Suolasumutesti

Suolasumutesti, known in English as the salt spray or salt fog test, is a standardized corrosion test used to evaluate the resistance of coatings and metal substrates to corrosive environments containing saline mist. The test aims to provide a controlled, accelerated method to predict long-term performance under exposure to seawater or de-icing salts.

In a typical procedure, prepared samples are placed in a closed chamber where a saline solution, usually 3.5% sodium chloride, is atomized to form a fine mist. The mist is maintained at a controlled temperature, commonly around 35°C, with regulated humidity and airflow. Depending on the specification, exposure can be continuous or cyclic, and test durations range from several hours to thousands of hours. Variants exist, including neutral salt spray (NSS), copper-accelerated acetic acid salt spray (CASS), and acetic acid salt spray (ACSS), each with distinct chemical environments to stress different coating systems.

Standards and variations are internationally recognized, with ISO 9227 and ASTM B117 among the most widely used guidelines. EN 60068-2-52 provides further methods for salt spray testing in European contexts. Results are typically evaluated by visual inspection and/or supplemental measurements such as adhesion tests or mass loss. Rating scales describe the extent of corrosion, coating delamination, or rust formation on the substrate.

Applications include quality control in coating manufacture, comparison of different coating systems, and product development. While useful for screening and comparison, the salt spray test is not a direct replica of real outdoor conditions and may over- or under-predict performance for specific environments.