Two in one → pickling degreasing → water washing → anodic electrolytic degreasing → hot water washing → water washing → nickel-iron alloy plating → recycling → water washing → chromium plating → recycling → hot water ironing [16]
(2) rolling a nickel-iron alloy coating
Rolling type 2 nickel-iron alloy:
Chemical degreasing → cleaning → cleaning → acid corrosion → cleaning → activation → rolling nickel-iron alloy → recovery → recovery → cleaning → hot water scalding → spin drying [8]
(3) polishing before plating, and chromium plating after nickel-iron alloy plating
Polishing (180 # ~ 240 # emery) → water washing → chemical degreasing → water washing → electrolytic degreasing (anode) → water washing → strong corrosion → water washing → weak corrosion → nickel-iron alloy electroplating → recovery → water washing → drying → chromium plating → recovery → water washing → drying [1
(4) The tool is plated with Ni-Fe alloy first, and then chrome plated.
Running the hanger with plated parts on the automatic line conveyor arm → soaking in warm water at 82℃ → degreasing with 7 1℃ alkali anode → countercurrent washing → activation with 3% phosphoric acid solution at 38℃ → countercurrent washing → removal of phosphoric acid stains with 71℃ cleaning solution → countercurrent washing → pickling with 0.5% hydrochloric acid → running water washing → electroplating of nickel-iron alloy for 12 min → running water cleaning. → Chrome plating for 2 minutes → Countercurrent washing → Soak in water containing sodium bisulfite twice (reducing hexavalent chromium to trivalent chromium) → Soak in water at 60℃ twice → Rinse in deionized water at 80℃ countercurrent (deionized water, resistance 2Mgt) → Blow dry → Dry [18].
(5) Nickel-iron alloy (6063, 2024 aluminum alloy) is plated on aluminum alloy.
Alkaline etching ①→ water washing→ acid washing→ bright ②→ water washing→ zinc dipping ③→ water washing→ activation ④→ water washing → secondary zinc dipping ⑤ → water washing → drying [19]① There are three formulas for alkaline etching.
A. Formula 1 sodium carbonate 20g/L, trisodium phosphate 20g/L, temperature 70 ~ 83℃, time l3min.
Formula B: sodium hydroxide 5% (mass ratio), temperature 60 ~ 65℃, time 30 ~ 60s.
C formula 3: sodium carbonate 2g/l, sodium hydroxide 14g/l, trisodium phosphate 12g/l, starch l2g/l and D- sorbitol 200g/l.
The complexing ability of Formula 3 to aluminum ions is greater than 140 g/L, and white caking will not occur after long-term use.