Effect of Al_2O_3 addition on the mechanical properties of biocompatible ZrO_2-Al_2O_3 composites

摘要

In this work, the effects of alumina additions on the properties of the ZrO_2-Al_2O_3 ceramic composites were investigated. Samples of ZrO_2 with Al_2O_3 additions varying between 0 and 30wt-% were prepared. The powder mixtures were milled, compacted by uniaxial cold pressing and sintered at 1600℃, in air, for 2 hours. The sintered samples were characterized by their relative density, phase composition and microstructure. As mechanical properties at room temperature, their Vickers hardness and fracture toughness were determined: In all sintering conditions and Al_2O_3 amounts, the samples presented relative density higher that 99%. The Al_2O_3 addition produces a linear increase of the hardness, reaching values between 1350 and 1610 HV for the addition of 0 and 30% of alumina, respectively. The fracture toughness was near to 8 Mpam~(1/2) in all conditions. The phase composition, microstructure and relative density were correlated in order to interpret the mechanical properties obtained.