Tribological studies of 1-alkyl-2,5-dithiohydrazodicarbonamides and their Mo–S complexes as EP and multifunctional additives

This communication reports a comparative study of the anti-wear, extreme pressure and friction reducing properties of 0.5% (w/v) admixtures of paraffin oil with 1-alkyl-2,5- dithiohydrazodicarbonamide ligands and their Mo–S complexes, i.e. μ-hydroxo-μ-(1-alkyl-2,5-dithiohydrazodicarbonamido)-bis-[dioxohydroxo molybdenum VI] using 12.7 mm diameter steel bearing balls in a four-ball test. In particular, the additive μ-hydroxo-μ-(1-n-butyl-2,5-dithiohydrazodicarbonamido)-bis-[dioxohydroxo molybdenum VI] exhibits an increase in the load carrying capacity of the lubricant and a decrease in the values of wear and coefficient of friction. The surface analysis of the wear-scar matrix of the used ball specimen has been investigated by SEM and AES techniques.