Acid galvanized nickel alloy: coating after passivation

Corrosion resistance test is as follows

(1) Experimental method

1 plating A3 steel plate from the alkaline plating solution containing nickel l% ~ l5%

2 Passivation paint The plating is passivated or phosphatized by chromate and dip coated with acrylic varnish, polyurethane varnish and amino baking paint, respectively.

3 Corrosion test:

a. The impregnation with 5% NaCl aqueous solution was used to measure the change of electrode surface potential and soaking time.

b. The test piece was hung in the 600mm position above the 40% hydrochloric acid tank, and the relative humidity was 80%. The change was observed by the acid mist corrosion.

c. Potentiodynamic scanning (1 mV/s) was used to measure the anodic polarization curve in 5% sodium chloride solution after painting of different coatings.

(2) Test results

1 After coating the film with the same conditions, the corrosion resistance of the zinc-nickel alloy coating containing 10% to 15% of nickel is superior to that of the nickel-containing zinc nickel alloy coating containing 1% to 3% of nickel.

2 In a 5% sodium chloride solution, the passivated and painted coating is more stable than the phosphatized and painted coating.

3 The ability of resistance to hydrochloric acid mist, passivated zinc-nickel alloy coating is stronger than the phosphating treatment.

4 Nickel-nickel alloys containing 10% to 15% nickel in a wide range of passivation potentials under anodic polarization conditions.

5 In the 5% sodium chloride solution, the paint film first peeled off, and then the plating corrosion occurred.