The theory of metal - ceramic interfaces

The theory of metal - ceramic interfaces is a collection of approaches which are complementary. They range from thermodynamic modelling based on empirical correlations, through the image model of adhesion, semi-empirical tight-binding calculations, to first-principles calculations based on applying the density functional theory or Hartree - Fock theory. This article reviews the present state of theoretical calculations, with particular reference to electronic structure and adhesion. A section on the thermodynamic background clarifies the concept of work of adhesion which is the goal of many calculations. Cluster models and periodic slabs have been considered, both self-consistent and non-self-consistent. The most sophisticated and complete calculations have been made for metals on MgO and alumina. There a consistent picture of the nature of the bonding has emerged, although there are still significant unexplained discrepancies in numerical values.