Investigation of structural, dielectric, impedance, and mechanical properties of hydroxyapatite-modified barium titanate composites for biomedical applications

Abstract

Abstract This report presents the synthesis of pristine barium calcium titanate (BCT) and composite samples of [x(HA)–100 − x(BCT)]; (0 ≤ x ≤ 20) through solid-state reaction with microwave sintering. Hydroxyapatite (HA)–BCT composites have been developed to minimize grain growth, thereby boosting the material’s physical, mechanical, and electrical properties. The evaluated samples were examined for the Fourier transform-infrared spectra, and the results showed a correlation with the X-ray diffraction patterns. The real and imaginary dielectric permittivity was applied to determine the AC conductivity, and the findings indicate a drop in the frequency exponent values (S) from 1 to 0.67 for samples with x = 0. Similarly, for samples with x = 5, the value of S decreases from 0.90 to 0.55. For samples with x = 10, the value of S reduces from 0.7 to 0.54. Lastly, for samples with x = 20, the value of S decreases from 0.63 to 0.45. The exponent S and temperature relationship may be attributed to a thermal activation mechanism. The grains and grain boundary resistivity were estimated using a Cole–Cole plot, and the results showed that the grain boundary resistivity is higher in comparison to the resistivity exhibited inside the grains. This demonstrated the distinct electrical conductivity at the interfaces between the grains in comparison to the interior of the grains. The analysis of hardness indicates that the average hardness of the samples ranges from 5.22 to 4.77 GPa, which is maintained at different HA concentrations. The data suggest that this composite may have the potential to be a biomedically helpful substance.