Microstructure and phase transformation behavior of Al2O3-ZrO2 under microwave sintering

Zirconia is an inorganic, nonmetallic material with excellent properties. However, the brittleness of the zirconia, resulting from the thermal performance during the heating and cooling process, seriously limits the application of zirconia in the metallurgical, military, and aerospace industries. Al2O3 doped ZrO2 was developed to improve the potential material's toughness. This paper studied the evolution of the surface functional groups, phase composition, toughening mechanism, and particle morphology of Al2O3 doped ZrO2 during the heating process. Especially microwave heating was selected as the heating method during the experiments to save energy con-sumption. The results showed that the phase transition temperature was reduced by the microwave sintering technique, which also promoted the transformation between the m-ZrO2 and t-ZrO2, advancing the crystallinity and structural properties of the samples. The specific surface area shows a positive relationship with the mi-crowave heating temperature, while the particle size of the powder decreased with the temperature increase. The optimized sintering effect appears at 1000 degrees C in the studied roasting temperature range (800 degrees C-1200 degrees C) for Al2O3-ZrO2 powders. With the optimized sintering temperature, the void of the granular zirconia material was controlled, and the best micromorphology was obtained. In practical production, the application of microwave sintering and alumina doping is beneficial to saving costs and protecting the environment.

Automated summary

This study investigates the evolution of surface functional groups, phase composition, toughening mechanism, and particle morphology of Al2O3 doped ZrO2 during the heating process. Microwave heating was found to lower the phase transition temperature, promote transformation between m-ZrO2 and t-ZrO2, and improve crystallinity and structural properties of the samples. The specific surface area was positively correlated with microwave heating temperature, while particle size decreased with temperature increase. The optimal sintering temperature for Al2O3-ZrO2 powders was found to be 1000 degrees C. Microwave sintering and alumina doping are beneficial for cost-saving and environmental protection in practical production.