by plasma spraying, or by electroplating in a bath; and the halide atmos. is pref. obtd. by heating the coated steel in a packing contg. a solid halide, esp. NH4Cl. The steel substrate is pref. a casing used for a sodium/sulphur battery. The coating is inexpensive.</p> |
