Friction and Sliding Wear Characterization of Ion Chrome Coating

The functions of a piston ring are to seal off the combustion pressure, to distribute and control the oil, to transfer heat and to stabilize the piston. Most piston rings and metallic sealing rings for modern application where running conditions are severe, require some form of coating to minimise abrasion and corrosion. The piston ring coating improves the life of engine as well as fuel efficiency. In this study, physical vapour deposition (ion chrome plating) was investigated; plates with similar composition as the piston ring material were prepared by the casting process using induction arc furnace and sand mould. Wear test of the coating was conducted on pin on disc machine under dry conditions. The wear rate was calculated using mass loss methods on an electronic balance having least count of 1× 10⁻⁴ g. The wear rate of the coating was found to be increased with increase in load as well as sliding speed for the ion plating with the counter body of tungsten carbide but in the case of ion plating with the HCS & MS it is found to be decreased. The microstructure of the worn surfaces of the coating was also examined with optical telescope and no change in microstructure of the coating due to frictional heat was found.