WETTABILITY AND INTERFACIAL ENERGIES IN SIC-LIQUID METAL SYSTEMS

The sessile drop technique is used to measure the contact angles of molten Si, Sn, Cu and Ni in contact with mono- and polycrystalline alpha-SiC as well as CVD beta-SiC in purified argon atmosphere and at various temperatures. The contact angle of silicon, near its melting point, is about 38-degrees on a mono- as well as polycrystalline alpha-SiC substrate and about 41.5-degrees on beta-SiC. Tin does not wet the SiC. Using data from the available literature, the work of adhesion and the interfacial energy between SiC and Si or Sn were calculated. In the alpha-SiC-Sn system, both quantities are linearly dependent on temperature in the investigated temperature range 523-1073 K. The metals copper and nickel react with silicon carbide. The silicon content of the copper drop depends on the annealing temperature. The nickel drop after cooling forms the compound Ni3Si2. The interferometric measured groove angle of SiC (thermal etching) in vacuum at 2020 K gives a mean value of 157.6 +/- 5.8-degrees.