Sliding wear behaviour of plasma sprayed coatings on nickel based superalloy

Abstract

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 10 N). 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.