Effect of BaTiO3 particle size and distribution on the BaTiO3-3Y-TZP interface reactivity of bioactive ceramic composites

The present study investigates the effect of BaTiO 3 particle size and its distribution on the interfacial reactivity between BaTiO 3 and 3Y-TZP, for ceramic-based biomedical composites, where bioelectric tissue stimulation, similar to the piezoelectric materials present in natural bone and soft tissues, is useful for implant integration in biological tissues. Two BaTiO 3 particle sizes were tested, namely 1.3 μm and 3.1 μm, and in the case of BaTiO 3 particles with 1.3 μm, the effect of agglomerated and homogeneously distributed particles was assessed. The specimens produced were characterized by grain size, surface roughness, crystallography, and bulk relative density. To further evaluate the effect of the composite shrinkage-induced stresses on the BaTiO 3 /3Y-TZP interfacial reactions generated during densification, BaTiO 3 green compacts were also placed on the surface of the 3Y-TZP specimen. The results were compared with the BaTiO 3 particles embedded in the composite and subjected to internal shrinkage-induced mechanical stresses during densification. Results showed that BaTiO 3 and 3Y-TZP coexisted without complete dissolution, even at high sintering temperatures (1500 °C). The BaTiO 3 particle size and distribution had a major influence on the interfacial reaction during sintering. Small single non-agglomerated particles remained stable during sintering, with the composite retaining the presence of two distinct phases. Bigger particles, and small agglomerated particles, that were equivalent to bigger particles, promoted a higher interfacial reaction between the materials, leading to increased porosity and surface roughness, and reduced relative density.