Dislocation Etch Pits in Silver

Abstract

A modification of the etchant used by Levinstein and Robinson is shown to be a reliable solution in producing etch pits at dislocations on the (111) surface of silver crystals and is used to investigate the dislocation structures in as-grown, annealed, and deformed silver crystals. Single crystals of silver with dislocation densities on the order of 104 cm−2 with a few subboundaries were prepared by high-temperature annealing. Two distinct sizes of dislocation etch pits are found in both as-grown and deformed crystals. The two sizes of etch pits are concluded to be associated with positive and negative edge dislocations through detailed observations of etch-pit rosettes produced by indentation. The modified Levinstein-Robinson etchant for silver thus corresponds to the Livingston etchant for copper. Additional observations are made on polygonization, dislocation interactions, and etch-pit morphology. Large etch pits not associated with individual dislocations are also described.