Ceramic Components for Engines in Japan

Various ceramic components are used in many industrial fields in Japan now. Some typical examples include a high precision lathe, a large fan used in steel making and electric power plants, and ball and roller bearings. In the high precision lathe area, components are made of sintered silicon nitride and alumina. The ceramic lathe gives high precision machining capability of about 0.3µm in surface roughness, 0.1µm in surface winding, and 0.03µm in round error, primarily because of the high rigidity and low thermal expansion of the ceramics. In the large fan (∼3 m in diameter), its blade is composed of alumina. The ceramic blade results in longer maintenance-free use for the fan, primarily through the high wear resistance of the ceramic surface. The bearings are made of silicon nitride or alumina. they make it possible to use the bearings at high temperature, in vacuum as well as in dry systems.