Sintering mechanism and grain growth in CaCu3Ti4O12 ceramics

In this work, a study of the densification of CaCu3Ti4O12 (CCTO) ceramics during conventional sintering process is presented. Dilatometric study was conducted in detail to find out which diffusion mechanism is responsible for densification. Based on the shrinkage curves, it was shown that densification is mostly controlled by grain boundary diffusion. The microstructure evolution of CCTO during conventional sintering was studied through the sintering trajectory, which corresponds to a unique relationship between grain size and density. According to SEM analysis, it was shown that abnormal grain growth takes place for samples sintered at high temperature stage with density > 80% of the theoretical density. Finally, the Master Sintering Curve (MSC) method was also used to characterize the densification process of CCTO and estimate the apparent sintering activation energy (Q = 730 kJ mol(-1)).