Dielectric and Pyroelectric Properties of HAp-BaTiO₃Composites

Abstract

In order to mimic the electrical properties of natural bone, the present work investigated the dielectric, AC conductivity, pyroelectric and piezoelectric properties of HA-40 wt% BaTiO 3 (HA-26 vol% BaTiO 3 ) and HA-60 wt% BaTiO 3 (HA-44 vol% BaTiO 3 ) composites. Multistage spark plasma sintering was used to achieve the desired combination of properties. The electrical parameters were measured as a function of temperature and frequency. The values of dielectric constant and loss for both the developed composites, measured at room temperature and at 1 KHz frequency was 21, 38 and 0.01 and 0.02, respectively. The AC conductivity for both the composites is found to be of the order of 10 −10 and 10 −9 ( cm) −1 , measured under similar conditions. Activation energy calculated from σ ac vs. temperature plot for HA-40 wt% BaTiO 3 is 0.50 eV. The room temperature pyroelectric coefficients for both the compositions are 2.35 and 21 µC/m 2 K, respectively. The piezoelectric coefficient values (d 33 ) for both the compositions are 0.9 and 1 pC/N, respectively. The observed values of electrical parameters closely resemble with that of the natural human bone.

Hydroxyapatite‐barium titanate piezocomposites with enhanced electrical properties

“…The room temperature values of dielectric permittivity and loss for highly densified HB40, and HB60 composites (98%) are 21, 38 and 0.01 and 0.02 respectively. In the present work, we have demonstrated that the obtained values of the sintered HA‐BT piezocomposites are significantly higher (nearly double ‐ie about 40 for HB40 and 70 for HB60‐ losses at 10 kHz are about 0.02) than the reported values in the literature . Remarkably, whatever the BT content, the dielectric permittivity decreases with the increase in BT grain size.…”

“…HA piezocomposites of alkali niobates is reported by Dubey et al to increase the electroactivity and to decrease the sintering temperature required to densify the piezocomposites. However, the room temperature values of the dielectric permittivity and loss for both of the developed composites, 60HA‐40BT, and 40HA‐60BT, are 21 and 38 and 0.01 and 0.02, respectively. Significant improvement was recently reported by Dubey et al in HA‐BT composites sintered at low temperature, using spark plasma sintering (SPS) multi‐step cycle.…”

Flow Cytometry Analysis of Cytotoxicity In Vitro and Long‐Term Toxicity of HA‐40 wt% BaTiO3 Nanoparticles In Vivo

“…The in vivo study carried out in dogs confirms the extensive new bone growth near to the HA‐BaTiO 3 samples as compared to monolithic HA . Piezoelectric coefficient of HA‐40 wt% BaTiO 3 (HA‐40BT) and HA‐60 wt% BaTiO 3 was measured as 0.9 and 1 pC/N, respectively, which is comparable to the bone (piezoelectric coefficient of 0.7 pC/N) . In a different work, piezoelectric coefficient of HA‐70 wt% BaTiO 3 and HA‐90 wt% BaTiO 3 has also been reported as 1.2 and 2.8 pC/N, respectively …”

“…The multistage spark plasma sintering [Dr. Sinter Lab SPS5S (Now, FUJI‐SPS), Fuji Electronic Industrial Co., Ltd., Kawasaki, Kanagawa, Japan] technique was used to sinter the HA‐40 wt% BaTiO 3 composition at 950°C. Details of heating cycle and procedure have been reported elsewhere . The sintered HA‐40 wt% BaTiO 3 samples were crushed in to fine particles using hand mortar followed by ball‐milling for 16 h in toluene medium.…”

“…Barium titanate (BaTiO 3 ; BT) containing HA composites are being investigated for bone tissue engineering application due to the piezoelectric property of BaTiO 3. In addition, piezoelectricity leads to the improvement in toughness due to dissipation of crack tip energy. In this perspective, Jianqinq et al .…”