| 摘要 |
PROBLEM TO BE SOLVED: To provide zirconia-based ceramics which are thermally stable, inexpensive and have high strength. SOLUTION: The ceramics have the composition consisting of 70 to 99.95 vol.% of substantial zirconium oxide containing MgO as a stabilizer or containing MgO as the essential component and at least one kind of oxide of Ca, Ti and rare earth elements by 5 to 15 mol% in total, 0.05 to 30 vol.% of at least one kind of SiC, TiC, MoC, WC, ZrC, HfC, MgAl2O4, ZnO and NiO, and <=3 vol.% of other impurities. The ceramics are manufactured by normal pressure sintering and hot isotropic pressurizing process. In the X-ray diffraction analysis using the Cu-Kα line for the surface of the ceramics after cutting, grinding and polishing into a mirror surface, the proportion (Vm) of the monoclinic phase calculated from the intensity of diffraction lines (Im, It) on the (-111) and (111) planes of the monoclinic crystal and on the (111) plane of the tetragonal crystal according to the formulae, Xm= Im(-111)+Im(111)}/ Im(-111)+Im(111)+It(111)} and Vm=1.311Xm/(1+0.311Xm)×100 ranges 4 to 40 vol.%. |
