| 摘要 |
PURPOSE:To easily and inexpensively obtain a zirconia refractory improved in strength and service life by mixing calcium salt with coarse grains of electric arc stabilized zirconia and also with monoclinic zirconia and then subjecting the resulting mixture to direct compacting and sintering. CONSTITUTION:A mixture is prepared by adding and mixing calcium salt into 90-50 pts.wt. coarse grains of electric arc stabilized zirconia and 50-10 pts.wt. monoclinic zirconia of <=15mu average grain size by 5-9wt.% expressed in terms of CaO based on the monoclinic zirconia, and the above mixture is directly compacted and sintered. It is necessary that the powdered monoclinic zirconia occurring in nature used as a starting raw material is pulverized to <=15mu average grain size. Since sintering proceeds at relatively low temp. and the sintered compact shows sufficient properties even it sintering is performed at 1450 deg.C, sintering at lower temp. is possible. However, in view of reheat shrinkage, etc., sintering at >=1400 deg.C is preferred. |
