Wollastonite coatings were deposited on the U-shape titanium alloy coupons by atmospheric plasma spraying.The effect of applied stresses on the microstructure and dissolution behavior of wollastonite coatings was investigated.The microstructure and composition of coatings were examined by scanning electron microscope(SEM)and electron diffraction spectroscopy(EDS).In addition,the dissolution behavior of coatings was evaluated by immersion in simulated body fluid(SBF).More apatite is observed on the surface of coatings under a tensile stress and a stress-free condition after immersion in the SBF solution,whereas almost no apatite can be found for the coatings under a compressive stress.The dissolution rate of coatings characterized by the pH changes and the ion concentration of Ca,Si and P in the SBF solution is lower under the compressive stress than those under a tensile stress or a stress-free condition.It can be concluded from the experimental results that the compressive stress inhibits the dissolution of wollastonite coatings and the formation of apatite,whereas a tensile stress enhances the two processes.
