A salt spray test chamber is an accelerated corrosion environmental testing device. The primary causes of metal corrosion include oxygen, salt particles, pollutants in the air, as well as changes in temperature and humidity. Without proper protection, metal products exposed to long-term use will eventually corrode, affecting both their appearance and functionality. Therefore, salt spray testing is essential before manufacturing metal products to determine material selection and protective measures.

If relying solely on natural atmospheric conditions, such testing would require significant time, labor, and financial resources. Salt spray test chambers reduce these costs by conducting efficient accelerated testing. So, how do they simulate atmospheric conditions for salt spray testing? Let’s delve into the working principle.

To accelerate corrosion, the salt solution concentration used in salt spray test chambers is typically several times or even dozens of times higher than that found in the natural atmosphere. The prepared solution is added to the chamber, and compressed air is delivered to a nozzle. Under pressure, the saline solution is ejected as a fine mist of tiny salt droplets, which are evenly sprayed onto the test specimens. Continuous spraying for 24 to 72 hours leads to the formation of corrosion spots. To speed up the test, the solution concentration and spray volume can be increased.

The later corrosion spots appear, the better the material’s corrosion resistance; conversely, earlier corrosion indicates weaker resistance.

Salt spray corrosion testing is essentially a chemical reaction process. Chloride ions in the salt solution penetrate the metal’s oxide layer, disrupting its stability. These ions continuously adhere to the metal surface, causing persistent damage.

While the principle of a salt spray test chamber is relatively simple, corrosion in natural environments is ever-present, making this test indispensable for product quality control across many industries. Understanding how the device works allows companies to adjust the equipment and test solutions according to their specific product requirements.