Inhibited Dissolution of {100} Surfaces of Single Crystals of Lithium Fluoride

Abstract

A technique is described for the determination of the dissolution rates of {100} lithium fluoride surfaces in dilute aqueous solutions of ferric fluoride. The effect of ferric ion content of the etchant on the rate is found to be constant for ion concentrations substantially in excess of the optimum for the production of smooth-faced square etch pits at dislocations. The results correlate well with recent theories concerning the adsorption of ferric ions during etching. The effect of lithium fluoride undersaturation varies greatly from specimen to specimen and demonstrates the heterogeneous nature of hole nucleation in the close-packed surfaces.