The salt spray tester adopts salt-containing solvent or acidic salt-containing solvent to accelerate corrosion of materials or products under a certain temperature and relative humidity environment to reproduce the degree of damage to the material or product within a certain period of time. What is the corrosion mechanism of the salt spray tester?
The corrosion of metal materials by the salt spray tester is based on the fact that the conductive salt solvent penetrates into the metal and undergoes an electrochemical reaction to form a "low-potential metal-electrolyte solvent-high potential impurity" microbattery system. The electron transfer takes place and the metal as an anode appears. Dissolve and form new compounds as corrosion products.
Similarly for the metal protective layer and the organic material protective layer, when the salt solvent as an electrolyte penetrates into the interior, a micro-battery with a metal as an electrode and a metal protective layer or an organic material as another electrode is formed.
Chloride ions play a major role in the corrosion damage of the salt spray tester. It has a strong penetrating power, easily penetrates the metal oxide layer into the metal, and destroys the passive state of the metal. At the same time, chloride ions have very little hydration energy and are easily adsorbed on the surface of the metal, replacing the oxygen in the oxide layer of the protective metal and destroying the metal.
In addition to chloride ions, the salt spray tester is also affected by oxygen dissolved in a salt solvent (substantially a salt solution that dissolves on the surface of the sample). Oxygen can cause the depolarization process on the metal surface, accelerate the dissolution of the anode metal, and continue to spray during the salt spray test, and continuously settle the salt liquid film on the sample surface, so that the oxygen content is always kept near saturation. The formation of the corrosion product expands the volume of the salt solvent penetrating into the metal defect, thereby increasing the internal stress of the metal, causing stress corrosion, and causing the protective layer to swell.
Customized Medical Blister,Hot-Pressed Paper Blister,Disposable Medical Products Sterile Blister,Disposable Medical Blister Packaging
Dong Guan Yi He Medical Packaging Technology Co.,Ltd , http://www.yhmedicalpack.com