Papers by Author: Vitaly Yu. Topolov

Abstract: This paper reports experimental and modelling results on the manufacture and properties of hydroxyapatite / BaTiO3 ceramic composites and studies their electromechanical properties with ferroelectric ceramic volume fractions, mFC ³ 0.7. In these composites the bio-active properties of hydroxyapatite are combined with the electromechanical properties of a perovskite-type ferroelectric BaTiO3 ceramic in an attempt to create a novel polarised bone-substitute material. Experimental results of the volume fraction dependences of the effective piezoelectric coefficients * 31 d (mFC), * 33 d (mFC) and dielectric permittivity e *s 33 (mFC) of stress free samples are analysed within the framework of a modified model of a porous piezo-active material that is described in terms of 1–3 (one-dimensional rods in a continuous matrix) and 2–2 connectivity (laminates). The role of several structural elements and physical factors in forming the electromechanical properties of the composites is discussed. It is shown that performance of these materials typical properties are 5 pC / N < | * 31 d |< 45 pC / N, 20 pC / N < * 33 d < 100 pC / N and 400 < e *s 33 / 0 e < 1300.

Abstract: This paper describes the effective electromechanical properties of hydroxyapatite-BaTiO3 0-3 composites as a potential bone substitute material. The permittivity, d3j and g3j piezoelectric coefficients are calculated for composites at a range of compositions and connectivities to understand the relationships between composite composition and piezoelectric and dielectric properties. The properties of the composites can be tailored by adjusting the volume fraction and aspect ratio of the BaTiO3 particles and the shape and level of porosity in the hydroxyapatite matrix.