In the bulk storage industry, where structural materials are constantly exposed to demanding conditions inside and outside silos, protecting steel from corrosion becomes not only a preventive measure, but a strategic decision. This approach has led Prado Silos to firmly commit to the ZM310 anti-corrosion coating as the standard protection shell for its steel silos. As a result, the company’s projects around the world can rely on enhanced durability, efficiency, and safety.
For decades, zinc has been steel’s greatest ally when it comes to resisting corrosion. Galvanised coatings such as Z600 or Z450 offer an efficient defence, extending the material’s useful life by providing a protective layer that absorbs the effects of the environment before they penetrate the silo’s metal core. However, this layer ends up deteriorating rapidly, especially in the case of aggressive atmospheres (such as ports and industrial environments). Today’s technologies are opening the door to more advanced solutions. As part of its commitment to innovation, the Prado Silos Materials Division set to work to find the ultimate anti-corrosion coating.
This is where ZM310 comes into play: an innovative alloy of zinc, magnesium and aluminium that delivers three to five times greater protection than conventional zinc galvanisation. The benefits go beyond technical trials—it delivers real-world advantages, translating into longer service life, reduced maintenance needs and increased safety in demanding settings such as agricultural or industrial plants in exposed, coastal or tropical regions.
One of the key advantages of the ZM310 coating lies in its ability to deliver superior anti-corrosion performance with a significantly reduced thickness. While Z600 galvanisation requires a 42-micron layer to provide adequate protection, the ZM310 solution achieves the same result with just 25 microns, thanks to the density and stability of its composition.
This enables a more uniform and controlled application, even on complex surfaces such as metal silos, with their folds, curves and structural reinforcements. Rather than acting merely as a surface barrier, the ZM310 coating forms a compact layer of simonkolleite—a stable mineral by-product that shields against moisture, salinity and other corrosive agents. Tests and real-world applications show a significant difference compared to the porous zinc oxides found in traditional galvanisation.
We are therefore talking about an eco-efficient innovating solution, delivering far superior performance to traditional galvanised products while requiring less material.
In silo manufacturing, steel sheets are cut, perforated and shaped. During on-site assembly, movement, handling and potential impacts can cause localised damage to the coating. These are exactly the areas most prone to corrosion – and where ZM310 makes a real difference.
With its self-repairing ability, the ZM310 coating regenerates in areas damaged by cuts or scratches. Zinc and magnesium within the alloy migrate to the exposed surface, rebuilding the protective simonkolleite layer. Put simply, this physico-chemical reaction provides extra protection against the inevitable wear and tear of a silo’s lifetime.
In addition, ZM310 stands out from traditional galvanising due to its higher surface hardness, which results in significantly higher resistance to abrasive conditions. In desert trials simulating the effect of sandstorms, exposed sheets coated with ZM310 reached a Vickers hardness of 141 HV—over twice the 64 HV measured in conventional galvanised steel sheets. As a result, ZM310 provides better thickness retention against mechanical erosion from abrasive particles, mirroring the conditions inside a silo filled with grain.
Additionally, the ZM310 coating offers a slower and more uniform response to white rust, a by-product of the initial corrosion of zinc that is characterised by powdery, whitish deposits on the surface. Although it does not cause an immediate loss of the coating, it can indeed accelerate corrosion processes if the protective layer becomes compromised. Comparatively, Z600 reaches level 3 corrosion in around seven weeks, whereas ZM310 requires up to 14.5 weeks to reach that stage, demonstrating much greater durability over time. In agricultural and livestock facilities, where humidity and aggressive chemical agents are ever-present, the occurrence of white rust poses both an aesthetic issue and a functional challenge, since it ultimately shortens the effective service life of metallic elements
Initially, Prado Silos applied ZM310 mainly to roof structural elements, as these are the most exposed parts of the silo and the most susceptible to weather damage. However, as part of its strategy of continuous product improvement, the decision has been made to extend this protection to the entire structure, including the cylinder. Consequently, comprehensive protection against corrosion is ensured, thereby raising the quality standard of all models manufactured with this coating.
This breakthrough becomes even more relevant in solutions like the recently updated new farm silo model, covered in detail in this article on our Prado Silos blog. Designed for the agricultural industry, this type of silo combines state-of-the-art materials and optimised design with the advantages of the ZM310 coating. The outcome is greater durability, improved safety in operation and lower maintenance expenditure for the agricultural operator.
The ZM310 not only enhances the performance of steel but also enables the design of lighter, more efficient structures. By allowing a more rational use of material without compromising strength, it is now possible to develop solutions that are easier to transport and quicker to assemble.
This advantage directly supports product sustainability: reduced material consumption, lower transport-related emissions and extended service life. For Prado Silos, innovation in materials is not merely a technical improvement but a key driver for the sector’s evolution.
As we reported in our last article, Prado Silos has recently completed the transfer of all its activities to a single advanced facility located in Mungia (Bizkaia, SPAIN). The concentration of all operations within a single, state-of-the-art facility dedicated exclusively to the design and manufacture of steel silos underlines the company’s position as a local manufacturer with international reach. Together with a permanent supply of ZM310-coated steel, this integrated production structure makes it possible to plan more efficiently, react more swiftly, while consistently meeting even the most stringent deadlines in times of high demand.
Beyond these technical benefits, the incorporation of ZM310 reflects a firm commitment to useful innovation, i.e., innovation that generates real benefits for the end customer. Greater durability, lower maintenance costs, increased operational safety, and a better use of materials: these are just some of the reasons behind the growing number of industries currently developing specific anti-corrosion solutions for their products.
What Prado Silos achieves with ZM310 goes beyond upgrading each silo that leaves its production lines; it represents a new way of conceiving protection against the effects of time. Corrosion is no longer an ever-present threat but a controllable element. Naturally, looking ahead, new technologies will inevitably arise, opening further opportunities for innovation.
