The effect of different metallic counterface materials and different surface treatments on the wear and friction of polyamide 66 and its composite in rolling–sliding contact

Abstract

The effect of different metallic counterface materials and different surface treatments on the tribological behaviour of polymer and polymer composite under unlubricated, non-conformal and rolling–sliding contact has been investigated. The most widely used polymer materials—unreinforced polyamide 66 (PA66) and its composite (RFL4036)—were tested. The metallic materials include aluminium, brass and steel and the surface treatments include Tufftride 1 Tufftride is a heat treatment process and many British companies, such as TTI Group Ltd., provide this process. 1 treated (known as nitrocarbonising) and magnesium phosphate treated, etc. Tests were conducted over a range of slip ratios at a fixed load of 300 N, 105 rad s −1 rotational speed using a twin-disc test rig. The experimental results showed that the polyamide composite exhibited less friction and wear than the unreinforced polyamide 66 when running against steel and aluminium counterfaces. However, when tested against brass, polyamide 66 exhibited lower wear than the composite. The surface treatment of steel has a significant effect on the coefficient of friction and the wear rate, as well as on the tribological mechanism, of polyamide 66 composites. It has been observed that a thin film on the contact surface plays a dominant role in reducing the wear and friction of the composite and in suppressing the transverse cracks. This study clearly indicates that both the characteristics of the different counterface metallic materials and the surface treatment greatly control the wear behaviour of polyamide 66 and its composite.