The effect of saline environment on the fatigue behaviour of HVOF-sprayed WC–CrC–Ni coatings

Abstract

This paper presents the effect of saline environment on the fatigue behaviour of high-velocity oxygen fuel thermal-sprayed WC–CrC–Ni coatings. These coatings are used to improve the surface hardness, corrosion and wear resistance of components or products, in the place of hard chrome plating. Although so far many tests on the wear and corrosion of coating behaviour were carried, the conduct of the joint action fatigue – a corrosive environment is not fully identified. In the frame of the experimental programme, similar axial fatigue tests at room temperature, on air or on specimens immersed in 3% NaCl solution and also chemical composition, structural analysis of the fracture surface were performed, using SEM and EDX. The saline environmentcauses material corrosion, generation of voids and microcracks on the specimen surface and their propagation through the specimen cross-section, accelerating the specimen failure.