A new selective chemical etchant was tested with regard to its ability to reveal dislocations in monocrystals of this compound. The best results were obtained by using a 1:1:1 volume ratio of HNO3, HCl and H2O; mixed with an 0.01 to 0.002M aqueous solution of FeCl•6H2O. It was found that the etchant formed etch pits with characteristics that were typical of dislocation etch pits. The etchant revealed both individual dislocations, and dislocations in grain boundaries, before and after various sample deformations. It was concluded that the features of this etchant, such as its retention of a high contrast, and an increase in pit size with etching time, make it a good choice for applications such as revealing dislocation structures on {001} surfaces and measuring dislocation mobilities. When combined with chemical polishing, the etchant was idea for studying the dislocation structure and its modification in the bulk of plastically deformed samples. The etching patterns demonstrated that the macroscopic motion of dislocations in this material, under local or bending deformations, took place mainly in the <¯110>{111} primary glide systems. Signs of dislocation cross-slip and multiplication were also observed.

G.K.Baranova, J.L.Iunin, E.M.Nadgorny: Scripta Materialia, 1996, 34[7], 1027-33