Tribological properties of aluminum-on-steel system under the lubrication of grease containing a complex of lanthanum N-salicylidene derivative of malonic dihydrazide

A complex of lanthanum and N-salicylidene derivative of malonic dihydrazide (Schiff base) was synthesized, and its tribological properties as additive in lithium grease were evaluated using a block-on-ring wear tester with a SAE52100 steel ring against an Al 2024 block. The protective film formed on the rubbed surface of aluminum was investigated by SEM, XPS and AES. Friction and wear tests reveal that this rare earth complex possesses an excellent load-carrying capacity and a very good antiwear ability for aluminum. The results of AES and XPS analyses illustrate that the prepared Schiff base La complex as additive in lithium grease forms a protective film containing lanthanum oxide and organic compound containing carbon and nitrogen on the rubbed surface of aluminum.