Processing and properties of bioinert ceramic materials in the system Al sub 2 O sub 3 -TiO sub 2 -SiO sub 2

Very fine and sinterable ceramic powders (100-600 nm) in the system Al sub 2 O sub 3 -TiO sub 2 -SiO sub 2 were obtained by the method of cohydrolysis from organo-metallic precursors. Isostatically pressed powder compacts could be densified to a relative high density (approx = 92% th. density) at relative low temperatures (1320-1380 deg C). The technical coefficient of thermal expansion was measured by dilatometry. The value obtained (8.8 10 exp -6 1/ deg C) corresponds closely to that of Ti, opening the possibility to use Al sub 2 O sub 3 -TiO sub 2 -SiO sub 2 ceramics to fabricate metal/ceramic composite implants. The measured mechanical properties of dense sintered Al sub 2 O sub 3 -TiO sub 2 -SiO sub 2 material: Young's modulus, flexure strength and compression strength, are higher than those of pure TiO sub 2 . Highly porous Al sub 2 O sub 3 -TiO sub 2 -SiO sub 2 ceramics (Papprox = 65%) were obtained by the method of evaporation of hydrogen peroxide. These materials exhibited interconnected porosity and their properties, particularly the Young's modulus, resulted very similar to those of bone, which is an important pre-requisite for the design of surgical implants.