{"id":5712,"date":"2026-09-10T10:00:54","date_gmt":"2026-09-10T01:00:54","guid":{"rendered":"https:\/\/ohtavn.com\/?post_type=media&p=5712"},"modified":"2026-09-07T20:06:30","modified_gmt":"2026-09-07T11:06:30","slug":"mechanism-and-solution-of-contact-corrosion-of-dissimilar-metals-electrolytic-corrosion","status":"publish","type":"media","link":"https:\/\/ohtavn.com\/en\/media\/mechanism-and-solution-of-contact-corrosion-of-dissimilar-metals-electrolytic-corrosion\/","title":{"rendered":"Mechanisms and solutions for galvanic corrosion of dissimilar metals (electrolytic corrosion): Guide to selecting optimal screws for procurement in Vietnam"},"content":{"rendered":"
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Introduction<\/h3>\n<\/div>\n
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In manufacturing, ensuring long-term product life and reliability is an eternal challenge. Particularly in high-temperature, high-humidity environments like Vietnam, metal parts can corrode much faster than expected, potentially leading to fatal product defects. Among these risks, “Dissimilar Metal Contact Corrosion” (Galvanic Corrosion, commonly known as electrolytic corrosion), which occurs when different types of metals come into contact, is a risk often overlooked during the design stage.<\/p>\n

This article provides a thorough explanation of the scientific mechanisms behind dissimilar metal contact corrosion, practical knowledge of potential differences, and anti-corrosion measures recommended by Ota Vietnam. By reading this article, you will gain specific guidelines to minimize recall risks due to incorrect fastening component selection and establish a cost-effective procurement strategy.<\/p>\n<\/div>\n

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Scientific Mechanisms and Conditions for Dissimilar Metal Contact Corrosion<\/h3>\n<\/div>\n
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Why Do Different Metals Rust When They Touch?<\/h4>\n<\/div>\n
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Dissimilar metal contact corrosion refers to a phenomenon where, in an environment containing an electrolyte solution (such as moisture or rainwater), different types of metals come into contact, causing an electric current to flow due to the difference in “corrosion potential (ionization tendency)” between them. This results in the metal with the lower potential (the anode) corroding severely. In essence, it is a state where a “battery” is unintentionally formed.<\/p>\n<\/div>\n

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For example, if a stainless steel plate is fixed with aluminum screws, the aluminum side will corrode rapidly because its potential is lower, acting as a “sacrificial” metal. This phenomenon can progress several to dozens of times faster than simple oxidation, making it feared as a “silent killer” in the manufacturing industry.<\/p>\n<\/div>\n

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The Three Essential Conditions for Occurrence<\/h4>\n<\/div>\n
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For electrolytic corrosion to occur, the following three conditions must be met simultaneously:<\/p>\n<\/div>\n

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  1. Contact of Dissimilar Metals<\/strong>: Two or more different metals must be electrically connected.<\/li>\n
  2. Presence of an Electrolyte<\/strong>: A conductive liquid, such as water droplets, moisture, or salt, must be present at the contact area.<\/li>\n
  3. Potential Difference<\/strong>: There must be a clear difference in corrosion potential between the metals in contact (generally 0.1V to 0.25V or more).<\/li>\n<\/ol>\n<\/div>\n
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    In Vietnam’s factory environments, where average humidity often exceeds 80%, the “presence of an electrolyte” is a constant reality. Therefore, stricter measures are required compared to those used in Japan.<\/p>\n<\/div>\n

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    Potential Difference Tables and Data Analysis for Practical Use<\/h3>\n<\/div>\n
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    When designers select screws, the most important indicator is the “corrosion potential.” Every metal has its own specific potential, and the greater the difference, the stronger the corrosion energy becomes.<\/p>\n<\/div>\n

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    Key Data: Statistics on Metal Corrosion Potential and Corrosion Rates<\/strong><\/div>\n<\/div>\n
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