Hydroxyapatite thin films deposited onto uncoated and (Ti,Al,V)N-coated Tialloys

Plasma-sputtered hydroxyapatite (HA) thin coatings (similar to 1 mu m) were deposited onto uncoated and (TiAlV)N-coated Ti-6Al-4V-alloy substrates at low temperatures. The (TiAlV)N coating interlayer was deposited by reactive sputtering. Depositions were achieved by utilizing unbalanced and balanced magnetrons in a capacitively coupled RF plasma. Characterization of the th ermostability, bioerosion resistance, and chemical composition of the coati ng layer was examined by scanning electron microscopy (SEM), energy-dispers ive X-ray analysis (EDX), and Fourier transform infrared spectroscopy (FTIR ). The results show that for deposition temperatures as low as 67 degrees C , the crystalline phase of the HA coating still is clearly detectable and t hat the underlying (TiAlV)N coating can increase, the crystallinity and the rmostability of the HA coating before and after heat treatment. The thin (s imilar to 1 mu m) sputtered HA coating shows strong HA characteristic peaks in the FTIR spectra even after a 30-day dissolution test. The experimental results show that a multilayer structure comprised of a bioinert (TiAlV)N and bioactive HA coating has the potential to improve the biocompatibility of implant materials. The bioinert (TiAlV)N coating also may provide a long -term stable interface between bone tissue and an alloy implant after the b ioactive HA coating is remodeled by the surrounding tissue. (C) 1999 John W iley & Sons, Inc. J Biomed Mater Res, 46, 408-417, 1999.