Ni-P Composite Plating on Piston Ring for Improved Wear Performance

Piston rings are used to seal the cavity formed between the piston and the cylinder in order to allow the engine to operate efficiently. The piston rings wear out due to constant rubbing action with cylinder wall and also have to withstand high temperature. This has lead to the development of new piston ring coatings with good wear properties under increasingly challenging running conditions. To improve the wear resistance of the piston rings several coating techniques are employed. One such technique is Ni-P composite coating which is widely used in the automotive industry. Reinforcement of ceramic particles enhances the tribological and mechanical properties of the coating. The base material of the piston ring used in this study is hardened carbon steel. The main objective is to develop an optimum Ni-P composite coating on piston ring to improve wear and friction resistance. The work involves development of Ni-P Metal Matrix with SiC particles by electroplating method to a coating thickness of 30 microns min. Microstructure, micro hardness, wear and friction properties of the coated piston ring were evaluated. The wear and friction study was conducted on pin on disc wear testing machine. Results indicate improvement of wear and friction properties in the coated piston ring.