Temperature Dependence of the Dissolution Rates of the (111) surface of Cu Single Crystals Etched in Young’s Solution

Abstract

The effect of etching temperature on the dissolution rates at edge dislocation sites and dislocation-free sites of the (111) surface of copper single crystals was studied. The etching was carried out at temperatures 270 to 285 K for 5 to 25 s with Young’s etchant containing (NH₄)₂S₂O₈ 1 kmol·m⁻³, NH₄OH 6 kmol·m⁻³ and NH₄Br 0.3 kmol·m⁻³. From the measured data on the width and depth of dislocation etch pits and the dissolved thickness of the (111) matrix surface as a function of etching time, the linear dissolution rates parallel and normal to the surface at dislocation sites, v_h and v_d, and the dissolution rate normal to the surface at dislocation-free sites, v_s, were calculated. As a result, it was found that the dissolution rates were in the order of v_h>v_d>v_s at any temperature and that they increased as the etching temperature increased. These results were qualitatively discussed by the kinetic theory of two-dimensional nucleation and step motion for crystal dissolution and some kinetic quantities relating to the formation of two-dimensional nucleus and the step motion were evaluated.