Etch Spirals Formed at Screw-Dislocation Sites on (111) Surface of Cu Crystal by Etching with Marukawa's Solution

Dislocation etch pits were produced by etching of the (111) surface of Cu single crystal for 10-50 s at 280-300 K with Marukawa's solution ( FeCl3·6H2O-HCl-HBr). From electron microscopic observation of their replicas, it was found that spiral terraces often occurred at apices of the etch pits formed at screw-dislocation sites. The spiral terraces tended to occupy somewhat wider regions as etching time and temperature were increased.