Salt mist/spray test is a standardized test method to check corrosion resistance of coatings and entire products. Corrosion not only affects metals, but also high-alloyed, tempered materials, plastics and painted surfaces. The test duration depends on the environmental conditions of the product in real life. High humidity, salty air, seawater and gritting salt influence corrosiveness of the product.
Salt mist/spray testing is popular because it is quick and well-standardized. To accelerate the corrosion, it is possible to introduce scratches in a coating. The length of the dendrites formed during the corrosion test is a coating quality measure. Salt mist testing is often used for quality control of materials and less for predicting the lifetime of a product in the real world.
For the execution of a salt mist/spray test, it is important to define which standard to use, how long samples should be exposed, what the inspection criteria are, inspection frequency and ways to characterize failure.