Wettability of SnAgCu–Cr alloys on graphite with different Cr contents

• Published in: Journal of materials science 2018-05, Vol.53 (9), p.6864-6871
• Main Authors: Hu, S. P., Lei, Y. Z., Song, X. G., Kang, J. R., Zhao, Y. X., Cao, J., Tang, D. Y.
• Format: Article
• Language: English
• Subjects: Alloys; Brazing alloys; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromium base alloys; Classical Mechanics; Contact angle; Crystallography and Scattering Methods; Degassing of metals; Graphite; Liquid alloys; Materials Science; Metals; Polymer Sciences; Solid Mechanics; Specialty metals industry; Substrates; Tin base alloys; Wettability; Wetting
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-017-1979-4

The wettability of brazing alloy on graphite surface is a key factor affecting the successful brazing of graphite to metals. By introducing active Cr, the traditional Sn0.3Ag0.7Cu brazing alloy can wet the graphite effectively. The design of active Cr introduction into SnAgCu alloy caused a significant decrease in contact angle, and the contact angle was decreased from 120° to 20° with the increasing content of active Cr. The influence of active Cr content on the wettability of SnAgCu/graphite system was investigated by sessile drop way at elevating and isothermal process in this work. Cr 3 C 2 reaction layer formed at the interface of liquid alloy and graphite substrate, which enhanced the spreading of liquid brazing alloy and then decreased the contact angle. The thickness of Cr–C reaction layer kept identical of 2.5 μm with the further increasing content of active Cr. Finally, the wetting mechanism of SnAgCu–Cr/graphite system was proposed.