Salt Spray Test

Salt spray corrosion is one of the most common and destructive atmospheric corrosion.

Salt spray test is a kind of environmental test which mainly uses artificial simulated salt spray environmental conditions created by salt spray test equipment to assess the corrosion resistance of products or metal materials. It is divided into two categories, one is the natural environmental exposure test, the other is the artificial accelerated simulated salt spray environmental test.

Artificial simulated salt spray environment test is to use a test equipment with a certain volume space - salt spray test chamber, in its volume space with artificial methods to create a salt spray environment to assess the quality of the product's salt spray corrosion resistance. Compared with the natural environment, the salt concentration of chloride in the salt spray environment can be several times or dozens of times the salt spray content in the general natural environment, which greatly improves the corrosion rate, conducts salt spray test on the product, and greatly shortens the time to obtain the results.

Reference standard:

GB/T 2423.17; IEC 60068-2-11;  GB/T 10125;  ISO 9227;  ASTM B 117;

GB.T 2423.18; IEC 60068-2-52;  ASTM B 368;  MIL-STD-202;  EIA-364-26

Artificial simulated salt spray test includes: neutral salt spray test, acetate spray test, copper salt accelerated acetate spray test, alternating salt spray test.

(1) Neutral salt spray test (NSS test)

It is the earliest and most widely used accelerated corrosion test method. It uses 5% sodium chloride brine solution, the PH value of the solution is adjusted in the neutral range (6 ~ 7) as the spray solution. The test temperature was set at 35℃, and the sedimentation rate of salt spray was required to be between 1 ~ 2ml/80cm2.h.

(2) Acetate spray test (ASS test)

It was developed on the basis of the neutral salt spray test. It is to add some glacial acetic acid to 5% sodium chloride solution, so that the PH value of the solution is reduced to about 3, the solution becomes acidic, and the salt spray finally formed is also changed from neutral salt spray to acidic. Its corrosion rate is about 3 times faster than the NSS test.

(3) Copper accelerated acetate spray test (CASS test)

It is a rapid salt spray corrosion test recently developed abroad, the test temperature is 50℃, and a small amount of copper salt - copper chloride is added to the salt solution to strongly induce corrosion. Its corrosion rate is about 8 times that of the NSS test.

(4) Alternating salt spray test

It is a comprehensive salt spray test, which is actually a neutral salt spray test plus a constant wet heat test. It is mainly used for cavity type machine products, through the penetration of tidal environment, so that salt spray corrosion is not only produced on the surface of the product, but also in the product. It is to convert the product alternately under the two environmental conditions of salt spray and wet heat, and finally check whether the electrical and mechanical properties of the whole product have changed.

Equipment parameters: