Fabrication and Properties of Functionally Gradient Bioactive Composites Comprising Hydroxyapatite Containing Glass Coated Titanium

摘要

We have developed a composite material (HA-G-Ticomposite) consisting of titanium coated with a glass-hydroxyapatite (HA) ceramic layer, wherein the ceramic layercomprises a gradient coating with increase in HA concentration fromthe innermost sub-layer toward the outermost sub-layer (70 wtpercent HA) and the surface has a roughened surface containing voidsand exposed HA particles. Titanium substrate contributes tomechanical strength of the composite, whereas exposed HA particleshave a role to provide bioactive performances. The aim of thepresent study is to describe the fabrication method of thiscomposite and to discuss particular properties applicable toimplant materials as follows. Coefficient of thermal expansion ofthe HA-glass layer was arranged to be compatible with that oftitanium metal to minimize residual thermal stresses. The HA-glasslayer was tightly bonded to titanium through under-coated glasslayer, and bonding strength varied with HA content.