Microstructures, mechanical properties and corrosion resistance of sprayed Ca-P coating for micropatterning carbon/carbon substrate surface

Carbon/carbon (C/C) surface micropatterning is a method of modifying the surface into the complete and regular geometry. In this work, we introduce a positive effect on bonding strength between sprayed Ca-P coating and surface micropatterning C/C substrate. Interestingly, C/C substrate coated by Ca-P coating provides textured surface for a new bone ingrowth. The sprayed Ca-P coating is then subjected to microwave-hydrothermal (MH) treatment with the aim of eliminating surface defects and obtaining a uniform purity phase. These objectives were achieved in our previous study by the MH method. The molar ratio of Ca/P in the coatings is nearly close to 1, which is far below that of Ca/P for hydroxyapatite (Ca10PO4)(6)(OH)(2), HA, 1.67). The purpose of this article is to transform the phases in the sprayed Ca-P coating, which owns the better bioactivity and high corrosion resistance. In order to raise the molar ratio of Ca/P, the coatings are treated under high-temperature (around 700 degrees C). They are analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a fourier transform infrared spectra (FTIR). The bonding strength (coating/substrate), biological activity and corrosion resistance of the coatings are investigated. The resulting coatings own the different microstructures and phase compositions from the original sprayed Ca-P coating. Especially, results show that the shear strength of the sprayed Ca-P coating deposited on surface micropatterning C/C substrate increases by 61% which is more than that of the coating on non-surface micropatteming C/C substrate. Additionally, high-temperature treated coating presents a good biological activity and an excellent corrosion resistance of current density (1.3078 x 10(-6) A/cm(2)) and potential (- 0.17 V-SCE).