MODELING OF COMPACTION KINETICS DURING SINTERING OF A NANOSIZED MIXTURE OF HARD ALLOY POWDERS

The article considers the kinetics of compaction of a meso-sized mixture of tungsten carbide and cobalt powders during sintering. It is noted that the sintering time of meso-sized powder blanks can increase several times compared to a mixture of larger powders. In addition, when sintering meso-sized powders of a mixture of tungsten carbide and cobalt, a significant instability of the geometric structure of the hard alloy was established, affecting the magnitude of the driving force of compaction. Therefore, in the hyperbolic equation obtained earlier, the kinetic constants of sintering are determined by a change not only in the structure, but also in the geometric factors of the compaction kinetics, including the coefficients of grain boundary and surface diffusion. Taking this circumstance into account, a differential equation was used to obtain a model of the kinetic equation for sintering a mixture of meso-sized tungsten carbide and cobalt powders. It determines the change in porosity during the viscous flow of porous bodies under the action of externally applied forces of uniform all-around compression, without taking into account the change in free energy associated with capillary phenomena.