Influences of processing parameters on bond strength of RF thermal plasma-sprayed HA/Ti composite coatings

Abstract

The influences of plasma gas composition on the adhesivensee of HA/Ticomposite coatings were investigated. HA/Ti composite coatings were deposited on titanium substrates by a radio-frequency (RF) thermal plasma spraying method with RF input powers of 10-30 kW. The ratio of HA and Ti powders supplied into the plasma was precisely controlled by two microfeeders so as to change the composition from Ti-rich to HA-rich toward the upper layer in the coatings. The bond strength (tensile) of HA/Ti composite coatings was 40-65 MPa in the case of sprayed in the plasma gas with small content of N2 addition. On the other hand, the HA/Ti composite prepared with pure Ar and O2 addition gave significant lower bond strength that is, under 33 MPa.