Sulfuric Acid Brightening Nickel Failure and Its Treatment
Cause Analysis
General stainless steel containing chromium and nickel are high, such as lCr18Ni9Ti, etc., so the surface of a layer of passivation film, especially those after welding and heat treatment of stainless steel, need to go through special pickling and activation in order to get a good adhesion Nickel layer.
Solution
Such parts should be 10% ~ 20% hot sulfuric acid in the loose oxide film, and then in the nitric acid 300mL / L, hydrofluoric acid 1OOmL / L, hydrochloric acid 30mL / L prepared in the solution, at 50 ~ 60 ℃ pickling number minute.
General stainless steel finishing parts are required in the chromium anhydride l50g / L and sulfuric acid 50mL / L solution for several minutes, after cleaning, and then in 1+1 hydrochloric acid erosion, and then quickly rinse with running water, immediately in the following The solution was subjected to impact nickel plating.
Nickel chloride 200 ~ 240g / L
hydrochloric acid 80 ~ 100mL / L
temperature room temperature
cathode current density 5 ~ 8A / dm2
time 2 ~ 3min
cathode movement 20 ~ 25m / min
Finally, in other nickel plating tank thickening
