Crystal Morphology and Mechanisms of Growth of Alpha-Fe[sub 2]O[sub 3] Whiskers on Iron

Abstract

The morphology of whiskers formed on iron at 400°–500°C in dry oxygen was studied. Diffraction patterns of individual whiskers and texture patterns of oxidized surfaces showed the whisker axis to be . The axial rotation indicated by the pattern is that resulting from an axial twist. This is good evidence that the most simple oxide whiskers have a single axial screw dislocation. Arguments are presented for the view that growth of the whisker occurs by diffusion of iron atoms or ions through the dislocation and reaction with oxygen at the tip.