Modification of the Ti–6Al–4V alloy by ion implantation of calcium and/or phosphorus

Ion implantation of Ca and/or P into Ti or Ti alloys is of interest in order to enhance mechanical properties and biocompatibility for medical applications. In this study, the microstructural changes of the implanted surface layer were studied. Surface near implantation of high doses of calcium results in an oxidation of the modified layer and the formation of CaO. For deeper calcium implantations, precipitation of the metastable hexagonal modification of calcium has been observed instead of the cubic equilibrium phase. Besides these new phases, partial amorphization is observed. High dose implantation of phosphorus leads mainly to amorphization of the implanted layer. This hinders the reaction with oxygen during implantation and room temperature aging. High dose double implantation with P followed by Ca also leads to partial amorphization. No indication for new phases containing Ca and P is found.