Microstructure and mechanical properties of ceramics prepared under simulated oxygen-enriched or oxy-fuel atmosphere

Different simulated sintering atmospheres, such as conventional air, oxygen-enriched air, and oxy-fuel atmosphere were utilized to prepare ceramic specimens. The effects of sintering atmosphere and Al2O3 content on the microstructure and properties of the ceramic samples were investigated. Increasing the O2 concentration in the simulated sintering atmosphere enhanced the crystallization. An optimized microstructure, resulting in improved bending strength, Vickers hardness, and bulk density was obtained through an increased O2 concentration in the simulated sintering atmosphere. Compared to ambient air, oxygen-enriched air or oxy-fuel atmosphere showed superior sintering performances, leading to ceramics with better mechanical properties and denser microstructures. However, an increase in the Al2O3 content led to the degradation in the mechanical properties of the ceramics, mainly due to the blocking effect of AlO6 groups.