Copper-Tin Materials for Tribotechnical Purposes

摘要

The products of mechanochemical synthesis in the Cu-20% Sn system at various stages of mechanical treatment were studied by X-ray diffraction, micro X-ray spectral analysis, and electron microscopy in backscattered electrons. At the initial stage (40 s), an intermetallic compound Cu_(6.26)Sn_5 is formed, the formation of a solid solution of tin in copper begins with an increase in the processing time, and after 20 min of treatment, a solid solution Cu(Sn) with nanoscale crystallites becomes the only product of synthesis. The products of mechanochemical synthesis of the Cu-20% Sn system were consolidated by electrocon-tact sintering. Sintering of mechanocomposites after treatment up to 8 min occurs by the liquid-phase mechanism. The coatings formed during sintering have a small number of pores, microhardness of 1460 MPa, and low wear intensity under dry friction (0.0049 mg/m). Electrocontact sintering of mechanocomposites with the structure of a solid solution Cu(Sn) formed after 20 min of mechanical treatment passes through the mechanism of solid-phase sintering and ends with formation of a homogeneous alloy Cu(Sn) with a significant number of discontinuities. The coating is characterized by high microhardness (2350 MPa) and increased wear intensity (0.087 mg/m). Combining precursors obtained by mechanical treatment for 40 s and 20 min in a ratio of 40 : 60 (wt %) allowed forming a coating with a high microhardness, low wear intensity, and low friction coefficient by the method of electrocontact sintering.