Combining thermodynamics and DSC to characterize the melting and wetting behavior of a composite powder used for joining ceramics

The diffusion-assisted melting behavior of a Cu-coated Ti-powder was characterized as a function of the intermetallic formation and corresponding melting temperature using DSC. The endothermic and exothermic events were identified using the respective binary phase diagram. The results demonstrated that initial melting is independent of the heating rate; however complete melting occurred at 900 degrees C when heated at 10 degrees C/min as oppose to 915 degrees C for a heating rate of 40 degrees C/min. The wetting results of the brazing alloy on Si3N4 ceramic show that the brazing alloy maintains its initial shape until the complete melting is achieved. Equilibrium contact angle measurements obtained are similar to results previously published but the wetting kinetics observed are different. (C) 2005 Springer Science + Business Media, Inc.