Influence of calcia addition on sintering behaviour of zirconia

The influence of the amount of calcia addition on the sintering characteristics of zirconia and the physical properties of the sintered products has been studied. It was noticed that the optimum amount of calcia addition was 0.50 to 0.75 wt % to obtain high density without cracking of the ware. Higher additions of calcia invariably resulted in lowered density. The extent of stabilization was studied by x-ray diffraction and dilatometry. Though the stabilization (conversion to the cubic structure) was not obtained with 0.50 and 0.75 wt % addition of calcia, and the presence of hysteresis loops in the dilatometric curves were noticed in the samples sintered at temperatures up to 1500degC, they were found to have sufficient thermal shock resistance to be used as refractory ware. (author)