INFLUENCE OF CHEMICAL COMPOSITION ON STRUCTURAL-PHASE STATE AND ADHESIVE STRENGTH OF METAL-COMPOSITE BRIQUETTES FOR FRICTION DRAFT GEARS AND BRAKE PADS OF HEAVY EQUIPMENT

DJTPJW

Abstract

The main requirements for friction plates and brake linings of heavy equipment are resistance to shock loads and thermal cycles in the temperature range from ambient temperature to 850...870 ° C, stability of the friction coefficient, lack of adhesion to the material of brake discs made of steel or cast iron, as well as the maximum possible specific energy intensity of brake pad materials. In this work, metallographic studies were carried out using optical microscopy and it was established that the unsatisfactory quality of the metal-ceramic coating of the friction plate is due to the localization of sulfide eutectic at the ceramic-substrate interface, as well as the presence of oxide films on the surface of particles of precursor powders, which in turn leads to the formation porous ceramic-substrate interface. A metallographic analysis of the influence of various microadditives in the powder precursor for the formation of metal composite plates, such as copper, nickel and iron powders of various fractions, was carried out. It has been established that the fractional composition of the added powders largely determines the structural-phase state, as well as the adhesive strength of the ceramic-substrate interface.