9714946 Shield Samarium-iron compounds with interstitial nitrogen (Sm-Fe-N) comprise a promising class of magnetic materials with properties competitive to those of Nd-Fe-B permanent magnets. This project seeks to accomplish two interrelated objectives: (1) to control the microstructure evolution in Sm-Fe-N-based permanent magnets through processing and alloy development; (2) to establish relationships between the microstructure and magnetic properties in Sm-Fe-N-based permanent magnets. Of primary concern is the influence of grain boundaries, second phases, and grain size on the magnetic properties. To control microstructure evolution, alloys are designed that effectively enhance the formation of the samarium-iron compound during rapid solidification processing. Alloying additions, such as Ti, Zr, Si, V, C, and combinations of these, are used to alter the solidification behavior of Sm-Fe alloys. The goal is to either enhance the formation of the Sm-Fe compound at lower solidification rates or to suppress the formation of crystalline phases altogether. In the latter case the resultant amorphous materials are crystallized to the Sm-Fe compound. Subsequent nitrogenation results in the hard magnetic Sm-Fe-N phase. The relationships between the microstructure and magnetic properties of Sm-Fe-N-based permanent magnets should be clarified in this project. %%% The most notable advantage of Sm-Fe-N materials over Nd-Fe-B magnets is the Curie temperature (approximately 150 degrees C higher) allowing applications in more demanding thermal environments. However, Sm-Fe-N magnets pose many challenges, especially with regards to intelligent processing and understanding of the microstructure-property relationships. ***
