Sintering behavior and mechanical properties of calcium phosphate–alumina composite porous scaffolds

Abstract

A novel composite ceramic porous scaffold consisting of calcium phosphate ceramics and alumina was fabricated using the gelation freeze-casting method. Notably, the temperature is important for the simultaneous sintering of different ceramics. A denser microstructure with better mechanical properties was obtained at a sintering temperature of 1450 °C. At sintering temperatures above 1500 °C, liquid-phase sintering occurred, resulting in substantial changes to the microstructure. The addition of alumina accelerated the phase transformation of hydroxyapatite into α-tricalcium phosphate. Furthermore, it was suggested that a mixture of calcium phosphate and alumina was formed at a sintering temperature of 1550 °C. Additionally, Young’s modulus and compressive strength increased with increasing sintering temperature. The increase in compressive strength was due to the smoothening of the microstructural surface via liquid-phase sintering.