Kinetics of the Interaction of Co–Cu Melts with Graphite and Microstructure of Formed Metal–Carbon Composites

The time dependences of the contact angles and the wetted surface spot diameters have been measured during the interaction between Co–Cu melts with copper contents of 20, 40, and 60 at % and graphite at temperatures of 1390, 1440, 1490, 1540, and 1590°C. Under these conditions, graphite is not wetted by the Co–Cu melts: the final contact angles for Co80–Cu20, Co60–Cu40, and Co40–Cu60 are 95, 110, and 100°, respectively. Therewith, the final diameters of the wetted surface spots somewhat increase. The metallographic analysis of the microstructure of the Co–Cu–C composite materials obtained by the contact alloying of Co–Cu melts with carbon has shown that the morphology of the structural components and the phase composition of the samples depend on the copper content. Composite materials (Co–27%C–10%Cu) + (Co–32%C–62%Cu) + C and (Co–19%C–15%Cu) + (Co–25%C–72%Cu) + C obtained by the interaction of the Co–Cu melts containing 20 and 40 at % copper with graphite have a macrohomogeneous structure.