Salt Spray Test
The test is simulating salt spray environment to check the corrosion resistance of coated metal or nonmetal materials. The strict level for test is determined by exposure duration.
Three types of laboratory simulating salt spray: NSS, ASS and CASS.
(1) NSS (Neutral Salt Spray) is the earliest test method and widely used recently. The salt solution concentration shall be 5% and the pH range is between 6.5 and 7.2, the test temperature of the salt spray chamber shall be maintained at 35℃, also sedimentation of salt solution shall be 1-2ml/80cm2/h.
(2)ASS (Acetic Acid-Salt Spray) is developed based on NSS. ASS adds some glacial acetic acid to 5% Nacl solution, to get a pH of 3, the solution becomes acid so the fog. Finally, the acidic solution can accelerate the corrosion rate to 3 times of NSS. 3)CASS (Copper-Accelerated Acetic Acid-Salt Spray) is a new method of accelerated salt spray test. The temperature in chamber is 50℃, the solution contacts some copper dichloride, so it can get a intense corrosion. The corrosion rate can be accelerated to about 8 times of NSS.
Test standard for reference
GB/T 2423.17，IEC60068-2-11,ISO4628-3, ASTM B117, JIS-Z2371, JIS-G3141, GJB 150.1, MIL-STD-810F, MIL-STD-883E etc