Technical knowledge of the various types of zinc coating is essential for selecting the most suitable coating by the mechanical, environmental, and regulatory requirements of each industrial application. Zinc coating not only protects against corrosion, but can also influence friction, electrical conductivity, paint adhesion, and other subsequent processes.
This article presents a detailed classification of the most commonly used types of zinc coating in industry, with special attention to the processes available at Jegan, their technical characteristics, and their usual applications.
In this other article, we provide information about the zinc plating process for parts.
Main Types of Zinc Coating
Electrolytic Zinc Coating
Electrolytic zinc coating is based on the deposition of zinc onto a metallic surface using an electric current in an electrolytic solution. This process enables precise control over coating thickness and a uniform finish, suitable for both technical and aesthetic requirements.
At Jegan, we apply electrolytic zinc coating in an automated in-line process, with options for white, blue, black, or iridescent passivation, complying with the most common sector specifications (ISO 2081, RoHS). This type of zinc coating is especially recommended for fasteners, automotive parts, electrical components, and precision metal elements.
Rack Zinc Coating
Rack zinc coating is used for parts with complex geometry or fragility that require individual treatment. The parts are fixed on racks and submerged in the electrolytic bath, ensuring uniform coverage without mechanical contact between them.
This method is ideal for parts that require a high level of surface quality and precise coating thickness accuracy. At Jegan, we have dedicated lines for this type of treatment, suitable for technical, ornamental, or structural components.
Barrel Zinc Coating
Barrel zinc coating, also known as bulk zinc coating, is designed for small or medium parts that can be treated together in rotating barrels. It is a process of high productive efficiency, although with less aesthetic control compared to rack zinc coating.
At Jegan, we optimise barrel zinc coating to offer a balance between productivity and technical quality, applying it to screws, nuts, clips, washers, and other high-use fasteners.
Black Zinc Coating
Black zinc coating is a variant of electrolytic zinc coating that includes a dark, usually trivalent passivation, which improves corrosion resistance and provides a technical or decorative visual finish. It can also offer functional properties such as reduced friction coefficient or electromagnetic compatibility.
This finish is applied in sectors such as automotive, electronics, or technical hardware, where a differentiated aesthetic and additional resistance in demanding environments are required.
Yellow Chromate Zinc Coating
Yellow chromate zinc coating incorporates a passivation process with chromium compounds, providing a golden or iridescent hue and high corrosion protection. Although the REACH legislation regulates the use of hexavalent chromium, it is still used in applications where its use is permitted and superior performance is required.
At Jegan, we offer yellow chromate alternatives that meet the client’s technical specifications, ensuring compliance with applicable standards and providing trivalent, Cr(VI)-free versions for RoHS-compatible applications.
The Importance of the Zinc Coating Process
Zinc coating is not a simple coating: it is a key process to guarantee the protection, functionality, and durability of metal components in demanding industrial environments. Its success depends on multiple factors, such as surface preparation, the selection of the type of zinc coating and passivation, control of the applied thickness, and post-process quality tests. A poorly executed process can compromise corrosion resistance, adhesion of subsequent treatments, or the mechanical performance of the final product.
In this context, choosing a supplier with technical infrastructure, sector experience, and a commitment to quality is decisive. Each application — from fasteners to electronic components or structural parts — requires specific coating parameters tailored to its conditions of use, applicable regulations, and functional requirements. Therefore, zinc coating should be considered not only as a final stage but as an integral part of product design and manufacturing.
Industrial Zinc Coating at Jegan: Technical Capacity and Quality Assurance
At Jegan, we have highly automated facilities for in-line zinc coating, both in racks and barrels, which allow us to adapt to short, medium, or large series. Our experience in sectors such as mobility, home appliances, electronics, and other applications enables us to provide precise and functional solutions tailored to each application.
We are committed to certified quality, offering a wide variety of technical and decorative finishes: white zinc, black zinc, yellow chromate, and advanced Cr(VI)-free passivations. We have rigorous technical control and traceability through thickness measurements, salt spray tests, and computerised batch tracking systems.
Additionally, we provide expert advice to select the most suitable coating based on the intended use, base material, and environmental conditions, ensuring that each treated piece exceeds expectations in terms of durability, surface quality, and technical performance.
