The structure-property-processing relationship for sintered yttria-stabilized zirconia (YSZ)/alumina bioceramics

The objective of this research is to study the effects of alumina addition on the microstructure-mechanical property relationship and sintering behavior of yttria (3 mol%)-stabilized zirconia (YSZ) ceramics. Well-dispersed YSZ/Al ₂O₃ ceramics containing 10-40 wt.% Al₂O ₃ were prepared by solid state reaction method. The relative density, average grain size, lattice parameters, microhardness, and fracture toughness of YSZ/Al₂O₃ ceramics system sintered in the temperature range of 1250∼1500°C as a function of Al₂O₃ content were investigated. Experimental results showed that the ceramics with high Al₂O₃ content and low sintering temperature tended to reveal low bulk densities. But the Al₂O₃ content dependence on relative density for YSZ/Al₂O₃ ceramics becomed deminishing when increasing the sintering temperature. Dense ceramics with composition of (80/20) (YSZ/Al₂O₃) and sintered at temperature of 1400°C and 1450°C revealed the optimal Vickers hardness and fracture toughness properties. These ceramics with high Al₂O ₃ content tended to reveal small grain sizes. The high sintering temperature governs the slow grain growth and high hardness in materials indicating the good correlation between microstructure of fabricated dense and mechanical properties.