Wear and vibration behavior of ZDDP-Containing oil considering scuffing failure

Abstract

The use of appropriate lubricant additives can reduce surface damage, extend machine lifetimes, improve machining accuracy, and reduce power consumption. In this study, the effects of zinc dialkyl dithiophosphates (ZDDP) additives in lubricating oil on the tribological performance, vibration characteristics, and scuffing thermal mechanism were experimentally investigated using a four-ball tribotester. The impact of the running-in process with ZDDP-containing lubricants on scuffing resistance was examined by varying the applied normal loads. The results showed that the addition of ZDDP and presence of the running-in process could effectively increase the scuffing load, which is in good agreement with previous research. This paper further describes the factors breaking the energy equilibrium caused by scuffing, including the lubricant temperature, friction, vibration, and wear particles. For different weight percentages of the ZDDP in the running-in and step-loading processes, the difference in wear curves was relatively small. The decrease in the number of large particles (>1 μm) before scuffing resulted in lower wear losses than that of the lubricant without ZDDP. The influence of oil in surface roughness valleys, represented by a void volume parameter, on the scuffing failure phenomenon was taken into account. A new modified friction power intensity criterion—which considers the effect of microcontact and oil flow characteristics, according to the ratio of the void volume parameter and the standard deviation of surface heights—is proposed to predict the onset of scuffing failure.