Neodymium/Iron/Boron - Material Information

Introduced in 1983, neodymium–iron–boron (Nd?Fe??B) magnets revolutionized permanent magnet technology by combining exceptionally high magnetic energy density with cost-effective production. These magnets have since become essential in a wide range of modern devices, from electric motors and wind turbines to hard disk drives and MRI systems. Despite their remarkable magnetic strength, their sensitivity to corrosion and high temperatures requires careful engineering and protective coatings for long-term use.

Material Overview

The Nd?Fe??B compound crystallizes in a tetragonal P4?/mnm structure, with neodymium contributing strong uniaxial magnetocrystalline anisotropy. This structure yields a theoretical maximum energy product exceeding (BH)??? = 512 kJ·m?³. The alloy’s high saturation magnetization (~1.6 T) and coercivity make it the strongest known permanent magnet at room temperature. According to Grieb (1997), optimized Nd–Fe–B compositions incorporating small additions of Co, Cu, or Nb achieve higher temperature stability and corrosion resistance, enabling applications up to 250 °C. Studies by Gao et al. (2021) demonstrated that aluminum cold-spray coatings enhance corrosion resistance by an order of magnitude without significantly degrading magnetic performance. He and Lin (2018) developed indium/tin nanoparticle doping methods to intrinsically improve corrosion resistance, reducing oxidation rates and extending service life under humid conditions. Additionally, Chen (2006) patented heat- and corrosion-resistant NdFeB alloys doped with Dy and Tb, further improving mechanical properties and thermal stability.

Applications and Advantages

Nd?Fe??B magnets are indispensable in high-performance electric motors, wind turbine generators, magnetic resonance imaging (MRI), and precision actuators. Their combination of high coercivity and remanence allows miniaturization of devices while maintaining strong magnetic fields. However, since neodymium and iron are reactive, surface protection (e.g., Ni, Al, or epoxy coatings) is often used to prevent corrosion. Wan Mahadi and Adi (2007) demonstrated that NdFeB magnets are ideal for linear generator systems, offering high efficiency and compactness compared to ferrite and AlNiCo alternatives. Ongoing innovations—such as nano-grain engineering and surface modification—are extending the operational lifetime of NdFeB magnets in harsh thermal and corrosive environments.

Goodfellow Availability

Goodfellow supplies Neodymium/Iron/Boron (Nd?Fe??B) alloys in research-grade compositions with high magnetic strength and chemical stability. Materials are available in various geometries suitable for prototyping and testing in magnetic, electronic, and mechanical applications. Custom fabrication options and protective surface coatings can be provided upon request.

Explore Neodymium/Iron/Boron (Nd?Fe??B) and other advanced materials in Goodfellow’s online catalogue: Goodfellow product finder.

References

• Gao, Y., Bai, Y., Zhu, H., Liang, W., Liu, Q., Dong, H., Jia, R., & Ma, W. (2021). Corrosion resistance, mechanical and magnetic properties of cold-sprayed Al coating on sintered NdFeB magnet. Journal of Thermal Spray Technology, 30(8), 2240–2251. https://doi.org/10.1007/S11666-021-01266-Z
• Grieb, B. (1997). New corrosion resistant materials based on neodymium–iron–boron. IEEE International Magnetics Conference. https://doi.org/10.1109/20.619610
• He, Q., & Lin, J. (2018). High corrosion resistance neodymium–iron–boron magnet and preparation method thereof. Patent.
• Chen, D. S. (2006). Heat- and corrosion-resistant Nd–Fe–B permanent magnetic material with good mechanical properties and producing method. Patent.
• Wan Mahadi, W. N. L. B., & Adi, S. R. (2007). Application of Nd?Fe??B magnet in linear generator design. Conference Paper.