Influence of Production Modes on the Structure and Tribological Properties of Sintered Tin Bronze during Friction with Lubricant in Friction Units

Abstract

The results of a study on the influence of the modes of obtaining sintered BrO12 bronze on its structure, phase composition and tribological properties during friction with a lubricant are presented. It is shown that the phase composition of BrO12 bronze sintered for 5 min consists of a solid solution of tin in copper and inclusions of intermetallic phases δ-Cu41Sn11 and Cu81nSn22. An increase in the exposure time during sintering leads to an increase in the homogeneity of the solid solution of tin in copper, a decrease in the crystal lattice parameter of copper from 3.69 to 3.68 Å, an increase in the grain size from 2–5 µm at 5 min of sintering to 15–46 µm at 120 min, a decrease in the content of the intermetallic phase δ-Cu41Sn11, and the disappearance of the Cu81nSn22 phase at 60 min of sintering and the virtual absence of intermetallic compounds after sintering for 120 min. Tribological tests have shown that the friction coefficient of bronze sintered for 5 min at a pressure of 4 MPa varies from 0.08 to 0.03, and at 20 MPa, from 0.105 to 0.04, the average wear value at a pressure of 4 MPa and 20 MPa was 2.0 µm. The coefficient of friction at the above pressures of bronze sintered for 60 min was 0.11–0.036 and 0.095–0.023; 0.045 and 0.12–0.5, respectively, wear was 6.3 µm.