Dissolution Rates at Dislocation Sites on the (111) Surface of Cu Single Crystals Etched in Young’s Solution at 290 K

抄録

The net dissolution rate at dislocation sites on the Cu (111) surface etched in Young’s etchant (1 kmol·m⁻³(NH₄)₂S₂O₈, 6 kmol·m⁻³NH₄OH, 0.3 kmol·m⁻³NH₄Br) has been determined from measurements of the dissolved thickness of the matrix surface as well as the three-dimensional size of dislocation etch pits. The etch pit size was measured by a replica electron microscopy. After etching time of 5 s, the width and depth of the etch pits increased at constant rates of \doth and \dotd, respectively, leaving the side slope unchanged. The dissolved thickness of the matrix surface was determined by an interferometric measurement of the step height which was produced along the boundary between the masked surface and the exposed surface. It was found that the matrix surface dissolved also at a constant rate \dots after 5 s etching. The net dissolution rate normal to the surface at a dislocation site, v_d, and that parallel to the surface, v_h, were estimated to be 1.7 times as large as the measured growth rates of etch pits \dotd and \doth, respectively. This fact indicates that dissolution of the matrix surface must not be neglected in describing the dissolution at dislocation sites. Using the values of v_d, v_h and \dots, the nucleation rates of two-dimensional etch pit nuclei at dislocation sites and matrix surface were obtained as 2.9×10² s⁻¹ per dislocation and 8.7×10⁶ μm⁻²·s⁻¹, respectively.