PURPOSE: To prevent or drastically reduce the diffusion of iron group metals developed in high temp. into a noble metal, in the iron group metallic layer coated with the noble metal.
CONSTITUTION: In a constitution material having the metallic layer coated with the noble metal, in which the metal contains at least 70 wt.% iron, cobalt and/or nickel and the thickness of the noble metal layer is 1-10 μm, the constitution material, in which metallic fine crystals exist on the surface of the metallic layer coated with the noble metal and at least 30% of the metallic fine crystals on the surface have at least 2 μm grain size or at least 50% of the metallic fine crystals on the surface have at least 1 μm grain size, or the constitution material, in which, before coating the noble metal, the metallic layer is heated at 500-1300°C in a non-oxidizing atmosphere till precipitating the metallic fine crystals having at least 2 μm grain size on at least 30% of the metal surface area or till precipitating the metallic fine crystals having at least 1 μm grain size on at least 50% of the metal surface area and the metallic layer is cooled and successively, the noble metal coating is applied to have the metallic layer coated with the noble metal, is produced.
RAINAA BINDEIGU
YURUGEN BURANDENBURUGAA
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