High-temperature oxidation of metals

The overall processes involved in the reactions of a metal with an oxidant to form a solid reaction product are described. Transport in the oxide is summarized, both by the movement of lattice defects and by short-circuit processes, and the location of the oxide growth step is discussed in terms of the transport. The problem of maintaining contact between oxide and metal in the case where the oxide grows at the oxide/oxidant interface is analysed, and the nature of oxide/metal adhesion, the structure of the oxide/metal interface, and the general problem of the transfer of atoms from the metal to the oxide are discussed. It is shown that vacancy injection is not a necessary requirement of any oxidation process, but may occur in an attempt to accommodate loss of metal volume without having metal/oxide contact; in this case the vacancies tend to condense as voids within the metal. (author)