Sm-Fe-X Alloys - New Permanent Magnets

Whereas mechanical alloying of Nd-Fe-B permanent magnets developed from amorphization studies in the Fe-Zr-B system without involving any amorphiz-ation, it will be shown in this section that amorphization by mechanical alloying is essential in the formation of new Sm-Fe-X phases, which show a high potential as novel generation of permanent magnets [3.80]. 

For ternary Sm-Fe-X alloys, the situation is only slightly modified. As an example, Fig. 3.34 shows X-ray diffraction patterns of as-milled Sm-Fe-Ti powders of different compositions. For Sm24Fe66Ti10, complete amorphization 

The A2 phase in the Sm-Fe-Ti system. We tried to reproduce the beneficial effect of an increased Sm content on coercivity also for the 1 12-type Sm-Fe-Ti system. Surprisingly, the remanence of the samples dropped rapidly to rather 

The Sm-Fe-Zr system. In the Sm-Fe-Zr system neither the 1 12 nor the A2 phase was observed for mechanically alloyed samples with a high Sm content. Instead, a (Sm,Zr)Fe3 phase forms with the rhombohedral PuNi3 crystal structure. Also this phase proved to be hard magnetic when prepared as a microcrystalline material by mechanical alloying [3.82]. Its coercivity reaches 11.8kA/cm. 

From DSC investigations [3.91], we conclude that the 2 17 nitride and carbide are metastable phases which form at relatively low temperatures where nitrogen or carbon can diffuse into the 2 17 phase, but both the iron and the 

---