The deformation of magnetite films forming on mild steel

Abstract Crack-detection techniques, developed for room temperature studies, have been applied to the study of magnetite layers growing on mild steel in NaOH solutions at 573 K and 10 MN/m 2 pressure, when subjected to varying tensile or compressive strains. It has been found that these films are extremely resistant to failure in compression but that they crack in tension at strains of 0·05–0·08%. Strains, below those necessary to cause cracking, result in changes in the rate of the electrochemical reactions associated with the oxidation process.