The Tribological Properties of PAI/PI-PTFE Coating Filled by WC/Ta on 1010 Steel and AS20 Aluminum Substrates under Different Temperatures and Contact Conditions

To improve the tribological performance of the oil distribution plate of the plunger pump under dry sliding wear and temperature rise conditions during the start–stop stage and reduce its cost, a polyamide imide (PAI)/polyimide (PI)–Polytetrafluoroethylen (PTFE) coating filled by three different content of tungsten carbide (WC)/Tantalum (Ta) were designed. The composite polymer coating was prepared on the surface of 1010 steel and AS20 aluminum substrate by liquid spraying, and its tribological properties under different temperatures and lubrication media were investigated. The results showed that the tribological properties of the coating were influenced by the hardness of the substrate, the content of the filled particles, the ambient temperature, and the lubricating medium. The hardness of the coating increased with substrate hardness and WC content. Under the condition of sliding wear at room temperature, the wear mechanism was mainly abrasive wear and adhesive wear. The wear rate of the coating decreased with an increase in WC content. The coating with 5% WC addition had the lowest wear rate on 1010 steel and AS20 aluminum substrate. Under the same coating condition, the tribological properties of the 1010 alloy steel were lower than those of the AS20 aluminum. The pear groove and adhesion of the coating increased with temperature. Compared with the CuPb24Sn at 100°C, coating on the surface of 1010 steel significantly reduce the coefficient of friction (CoF) and wear rate. The CoF and wear rate under dry sliding wear were reduced by 57.5 and 8.7% and those under oil lubrication were reduced by 45.7 and 11.1%, respectively. The supporting effect of the matrix, the bonding of the internal particles in the coating, the softening degree of polymer materials such as resin, and the lipophilicity of the coating are the main reasons.