Role of interface structure and interfacial defects in oxide scale growth
- Laboratoire des Materiaux, Toulouse (France)
- Ohio State Univ., Columbus, OH (United States)
- Washington State Univ., Pullman, WA (United States)
Recent studies of the structure and dynamics of solid-solid interfaces have provided some understanding about the role of the scale-metal interface in the growth of reaction product scales on pure metals. The action of interfacial defects (misfit dislocations, misorientation dislocations and disconnections) in the creation and annihilation of the point defects supporting the diffusional growth of scales is considered. Anion point defects (vacancies/interstitials) supporting scale growth by anion diffusion are annihilated/created by the climb of misorientation dislocations or disconnections in the scale at the interface. For scale growth by cation diffusion, cation point defects (vacancies/interstitials) can be annihilated/created by the climb of interfacial misfit or misorientation dislocations in the metal. Because of their necessarily high density, in most cases, the dominant climb of misfit dislocations would be favored. The blocking of interfacial reaction steps can be a means to retard the scaling kinetics and to alter the fundamental scaling mode. For instance, the interfacial segregation of large reactive element ions can point the interface dislocations, an action which poisons the usual interfacial reaction step. Such considerations are consistent with the well-known phenomena ascribed to the reactive element effect (REE).
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 207140
- Journal Information:
- Oxidation of Metals, Vol. 44, Issue 1-2; Other Information: PBD: Aug 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Chromia scale growth in alloy oxidation and the reactive element effect
Interface dynamics in diffusion-driven phase transformations for metallic systems