Stress generation and its effects during thermal and anodic oxidation of zirconium

Results of thermal and anodic oxidation of Zr are presented. It was found that in any situation where an oxidation process leads to a highly stressed oxide film, in interpreting the results of experimental work, it is necessary to ensure that effects arising from these oxide stresses be considered. In the particular case of zirconium where the oxide is formed with a large compressive stress, the forces involved are sufficient to deform the substrate metal where test specimens are very thin, or to fracture the oxide film on thick substrates at low growth rates. This can lead in both thermal and anodic oxidation to marked effects on the oxidation kinetics. (U.S.)