How are corrosion coupons handled before testing?

Corrosion coupons are specifically designed pieces of material used to monitor the rate of corrosion in a given environment. Before testing, it is crucial to handle these coupons properly to ensure that the results reflect the actual corrosion processes occurring in the system, without contamination or damage to the coupons.

Keeping corrosion coupons in specially treated envelopes is an important practice because these envelopes serve to protect the coupons from environmental contaminants, oils, and moisture that could interfere with the test results. The envelopes are often made from materials that do not react with the samples and are treated to remove any potential sources of contamination. This ensures that when the coupons are tested, their integrity and the conditions they are exposed to remain consistent and valid for accurate corrosion assessments.

In contrast, options such as touching them with bare hands or placing them in water can lead to contamination, which could yield misleading results in testing. Cleaning with solvents might not be advisable either, as some solvents can potentially leave residues or chemically alter the surface of the coupons. Thus, maintaining a controlled and contamination-free environment through specialized envelopes is the best approach for accurate testing and monitoring of corrosion.