Salt spray testing is a standardized and popular corrosion test method, used to check corrosion resistance of materials and surface coatings. The appearance of corrosion products (rust) is evaluated after a pre-determined period of time.
In the salt spray test, samples are placed in an enclosed chamber built to standard specification and subjected to un-interrupted indirect fog or spray of a salt water solution. This environment is maintained throughout the duration of the test. Chamber construction, testing procedure and testing parameters are standardized under National and International standards like ASTM B117 and ISO 9227.
The temperature is maintained at 35°C, with a pH range of 6.5 to 7.2 and salt atmosphere of 5 parts sodium Chloride to 95 parts water, introduced into the chamber at specific air pressure. The salt spray test standard is extensively used to measure normal corrosion resistance to ocean water type environments. Test duration depends on the specification at the corrosion resistance of the material.
Salt spray test is used to :
Relate the corrosive resistance of various materials to determine coating adhesion and corrosion creep.
Evaluate corrosion resistance in a marine environment.
Salt spray testing is popular as it is well standardized and rationally repeatable. Salt spray tests are extensively used for the evaluation of corrosion resistance of parts or finished surfaces in :
Aircrafts and Military Equipment