Effect of Titanium Addition on Thermal Stability of Hydroxyapatite /zirconia Nanocomposite

Abstract

HA/ZrO2 composite nanpowder with various addition of titanium (0.2-2.4wt%) were synthesized via wet chemical method using ZrOCl2.8H2O, H3PO4, Ca(OH)2 and tetraethylorthotitanate as precursor materials. The composites were then sintered at 900-1200ºC for 2h, respectively. Effect of titanium addition to the composite on the phase composition and thermal stability during thermal treatment was investigated. The results suggested that as the sintering temperature increased from 900°C to 1200ºC and with the addition of titanium to the composite below 0.8wt%, main phases were HA and ZrO2. As the sintering temperature increased to 1200°C and with the addition of titanium to the composite above 0.8wt%, main phases were HA, ZrO2 and a small amount of dicalcium phosphate (DCP). There were still no tricalcium phosphate (β-TCP) and CaZrO3 phases observed, which indicated that the addition of titanium restrained decomposition of HA and thermal reaction between HA and ZrO2. It also suggested that the addition of 0.8wt% titanium to the composite was optimum for producing HA/ZrO2 composite nanopowder with expected main phases. With the addition of 0.8wt% titanium to the composite, SEM images showed that the individual particles of the two materials were still visible, which also implied that the reaction between HA and ZrO2 did not occur.