| 摘要 |
PURPOSE:To stably produce zirconia ceramics in partially stabilized zirconia powder blended with magnesia by specifying a-axis among lattice constant of zirconia of monoclinic system. CONSTITUTION:This zirconia powder contains 6-12mol% MgO, has a crystal phase consisting essentially of monoclinic system and >=5.148Angstrom a-axis among its lattice constants. Since this zirconia powder provides high sintering density and has stable sintering characteristics, ceramics having excellent high- temperature mechanical strength, thermal shock resistance and stability of these properties can be produced. The powder is obtained by blending zirconia powder with MgO powder and grinding or calcining zirconia-magnesia two components powder obtained by co-precipitation method at 700-1,450 deg.C and grinding. When the a-axis has <5.148Angstrom , the powder is repeatedly calcined at 1,170-1,450 deg.C wherein zirconia of tetragonal system is stable so that diameter of crystallite and uneven strain of crystal are increased and the a-axis is made >=5.148Angstrom . |
