This paper presents the results of experimental studies of the influence of a high-frequency electromagnetic field on the physical, mechanical, and tribological properties of polymer friction composites for automotive brakes. It was shown that, in some cases, the treatment with an electromagnetic field results in the transformation of the polymer supramolecular structure. In the case of treatment of initial powder compositions, significant changes (up to 20%) in the dynamic modulus of elasticity and the tribological properties of the final materials were found. The possible mechanisms of the effect of pulsed high-frequency electromagnetic treatment on the physical and mechanical properties of friction materials, as well as the correlation of the properties with the acoustic noise of friction units, are under discussion.
The paper presents the results of experimental studies of the effect of a high-frequency electromagnetic field on physicomechanical and tribotechnical properties of polymeric frictional composites used for automotive brakes. It is shown that treatment by an electromagnetic field, in some cases, results in the transformation of the supramolecular structure of the polymer. In case of the treatment of the initial powder compositions, there is an evident change (up to 20%) of the dynamic modulus of elasticity and tribological properties of the finished materials. Possible mechanisms of the effect of the pulsed highfrequency electromagnetic treatment on the physicomechanical properties of the friction materials and their relation to the acoustic noise of tribounits are discussed.
PTFE transferred layers were found to decrease or increase the friction force depending on variations in adhesional interaction on the contact area when the layer is being formed. The molecular component of adhesion is of great importance.After a layer of transferred PTFE has formed on the contacting surface, PTFE begins to wear by a thermoactivation mechanism with an activation energy of 40-60 kJ mol-1. These low values of activation energy indicate PTFE wear to be associated most of all with the breaking of weak intermolecular bonds and with interplanar shear and slipping of crystalline aggregates formed in the band structure of the material.