Thin hydroxyapatite coating produced by the ion beam dynamic mixing method.

An ion beam dynamic mixing (IBDM) method was used to produce thin hydroxyapatite coatings on titanium substrates. Structure, solubility and bond strength of coatings were evaluated. The hydroxyapatite-type structure was obtained from heat-treated coatings. As-coated coatings seemed to be almost dissolved within 1 d in Hanks' solution. The thin layer of films, however, was recognized with a firm intermediate compound (such as Ti3P4) to the substrate by X-ray photoelectron spectroscopy, indicating the high tensile bond strengths from the as-coated films. Although slight reductions of the bond strength were observed in heat-treated specimens, the strengths were not reduced by immersion in Hanks' solution for 30 d.