Tribological analysis of PTFE–304L stainless steel friction pair under different contaminated water conditions and contact pressures

Purpose The study aims to elucidate the tribological behavior and wear mechanisms of a friction pair composed of polytetrafluoroethylene and 304L stainless steel in water-lubricated environments containing various types of abrasive contaminants and contact stresses. Design/methodology/approach Three different abrasives comprising SiO2, Al2O3 and an equal-proportion mixture of the two were separately mixed with water to create contaminated lubricating media of equal mass concentration, and compared with the water lubrication conditions without any abrasive added. Those lubricating mediums were pre-placed between the friction pairs, followed by the application of three different normal loads corresponding to contact stresses of 0.5, 0.75 and 1 MPa to conduct the tribological tests. Findings Abrasive contamination significantly increases wear compared to unpolluted water lubrication. At lower contact stresses, the wear behavior is mainly influenced by the average hardness of abrasive particles. However, as contact stress increases, the type and interaction of abrasive particles become the main factors affecting wear. Under single SiO2 abrasive conditions, the primary wear mechanisms involve both open three-body and closed three-body abrasion. In contrast, under Al2O3 or mixed abrasive conditions, wear is dominated by closed three-body abrasion and tribochemical transformation. In mixed abrasive conditions, the synergistic interactions of mixed abrasives cause fragmentation of low-hardness particles and clustering with harder particles and form new abrasive clusters, intensifying wear severity, and this effect becomes more significant with increasing contact stress. Originality/value This work highlights the synergistic effects of abrasive mixing and stress on tribological behavior in water-lubricated systems, offering insights for the design of durable tribo-pairs in contaminated environments. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2025-0261/