To obtain a disc valve which has sufficient adhesive property to a sliding surface between a ceramic valve body and a valve seat for preventing leakage of water or liquid, is smoothly operated with a proper frictional coefficient, keeps such a state for a long time and has excellent durability.
In a disc valve, valve holes 6, 7 are opened on a valve seat 5 which is in sliding contact with a valve body 8. In such a disc valve, one of the valve seat 5 and the valve body 8 is formed of self-lubricating ceramic mainly composed of ceramic oxide, including one or more of friction reducing agent selected from iron, nickel, cobalt, and oxides, nitrides and cargbide thereof. The other is formed of aluminum oxide ceramic having an area smaller than the one of the valve seat 5 and the valve body 8. A sliding surface between the valve seat and the valve body shows a smoothly rising state hither by 0.1 to 1μm than an outer peripheral edge at its center. Sum of the rising rates of the valve seat 5 and the valve body 8 is not more than 1.6μm.
MURAMATSU KATSUTOSHI
INOUE HIROYUKI
ISHIHARA MAKOTO
KVK CORP