Tribological properties of Tin-based Babbitt bearing alloy with polyurethane coating under dry and starved lubrication conditions

To improve the tribological properties of Babbitt alloy used as journal bearing pad specifically under severe condition, Babbitt substrate was prayed with a coating of polyurethane (PU) polymer which had been suitably modified with PTFE particles. Tribological performances, under dry and starved lubrication conditions, of the Babbitt alloy substrate (i) sprayed with PU composite coating and (ii) with bare surface were investigated. Results showed that Babbitt substrate sprayed with PU composite coating gave better friction reduction and wear resistance than the counterparts of bare Babbitt. This was because the PU composites coating served as protective layer leading to the formation of PTFE transfer film on mating surface, hence improving the associated tribological properties during sliding.