Galvanized neodymium magnets are an economical method for surface protection. There are different types of galvanized neodymium iron boron magnets based on the passivation process used.
Principle of Galvanized Neodymium Magnets
During the galvanizing process, the neodymium magnet acts as the cathode and is immersed in an electrolyte solution containing zinc ions (such as potassium chloride galvanizing solution). By applying a direct current from an external power source, zinc ions (Zn²⁺) gain electrons at the surface of the cathode, undergoing a reduction reaction to form metallic zinc, which deposits onto the surface of the magnet.
Advantages of Galvanized Neodymium Magnets
| Low Cost: The galvanizing process is relatively simple, with lower raw material and production costs, making it suitable for cost-sensitive applications.
| Minimal Impact on Magnetic Properties: Zinc is a non-magnetic material, and the galvanization layer does not provide magnetic shielding, so it has virtually no impact on the magnetic properties of neodymium iron boron magnets (such as magnetic induction intensity and coercivity).
Types of Galvanized Neodymium Magnets
| Blue-White Zinc
Appearance: The surface is blue-white and relatively smooth, though it may slightly discolor from oxidation or wear with prolonged use. It can resist mild corrosion in short-term environments, but its anticorrosion performance is limited under long-term exposure or harsh corrosive conditions, potentially leading to powdery oxidation on the surface.
Passivation Treatment: A trivalent chromium blue-white passivation process is applied, immersing the galvanized magnet in passivation solution to form a blue-white passivation film on the surface, enhancing corrosion resistance.
| Color Zinc
Appearance: Color zinc exhibits a rainbow or colored sheen due to special passivation treatment, making it visually appealing with good color stability. Its corrosion resistance is superior to that of blue-white zinc, allowing it to better withstand organic corrosive atmospheres, salt spray, and other harsh environments, showing fewer signs of surface corrosion after prolonged use.
Passivation Treatment: A special colored passivation agent, such as metal salts containing chromium or nickel, is used, and parameters like passivation time and temperature are controlled to form a rainbow-colored passivation film on the surface.
| White Zinc
Appearance: The coating appears silvery-white and is smooth, though it may darken and become rougher due to oxidation or wear over long-term use, providing relatively weaker decorative appeal. Being a non-magnetic material, the zinc coating does not affect the magnetic properties of the neodymium iron boron magnet and does not create a magnetic shielding effect.
Passivation Treatment: After electroplating, a passivation treatment is conducted to form a passivation film that improves the corrosion resistance and stability of the coating. A common trivalent chromium passivation solution is used, and it must be thoroughly cleaned and dried post-passivation to avoid residual acidic substances that could corrode the coating.
Applications of Galvanized Neodymium Magnets
| Low-End Motors: In cost-sensitive applications, such as some low-end motors with relatively simple operational environments, galvanized neodymium magnets can be used as a magnetic source to satisfy basic magnetic performance requirements while reducing overall manufacturing costs.
| Common Hardware Products: For hardware tools and accessories used in dry indoor environments, galvanized neodymium magnets can provide basic oxidative protection at a low cost, meeting everyday usage needs.
Magnets Manufacturer
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Bwmagnet & Gtekmagnet & Linengineering & Magnet & Ndmagnets
