What is Salt Spray Testing?

The salt spray testing, or salt fog test) is a standardized and popular corrosion test method used to check the corrosion resistance of materials and surface coatings. Usually, the materials to be tested are metallic.

Salt spray testing is an accelerated corrosion test that produces a corrosive attack to coated samples in order to evaluate the suitability of the coating for use as a protective finish. The appearance of corrosion is evaluated after a pre-determined period of time. Test duration depends on the corrosion resistance of the coating; generally, the more corrosion resistant the coating is, the longer the period of testing before the appearance of corrosion or rust.

The salt spray test is one of the most widespread and long-established corrosion tests. ASTM B117 was the first internationally recognized salt spray standard, originally published in 1939.