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.