The grain-boundary energy in alumina was estimated by using high-purity bicrystals and the thermal grooving technique. Alumina bicrystals having a [00•1] symmetrical tilt axis were fabricated by joining single crystals at high temperatures. The bicrystals included low-Ʃ boundaries (23, 27), high-Ʃ boundaries (219, etc.), low-angle boundaries and high-angle boundaries. The grain-boundary energies ranged from 0.4 to 0.7J/m2. The low-Ʃ boundaries, 23 and 27, exhibited the extremely low energy of about 0.05J/m2. The energy was related to the structure of the grain boundaries.

Grain Boundary Energy and Atomic Structure in Alumina Bicrystals. T.Watanabe, H.Yoshida, T.Saito, T.Yamamoto, Y.Ikuhara, T.Sakuma: Materials Science Forum, 1999, 304-306, 601-6