Surface activation of group IVb, Vb and VIb metals, especially nickel-titanium shape memory elements for micro-systems, comprises two-stage pickling in hydrofluoric acid-free solutions prior to metal coating

摘要

Surface activation of group IVb, Vb and VIb metals comprises two-stage pickling in hydrofluoric acid-free solutions. Surface activation of group IVb, Vb and VIb metals (preferably titanium and its alloys), for subsequent coating with another metal, comprises two-stage pickling in hydrofluoric acid-free solutions of the following compositions: (initial pickling solution) 300-800 ml/l concentrated hydrochloric acid, 200-700 ml/l water and 5-70 g/l sodium fluoride; and (main pickling solution) 300-900 ml/l concentrated sulfuric acid, 100-700 ml/l water and 0.1-10 g/l iron(II) chloride or chromium trioxide.