| Abstract: | The interaction of zinc dialkyldithiophosphate (ZDDP) with cerium fluoride and cerium dioxide in lithium grease has been studied for friction, wear, and EP characteristics on a four-ball and SRV tester. The combination of ZDDP and cerium trifluo-ride has been shown to be beneficial in reducing wear, especially over a long period of friction and with increasing EP load. The test results show that adding cerium dioxide to lithium grease does not improve the antiwear and friction performance of the paste. The analytical results of X-ray photoelectron spectrum (ESCA, XPS) reveal that ZDDP inhibits the decomposition of cerium fluoride and improves its film-forming property. The wear scar reaches a minimum at an atomic concentration ratio of 3P:2Zn:1S:25F, and an atomic concentration ratio of 2S:2P:1Zn:4F gives the highest EP load. The scratch test results show that combining ZDDP with cerium trifluoride improves the tenacity of the surface film. The stabilisation of cerium trifluoride by ZDDP is proposed. |
