| 摘要 |
PURPOSE:To improve erosion resisting performance and to prevent scale from adhering, by coating surfaces of a valve seat and a valve unit with a compound multiple coating material consisting of titanium carbide, titanium carbide nitride and titanium nitride. CONSTITUTION:A compound multiple coating material successively piles three ceramic materials of titanium carbide, titanium carbide nitride and titanium nitride by the chemical evaporation method on the surface of a foundation, which pad welds a cobalt system alloy to be finished on a base material consisting of stainless steel, or a foundation, in which martensite system stainless steel of SUS440C or the like is heat treated to be finished to predetermined hardness, and a thin film of the compound multiple coating material is firmly formed in a closely attached condition respectively to a fluid contact part, mainly composed of a cutoff part 18 of a valve seat 15, breast part 19 and a discharge hole part 20, and a fluid contact part mainly composed of a cutoff part 21 of a valve unit 16 and a plug part 22.
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