Tribological performance of surface treated piston assembly with infiltrated layer

By applying surface treatment on piston assembly and typical samples, an infiltrated layer with the depth of about 30 μm was formed on the treated sample surface. The surface hardness and linear expansion coefficient of treated piston sample decreased, while the hardness of treated ring sample increased. The results of ball-on-disc rotating friction test indicated that the infiltrated layer is helpful for improving the tribological properties of aluminum alloy, reducing friction coefficient under both dry friction and oil lubricated conditions, and improving the anti-friction and wear resistance performance of cast iron. In addition, the reciprocating friction testing results showed that surface treatment technology has stable anti-friction effect on piston/liner pair under various working conditions, with the average friction coefficient being reduced by about 10.2-22.1 %; while the anti-friction effect on ring/liner pair is mainly reflected under low-speed heavy-load condition, with the average friction coefficient being reduced by approximately 7.2-9.9 %.