ABSTRACTProduction of porous alumina ceramics by capsule-free hot isostatic pressing of bimodally distributed alumina powders with a large size difference (>10) and reaction sintering of alumina powder and boron oxide formed by oxidation of boron nitride during sintering were investigated. The influence of the composition of bimodally distributed alumina and alumina-boron nitride mixture of powders on open and closed porosity was studied.HIP treatment at 1600°C provided sintering of only fine-grained powder. A small loss in open porosity (about 4%) is observed with increasing of the fine powder weight fraction up to 0.4.Reaction sintering of a fine-grained alumina powder with boron oxide gives significant (about 30%) increase of open porosity.
