In this study, the effects of aging on the crystalline phases, crystallite sizes and sintering properties of coprecipitated Al2O3- ZrO2 powders are investigated using thermogravimetry (TG), differential thermal analysis (DTA), X-ray diffractometry (XRD), dilatometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Coprecipitated Al2O3- ZrO2 powder aging in the solution promoted the dissolution and reprecipitation process, which resulted in the boehmite structure subsequently transforming into bayerite. The densification and microstructural development of the coprecipitated Al2O3-ZrO2 powders were dependent upon the aging time which shifted the θ→α-Al2O3 phase transformation to a higher temperature, lowered the crystallite growth rate, and prevented the occurrence of intragranular ZrO2 particles during sintering.

Keywords: Ceramics, coprecipitation, Al2O3-ZrO2, Phase transformation, Sintering