Defect Study of MgO-CaO Material Doped with CeO2

MgO-CaO refractories were prepared using analytical reagent chemicals of Ca(OH) 2 and Mg(OH) 2 as starting materials and CeO 2 as dopant, then sintered at 1650°C for 3 h. The effect of CeO 2 powders on the defect of MgO-CaO refractories was investigated. The sample characterizations were analyzed by the techniques of XRD and SEM. According to the results, with the addition of CeO 2 , the lattice constant of CaO increased, and the bulk density of the samples increased while apparent porosity decreased. The densification of MgO-CaO refractories was promoted obviously. In the sintering process, MgO grains grew faster than CaO, pores at the MgO-CaO grain boundaries decreased while pores in the MgO grains increased gradually, and no pores were observed in the CaO grains. The nature of the CeO 2 promoting densification lies in the substitution and solution with CaO. Ce 4+ approaches into CaO lattices, which enlarges the vacancy concentration of Ca 2+ and accelerates the diffusion of Ca 2+ .