Kinetics of interaction of Co–Cu melts with graphite and microstructure of forming metal-carbon compositions

The time dependences of the contact angle and the wetted surface spot diameter were measured during the interaction of Co–Cu melts with copper contents of 20, 40 and 60 at. % with graphite at temperatures of 1390, 1440, 1490, 1540 and 1590°C. Wetting of graphite by Co–Cu melts does not occur under these conditions: the final contact angle for Co80–Cu20 is 95°, Co60–Cu40 is 110°, Co40–Cu60 is 100°. The final value of the diameter of the wetted surface spot increases somewhat. Metallographic analysis of the microstructure of Co–Cu–C composite materials obtained by contact alloying of Co–Cu melts with carbon showed the dependence of the morphology of the structural components and the phase composition of the samples 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 Co–Cu melts with a copper content of 20, 40 at. % with graphite, have a macro-homogeneous structure.