Wettability of SiC/ l iquid Co with Cr additive system

The wettability of a reaction bonded SiC/ Co-Cr system was studied by the sessile drop technique in highvacuum. The effect of Cr content and technological parameters including wetting temperature and dwelling time onthe wettability of the system was investigated. Compared with the reaction bonded (RB) SiC/ pure Co system , thewettability of the system is remarkably improved by adding active element Cr. The relatively small contact angles ofthe RB SiC/ Co-Cr system are obtained with the Cr content of 5 % , 7 % and 42 % , respectively. Wetting temperatureand dwelling time st rongly affect the contact angle. The experimental result s show that the wetting processes ofboth RB SiC/ pure Co system and RB SiC/ Co-Cr system belong to reactive wetting. Microst ructure study and XRDphase analysis indicate that interfacial reactions take place in the RB SiC/ pure Co system , leading to the formation ofCoSi , and resulting in the decreasing of the contact angle ; but for the RB SiC/ Co-Cr system , interfacial reactionscause the formation of Cr₂₃C₆ , leading to the decreasing of the interfacial energy of the system , and consequently thewettability of the system is improved.