Microstructural evolution and interfacial reactions between Ti and ZrO 2 /CaTiO 3 composites

Various proportions of ZrO 2 /CaTiO 3 powders were mixed and hot pressed at 1500°C/30 min for Ti casting. The hot‐pressed ZrO 2 /CaTiO 3 composites were reacted with pure Ti at 1700°C/10 min in Ar. The interfacial reaction between Ti and ZrO 2 /CaTiO 3 composites was investigated through X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. The ZrO 2 /CaTiO 3 composites with less than 10 vol.%, CaTiO 3 , and a minor amount of residual TiO 2 were found. When the content of ZrO 2 was increased to larger than 10 vol.%, two Ca 2 Zr 5 Ti 2 O 16 and CaZrTi 2 O 7 phases appeared in the composites. The amount of CaTiO 3 and CaZrTi 2 O 7 in the composites gradually decreased as the amount of ZrO 2 increased. When Ti came in contact with ZrO 2 /CaTiO 3 composites with less than 10 vol.% ZrO 2 , the resulting eutectic reaction produced a liquid phase and induced melting. When ZrO 2 was increased to more than 30 vol.% in the composites, Ca 2 Zr 5 Ti 2 O 16 and CaZrTi 2 O 7 changed completely to CaZrO 3 , Ti 2 O, CaO, and ZrO 2 . With more than 30 vol.% ZrO 2 , no other reaction phases occurred in the Ti side after contact with the ZrO 2 /CaTiO 3 composites, which is conducive for producing ceramic composites for Ti casting applications.