Sintering Kinetics at Constant Rates of Heating: Mechanism of Silica‐Enhanced Sintering of Fine Zirconia Powder

Abstract

The sintering behavior of 3 mol% Y2O3‐doped ZrO2 powders with and without a small amount of SiO2 was investigated to clarify the effect of SiO2 addition on the initial sintering stage. The shrinkage behavior of a powder compact was measured under constant rates of heating (CRH). The sintering rate increased remarkably with the addition of a small amount of SiO2. The apparent activation energy (nQ) and apparent frequency factor , where n is the order depending on the diffusion mechanism, were estimated at the initial sintering stage by applying the sintering‐rate equation to the CRH data. The diffusion mechanism changed from grain‐boundary diffusion (GBD) to volume diffusions (VD) on SiO2 addition, and both nQ and increased with the GBD→VD change. It is, therefore, concluded that the sintering rate increases by SiO2 addition because the increase in rather than nQ is predominant.