Studies on tribological behaviour of sintered coppertin graphite composites

Abstract

Tremendous advancements have been achieved in the area of the composite produced by the powder metallurgical technique in the past two decades. This is due to the enhancement in physical and mechanical properties of the composite such as, hardness, brilliance, wear resistance, and lubricity of the composite which cannot be obtained with any of the individual metals. The development of the engineering field requires the creation of new anti-friction materials with a capacity to operate under a different environmental condition and at higher loads. An important task of the above field is to reduce the coefficient of friction and wear of the moving parts of the machinery and mechanism. For sliding contact applications like textile/food and aircraft industries as bearings and bushes, metal with a very low coefficient of friction, high hardness, high load carrying capacity, and good fatigue resistance is required. Bronze is an excellent and well-known bearing material. It also possesses a low dry coefficient of friction, high hardness, excellent wear-resistant property, and also the loadcarrying capacity is high. Graphite is a very good dry lubricant, and which is incorporated into a metal matrix imparts nonstick, lubricating properties and will lower its coefficient of friction. The properties required for the bearing is almost satisfied by the copper-tin graphite sintered composite. The addition of graphite helps to reduce sliding contact between machine parts, especially where no grease and oil lubricant can be used. Composites are developed because no single, homogeneous material that had all of the desired characteristics for a given application could be found. The incorporation of finely dispersed particles in the metal matrix by a suitable process allows the production of a large number of composites with unique properties. Thepresent investigation is focused on obtaining a lubricant composite of bronze (copper with 10% tin) with graphite particles, produced using powder metallurgical route, and to evalua