SST – Salt Spray Test Resistance Chamber Analysis
- May 26, 2019-
Salt Spray Test (SST) is a really widespread corrosion method, applied in order to check materials and surface coatings corrosion resistance. This kind of test is an accelerated corrosion test which produces a corrosive attack to coatings to evaluate, after a pre-determined period of time, if they can be used as a protective finish. The duration of Salt Spray Test depends on coating corrosion resistance: if the coating has high corrosion resistance, the testing period is longer before the appearance of corrosion.
It can be used for different materials such as: zinc, phosphate surfaces, electroplated chromium, nickel, copper and tin and also for paint coating. Moreover Salt Spray testing is fundamental in order to evaluate product or component corrosion aimed at outdoor uses or in cold or wet environments.
Summarizing it is possible to say that Salt Spray test is used to:
Analyze corrosive resistance of different materials and finishing
Measure the corrosive inclination when a metal or coating is scratched
Determine coating adhesion and corrosion creep
Evaluate corrosion resistance in a marine environment
Products without SSL resistance would corrode under saline air influence.
Salt Spray test (SST) is really widespread because of its many advantages: it is quite inexpensive, multi material, quick, standardized and repeatable.
It is done using a salt spray chamber where inside are inserted parts or components to be tested. In fact Salt Spray test is used to predict which materials will resist corrosion in real conditions. The apparatus for testing is composed by a closed testing chamber, where salt water solution is sprayed due to pressurized air.
The classic Salt Spray test is atomizing salt solution into a chamber supported or suspended between 15-30° from the vertical. This solution is made of 5% of NaCI (Sodium Chloride), while the exposure zone is maintained at 35° C. The test is continuous for the entire period of test: the period can reach more than 1000h.
The consequence is an environment extremely corrosive made of dense salt water fog in this chamber where samples are exposed to it and to corrosive conditions