Preparation of hydroxyapatite layer by ion beam assisted simultaneous vapor deposition

Hydroxyapatite layer was prepared by using ion beam assisted simultaneous vapor deposition. The method comprised of an electron beam heater and a resistance heater vaporizing CaO and P2O5, respectively, while an argon ion beam was focused onto the substrate to assist the deposition. The effects of ion beam assistance during deposition were investigated. All deposited layers were amorphous, regardless of the current density level of the ion beam. Post-heat treatment was applied to crystallize the deposited coatings. The Ca/P ratio increased with increasing ion beam current density presumably due to the high sputtering rate of P compared to that of Ca from the layer being coated. Annealing the samples increased the ratio even further due to the evaporation of P at high temperature. Significant improvement in the bond strength between the layer and the substrate was observed. The formation of an intermixed layer at the interface due to the effect of ion beam bombardment is believed to have caused such adhesion property.