Salt Spray Testing (One)
Salt spray test is an environmental test that mainly uses the artificial simulated salt spray environmental conditions created by salt spray test equipment to evaluate the corrosion resistance of products or metal materials. It is divided into two categories, one is natural environmental exposure test, the other is 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 to create a salt spray environment by artificial method in its volume space to evaluate the salt spray corrosion resistance and quality of products. Many products will shorten their service life after corrosion. Products from hand tools to bridges must be properly designed and coated to deal with this phenomenon.
a. Neutral Salt Spray TestingNeutral salt spray test is one of the earliest and most widely used accelerated corrosion test methods. Under normal circumstances, it uses 5% NaCl solution and the pH value is adjusted to neutral range (6.5 to 7.2) as a spray solution. The test temperature is 35 ℃, and the sedimentation rate of salt spray is required to be 1 ~ 3ml / 80cm2 H, the settlement is generally 1 ~ 2ml / 80cm2 H.
b.Acetate MistAcetate spray test is developed on the basis of neutral salt spray test. It is to add some glacial acetic acid to 5% sodium chloride solution to reduce the pH value of the solution to about 3, turn the solution into acid, and finally form a salt mist from neutral salt mist to acid. Its corrosion rate is about 3 times faster than that of NSS test.
c. Copper Salt Accelerated Acetate SprayCopper salt accelerated acetate spray test is a rapid salt spray corrosion test developed recently 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 NSS test.
d.Alternating Salt Spray
Alternating salt spray test is a comprehensive salt spray test, which is actually a neutral salt spray test plus constant damp heat test. It is mainly used for cavity type complete machine products. Through the penetration of humid environment, salt spray corrosion occurs not only on the surface of the product, but also inside the product. It is to alternately convert the product under salt fog and humid and hot environmental conditions, and finally check whether the electrical and mechanical properties of the whole product have changed.
This article mainly introduces the definition of salt spray test and corrosion, as well as the classification of salt spray test. The next article will introduce the standards of salt spray test and the steps of salt spray test. If you are interested in this topic, you can follow us, or you are welcome to contact us if you have any comments.