Tribological Performance of Polyamide-Imide Seal Ring Under Seawater Lubrication

High-performance engineering polymers are potential candidate materials for mechanical seals, especially in corrosive environments and environments where substantial shock and vibration loads are present. This study addresses the friction and wear performances of polyamide-imide (PAI) sliding against tungsten carbide (WC) in seawater for seal applications. The experimental setup consists of two nominally flat rings rotating against each other to simulate the contact in mechanical seals. Three types of experiments were performed, i.e., measurement of friction and wear in a series of 8-h tests, measurement of the friction coefficient as a function of speed and load and measurement of PV (pressure times velocity) limit. Test results show that at lightly loaded conditions WC/PAI seal rings in seawater can reach hydrodynamic lubrication with ultra-low friction coefficient and wear rate.