Effect of Particle Size on Tribological Properties of Rubber/Steel Seal Pairs Under Contaminated Water Lubrication Conditions

Abrasive wear is a common failure phenomenon that often limits the service life of seals. In this study, the abrasive wear test of acrylonitrile–butadiene rubber against steel was developed under conditions of lubrication contaminated with abrasives. The influence of particle size on coefficient of friction (COF) evolution, particle activities, wear morphologies, and damage mechanisms were discussed in detail. Results showed that the presence of abrasive particles dispersed in lubricated medium clearly deteriorates the tribological performance of the seal pairs. Two threshold values (approximately 7.5 and 75 μm) related to the “particle size effect” were obtained. And on this basis, the damage mechanism can be divided into three types. Several damage characteristics presented on respective worn surface, such as, cutting effect, rolling effect, the pinning effect of the “abrasive group,” an alternated feature with “ridge–valley–ridge,” or in the form of furrows and craters. In addition, the particles in the medium destroyed the lubricating film between the rubbing pairs and increased the COF and material removal capacity of tribo-pairs. Furthermore, the wear mode that clearly describes the wearing behavior of the seal pairs under abrasive-contained water lubrication conditions was identified. The results of this study enhanced our understanding of the wear degradation of rubber seal in all types of contaminated lubrication conditions.