Importance of open-shell effects in adhesion at metal-ceramic interfaces

We demonstrate markedly enhanced adhesion between oxide ceramics and conducting metals via promoting open-shell electronic structure at the interface, by using a more covalent oxide or doping with early transition metals. Open-shell character suppresses closed-shell repulsions and permits local covalent and/or donor-acceptor bonding, even in the absence of a conventional reaction layer. The dramatic impact of such local bonding attractions, predicted from density-functional calculations, contradicts the idea of classical electrostatic forces dominating metal-oxide adhesion.