SmFeN alloys have made significant progress in recent years, enabling SmFeN to become a potential substitute for NdFeB magnets even in automotive applications. Injection molded SmFeN materials reach remanent flux densities above 800 mT, a majority of isotropic injection molded NdFeB magnets can be substituted, and SmCo materials at least partially. At Max Baermann, we support our customers from material selection and simulation through compounding, tool making and injection molding to the magnetized and measured part.
Author: T. Schliesch, Head of Research & Development | 17 August 2026
Why alternatives to NdFeB are gaining importance
Due to generally high prices for rare-earth-based permanent magnetic materials, as well as insecure availability caused by political factors, alternative materials have become increasingly interesting. One of these alternatives is based on SmFeN alloys, originally developed in the 1990s, which have made significant progress in recent years. This improvement is mainly due to enhanced stability, enabling SmFeN to become a potential substitute for NdFeB magnets even in automotive applications.
Like other rare earth elements, samarium is currently mainly mined and processed in China, but this element is abundant in most other parts of the world. In mines outside China, samarium is often discarded due to its low price; however, this offers a good basis for developing stable supply chains. Max Baermann has already established supply chains for SmFeN materials that are independent of China. Currently, the price for 1 kg of neodymium oxide is around 80 US$, whereas that of samarium oxide is not much higher than 2 US$ [1]. Pure neodymium metal is rated at around 140 US$/kg, whereas pure samarium is estimated at 10 to 12 US$/kg. (Ratings are based on price charts from the beginning of 2026 and might have varied since then.)
1. Performance: closing the gap to high-end magnet materials
The major manufacturers of SmFeN alloys as well as of compounds for injection molding are currently Japanese companies [2–3]. Both anisotropic and isotropic materials are available. Anisotropic grades can also play a role in substituting sintered magnets due to their high magnetic strength, although, due to the dilution by polymer, there is still a gap to sintered NdFeB with typical remanences around 1.2 to 1.3 T. Injection molded SmFeN materials reach their highest remanent flux densities in the range above 800 mT.
Figure 1 displays typical demagnetization curves of materials for injection molded magnets to give an impression of the different strengths of commercial materials. Hybrids of SmFeN and anisotropic HDDR-based NdFeB can even reach remanence values around 950 mT.
Additionally interesting is the fact that a majority of isotropic injection molded NdFeB magnets can also be substituted by isotropic SmFeN. Here, remanence values close to 600 mT are achievable, and the respective specimens can be manufactured based on both polyamide and PPS compositions.
2. Proven in application: established processes, complex pole patterns
Manufacturing is done by conventional injection molding methods that are well known for other magnetic materials. For anisotropic compounds, pre-orientation inside the mold by permanent magnet assemblies or DC coils is standard, followed by a final magnetization into saturation by pulse discharge magnetization. Complex pole patterns can also be realized, as depicted in Fig. 2. Here, simulated and measured results are presented for a pump motor magnet that was originally designed as a ferrite version. The enhanced field performance of anisotropic SmFeN and NdFeB compared to the original ferrite specimen can be clearly observed.
Another interesting aspect of SmFeN is its relatively low temperature coefficient of remanence, which offers the chance to at least partially substitute SmCo materials. Fig. 3 illustrates this with a sensor magnet originally designed with Sm₂Co₁₇, for which the fields of different materials have been measured at different distances. One can observe that the field ranges of the original SmCo magnet can easily be reached by SmFeN.
Table 1 summarizes the remanence and the temperature coefficient of remanence of the materials compared in Fig. 3. The temperature coefficient of SmFeN is about half that of NdFeB, which explains its suitability as a substitute for SmCo in many sensor applications.
Material |
Remanence Br |
Temperature coefficient of remanence TkBr |
| Sm₂Co₁₇ (original magnet) | 600 mT | −0.03 %/K |
| SmFeN | 690 mT / 830 mT | −0.06 %/K |
| NdFeB | 750 mT | −0.12 %/K |
Table 1: Remanence and temperature coefficient of remanence (TkBr) of the materials compared in Fig. 3 (sensor magnet originally designed with Sm₂Co₁₇).
3. Automotive-ready: long-term stability under real conditions
For automotive applications, long-term stability against magnetic ageing and flux losses is essential for viable magnets. Here, stability over the whole temperature range from −40 °C up to 120 °C or 150 °C is generally demanded. Low corrosion levels in typical salt spray or humidity tests, as well as sufficient mechanical stability, are also required for a successful application. In addition, stability in aqueous solutions or other media can be an aspect. All these requirements can currently be met by tailored SmFeN compounds for injection molding. While PA12-based materials are used for highly filled compositions with remanent flux densities around 800 mT or more, more stable polymers such as PPS can be applied for water and chemical resistance and the highest application temperatures. Some suppliers of SmFeN materials also apply specific coatings to the magnet grains to enhance stability.
Your benefit: one partner from material to magnetized component
Whether you want to upgrade a ferrite design, reduce dependency on NdFeB or replace SmCo in a sensor application: SmFeN opens up new options for performance, cost and supply security. Our experts evaluate your application, simulate the magnetic design and develop the right compound and process for series production.