Investigation of wear and corrosion resistance of WC-coated Pearlitic railway steel in dry and wet conditions

Abstract

In this study, the effect of WC coating on the tribological performance of R260 rail steel was investigated by roller-on-plate wear tests and potentiodynamic polarisation corrosion tests carried out in dry and pure water environments. The High-Velocity Oxygen-Fuel (HVOF) method was used for the coating process. The tests were conducted with a weight of 40 N and a sliding speed of 0.03 m/s. An Ag/AgCl reference electrode was also used for corrosion tests in a 3.5 % NaCl solution. To produce cyclic polarisation curves, the experiments were carried out at a scan rate of 1 mV/s within a potential range of ±0.25 V. The effect of WC coating on the wear performance of rail steels was analysed quantitatively with the friction coefficient and volume loss parameters and visually with SEM and 2D-3D topography images. The effect of the coating on the corrosion performance was evaluated numerically with the corrosion potential, corrosion current intensity, and corrosion rate values, as well as elementally and visually with SEM and EDX images. Wear test results showed that the wear volume in WC-coated rail steels decreased by 43.07 % and 46.94 % compared to uncoated rail steels in dry and wet conditions. Corrosion test results showed that the corrosion rate of WC-coated rail steels was lower compared to uncoated rail steels, and the corrosive effect spread to a smaller area.