Theoretical analysis of experimental densification kinetics in final sintering stage of nano-sized zirconia

摘要： The experimental densi?cation kinetics of 7.8 mol% Y2O3-stabilized zirconia was analyzed theoretically during isothermal sintering in the ?nal stage. By taking concurrent grain growth into account, a possible value of the grain-size exponent n was examined. The Coble’s corner-pore model recognized widely was found not to be applicable for explaining the densi?cation kinetics. The corner-pore model of n = 4 shows a signi?cant divergence in the kinetics at di?erent temperatures. Microstructural observation shows that most pores are not located at grain corners and have a size comparable to the surrounding grains. The observed pore structure is similar to the di?usive model where single pore is surrounded by dense body. The di?usive model combined with theoretical sintering stress predicts n = 1 or n = 2, which shows a good consistence to the measured densi?cation kinetics. During sintering of nano-sized powder, it is found that the densi?cation kinetics can be explained distinctively by the di?usive single-pore model.