Dielectric and electrical conductivity properties of multi-stage spark plasma sintered HA–CaTiO3 composites and comparison with conventionally sintered materials

One of the different issues limiting the wider application of monolithic hydroxyapatite (HA) as an ideal bone replacement material is the lack of reasonably good electrical transport properties. The comprehensive electrical property characterization to evaluate the efficacy of processing parameters in achieving the desired combination of electroactive properties is considered as an important aspect in the development of HA-based bioactive material. In this perspective, the present work reports the temperature (RT-200°C) and frequency (100Hz–1MHz) dependent dielectric properties and AC conductivity for a range of HA–CaTiO3 (HA–CT) composites, densified using both conventional pressureless sintering in air as well as spark plasma sintering in vacuum. Importantly, the AC conductivity of spark plasma sintered ceramics [∼upto 10−5(Ωcm)−1] are found to be considerably higher than the corresponding pressureless sintered ceramics [∼upto 10−8 (Ωcm)−1]. Overall, the results indicate the processing route dependent functional properties of HA–CaTiO3 composites as well as related advantages of spark plasma sintering route.