Influence of sintering technology on structure and properties of alumina composite ceramics containing barium hexaaluminate

Composite ceramics based on alumina with 15 wt% barium hexaaluminate obtained by hot pressing, pressureless and spark plasma sintering have been studied. The highest relative density (97.5 $\pm$ 0.2% of theoretical) was obtained for the composite sintered by hot pressing. The smallest average size of Al$_2$O$_3$-grains (0.90 0.06 $\mu$m) is observed for the material obtained by pressureless sintering. The highest fracture toughness (5.73 and 5.74 MPa $\cdot$ m$^{1/2}$) possesses the materials obtained by pressureless sintering and hot pressing.