Effect of different heat treatment temperatures on Fe-W alloy electrodeposits: Tribological and electrochemical analysis

This study aims to investigate the impact of different heat-treatment temperatures on the properties of Fe - W alloy coatings. Fe - W alloy coatings were fabricated and subsequently subjected to heat-treatment at different temperatures of 400 degrees C, 450 degrees C, 500 degrees C, 550 degrees C, and 600 degrees C, respectively. Dry sliding tests were conducted on the obtained samples, revealing a noticeable reduction in the coefficient of friction in the heat-treated samples. The lowest coefficient of friction, 0.17 mu, was obtained in the sample heat treated at 500 degrees C. This phenomenon was attributed to the precipitated phases such as Fe 6 W 6 C, Fe 2 W, Fe 7 W 6 , FeWO 4 during the heat treatment process. Considering the hardness values, the highest hardness value was obtained in the sample heat treated at 500 degrees C, with a HV hardness value of 634.5. The phases formed as a result of the heat treatment also positively affected the mechanical properties of the coating. To assess the electrochemical performance of the coatings, Open Circuit Potential (OCP), potentiodynamic polarization, and Electrochemical Impedance Spectroscopy (EIS) tests were performed. The results indicated that the sample produced at 500 degrees C are exhibited better corrosion and wear resistance compared with other heat-treatment temperatures. Considering the results obtained from the Tafel curves, the Ecorr value of the sample heat treated at 500 degrees C was found to be -0.54 V, the Icorr value was 2.01 x 10 -5 and the corrosion rate was 0.079mpy. This corrosion rate means an approximately 5 times more improvement compared to the as-plated sample. As a result, it can be concluded that the alloy formed by combining W with Fe, presents a promising alternative to Nickel and Cobalt coatings.