Bearings material Bronze bearings Cu–Sn–Zn/Gr alloy Cu–sn–zn/graphite alloy Density (specific gravity) Extreme conditions Graphite Hardness Lubrication / Mechanical characteristics Mechanical properties Metal matrix composite Metallic matrix composites Metals Microstructural characteristics Molybdenum compounds Porosity Powder metallurgy Powder metals Sintering Solid lubricants Strength values Sulfur compounds Tribological contacts Wear of materials Wt% graphite Yield stress Zinc alloys wt% graphite