MODIFICATION OF ANTIFRICTIONAL COVERINGS ON THE BASIS OF TIN BRONZE SHORT-PULSE LASER PROCESSING
Questions of modification of antifrictional bronze coverings are considered by method of short-pulse laser processing. The features of formation of structure of bronze antifrictional coverings which are characterized by the increased heterogeneity owing to low solubility of the alloying components in copper are analysed. It is revealed that for decrease in heterogeneity it is necessary to reduce the period of recrystallization of structure and also to provide formation of intermetallic phases. The original technology of increase in tribotechnical and mechanical properties of olovyanisty bronze antifrictional coverings by short-pulse laser processing with deep remelting of a basis is for this purpose offered. Techniques of modification and laboratory researches of antifrictional coverings are developed. Tribotechnical and mechanical properties of the modified coverings are considered, in particular increase in the bearing ability of an antifrictional covering, decrease in coefficient of friction and also stability to the tease is revealed. The executed measurements of microhardness of a covering characterize correctness of the choice of the modes of processing at which there is a full remelting of an antifrictional covering, to formation of high-disperse structure the increased hardness. The submitted characteristics of coverings give an evident idea of increase in operability of the modified coverings in the conditions of boundary friction. For identification of the reason of increase in microhardness and tribotechnical properties of the modified coverings have carried out the comparative X-ray diffraction analysis of coverings. The received results of X-ray diffraction researches allow to claim about change of quantitative phase structure of an antifrictional covering after short-pulse laser processing, in particular after processing the quantity of an intermetallic phase and also amount of pure tin considerably increases. During the researches the phase changes of structure at a temperature over 1800 C leading to receiving intermetallic phases the increased thermal stability and durability are revealed. Thanks to these phases stability of an antifrictional covering considerably increases at the raised kinematic modes of operation and limited lubricant.