Effects of Copper Powder Bearing Material Composition on Working Characteristics

Effects have been established for phosphorus and lead on the working characteristics of tinned bronze with high-speed operation (up to 20000 rpm or up to 2 m/sec) at low pressures (up to 2.0 MPa). It has been found that Cu - Sn - Pb - CP powder bearing material, where CP is a copper-phosphorus alloy, under such conditions has a lower coefficient of friction than does tinned bronze and a much higher wear resistance, while sliding bearings based on it have high working life. A microheterogeneous structure is formed in this material: an α-solid solution of tin in copper, along the boundaries of which there is uniformly distributed a strengthening phase (network of copper phosphide Cu₃P with inclusions of the phosphide eutectic Cu₃P + Cu₃Sn + (Cu - Sn), and there are lead inclusions at the grain boundaries intersections. This material has very good tribotechnical characteristics at high rotation speeds and low pressures and also low coefficient of friction, low wear, and consequently long working life of bearings made of it.__________Translated from Poroshkovaya Metallurgiya, Nos. 3–4(442), pp. 120–126, March–April, 2005.