The effect of tungsten nanoparticles on interaction of sintered Sn-Cu-Co metallic matrices with diamond has been studied. Nanoparticles were obtained by grinding standard tungsten powder in a planetary-centrifugal mill. Commercially pure tin, copper, and cobalt powders were mixed with synthetic diamonds and the milled tungsten. Samples were shaped by static pressing in a mold and sintered in vacuum at 820°C. The sintered samples were subjected to static compression test, and hardness of the metallic matrices was measured. The structure of fractures and distribution of the elements over them were explored by the SEM and energy dispersive X-ray microanalysis methods. It has been determined that introducing tungsten nanoparticles into the composite material contributes to dispersion hardening of the metallic matrix and higher strength of its adhesion to diamond.

The objective of the work is identifying the modes of ball milling of the W16,5 and PWT grade tungsten that ensure obtaining nanosized powders. Milling was performed with the AGO-2U planetary-centrifugal mill for 5, 15, 60, and 120 min at the carrier rotation frequencies of 400, 800, and 1000 rpm. After milling, the shape and size of tungsten powder particles was studied by scanning electron microscopy. The effect of work hardening and aggregation on milling of the powders has been demonstrated. As a result of ball milling, nanoparticles of tungsten sized from 25 nm have been obtained. It has been found that the minimum size of particles is achieved at the carrier rotation frequency of 800 rpm and milling duration of not less than 60 min.

In this work, the structure formation of powder diamond-containing coatings with Sn-Cu-Co binders during sintering of specially-shaped grinding wheels has been studied. The kinetics of structure formation was studied using diamond-free metallic binders and diamond-containing samples. Powder components of the coatings were mixed with an organic plasticizer and applied on steel workpieces by rolling. Sintering was performed in vacuum at 700–820 °C. The microstructure, phase composition, and distribution of elements in metallic binders and interface layers between the binders and steel base were studied. The morphology of the surface and structure of fractures of the diamond-containing samples have been examined. Stages of structure formation of the coatings during heating and sintering have been found. At 700–780 °C, diffusion of tin into copper particles plays the key role in the structure formation of the coatings. Dissolution-reprecipitation of cobalt at 780–820 °C has a significant effect on formation of the coating structure and interface layers between the coating and steel base.