Friction and wear characteristics of different Pb-free bearing materials in mixed and boundary lubrication regimes

Abstract

a b s t r a c tTraditional bearing materials contain different amounts of lead (Pb) because of its friction reducing properties. However, in view of the negative health and environmental impact of Pb, there is growing emphasis on restricting the usage of Pb in engine bearings. Owing to this, new bearing materials that provide at least comparable tribological performance to that of Pb containing alloys are being developed and some new Pb-free materials are being already used in engine bearing applications. It is, however, still unclear how these new engine bearing materials would perform in mixed and boundary lubricated conditions. In this study, a block-on-ring test setup was employed to investigate the tribological performance of several bi-metal and multi-layer Pb-free bearing materials with different compositions of bearing lining and overlay plating. Pb-containing bearing material was also studied as a reference material. Friction and wear properties of these bearing materials were investigated and their wear mechanisms under lubricated conditions have been analysed. Bearing material with Polyamide-Imide based overlay containing graphite and MoS 2 exhibited better friction and wear properties than Pb-based and Al-Sn based materials. Pb-containing bearing material shows higher wear of material and Al-Sn based material has shown higher friction compared with the other test materials.

Evaluation of Wear Phenomena of Journal Bearings by Close to Component Testing and Application of a Numerical Wear Assessment

“…These regimes are characterized by the coexistence of hydrodynamic and asperity contact pressure where the latter is generally responsible for increased frictional losses, wear and a higher chance of failure. On the one hand, these circumstances demand a continuous further development of the tribological partners shaft and journal bearing material as well as the lubricant by experimental investigations [2][3][4][5][6][7][8][9]. On the other hand, the prediction of wear based on numerical investigations becomes increasingly important especially in the course of the design process and the evaluation of life expectancy [10,11].…”

Investigation on Lubrication State of Sliding Bearings in Low-Speed Rotor System Subjected to Torque Load

“…Wu et al [14] studied the wear mechanism of sliding bearings involving various moisture contents and rotating speeds. Comparative experimental studies on the friction properties and wear mechanism of different materials of sliding bearings under different working conditions have also been studied [15][16][17][18].…”

Design and Setup for a Journal Bearing Universal Test Rig

“…Those outcomes were derived after studying various types of coating materials used in different alloys. In addition, Gebretsadik et.al [10] and [11], were among those who have traced the tribological performance of thin over lays for journal bearings aiming at increasing the wear resistance and eliminating adhesive and abrasive wear. Their results obtained later have stressed that seizure load was higher for the Sn-based overlay plated materials, in fully formulated engine oil, than in base oil.…”