What Does Copper Accelerated Salt Spray Test (CASS Test) Mean?
A Copper Accelerated Salt Spray Test (CASS Test) is a test used to determine the resistance to corrosion of aluminum alloys. The test also is used to determine the corrosion resistance of chromium plating found on steel and zinc die casings. It was initially used to test decorative coating originating from nickel, copper or chromium that was electrodeposited onto the metal's surface.
The test has allowed organizations to produce new and superior electroplating processes.The use of the test includes areas such as research and development(R & D), manufacturing control processes, specification acceptance and simulated service evaluations.
Corrosionpedia Explains Copper Accelerated Salt Spray Test (CASS Test)
A CASS test is carried out by using 95 parts of water to 5 parts by weight of salt to make a standard ASTM B 117 solution. A reagent of grade copper chloride is then added, which dehydrates at the rate of 1g to 4 liters of the solution. The solution is then atomized after mixing, and the cabinet is maintained at 490C (1200F). The fog is then collected, tested and the solution adjusted to a pH between 3.1 and 3.3. This is done by adding the reagent-grade glacial acetic acid.
Samples have multilayered, plated or coated edges that are coated to prevent edge corrosion. When the test cabinet is ready, the metallic and the metallic-coated samples are cleaned using an appropriate cleaning solution. The organic and non-metallic samples are not cleaned. The samples are placed at a 15-degree angle from the vertical position. Components used for automobile or aerospace are placed in an "as used" position. During testing, the samples can be rotated 180 degrees. When testing is conducted, the required time is 24 hours, but time may be added. The ideal option is to evaluate the samples at any interval and then return the samples to the cabinet.
This method prescribes the required conditions in copper-accelerated acetic acid-salt spray (CASS) testing for the purposes of specification. The test also is applicable for the testing of anodized aluminum. It evaluates the corrosive performance of copper, nickel or chromium.