Stability optimisation of CaO-doped partially stabilised zirconia by microwave sintering

Abstract

Abstract In this study, the stability of CaO-doped partially stabilised zirconia was optimised by microwave sintering at 950\u202f°C with holding times between 1 and 4\u202fh. The sintered products are potential refractory ceramics having applicability in high-temperature processes in the metallurgical industry. Thermogravimetry/differential scanning calorimetry (TG/DSC) analysis was used to investigate the thermal degradation of the material during the sintering process. The sintered products were characterised by X-ray diffraction (XRD), Raman spectroscopy, and particle size analysis to evaluate the transformation of polymorphs. The characterisation results indicated that the proposed sintering process was beneficial for improving the crystallinity of the material. The stability value of the as-received zirconia, which was 88.14%, increased upon sintering. That is, the stability values of the sintered products obtained with holding times of 1\u202fh, 2\u202fh, 3\u202fh, and 4\u202fh were 93.72%, 95.35%, 94.72%, and 95.12%, respectively. Additionally, stabilised tetragonal zirconia was formed successfully, and its particle diameter was smaller than that of the as-received zirconia.