The conductivity of an Al2O3-Al composite, that had been synthesized by the directed oxidation of an Al alloy, was compared with that of sintered Al2O3-4%MgO. A high relative conductivity of the Al2O3-Al composite was taken to be proof of the existence of continuous metal channels in the composite. The conductivity data were used to determine the activation energy for the diffusion of the predominant charge carrier in the oxide matrix (figure 3).

H.Venugopalan, K.Tankala, T.DebRoy: Journal of the American Ceramic Society, 1994, 77[11], 3045-7