Corrosion resistance testing conducted in accordance with ISO 9227 or ASTM B117-19 is aimed at verifying the effectiveness of protective paint systems, protective coatings, temporary protection, as well as corrosion resistance of other uncoated materials. Salt mist / acid salt mist / acid salt mist with the addition of an accelerator is produced in the chamber where the temperature is kept at a constant point of 35 ± 2 ° C / 50 ± 2 ° C depending on the method. The conducted comparative tests allow to determine the influence of an aggressive environment on the quality of tested samples, structures or elements after a defined period of time. After exposure of tested objects, coating degradation can be observed, in particular blistering, corrosion, peeling, cracks, filiform corrosion, or corrosion at the discontinuity of the coating when the plates are cut. This allows for a comprehensive analysis of the resistance of coatings and construction materials. It provides information on the quality of paints, coating systems or security measures applied to structures. The detected inconsistencies in the results may be caused by improper preparation and coating of elements. The tests allow you to verify whether a given product meets the declared requirements / classes.
The test conditions depend on the application-oriented method
In the atmosphere of neutral salt spray, the following are mainly evaluated.
- metals and their alloys
- metallic coatings (anodic, cathode)
- conversion coatings
- anodically oxidized coatings
- organic coatings on a metallic substrate
Method AASS or CASS (copper method) in the acid salt spray are used to run tests on following objects:
- decorative coatings
- anode coatings on aluminium
- organic coatings on aluminium
Depending on the client’s needs, laboratory analysts help in selecting the appropriate research methodology.
The laboratory is equipped with salt chambers of various dimensions. This allows you to evaluate both standard samples and entire elements of large-size structures.
Stable conditions in the chamber are crucial for the proper test conduct. Test parameters are checked daily and registered. The samples are exposed at the right angle and arranged so as not to disturb the course of the research. During the exposure, in the event of exceeding the specified required values related to the result, the laboratory informs the customer about this fact. Customer decides whether to continue or cease the test. We regularly conduct environmental corrosivity assessments in the chambers to ensure the necessary repeatability and reproducibility of the obtained results. Reference samples are exposed for an appropriate time, defined in a standard document, and then cleaned and the weight loss is determined. Thanks to verifications both laboratory employees and customers rest assured that the devices are working properly.
In addition to standard tests, conducted individually to assess corrosion resistance, salt spray tests are also used in cyclic tests or evaluating the protective properties of paint systems, as one of the components used to confirm the declared corrosivity category and durability period of a given product / coating system.