Triboanalysis of Antifrictional Materials Based on Polyamides for Metal-Polymer Sliding Bearings

An experimental and theoretical method of triboanalysis is proposed to characterize the antifriction properties of polyamides and composites based on them, used in self-lubricated metal-polymer sliding bearings. The indicators of wear resistance of the materials are determined experimentally. The generalized parameters of the mathematical model of wear used in the design of metal-polymer bearings are calculated. The dependences (diagrams) of wear resistance of unfilled polyamides PA6, PA66, and polyamide composites PA6 + 30GF, PA6 + 30CF, PA6 + MoS₂, and PA6 + oil paired with steel 45 on specific friction force are obtained and a comparative assessment of the wear resistance is given. The influence of contact pressure on the friction coefficient is studied and a significant decrease in the latter with increasing contact pressure is shown. A decrease in the Vickers hardness and elastic modulus of the surface layer of the studied materials during wear is also established. It is more significant for unfilled polyamide PA66 (by 1.66 times), PA6 + 30CF (by 1.5 times), PA6 + MoS₂ (by 1.41 times), and less noticeable for polymer composites PA6 + 30GF and PA6 + oil by 1.21 and 1.09 times, respectively. The fact should be taken into account in tribological calculations of metal-polymer sliding bearings. The research results are presented in the form of diagrams, which allow one to compare the wear resistance of the investigative materials in a wide range of specific friction forces. Thus, the practical significance of the results lies in the possibility of their use in tribological engineering to predict the service life of metal-polymer plain bearings and validate the choice of antifriction materials for their manufacturing.