| 摘要 |
Procedure is degreasing, pickling, metallising, neutralising and drying. Pickling is electrolytic, with 2-20 amp/dm2 in acid sulphate or phosphate containing solution at 40-80 degrees C for 3 min. Preferably, sulphate ion concentration is 2-25 wt. %, calculated as sulphate, or phosphate ion 2-20 wt.% as phosphate. Sulphate is sulphuric acid, or neutral and acid sulphates of alkali metals and/or Mg. Phosphate is phosphoric acid and/or neutral and acid phosphates of alkalis and/or Mg, pref. 1-50 wt.% MgH2PO4. Pickling time is 0.2-3 mins., bath temp. 60-70 degrees C. Degreasing is electrolytic. Pickling is followed by electroplating with Ni or Co, 0.3-0.7 g/m2, in bath containing water-soluble Ni and/or Co salts 8-30 (pref. 15-20) g/l. Advantages: pickling time is reduced; so is pickling erosion necessary for good adhesion. |
