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

By means of first-principles computational experiments, the microscopic mec hanism of metal-carbide adhesion is revealed. Density-functional-theory res ults for the Co/TiC(001) interface show the interface bonding to be dominat ed by Co-C bonds. The effective number of bonds is controlled by an interpl ay between lattice mismatch and relaxation effects. The particular strength of the Co-C bond is explained in terms of interface-induced features of th e electronic states, in particular, a novel metal-modified covalent bend. T he calculated adhesion strength agrees well with results of wetting experim ents.