Improved wettability of barium-aluminium-silicate glass on carbon/carbon composites via coating modification

In this paper, three kinds of modification coating were prepared to improve wettability of barium-aluminium-silicate glass on carbon/carbon (C/C) composites. The SiC coating was prepared by pack cementation; Cr ₃C₂ and ternary Cr-Si-C coatings were prepared by evaporation reaction process. Contact angles of glass on modified C/C composites were measured at different temperatures by sessile drop technique. Microstructures and morphologies of the wetting interface were determined by scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. Wetting experimental results revealed that barium-aluminium- silicate glass failed to wet the surface of pure C/C composites, but wettability of molten glass on C/C composites clearly improved by surface coating modification. Cr₃C₂ and Cr-Si-C coatings have a better wettability with glass than SiC coating. Cr-Si-C coating shows the best wettability with barium-aluminium-silicate glass, and the contact angle between them can be reduced to only 10° at 1673 K. The effects of test temperatures of sessile drop, coating surface condition and coating dissolution on wettability between glass and coated C/C composites were discussed.