Friction and wear properties of gear materials polyoxymethylene (POM) combined with polyamide 66 (PA66)

Polyoxymethylene (POM) and polyamide 66 (PA66) exhibit extensive utilization in gear systems owing to their superior self-lubricating capabilities, elevated thermal stability, and favorable anti-frictional characteristics. As for metals, different mateal combinations can prevent abrasive wear because of small surface energy. How is the tribological properties of POM combined with PA66? In this study, the influence of PV value on the tribological properties of PA66 and POM are researched by using a pin-on-disk friction test device. The result shows that under high PV conditions, the friction coefficient and wear rate of the PA66-POM and POM-PA66 sliding combinations are consistently lower than those of POM-POM and PA66-PA66 due to the transfer film layer which effectively reduces the impact of friction heat on the contact surface. In addition, the wear mechanism of PA66-PA66 and POM-POM sliding combinations is mainly adhesive wear, whereas the wear mechanism of PA66-POM and POM-PA66 sliding combinations is abrasive wear and adhesive wear. For the PA66-POM and POM-PA66 sliding combination, grease destroys the formation of the transfer film, which increases the wear rate at high PV values.