Kesternichtest

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Kesternichtest is a common name for the corrosion test with sulfur dioxide under general moisture condensation. This test was developed in 1951 by Wilhelm Kesternich to simulate the damage effects of acid rain. The test can be used for coatings or for base materials. The test method is defined by various standards (DIN EN ISO 6988, DIN 50018). The parts to be tested are placed in a test chamber and exposed to warm, moist air in combination with a certain amount of sulfur dioxide. The test is usually carried out in cycles of 24 hours each.

Test facility

The test chamber usually has a volume of approx. 300 l. Larger or smaller test chambers are also possible, but for a standardized process, the amount of water and the amount of sulfur dioxide must be proportionally adapted to a chamber volume other than 300 l. The material of construction of the inner housing of the chamber and the devices for placing the samples must be made of inert and corrosion-resistant materials so that there is no reaction between the sample to be tested and the material of the chamber.

principle

The principle of the test is simple: A defined amount of distilled or deionized water is poured into the floor pan of the test chamber. The samples are placed in the chamber above the water level. The door or hood of the chamber is tightly closed. A fixed amount of sulfur dioxide is introduced into the chamber. Attention: observe the safety regulations! The chamber is heated to 40 ° C by a regulated heating device. At the end of a test cycle or before the chamber is opened, the sulfur dioxide-containing air in the chamber must be exchanged for fresh air. Caution: The air containing sulfur dioxide must not be released into the room air. The test duration depends on the specification.

After the exam

Take samples from the chamber and let them dry in the room air. An initial assessment is made before any corrosion products are removed. When the tested parts are cleaned, the evaluation criteria must be taken into account.

evaluation

Possible characteristics for evaluation: appearance after the test, appearance after removal of the corrosion products, number and size of imperfections, time until the first appearance of corrosion, loss of mass. The results are described in a test report.

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  • DIN EN ISO 6988 Metallic and other inorganic coatings - Test with sulfur dioxide with general moisture condensation, March 1997.
  • DIN 50018 testing in an alternating condensation climate with an atmosphere containing sulfur dioxide, June 1997.
  • The importance of corrosion test procedures with special consideration of the SO2 test according to DIN 50018, Wilhelm Kesternich, published in Materials and Corrosion Volume 16, Issue 3, pages 193-201, March 1965.