On the Fundamental Nature of Metal-Metal Adhesion

Abstract

The cohesion of metals and their adhesion to other metals are complicated and poorly understood processes. Theories of adhesion have been judged by the use of indirect friction and wear data because of the scarcity of good experimental adhesion data.

The adhesion of one metal to another appears to be a manifestation of the electronic configuration of the atoms involved because the cohesive nature of materials results from these atomic forces. Therefore, the atomic binding energies, the distribution of the atomic species in the surface layers, the surface structure, and the crystal lattice disregistration must be influential in metal-metal adhesion. Adhesion is a surface oriented process and, thus, the bulk properties of metals should have only secondary influences.

Those metals having an electron deficiency in their outer atomic orbitals should adhere better than those metals which do not in order to minimize the total free energy and approach a more stable state. A correlation is shown between outer s or p electron orbital deficiency and Sikorski's adhesion data. Other measures of the atomic binding forces such as boiling point and heat of sublimation are shown to correlate with adhesion whereas mechanical properties such as hardness show relatively poor correlation.

Presented at the 32nd Annual Meeting in Montreal, Quebec, Canada, May 9–12, 1977

Notes

Presented at the 32nd Annual Meeting in Montreal, Quebec, Canada, May 9–12, 1977