Magnet Coatings and Compatibility with Liquids

Neodymium Magnet Coatings and Liquids

Neodymium magnets, known for their strong magnetic properties, are often coated to protect them from corrosion and to enhance their performance in various environments [1]-[5]. The choice of coating can significantly affect the magnet's durability and compatibility with different liquids. Below is an overview of common coatings used for neodymium magnets and their interactions with various substances.

Water and Oils Compatibility

Nickel-Copper- Nickel (Ni-Cu-Ni) Coating: Can withstand occasional exposure to water but may corrode if submerged for long periods. Susceptible to acids and halogenated oils.

Epoxy Coatings: Provides excellent water resistance, making it suitable for humid environments. Good resistance to mineral and synthetic oils.

Zinc Plating Coating: Offers some resistance to water but can corrode if exposed to saltwater or acidic conditions. Poor behavior in many types of oils.

Teflon PTFE Coating: Excellent chemical resistance. Compatible with many types of oils.

Conclusion

Choosing the right coating for neodymium magnets is essential for ensuring their longevity and performance in various environments. Understanding the compatibility of these coatings with different liquids and oils, as well as their temperature resistance, can help in selecting the appropriate magnet for specific applications.

Please contact us if you need assistance with projects with neodymium magnets immersed in liquids

References

[1] A. Kim and J. Jacobson, "Oxidation and oxidation protection of Nd-Fe-B magnets," in IEEE Transactions on Magnetics, vol. 23, no. 5, pp. 2509-2511, September 1987.

[2] A. Maizelis and B. Bairachniy, "Protection of NdFeB Magnets by Multilayer Coating," 2019 IEEE 39th International Conference on Electronics and Nanotechnology (ELNANO), Kyiv, Ukraine, 2019, pp. 596-599, doi: 10.1109/ELNANO.2019.8783526.

[3] Primc, G.; Mozetič, M. "Recent Advances in Corrosion Inhibition of Bonded NdFeB Magnets," Materials 2024, 17, 2475.

[4] Rampin, I., Bisaglia, F. & Dabalà, M. "Corrosion Properties of NdFeB Magnets Coated by a Ni/Cu/Ni Layer in Chloride and Sulfide Environments," J. of Materi Eng and Perform 19, 970–975 (2010).

[5] D.F. Cygan, M.J. McNallan, "Corrosion of NdFeB permanent magnets in humid environments at temperatures up to 150°C," Journal of Magnetism and Magnetic Materials, Volume 139, Issues 1–2, 1995, Pages 131-138.

[6] AMF Magnet, Technical Article: Magnet Coatings – AMF Magnets New Zealand