How can I determine the atmospheric corrosion performance of thermal spray coatings?

Frequently Asked Questions

Coating corrosion performance can be evaluated while the coating is subjected to a corrosive atmosphere. One approach is to use a salt spray test in which a corrosive solution is atomised onto the test piece in an enclosed chamber. The salt spray solution can be neutral or modified to be more acidic for example.

An alternative approach is the saline droplet corrosion test, where a pattern of discrete droplets of a specified test solution are placed on the surfaces being tested. The test specimen is stored in conditions of high humidity, and the test solution reapplied only when it is needed to maintain the pattern of droplets.

Some standards relative to corrosion testing in a corrosive atmosphere are:

• ASTM B117: Standard practice for operating salt spray (fog) apparatus
• ASTM G85: Standard practice for modified salt spray (fog) testing
• ISO 4536: Metallic and non-organic coatings on metallic substrates - Saline droplets corrosion test (SD test)
• ISO 4538: Metallic coatings. Thioacetamide corrosion test (TAA test)
•  
• ISO 4541: Metallic and other non-organic coatings. Corrodkote test (CORR test)
• ISO 6988: Metallic and other non-organic coatings. Sulfur dioxide test with general condensation of moisture

• ISO 10289: Methods for corrosion testing of metallic and other inorganic coatings on metallic substrates -- Rating of test specimens and manufactured articles subjected to corrosion tests

• ISO 9227: Method for salt spray corrosion tests in artificial atmospheres

For further information about Materials & Corrosion Management or please contact us.