Nanosized alumina from boehmite additions in alumina porcelain: Part 2: Effect on material properties

The influence of boehmite gel additions on the green and sintered properties of alumina porcelain is investigated. Green bodies are reinforced in the presence of gel through the building of hydrogen bonds within porcelain mixtures. The particular reactivity of this system leads to shrinkage inhibition and densification problems during sintering. Adjusting the formulation of these materials slightly modifies phase formation during thermal cycles but allows good densification because of extra glass production. Sintered samples have undergone thermomechanical tests: using boehmite gel additions increases both bending strength and thermal shock resistance of alumina porcelains by shifting the size of residual pores towards lower diameters and enhancing mullitisation.