“…In diffusion bonding chemical reaction takes place between the metal and the ceramics, and the properties of the reaction product layer dictate the usefulness of the bind and thus of the whole assembly at high temperature. The reaction product layer should provide a strong bond between the two dissimilar materials, which means: (i) it should accommodate for the thermo-mechanical mismatch resulting from differences in thermal expansion coefficients, and (ii) the reaction product layer should not consist of compounds that have mechanical properties significantly inferior to those of the metal and the ceramic (He et al, 2010;Roy et al, 2009). Al 2 O 3 has been widely used as a very promising structural ceramics in a variety of engineering applications due its excellent performance in various severe working environments (Walker and Hodges, 2008;Nono et al, 2006).…”