Formation and growth of calcium phosphate on the surface of oxidized Ti–29Nb–13Ta–4.6Zr alloy

The bioconductivity of a new biomedical titanium alloy Ti–29Nb–13Ta–4.6Zr achieved by a combination of surface oxidation and alkali treatment is reported in this paper. Oxidation treatment at 400°C for 24 h was found to result in the formation of a hard layer on the surface of the alloy. Immersion in a protein-free simulated body fluid and fast calcification solution led to the growth of calcium phosphate (Ca–P) phase on the oxidized and alkali-treated alloy, and the new bioconductive surface was still harder than the substrate. The surface processes during various treatment and immersion processes were investigated in detail, and the morphology of the calcium phosphate crystals was shown to be determined by the concentrations of Ca and P in the solution.