Fused calcium zirconate for refractory applications

摘要

This article investigates dense CaZrO_3 produced by electric arc melting and compares it to solid state synthesized CaZrO_3 The fused CaZrO_3;;had a considerable lower porosity than the solid state synthesized material, however due to evaporation of some CaO during the electric arc melting the stoichiometric ratio of CaO/ZrO_2 was slightly smaller than one, resulting in the formation of cubic ZrO_2 as a second phase. To determine the local phase distribution the materials were investigated with EBSD in addition to integral XRD. The vibration polishing of the ceramics resulted in excellent EBSD patterns. Die pressed cylinders of the fused material led to a porosity as low as 14.3%. The linear thermal expansion coefficient from 25 °C to 1000 °C was 10.45 x 10~(-6) K~(-1). The cold isostatic pressing of larger crucibles resulted in higher porosity of 15.9-16.5%. The EBSD analysis and the cold isostatic pressed crucibles can be applied in corrosion tests for titanium melts.