The bright nickel layer on stainless steel is a silver-white metal with yellow light. Its hardness is higher than copper, zinc, tin, cadmium, gold, silver and so on, but lower than chromium and rhodium metals. Bright nickel has high chemical stability in air and good stability to alkali. The specific steps are as follows:
Organic solvent degreasing → chemical degreasing → washing → cathode electrolysis activation → flash nickel plating → washing → activation → washing → bright nickel plating → washing → passivation → washing → washing → hot water washing → shake drying → drying → acceptance.
In recent years, there are many kinds of brighteners in the solution of stainless steel bright nickel plating. To sum up, the development of brighteners has experienced four years. The first and most original product is saccharin plus butanediol. It can be plated with bright nickel with high levelness. Its use flourished in the 1960s and 1970s. But as a result of butynediol instability in nickel plating tank, life is short, organic impurities accumulated quickly, need to deal with nickel tank often, so by epichlorohydrin or epoxy propane branches of acetylene with butyl glycol, the synthesis of the second generation of nickel plating brightener, such as BE, 791 brightener, things have improved, and 791 reserves have alkynyl, then progress will pyridine polymerization, Formed the third generation of products, faster light speed, less brightener dosage, longer service life. Now further use of nickel plating brightener intermediate a variety of combinations of new brightener has been developed to the fourth generation of products. It uses less, produces light faster, takes longer processing cycles, and has a stronger ability to deep coat.
Process flow of bright nickel plating on stainless steel: organic solvent degreasing → chemical degreasing (Sodium oxyoxide 40g/L, sodium carbonate 30g/L, trisodium phosphate 50g/L, OP-emulsifier 3mL/L, temperature 80-90 ℃, time 30min)→ washing → cathodic electrolysis activation (Hydrochloric acid solution 1+1, room temperature, DK1-3A /dm2, Time 5min, anode cloth coated carbon plate)→ Flash nickel plating (Nickel chloride 180~220g/L, hydrochloric acid 120g/L, room temperature, current density 4A/dm2, time 5~lOmin, anode nickel plate)→ washing → activation [sulfuric acid 5%(V), time 5s]→ washing → plating bright nickel (time 5~lOmin, Or according to the thickness required time)→ washing → passivation (potassium dichromate 1s0g/L, sodium dichromate 150g/L, sulfuric acid 30~50mL/L, room temperature, time 20~25s)→ washing → washing → hot water washing → drying → drying → acceptance.
Stainless steel through the use of brightener, without polishing direct plating bright nickel, in order to improve the surface hardness, wear resistance and leveling, in the appearance of stainless steel and other nickel plating appearance consistent, and avoid stainless steel and other bright nickel contact potential difference corrosion.
