| 摘要 |
PURPOSE:To obtain engine parts each perfectly exhibiting the characteristics of ceramic and metal members by joining both the members with a specified metallizing layer and a metal buffer in-between. CONSTITUTION:A discoid piston crown 1 is made of partially stabilized ceramics contg. MgO or Y2O3, one side of the crown 1 is coated with metallizing paste contg. a compsn. consisting of, by weight, 7090% Mo 0.5-15% MnO 0.1-10% Y2O3, 0.1-15% Al2O3 and 0.1-15% SiO2 in about 1mm film thickness and the paste is dried and heated at about 1,300 deg.C for about 10hr in an atmosphere of a gaseous H2-N2 mixture to form a metallizing layer 2. The crown 1 with the formed layer 2 is joined to a piston cart 6 made of graphite cast iron with a metallic Ti sheet 3 of about 1mm thickness in-between by silver brazing in vacuum to obtain a piston for a heat insulating engine. The Ti sheet 3 is a metal buffer and the coefft. of thermal expansion is equal to or lower than that of the ceramic member and is <=14X10<-6>/ deg.C. A tappet composed of ceramics and a metal can be produced in the same way. |
