What Does Copper Accelerated Acetic Acid Salt Spray Test (CASS Test) Mean?
The copper accelerated acetic acid salt spray (CASS) test is a method discovered in 1945 that involves adding acetic acid to a solution containing salt used in salt spray tests. This method is much more corrosive than the ordinary salt spray method of testing.
The copper accelerated acetic acid salt spray (CASS) test is also known as fog testing.
Corrosionpedia Explains Copper Accelerated Acetic Acid Salt Spray Test (CASS Test)
The copper accelerated acetic acid salt spray test is a standardized test utilized to check coated samples for corrosion resistance.
This test is a form of accelerated corrosion test of that yields a corrosive attack to the covered samples to predict suitability of a protective finish. Corrosion products like oxide are assessed after a certain period. The duration of the test depends on the type of corrosion resistance coating. Hence, the higher corrosion resistance the coating has, the longer the time before signs of corrosion are observed.
This type of test is widely used because it is:
- Cost effective
- Well standardized
However, there is only a small association between the test duration and the coating's life expectancy, especially in cases of galvanized steel that involve thorough drying cycles for increased durability. Nevertheless, this test is commonly used in various industrial sectors for corrosion resistance evaluation of finished parts and surfaces.
The types of coatings that can be assessed through the copper accelerated acetic acid salt spray test include:
- Phosphate surfaces (with successive primer, paint, rust preventive, lacquer)
- Copper, tin, nickel, electroplated chromium
- Zinc flake and other coatings that are not electrolytically applied
- Zinc alloy and plain zinc plating
- Organic coatings
This test is widely employed in industrial settings. It is very beneficial for replicated service evaluation, development and research as well as manufacturing control. Specifically, it is developed for electrodeposited, decorative chromium/nickel as well as chromium/nickel/copper.
Utilizing this test leads to enhanced electroplated parts quality and the creation of finer electroplating processes.