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JapanSteel is the backbone of modern industries that impact our lives every day- from vehicles and appliances to infrastructure and construction (like bridges, pipelines and buildings) and even materials that come into contact with drinking water. Steel's strength, formability, and cost-effectiveness make it indispensable across sectors; however, its susceptibility to corrosion, particularly in humid or chemically aggressive environments, presents a significant challenge. Protecting steel against rust and degradation is essential for ensuring structural integrity and extending product lifespans—this is where electrogalvanization (EGL) comes into play.
Electrogalvanization of Steel: A Key to Durable Industrial Infrastructure
What is electrogalvinization?
Electrogalvanization (also known as electroplating) is an electrochemical process that deposits (or plates) a thin layer of zinc onto the surface of steel to protect it from corrosion. Unlike hot-dip galvanizing, which involves immersing steel into molten zinc, electrogalvanization occurs at room temperature through an electrolytic cell, offering precise control over coating thickness and uniformity. The process not only improves corrosion resistance but also enhances surface appearance and paint adhesion, making it highly favored in industries that demand high-quality finishes, such as the automotive and appliances sectors.
The EGL process
The electrogalvanization process begins with steel sheets or components being thoroughly cleaned to remove oil, rust, and other contaminants. Once cleaned, the steel is immersed in an electrolytic bath containing a zinc salt solution, commonly zinc sulfate or zinc chloride. An electrical current is then passed through the bath. The steel acts as the cathode (negative electrode), while the anodes are placed at the opposite end of the cell. When current flows, zinc ions in the electrolyte migrate to the steel surface and are reduced to metallic zinc, forming a coherent, protective layer. The thickness of this layer can be adjusted by controlling the current density and plating time. The process is relatively quick and ideal for continuous operations such as coil coating.
What is the role of insoluble anodes in EGL?
A critical component in this electrochemical process is the anode. In traditional galvanic systems, soluble anodes, made of zinc dissolve over time, contributing zinc ions to the solution. However, modern electrogalvanization often utilizes insoluble anodes, especially in high-performance and large-scale operations. These anodes, mixed metal oxide (MMO) coated on to a titanium substrate, do not dissolve but serve as stable conductors, facilitating the oxidation reaction that maintains electrical flow in the system.
One of the leading global players in the production of insoluble anodes for electrogalvanization is De Nora. Known for its innovations in electrochemical technologies, De Nora provides advanced anode solutions that enhance the efficiency, safety, and sustainability of metal finishing processes. Their DSA® anodes, pioneered in the 1960s, are now an industry standard for various electrolytic applications, including EGL.
De Nora’s DSA anodes are engineered to:
• deliver consistent current distribution,
• offer long service life, and
• minimal maintenance and downtime.
These qualities are vital in continuous steel processing lines where downtime can lead to significant economic losses. Furthermore, the use of insoluble anodes allows for precise process control, reducing zinc waste and improving electrolyte stability, and cost management.
In conclusion, electrogalvanization is a vital technique for enhancing the durability and value of steel across industries. By leveraging controlled electrochemical deposition of zinc and advanced materials like De Nora's insoluble anodes, manufacturers can deliver corrosion-resistant products with high aesthetic and functional standards.