Enhanced electrical properties of BNKT-BMN lead-free ceramics by CaSnO₃ doping and their bioactive properties

There is an increasing interest in using piezoelectric materials, including lead-free piezoceramics for medical applications. As a result, more attention has been placed on investigating the biological properties of these materials. In this research experiment, electrical, mechanical, and biological properties of lead-free 0.99Bi_0.5(Na_0.8K_0.2)_0.5TiO₃-0.01Bi(Mg_2/3Nb_1/3)O₃ or 0.99BNKT-0.01BMN doped with CaSnO₃ (CSO) were investigated. The samples were synthesized by a modified solid-state reaction technique. X-ray diffraction (XRD) analysis showed that the samples presented a single perovskite phase. After adding CSO, electrical properties such as energy storage density (maximum W _rec = 781 mJ cm^-3) and electro-strain properties (maximum S _max = 0.3%) were improved at room temperature. Mechanical properties were also enhanced for the modified samples with maximum values for Vickers hardness (H _V) and elastic modulus (E _m) of 6.11 GPa and 135 GPa, respectively. Biological assays for cytotoxicity, indicated that the samples had high cell viability, while the simulated body fluid (SBF) test revealed a moderate apatite forming ability. The samples were then coated with hydroxyapatite to improve their apatite-forming ability. The SBF testing for the coated samples showed that the coated samples had high apatite-forming ability. The obtained results pointed to the possibility of ceramics being used for multifunction electrical devices at room temperature and biomaterial applications.