Dilatometry as a tool to study a new synthesis for calcium hexaluminate

By using a wet chemical route, pure calcium hexaluminate (CA6) was yielded, significantly lowering the reaction temperature and shortening the synthesis time if compared to usual industrial procedures. owever, dilatometric studies performed on compacts made of the as-prepared powder, just after pre-heating at 450°C, has shown a superposition between sintering shrinkage and expansion related to CA2 formation, an intermediate phase formed during calcination and phase evolution to CA6. oupling of such opposite phenomena led to microcracking of the material, mainly if the heating rates (10°C min-1) were high. However, lower heating rates (1-5°C min-1) could quite avoid microcracking but also limit densification.