This paper describes some properties of the Fe-based materials infiltrated with tin bronze and Cu-based materials infiltrated with tin. It was shown that due to the increased thermal conductivity infiltrated materials based on iron and copper have high tribotechnical properties. With an increase the thermal conductivity the coefficient of friction is reduced, and the seizure pressure increases in infiltrated iron-based materials as a result of the increase in the copper phase and certainty of its morphology, and in copper materials through the creation of a gradient structure in content of tin.

There are mechanical, electrical, thermal, vibratory and chemical processes in the friction of machinery. Under the influence of these processes changes occur in the structure of anti-friction material, associated with metal hardening or relaxation, carburization and decarburization, hydrogen saturation or depriving, metal oxidation. This can lead to a premature wear of the machine parts. The wear rate depends on many factors, one of which is the material antifriction properties.

According to the molecular–mechanical theory of friction and wear the temperature that develops in the process of friction has the great influence on the performance of the antifriction material. Very high temperatures can arise in the local areas and then in the entire areas of the working surface, which can cause phase transformations in the surface layer and even melting of the material. The high temperature and plastic deformation lead to diffusion processes. As a result of that the coagulation of the individual structural components and the mutual diffusion dissolution of materials of friction pairs are possible. To prevent the development of high temperatures in the area of friction, antifriction materials should have high thermal properties, particularly conductivity, a heat capacity and a stable coefficient of the linear thermal expansion. High thermal properties provide a removal and a dissipation of heat generated in the friction zone, protecting the friction units from the excessive heat that can cause decreasing of the mechanical and tribotechnical properties of materials. In addition, the layer of a lubricant can be destroyed that accelerates wear surface oxidation processes, both due to an atmospheric oxygen and oxygen formed due to the decomposition of lubricant decomposition at high temperatures.

This article appeared in the Jan/Feb issue of Metal Powder Report. Log in to your free profile to read the article.

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