Characterization of hydroxyapatite and titanium coatings sputtered on Ti-6Al-4V substrate

A series of thin (<10 mu m), single-layered HA/Ti coatings were deposited o n Ti-6Al-4V substrate using a radio frequency magnetron-assisted sputtering system. The adhesion strength, microstructure, and chemistry of the coatin gs were characterized. Experimental results showed that higher Ti contents in targets or coatings resulted in higher deposition rates. When Ti was add ed the highly crystalline structure of monolithic HA coating was largely di srupted and the coating became amorphous-like. The highly crystalline struc ture of the monolithic Ti coating was also disrupted by introducing small a mounts of Ca, P, and O into the coating. The HA/Ti coatings had quite unifo rm thicknesses and appeared smooth, dense, and well bonded to the substrate . A scanning electron microscope with an energy dispersive spectroscopy sys tem showed that monolithic HA, 95HA/5Ti, 25HA/75Ti, and 50HA/50Ti coatings had the lowest Ca/P ratios while the 75HA/25Ti coating had the highest. The adhesion strengths of all coatings were between 60 and 80 MPa. (C) 1999 Jo hn Wiley & Sons, Inc.