This standard specifies the apparatuses, the reagents and the procedures to be used in conducting the neutral salt spray (NSS), acetic acid salt spray (AASS) and copper-accelerated acetic acid salt spray (CASS) tests.
The standard is applicable to assessment of the corrosion resistance of metallic material and coating layer, with or without permanent or temporary corrosion protection.
The standard also specifies the method employed to evaluate the corrosivity of the test-cabinet environment.
The standard does not specify the dimensions of test specimens, the exposure period to be used for a particular product, or the interpretation of results. Such details are provided in the appropriate product specifications.
The tests are particularly useful for detecting discontinuities, such as pores and other defects, in metals and their alloys as well as metallic, organic, anodic oxide and conversion coatings.
The neutral salt spray test particularly applies to:
- metals and their alloys;
- metallic coatings (anodic and cathodic);
- conversion coatings;
- anodic oxide coatings;
- organic coatings on metallic materials;
The acetic acid salt spray test is especially useful for testing decorative coatings of copper + nickel + chromium, or nickel + chromium. It has also been found suitable for testing anodic coatings on aluminum.
The copper-accelerated acetic acid salt spray test is useful for testing decorative coatings of copper + nickel + chromium, or nickel + chromium. It has also been found suitable for testing anodic coatings on aluminum.
The test is all suitable for checking that the comparative quality of a metallic material, with or without corrosion protection but not intended to be used for comparative testing as a means of ranking different materials relative to each other with respect to corrosion resistance.
2 Normative References
The following documents for the application of this document are essential. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1514:2004 Paints and Varnishes Standard panels for Testing
ISO 2808:2007 Paints and Varnishes Determination of Film Thickness
ISO 3574:1999 Cold-reduced Carbon Steel Sheet of Commercial and Drawing Qualities
ISO 8407:2009 Corrosion of Metals and Alloys Removal of Corrosion Products from Corrosion Test Specimens
ISO 17872:2007 Paints and Varnishes Guidelines for the Introduction of Scribe Marks through Coatings on Metalie Panels for Corrosion Testing
3 Test Solutions
3.1 Preparation of the Sodium Chloride Solution
Dissolve a sufficient mass of sodium chloride in distilled or deionized water with a conductivity not higher than 20μS/cm at 25℃±2℃ to produce a concentration of 50g/L±5g/L. The sodium chloride concentration of the sprayed solution collected shall be 50g/L±5g/L. The specific gravity range for a 50g/L±5g/L solution is 1.029 to 1.036 at 25℃.
