Synthesis and phase evolution of a glass-ceramic biomaterial with near-eutectic composition of the pseudo-binary system diopside–tricalcium phosphate

Abstract

A glass-ceramic biomaterial with near-eutectic composition of the pseudo-binary system diopside (CMS2, CaMgSi2O6)–tricalcium phosphate [C3P, Ca3(PO4)2], with a weight composition of 61% CMS2–39% C3P, was synthesized by the so-called “petrurgic method”. Three different cooling rates (0.5, 1 and 2°C/h) were used through the mushy zone. The synthesized materials showed a microstructure consisting of β-C3Pss (solid solution of CMS2 in C3P) primary skeletal dendrites, with a peculiar comb-like morphology, and which were embedded in a matrix of lamellar CMS2–β-C3Pss eutectic phase. The matrix also presumably contained a small amount of CaO–SiO2 glass segregated during formation of the β-C3Pss phase. The cooling rate used through the mushy zone affected the microstructure and phase composition of the synthesized materials. The dendrites of the primary β-C3Pss phase became smaller and thicker with decreasing cooling rate, while the level of substitution of Mg for Ca (x) decreased and that of Si for P (δ) increased in the latter phase, and the CMS2/β-C3Pss weight ratio tended to increase slightly in the interdendritic matrix, with increasing cooling rate.