Aging Characteristics and Mechanical Properties of Ti-29Nb-13Ta-4.6Zr Coated with Calcium Phosphate Invert Glass-Ceramic for Biomedical Applications

Abstract

Aging characteristics and mechanical properties of biomedical β type titanium alloy, Ti-29Nb-13Ta-4.6Zr, coated with calcium phosphate invert glass-ceramic were investigated. Vickers hardness values of cross sections of Ti-29Nb-13Ta-4.6Zr, TNTZ, prepared for dip-coating treatment, DCT, composed of a firing treatment, FT, at 1073 K for 0.9 ks or 3.6 ks followed by furnace cooling and conducted with only FT are almost the same, and are around 240 Hv. This value is much higher than that of TNTZ prepared for solution treatment, ST, at 1063 K for 3.6 ks. The increasing hardness is due to the precipitation of ω phases in the matrix, β phase, during FT. Tensile bonding strength of 5 μm thick coating layer of calcium phosphate invert glass-ceramic on TNTZ is not degraded by aging, but 20 μm thick coating layer is degraded. The modulus of elasticity of TNTZ prepared for DCT or aging after DCT is relatively higher than that of TNTZ prepared for ST, that is, around 80 GPa and 110 GPa, respectively.