Effect of Sintering Temperature on the Properties of Titanium-AluminaHydroxyapatite Composite Prepared by Spark Plasma Sintering

In the present study, spark plasma sintering (SPS) technique was used to fabricate Ti-Al۲O۳-HA composite. Powders were sintered at ۴۰ MPa pressure for ۵ min at ۱۲۰۰ and ۱۳۰۰۰C. Microstructural characterisation was carried out using scanning electron microscopy (SEM). Density, hardness, electrochemical impedance and polarization test were performed to evaluate the properties of the samples. The results showed that by increasing the sintering temperature from ۱۲۰۰ to ۱۳۰۰ ۰C the density of the samples increases and the apparent prosity decreases. Also with increasing temperature the hardness of the samples increased from ۵۲۸HV to ۶۱۲HV. The result of electrochemical impedance test showed the polarization resistance of the sample enhanced from ۲۲۲ Ωcm۲ to ۹۹۶ Ωcm۲. Furthermore, according to polarization measurements, the corrosion current density was reduced from ۱۶.۳۵ μA/cm۲ to ۱.۴۷ μA/cm۲. The improvement in the corrosion resistance was attributed to the reduction of prosity and the formation of stronger passive film on the sample surface with increasing sintering temperature.