Synthesis, Characterization, and Numerical Modeling of Hydroxyapatite–Barium Titanate Composites for Piezoelectric Performance Evaluation

Abstract

Bone exhibits essential electroactive properties for regeneration, arising from hydroxyapatite crystals, collagen fibres, and body fluid interactions under biomechanical stimuli. Thus, current research focuses on the development of hydroxyapatite-barium titanate (HA/BT) composites to mimic innate electroactive characteristics of bone, utilizing the HA’s biocompatibility and BT’s piezoelectric properties. Despite their promise, HA/BT composites remain in the research stage, and experimental evaluation is hindered by high costs, time-intensive procedures, ethical concerns, and purity challenges. This study employs simple, cost-effective synthesis techniques, solid-state reaction for BT and wet chemical precipitation for HA and produces HA/BT composites at varying volume fractions, alongside Finite Element Analysis (FEA) via a Representative Volume Element framework (RVE) to predict effective dielectric and piezoelectric properties. The crystalline structure and microstructural analysis confirmed the existence of pure HA and BT phases with homogeneous BT dispersion in the HA matrix. Dielectric measurements showed relative permittivity of the composite increasing with BT volume fraction, aligning closely with FEA predictions to validate the model. Further, simulations revealed non-linear enhancement in piezoelectric coefficients, with rapid divergence beyond 40% BT volume content, indicating percolation onset and transition from 0-3 to quasi 3-3 connectivity for improved stress transfer and polarization tailored to match native bone.