Tribological performance of thin overlays for journal bearings

This paper describes the analysis of overlay materials used in journal bearings. We conducted model tests using ring-on-disc test configuration and component tests on bearing test rigs. Appropriate test strategies were designed for investigating the running-in, stable operating, emergency running and break-down behaviour. We investigated three different types of overlays: PbSn18Cu2 galvanic, polymeric overlay (PAI matrix with MoS2-lamellae and graphite), PVD-coated AlSn20Cu-Sputter. Main results are: PbSn18Cu2 improves emergency running conditions. Polymeric overlay shows high need for running-in, where a particle structured surface is formed. AlSn20Cu-Sputter exhibits lowest wear and highest load capacity in component tests, but requires optimum running conditions.

Research Highlights►We tested journal bearing overlays and employed damage analysis techniques. ►Designed methodology is able to resolve tribological processes in high resolution. ►Electroplated Pb-based overlay improves emergency running conditions. ►Polymeric overlay with MoS2-lamellae forms particle structured surface. ►PVD overlay exhibits lowest wear and highest load carrying capacity.