Sliding wear behaviour of plasma sprayed coatings on nickel based superalloy

In this paper, the sliding wear behaviour of nickel based superalloy pin was investigated on disc with two different coatings. The plasma sprayed NiCr-Cr2O3 coating and Al2O3+40%TiO2 (A40T) coating were used on the disc for wear studies. The sliding wear tests were performed on dry conditions at room temperature for a constant sliding velocity for two different applied loads (5 and 10N). The mass loss, wear resistance and coefficient of friction between the pin and disc were studied during investigations. The wear mechanism involved in the NiCr-Cr2O3 coatings is three-body abrasion and Cr2O3 being the third body between pin and disc. The wear rate is high due to the applied load and suppressed cracks. In A40T coating, the minute debris collected on the surface of the coatings acts as a solid lubricant and reduces friction and wear rate. The SEM and energy dispersive spectroscopy analysis were also carried out for characterisation studies on pin after wear studies. The life of nickel pin on A40T coatings is found superior than the NiCr-Cr2O3 coated disc.