Effect of Yttria on the Phase Formation and Sintering of HA-Al2O3 Biocomposites

Hydroxyapatite is very-well known as the main component of hard tissues and, as such, it has attracted much attention by researchers in the recent decades. This study was aimed to present the characterization of Y2O3 doped 50 wt.% hydroxyapatite -50 wt.% Al2O3 composite materials fabricated at relatively high temperature of 1600 degrees C. Hydroxyapatite powder was obtained from bovine bones via calcination and ball milling technique. Fine powders (<= 1 mu m) of hydroxyapatite/Al2O3 were admixed with 0.5 and 1 wt.% Y2O3 powders. Powder compacts were sintered at 1600 degrees C for 4 h in air atmosphere. The field emission scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction studies following the relative density measurements were conducted. Moreover, the microhardness was studied as the mechanical property of sintered samples. The effect of increasing Y2O3 content on surface morphology, elemental distribution and phase evaluation was investigated in hydroxyapatite/Al2O3 biocomposite materials. It was found that by increasing Y2O3 content, the relative density increased up to 98.8%, while the hardness increased to 863 HV(0.2). The main phases, which were found, are Hibonite -CaO(Al2O3)(6) and beta-tricalcium phosphate -Ca-3 (PO4)(2), according to X-ray diffraction pattern.