Effects of hydroxyapatite addition on corrosion behavior and in-vitro bioactivity of Ti-10Mo matrix biocomposite

Abstract

Ti-10Mo/HA (hydroxyapatite) biocomposites were prepared by powder metallurgy. The electrochemical corrosion behavior and in-vitro bioactivity were investigated in this study. After addition of HA, the results of the electrochemical tests show that the corrosion resistance of the composites decrease. The non-uniform distribution of β phase region (Mo rich) and partition effect of pores lead to the inhomogeneity and discontinuity of oxide films on the surface of titanium alloy matrix. The introduction of O and incomplete diffusion of Mo make much more α-Ti reserved, which is inferior to β-Ti in terms of the corrosion resistance. Besides, the large and interconnected pores in the composites may cause the crevice corrosion. With addition of HA, the increased ceramic phases and micropores improve the bioactivity obviously. After soaking in SBF for 7 d, a lot of spherical apatite was deposited on the surface of Ti-10Mo/HA composite, while the modified Ti-10Mo alloy was partially covered by several apatite particles. The ceramic phases and micropores enhance the surface energy of the composites, and the wettability is improved, which is conducive to apatite deposition and cell adhesion, but unfavorable to the corrosion resistance. So that the HA content should be controlled in a reasonable range according to the performance requirements of the composites.