Study on tribological and corrosion inhibiting properties of thiadiazole derivative as lubricant grease additive

Purpose - Pure 2,5-dimercapto-1,3,4-thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial seizure load and exhibits certain corrosion, which accelerate oxidation of the lubricant by catalytic effect on metals. The author make efforts to resolve problems said by design a novel thiadiazole complex. Design/methodology/approach - The complex of thiadiazole dimmer and polyglycol (DMS2-GL) was synthesized as ashless grease additive. The antiwear and load carrying properties of the additive and their synergistic effects was evaluated by four ball tester in four types of lubricant grease. Moreover, corrosion inhibiting properties of compositions said was investigated by copper corrosion test. Findings - The additive DMS2-GL possessed good load carrying capacity, and exhibits good synergistic antiwear and load carrying prop with rust inhibitor. In addition, dates obtained from copper corrosion test show that it does not corrode copper but coats the metal with a film, and could improve the anticorrosion of corrosive additives molybdenum dialkyldithiophosphate (MoDDP) and molybdenum dibutyldithiocarbamate (MoDTC) by forming protective films on rubbing surface, which contribute to improving corrosion inhibiting property of greases. Finally, the tribo-chemical mechanism was proposed that thiadiazole dimer and polyglycol could coordinate with each other by polydentate surface interaction, which means thiadiazole rings interact with the metal surface, polyglycol affords a bridging technology linked thiadiazole climmers so as to lighten loads and strengthen forces between thiadiazole dimmer moleculars. Originality/value - This paper provides a good ashless additive which has good antiwear, extreme pressure and corrosion inhibiting properties, and fulfils an identified resources need, which can offer practical help in industrial applications and to an individual starting out on an academic career.