| 摘要 |
PROBLEM TO BE SOLVED: To increase surface electric conductivity without deteriorating the mechanical characteristics of a composite material consisting of TZP or Y-TZP and alumina by forming a core (bulky part) contg. a tetragonal zirconia alloy or its composite and a shell (surface part) contg. zirconium boride. SOLUTION: Zirconia powder 100 having 99.9-99.99wt.% purity and 0.1-0.01μm crystal grain diameter is mixed with a secondary oxide 102 selected from among MgO, CaO, Y2 O3 , Sc2 O3 , CeO2 , etc. The resultant zirconia alloy powder 104 is filled into a metallic mold in the presence of a binder in a filling ratio of (2.5-3.5):1 and an untreated compact 106 is formed by compression under 10,000-30,000psi pressure for 10-60sec. The surface of the untreated compact 106 is coated with a boron carbide slurry and the coated compact is dried or dewaxed and fired at 1,200-1,600 deg.C for 1-3hr under 69-207MPa pressure in an inert atmosphere. By this firing, a core 114 of a tetragonal zirconia alloy is coated with a shell 116 of zirconium boride. |
