Influence of Chemical Composition on the Structural-Phase State and the Adhesive Strength of Metal-Composite Briquettes for the Friction Draft Gears and the Brake Pads of Heavy Vehicles

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