Modified Tribo-Phosphorylated Phosphoric Acid (modtp) is an additive in lubricants that imparts antifriction, antiwear, and antioxidation properties. It can be used in engine oils, hydraulic oils and greases.
Compared with other tribo-polyphosphates, molybdenum dialkyl phosphorodithioate (modtp) complexes have a higher tribological performance at low temperatures and low loads. In addition, it has good oxidation resistance, which can extend the shelf life of lubricants.
Four modtp complexes with alkyl chain lengths ranging from C5 to C10 have been synthesized and their antifriction, antiwear and antioxidant properties have been characterized vis-a-vis commercial molybdenum dithiophosphate. The synthesized products exhibit appreciable anti-friction, antiwear and antioxidant performance in mineral oil, base oil and finished engine oil and are comparable to commercial modtp.
The tribological behavior of piston ring sliding against grey cast iron cylinder liner under the lubrication of petroleum based engine oil SJ/5W-30 containing molybdenum dithiocarbomate (MoDTC) or molybdenum dithiophosphate (modtp) was studied in reciprocating test rigs at different temperatures. The friction coefficient curve of both compounds exhibited a "V" shape when the test temperature increased from 125degC to 320degC.
The tribofilm formed by MoDTC was mainly composed of MoS2 while that formed by modtp was largely composed of FePO