Metal/Ceramic Interfaces: Relationships Between Structure and Chemistry

Studies have been conducted on interfaces between Al2O3, and three different metals Nb, Pd and Ni. The objectives have been to establish orientation relationships and to understand the atomistic structure along the interface. In the case of Ni, the formation of a spinel reaction product has also been explored. For NbAl2O3, it has been found that the orientation relationships and the atomic arrangements depend on the temperature at which the interface was formed. Those formed at high temperature by diffusion bonding have 110 planes in the Nb parallel to the interface. There are also misfit dislocations which stand-off the interface. Conversely, interfaces formed at lower temperatures by molecular beam epitaxy have 111 planes in the Nb parallel to the interface. Moreover, the misfit dislocations are located at the interface itself. The differences are attributed to diffusional effects, such as dislocation climb, that can occur at the higher temperatures.