The attack of metals by free radicals and atoms

Abstract

Numerous but scattered reactions are known where the surfaces of metal containers are attacked during the chemical changes in contiguous gases or liquids. In many cases the basic physico‐chemical interpretation of such attack is incomplete. In the present paper a number of examples are discussed in terms of thermodynamics and kinetics. A consideration of the kinetics may involve atoms or free radicals, and a transient concentration of these may be established which greatly exceeds the equilibrium concentration. This can favour internal reduction of metal carbides, nitrides, sulphides and oxides and can lead to extremely high disruption‐pressures at internal voids in the metal. Other cases of enhanced attack on metal surfaces due to transient concentrations of atoms and free radicals are also discussed.