Nature of metal-ceramic adhesion: Computational experiments with Co on TiC

By means of first-principles computational experiments, the microscopic mechanism of metal-carbide adhesion is revealed. Density-functional-theory results for the Co/TiC(001) interface show the interface bonding to be dominated by Co-C bonds. The effective number of bonds is controlled by an interplay between lattice mismatch and relaxation effects. The particular strength of the Co-C bond is explained in terms of interface-induced features of the electronic states, in particular, a novel metal-modified covalent bend. The calculated adhesion strength agrees well with results of wetting experiments.