Fabrication of Hydroxyapatite-incorporated ZrO2-20 wt% Al2O 3 by Spark Plasma Sintering and Characterization

Abstract

Yttria-stabilized tetragonal zirconia/20 wt% alumina (TZP-3Y20A) composites were fabricated by spark plasma sintering at various sintering temperatures over the range of 1000—1400°C. Hydroxyapatite (HA) additive was added in volume fractions of 10—50% in order to increase the biocompatibility of the composite. The densification behavior of the TZP-3Y20A composite and that of the composites with HA were investigated. In the case of TZP-3Y20A composites, the density increases steadily with temperature and reaches a maximum value of 97.8% of the theoretical density at 1400°C. The solution interface formed between zirconia (ZrO2) and alumina (Al 2O3) strengthens the bond between ZrO2 and Al 2O3 grains and facilitates densification. In the case of TZP-3Y20A/HA composites, sintering at 1400°C led to the formation of tricalcium phosphate in the samples, which resulted from the decomposition of HA due to its limited thermal stability at high temperature; no reaction was observed between ZrO2 and HA. The addition of HA imposes a barrier effect on the diffusion between ZrO2 and Al2O3 grains, thus limiting the grain growth of ZrO2 and Al2O 3.