Formation of discrete β-Ca3(PO4)2-Y2O3 phase mixtures influenced through elevated heat treatments

Abstract

The possibility to attain a discrete β-tricalcium phosphate (β-Ca3(PO4)2)/yttria (Y2O3) composites starting from the solution based precursors were deliberated. The sequential steps of calcination temperature and the associated phase changes to yield a pure form of β-Ca3(PO4)2/Y2O3 were elaborated through a wide range of analytical techniques. Alteration in the precursor concentrations yielded β-Ca3(PO4)2/Y2O3 composite with a wide range of individual compositional ratios. The advanced crystallization of Y2O3 is evident whereas the delayed formation of β-Ca3(PO4)2 is mainly contributed by the sluggish phase transition of calcium deficient apatite. The formation of pure β-Ca3(PO4)2/Y2O3 composite is attained only at 1500 °C, where Y3+ prefers accommodation at the Ca2+(1), Ca2+(2) and Ca2+(3) sites of β-Ca3(PO4)2 structure. The selective mechanical properties determined from the indentation technique implied a detrimental role of Y2O3 in the resultant mechanical data of β-Ca3(PO4)2/Y2O3 composites.