Thin hydroxyapatite surface layers on titanium produced by ion implantation

In medicine metallic implants are widely used as hip replacement protheses or artificial teeth, The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (alpha, alpha) backscattering and the resonant nuclear reaction H-1(N-15,alphagamma)C-12. The results of X-ray photoelectron spectroscopy indicate the formation of HAp In addition a first biocompatibility test was performed to compare the growing of marrow bone cells on the implanted sample surface with that of titanium. (C) 2002 Elsevier Science B.V. All rights reserved.