Preparation, mechanical, and leaching properties of CaZrO ₃ ceramic cores

Abstract The CaZrO ₃ ceramic core materials with excellent mechanical and chemical properties were successfully prepared using single‐phase CaZrO ₃ powders. Effects of particle size ratio and sintering temperature on the mechanical and chemical properties of CaZrO ₃ ceramic core materials were researched. The chemical property was analyzed by leaching research of core materials in 10 wt% and 20 wt% HNO ₃ solution at the boiling point. Results showed that the suitable particle size ratio was important for the preparation of CaZrO ₃ ceramic core materials with excellent comprehensive properties. The addition of fine particles in ceramic core materials promoted the densification process owing to the framework formed by coarser particles and sintering neck formed by fine particles between coarse particles, which was beneficial for further improving their bending strength. When the content of particles with 200 mesh size was 80wt%, the highest bending strength was obtained, 54.38 ± 5.28 MPa. The porosity was 17.45% and the volume density was 3.86 g/cm ³ . The increasing sintering temperature increased the densification of CaZrO ₃ ceramic core materials by offering the sintering driving force, further leading to the improvement of bending strength. When the temperature was 1650℃, at the 20% content of particles with 200 mesh size, the highest bending strength of CaZrO ₃ cores reached 51.01 ± 5.18 MPa. Meanwhile, the porosity was 18.65% and the volume density was 3.83 g/cm ³ . Additionally, the CaZrO ₃ samples could be effectively leached in 10 wt% HNO ₃ solution. Therefore, CaZrO ₃ materials with good mechanical and leaching properties were believed to be a suitable candidate for ceramic core materials in the investment casting of alloys with high melting point.