Wetting and interfacial behavior of molten Cu on Co–Si(–Mo) coated SiC

Abstract

The wetting and spreading of molten Cu on SiC substrates with or without Co–Si(–Mo) coatings at 1120°C were investigated by the sessile drop technique. The Co–Si(–Mo) coatings on the SiC substrate were prepared by liquid phase sintering process under a vacuum. The interfacial behaviors of the coating/substrate systems and the Cu/coated SiC wetting couples were analyzed. The experimental results indicated that the final contact angle of the Cu/SiC system at 1120°C, for a holding time of 10min, decreased from ~142° without coating to 12°, 15–27° and 7° with the corresponding Co–Si, Co–Si–10Mo and Co–Si–20Mo coatings. This result was closely related with the interactions between the Cu drop and the coatings. No reaction layer was observed at any of the coating/SiC interfaces before the wetting tests. However, a thin Mo–Co–Cu–Si layer and a graphitization layer with different thicknesses formed at the Cu/Co–Si–10Mo coated SiC and Cu/Co–Si–20Mo coated SiC interfaces. Moreover, the graphitization layer disappeared at the Cu/Co–Si–10Mo coated SiC interface when the thickness of the Co–Si–10Mo coating increased to ~60μm.