1 Salt spray corrosion
Corrosion is the material or its performance in the role of the environment arising from the destruction or degeneration. Salt spray corrosion is a common and the most destructive atmospheric corrosion. Salt spray contains a high concentration of mineral salts, particularly chloride anions. Salt spray corrosion on the surface of metal materials due to the chloride ion penetrating the surface of the metal oxide and protective layer. At the same time, a chloride ion has some hydration energy, easily absorb on pores, cracks of the metal surface and replace the oxygen of chlorination, change the insoluble oxides into the soluble chloride, the passive state into a lively surface. It affects a very bad side effect of product.

2 Salt spray tests
Salt spray test is an accelerated corrosion test that produces a corrosive attack to the coated samples in order to predict its suitability in use as a protective finish. It is can be divided into two categories, one is artificial atmospheres exposure test, and the other is artificial accelerated stimulation salt spray tests. Artificial accelerated stimulation salt spray tests include the neutral salt spray (NSS), acetic acid salt spray (AASS) and copper-accelerated acetic acid salt spray (CASS) tests, alternation change salt spray test.

3 Salt spray standards
Salt spray standards describe the necessary condition information to carry out this test; testing parameters such as temperature, humidity, concentration of sodium chloride, pH, etc. Select which salt spray standard according to salt spray characteristic, corrosion speed of metal and sensitivity of salt spray. The following is some test standards, such as GB/T 2423.17-1993 Basic environmental testing procedures for electric and electronic products Test Ka: Salt mist, GB/T 2423.18-2000 environmental test for electric and electronic products, GB/T1771—91 Paints and varnishes performance test of nature salt spray.