Test method for salt spray

Neutral Salt Spray Test (NSS)

The neutral salt spray test is a method of accelerated corrosion testing and is carried out in a dedicated salt spray chamber. It is suitable for the corrosion resistance inspection of galvanizing, cadmium, oxidation and phosphating coatings on steel parts.

The saline prepared for the neutral salt spray test was 5% NaCl solution, the pH was 6.5~7.2, and the temperature in the chamber was 35±2? C, the relative humidity is more than 95%.

Neutral salt spray test spray sedimentation is 1mL~2Ml/80cm?? h, the concentration of collected salt spray NaCl should be 5±1%, the PH should be 6.5~7.2, and the nozzle pressure should be 0.07MPa~0.1 Mpa.

Steps of the neutral salt spray test:

(1) Use organic solvent to clean the surface of the specimen, so that the surface of the specimen is free of oil stains and other items that corrode the plating.

(2) Place the test piece in a salt spray box, and the test surface of the test piece is facing up and the vertical line is 15?~30?.

(3) Salt spray test according to the provisions of the inspection cycle.

(4) Take out the sample and gently rinse it with running water or gently wipe the surface with sponge with water to remove the salt deposits, and then remove the salt deposits at 80? C～ 100? C drying for about 30min.

(5) Evaluate the corrosion level of the sample.

Acetate spray test (ASS method)

It is mainly suitable for the corrosion resistance test of copper-nickel-chromium or nickel-chromium and other decorative coatings, and the acetate spray solution used for the resistance test is prepared with chemically pure glacial acetic acid, with a pH of 3.0~3.1 and a spray collection solution PH of 3.2±0.1.

Copper Salt Accelerated Acetate Spray Test (CASS Method)

It is mainly suitable for the corrosion resistance test of copper-nickel-chromium or nickel-chromium and other decorative coatings on steel parts and zinc die castings, and is also suitable for the corrosion resistance test of aluminum and aluminum alloy anodized films.

The preparation method of the test salt solution is as follows: the NaCl solution is prepared according to the neutral salt spray test method. 0.26±0.02g/L of chemically pure copper chloride (CuCl2?2H2O) was added to NaCl solution, and the pH was adjusted to 3.0~3.1 with chemically pure glacial acetic acid.

The test temperature is 50±1? C. The PH of the spray collection solution is 3.2±0.1, and other requirements are the same as those of the neutral salt spray test.