Corrosion testing by immersion is a common method used to evaluate the corrosion resistance of materials, especially metals. This test involves immersing a test specimen in a solution of salt water with a concentration of 5% (by weight) for a specified period of time.

The test conditions can vary depending on the standard or specification being followed, but typical test parameters may include a temperature of 25°C to 35°C and a test duration of several hours to several weeks. During the immersion test, the test specimen is periodically examined to evaluate the degree of corrosion that has occurred.

The degree of corrosion is typically evaluated using a rating system, such as the ASTM G31 standard, which assigns a numerical value to the degree of corrosion based on the appearance of the specimen. The corrosion products that form on the surface of the specimen can also be analyzed using techniques such as microscopy or spectroscopy to provide more detailed information about the corrosion process.

Immersion testing in 5% salt water is a relatively simple and cost-effective method for evaluating the corrosion resistance of materials, and it can provide useful information for material selection and product design. However, it is important to note that the results of this test may not always accurately reflect the actual corrosion performance of a material or coating in real-world applications, and other types of corrosion testing may be necessary to fully evaluate the material’s performance