Salt spray corrosion
Nov 21, 2019| Shenzhen Shenchuang Hi-tech Electronics Co., Ltd(SChitec) is a high tech enterprise which specialized in phone accessories production and sales. Our main products include travel chargers, car chargers, USB cables, power banks and other digital products.All products are safe and reliable, with unique styles.products pass certificates like CE,FCC,ROHS,UL,PSE,C-Tick,etc, If you are interested in, you can contact ceo@schitec.com directly.
Stay Charging Safely with SChitec
Salt spray corrosion
Corrosion hazard
Salt spray corrosion will destroy the metal protective layer, make it lose its decoration and reduce the mechanical strength; some electronic components and electrical circuits will be interrupted by corrosion, especially in the vibration environment; when the salt spray falls on the insulator surface, it will reduce the surface resistance; after the insulator absorbs the salt solution, its volume resistance will be reduced by four numbers The moving parts of mechanical parts or moving parts increase friction due to the generation of corrosive substances, so that the moving parts are stuck.
corrosion mechanism
The corrosion of metal materials by salt spray is mainly due to the electrochemical reaction of the conductive salt solution penetrating into the metal, forming a "low potential metal electrolyte solution high potential impurity" micro battery system, electron transfer, dissolution of the metal as the anode, forming a new chemical compound, i.e. corrosion compound. The metal protective layer and the organic material protective layer are the same. When the salt solution as the electrolyte penetrates into the interior, a micro battery with metal as the electrode and metal protective layer or organic material as the other electrode will be formed.
Chloride ions play an important role in the process of salt spray corrosion. It has a strong penetration ability, easy to penetrate the metal oxide layer into the metal, and damage the metal blunt state. At the same time, chloride ion has a very small hydration energy, which is easy to be adsorbed on the metal surface, replacing the oxygen in the oxide layer to protect the metal and damaging the metal.
In addition to chloride ions, the mechanism of salt spray corrosion is also affected by oxygen dissolved in the salt solution (essentially the salt film dissolved on the surface of the sample). Oxygen can cause the depolarization process of the metal surface and accelerate the dissolution of the anode metal. Because of the continuous spray during the salt spray test, the salt film on the surface of the sample continuously settles, so that the oxygen content is always kept near saturation. The formation of corrosion products makes the volume of salt solution infiltrated into metal defects expand, thus increasing the internal stress of metal, causing stress corrosion, leading to bulge of protective layer.