Raindrops Can Cause Car Corrosion Through Electrical Charges, Study Finds

3:15 PM ETDeveloping

Science Desk

In Short: A new study reveals that raindrops can carry electrical charges, potentially causing corrosion even when protective coatings are present.

Raindrops can carry electrical charges, according to a new study published in the journal PLoS ONE. This phenomenon, known as "slide electrification," has been quantified for the first time, providing a deeper understanding of how rain can cause corrosion. The study, led by Zhongyuan Ni, Rüdiger Berger, and Hans-Jürgen Butt at the Max Planck Institute for Polymer Research in Mainz, Germany, found that once a protective coating is breached, a water drop can carry a charge large enough to punch through the coating, initiating corrosion.

The researchers used advanced techniques such as Raman spectroscopy and X-ray diffraction to identify the corrosion products on copper. They observed that as water droplets slide down common surfaces, including leaves and a commercial kind of glass called polystyrene glass, they can pick up an electrical charge. This charge can then be transferred to materials with the right electrical properties, including metals, leading to degradation.

The study suggests that the standard explanation for rain-induced corrosion, which involves water carrying dissolved salts and acids and constant abrasion, is not the whole story. Instead, the electrical charge carried by raindrops can directly damage protective coatings, allowing corrosion to begin even when a protective layer is present. This finding could have significant implications for industries that rely on protective coatings, such as the automotive and construction sectors.

The impact of corrosion on the global economy is substantial, and this new understanding could lead to the development of better anticorrosion coatings. Stefan Weber, a physicist at the University of Stuttgart in Germany who was not involved in the study, believes that this work could pave the way for improved protective measures. Weber notes that earlier research had shown that sliding along many surfaces causes water drops to become charged, but this study represents a step forward by linking this charge to the initiation of corrosion.

The study's findings could also have broader implications for infrastructure and public works, where metal structures like bridges and monuments are vulnerable to corrosion. By understanding the role of electrical charges in corrosion, engineers and scientists may be able to develop more effective strategies to prevent and mitigate this damage.

In conclusion, the new study provides a fresh perspective on the mechanisms of corrosion caused by rain. By recognizing the role of electrical charges in damaging protective coatings, researchers and industry professionals can develop more effective strategies to protect metal structures from corrosion. This breakthrough could lead to significant advancements in anticorrosion technologies, benefiting a wide range of industries and infrastructure projects.

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Sources

Ars Technicalink