Abstract: Three thiadiazole dimer derivatives (TDD-7，TDD-10 and TDD-15) were synthesized and their structures were characterized by FT-IR. The tribological properties of these derivatives used as additives in distilled water were evaluated with a four-ball machine, and the chemical states of some typical elements on the worn surface were analyzed by XPS. Results indicated that these additives possessed excellent load carrying capacity and extreme pressure property in distilled water, and the antiwear and friction reducing performance of distilled water with additives were improved in some extent. Among these three additives, TDD-10 exhibited the best load carrying capacity and TDD-15 exhibited the best antiwear performance. The improved tribological behavior of distilled water by these additives could be attributed to the formation of adsorption film containing nitrogen, chemical reaction film containing Fe2O3, FeS and FeSO4, and the synergetic effect of these two types of films led to a further improvement.

Key words: thiadiazole dimer, heterocycle, water soluble, tribology