Thermal sprayed piston ring coatings for tomorrow’s heavy duty engines

Abstract

Plasma arc sprayed coatings are under development at Perfect Circle Europe because of the large numberof possible coating materials, ensuring a wide range of tribological properties. Spraying parameters are of great importance in improving coating structure and hence coating wear, adhesion, cohesion, and corrosion resistance. First of all the plasma gas was studied; experiments were then conducted to optimise the spraying parameters. To a greater extent than the spraying parameters, it was found that the powder formulation has a major influence on the coating tribological properties. Several powders have been studied with the aim of reducing the ring–liner system wear. Tests on idealised specimens coupled with engine tests help to characterise the tribological behaviour of some molybdenum based coatings.