アルミニウムのEtch pitについて

抄録

Etch pits in aluminium have not always one-to-one-correspondence to dislocations, they are affected by the etching condition, the surface condition and impurities contained. The linear arrangement of pits along slip bands which is seen on a heavily worked specimen is considered to be due to the surface condition, because it is general that it does not appear after the surface layer is removed by a subsequent electropolishing.
The pit has the form of a circular cavity at the beginning of growth, but when it becomes the size greater than several hundred Å in size, it is angular so that the type of the pit can be determined. In most cases it has an etching germ, around which there are seen fine contour lines. These lines suggest that the etch pit is formed with a similar mechanism as in the case of the spiral growth of a crystal. Moreover, the growth rate of etching is quickest along ‹100› directions on {100} plane.
On the fracture surface, there have been found abnormal pits named pit of the second kind, which are shallow and composed of complex planes having numerous fine rumples. The pits of this kind have edges parallel to those of the normal, but they have the form inverted from that of the latter.