Application of response surface methodology (RSM) for optimization of the sintering process of preparation calcia partially stabilized zirconia (CaO-PSZ) using natural baddeleyite

Response surface methodology (RSM) was successfully applied to process of preparation calcia partially stabilized zirconia (CaO-PSZ). Besides that, natural baddeleyite was used as starting materials instead of chemical pure zirconia. The pressureless sintering process was optimized by the application of RSM. The independent variables, which had been found as the most effective variables on the relative density and bending strength by screening experiments, were determined as holding time, sintering temperature and heating rate. Two quadratic models were developed through RSM in terms of related independent variables to describe the relative density and bending strength as the responses. Based on contour plots and variance analysis, optimum operational conditions for maximizing relative density and bending strength, at cooling rate of 3 °C/min, were 1540 °C of sintering temperature, 5 h of holding time and heating rate of 3 °C/min to obtain 98.57% for relative density and 165.72 MPa for bending strength.