Influence of sintering temperatures on hardness and Youngʹs modulus of tricalcium phosphate bioceramic by nanoindentation technique

Nanoindentation experiments on tricalcium phosphate (TCP) bioceramic sintered at different temperatures were performed with a Berkovich indenter for determining hardness and elastic modulus from load and displacement data. The hardness and Youngʹs modulus increased with the increase of sintering temperature up to 1300 °C, but the Youngʹs modulus decreased with the further increase of sintering temperatures at 1400 and 1500 °C. X-ray diffraction (XRD) results showed that the transformation β→α-TCP happened when the sintering temperature reached around 1400 °C, which contributed to the decreases of modulus at 1400 and 1500 °C. Scanning electron microscopy (SEM) results showed that the sintering effect was improved with the increase in sintering temperature.