Investigations on Dry Sliding Wear and Corrosion Resistance of Thermal Sprayed Molybdenum Coatings

Abstract

This paper aims to investigate the characteristics of molybdenum thermal sprayed coatings deposited on 1.0570 steel substrate and compare them with the characteristics of the uncoated carbon steel (1.0570), respectively alloyed steels (1.7219 and 1.6582), which are currently used for similar applications, such as parts and structural components used at temperatures down to -100°C, aircraft, terrestrial transportation and other industries. The Mo coating deposition was performed by wire metallization and aimed to increase the wear and corrosion resistance of steels typically applied in railway transportation industry. The microhardness, wear behaviour and corrosion resistance have been investigated for all the presented materials. Molybdenum coatings deposited by wire metallization technique possess superior frictional behaviour due to the formation of an oxide tribo-film. Therefore, the friction coefficient of the presently investigated Mo coatings reached a value of 0.65, correlated with a low wear rate of about 0.65·10-5 mm3 N-1 m-1. The porosity degree of the Mo coatings was found to be around 3.50%, a common value for this type of coatings. Microhardness average value of Mo coating was 480 HV0.3 and the corrosion behaviour was found to be superior in comparison to the other materials, exhibiting an inclination to passivation at around 300 mV.