Fabrication of fluoridated hydroxyapatite-calcium silicate coatings by suspension plasma spay

The wok aims to prepare fluoridated hydroxyapatite (FHA)/calcium silicate (CS) composite coatings on Ti substrate by suspension plasma spraying technique. The phase compositions, microstructure and morphology of FHA/CS composite coatings were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. The corrosion behavior and bone-like apatite forming ability of the composite coatings in simulated body fluid (SBF) were studied by potentiodynamic polarization test and bioactivity test. The chemical stability of the composite coatings was assessed by evaluating the release of Ca2+ ions with inductively coupled plasma spec-trometer (ICP). The adhesion strength of the composite coatings was characterized by scratch test. The coating prepared by SPS had a rough surface and lamellar structure. FHA and CS distributed homogeneously in whole coating with a good crystallization. The critical load of the composite coatings reached 111.43 N, which was 62.5% higher than that of single FHA coatings. Compared with the pure titanium, the coating samples showed a high corrosion potential (Ecorr) and low corrosion current density (Jcorr). The bone-like apatite was formed on the surface of the composite coatings soaked in SBF for 3 days. The ICP examination showed that Ca2+ ion release rate of the composite coatings was lower than that of the single CS coatings. FHA/CS composite coatings prepared on pure titanium possesses high corrosion resistance, excellent bioactivity as well as strong bonding to Ti substrate. The presence of FHA component in the composite coatings is beneficial to improve the chemical stability of coatings. © 2019 Chongqing Wujiu Periodicals Press. All rights reserved.