Synthesis of Calcium-Dialkyldithiophosphate and Evaluation of Its Lubricating Properties

Calcium-di-2-ethylhexyldithiophosphate (CaDTP) was synthesized and its lubricating properties were compared with those of zinc-di-2-ethylhexyldithiophosphate (ZnDTP) and chlorinated pentadecane (CP). CaDTP was similar to and better than ZnDTP regarding anti-wear property and load-carrying capacity in a high speed four-ball tester. CaDTP also performed as good as CP and better than ZnDTP in cutting and forming tests. The results suggest that the lubricating mechanism of CaDTP may be slightly different from that of ZnDTP and calcium atoms play an important role in the performances of the compound