Decomposition mechanism, sintering process and properties of zircon ceramics: Role of CaO, MnO and Cr2O3

In this paper, the influence of the CaO, MnO and Cr 2 O 3 on the decomposition mechanism, sintering process and properties of zircon ceramics were studied. The X-ray diffraction (XRD), microstructure, pore characteristics and densification behaviour were used to evaluate the decomposition mechanism and the properties of the zircon ceramics. The results indicated that the addition of CaO could accelerate the decomposition rate of zircon by the formation of the solid solution, which caused the appearance of the large pores to weaken the properties. Cr 2 O 3 could limit the sintering process, decomposition reaction and grain growth of zircon to degrade the performance of the zircon ceramics. The addition of MnO promoted the grains growth and had no effect on the decomposition of zircon by the formation of solid solution. Thus, the zircon ceramics with MnO rendered an optimal bulk density and an apparent porosity of 3.53 g/cm 3 and 22.5%, a high compressive strength of 212.6 MPa sintered at 1550 °C.