Valve with ceramic valve seats

摘要

The invention aims to provide a ceramic valve which can stably exhibit excellent sliding properties over a long period of time, in which water leakage is unlikely to occur, and which provides excellent maintainability. A ceramic valve (10) includes a stationary valve body (11) made of ceramic and a movable valve body (12) made of ceramic. A sliding surface (12a) of one of the valve bodies (11) and (12) is covered with a hard carbon film (40) formed mainly of amorphous carbon. The sliding surface of the stationary valve body and the sliding surface of the movable valve body each have an arithmetic mean roughness Ra of not greater than 0.08 mu m. Also, V1 is greater than V2, wherein V1 is the Knoop hardness Hk of the hard carbon film, and V2 is the Vickers hardness Hv of a ceramic substrate which forms a sliding surface (11a) of the other valve body (11), on which the hard carbon film is not formed.