Apatite/titanium composite coatings on titanium or titanium alloy by RF plasma-spraying process

To improve adhesiveness of hydroxapatite (HA) coatings to the titanium subs trates, a HA/Ti composite was formed on substrates using a radio-frequency (RF) plasma spraying process. This process would reduce the residual stress caused by the large difference between the linear thermal expansion coeffi cient of the substrate and of HA. The HA/Ti composites were prepared by con trolled feeding ratio of HA and Ti powder, with the composition of coatings becoming HA-rich toward the outer surface. Coating layers were evaluated b y SEM EDX, XRD, micro FT-IR and tensile testing. Orientation in c-axis dire ction of the prepared coatings was established from X-ray diffraction patte rns. The adhesive (tensile) strength of HA/Ti composite coatings was approx imately 50 MPa. The adhesiveness of the HA/Ti composite coatings was increa sed with increasing the inductive power of plasma. (C) 2001 Elsevier Scienc e B.V. All rights reserved.