Improved mechanical and tribological properties of tin-bronze journal bearing materials with newly developed tribaloy alloy additive

Tin-bronze-based composites with the newly developed tribaloy alloy additive, T-401 with the chemical composition of Co-17Cr-22Mo-1.2Si, are developed for journal bearing applications. Two types of tin-bronze are employed, one is in a premixed state, the other prealloyed. Different from conventional tribaloy alloys, T-401 has better ductility owing to the primary solid solution rather than Laves phase and excellent corrosion resistance due to the increased chromium content. The specimens are fabricated using the powder metallurgy (PM) and hot isostatic pressing (HIP) consolidation techniques. The sintering/HIPping cycles are designed based on the differential scanning calorimetry (DSC) analysis of the specimen powders. The material characterization includes microstructural analysis, determination of mechanical and tribological properties. The experimental results demonstrate that the tribaloy alloy T-401, as an additive, increases the wear resistance and mechanical properties of the bronze materials; the presence of the tribaloy particles reduces the grain size of the matrices and refines the microstructures.