NdFeB magnets achieve the highest energy density today. The most used production process is the powder metallurgical procedure.
The saturation magnetic polarization of the ferromagnetic main phase Nd²Fe14B constitutes 1.62 T. From this follows a maximum achievable energy density of 64 MGOe.
At laboratory conditions a maximum energy density of approx. 59 MGOe was achieved. With regard to mass production it is possible to produce permanent magnets with energy densities of ca. 59 MGOe for applications at up to 70°C. In spite of these excellent material properties sintered NdFeB magnets are characterized by some “weaknesses” compared to SmCo magnets.
- Comparatively low Curie temperature of 312°C, which results in higher temperature coefficients of the remanence and coercivity and which limits the possible operating temperatures
- High corrosion sensitivity
Our TERRAMAG® Series:
Through intensive Research and Development work in cooperation with our Chinese partner we developed and proudly present our own corrosion and temperature proof material grades, the TERRAMAG® Grades.
Compared to the usual N-material the TERRAMAG® Magnets are characterized by considerably improved corrosion performance, which is similar to ST 37 Steel.
Under the extreme conditions of our autoclave test the mass loss resulting from corrosion is very low (The typcial mass loss of TERRAMAG® S – Grades is max. 3 mg/cm² after 7 days). Our self-developed series the TERRAMAG® S-Grades and TERRAMAG® H-N Grades are suitable for temperatures up to 200°C.
Our TERRAMAG® S-Grades (S like “stable”) are known as modern Nd-Fe-B magnet material characterized by very high stability against degaussed magnetic fields and have been developed under technical instructions of the “BEC Gesellschaft für Produktmanagement mbH” specifically for applications up to 200°C without having appreciable irreversible losses.The main feature of this excellent material is the special microstructure, which has been changed with appropriate additives.
At the same time we have improved the corrosion resistance significantly by replacing the corrosion sensitive Nd-rich phase with stable intermetallic phases.Compared to the usual BEC N-material the TERRAMAG® Magnets are characterized by considerably improved corrosion performance, which is similar to ST 37 Steel.In contrast to the most common Chinese grades with their limited application possibilities due to the so called “White Corrosion” effects, our TERRAMAG® S-Grades can be used for high tech applications with the known cost advantages.
A further TERRAMAG® grade is the self-developed cost effective TERRAMAG® H-N Series. This magnetic material only differs in a max. mass loss of 5mg/cm² during our autoclave test and is suitable for working temperatures up to 220°C.