Studies Directed Toward New and Improved Permanent Magnet Materials.
Abstract
The utility or a permanent magnet is in many applications determined by its maximum energy product, (BH ) sub max. This is the maximum value of the product of B and H in the 2nd quadrant of the hysteresis loop. The amount of magnetic material to meet a certain need is inversely related to (BH) sub max. If size of a device is controlled by the volume of magnetic material needed, it is clear that on may downsize the device by using a higher energy product material. High energy permanent magnets find utility in many devices - TWT's, klystrons, linear induction accelerators, etc., as well as electric motors and generators. At present there are only 3 permanent magnet materials in widespread use - SmCo5, Nd2Fe14B and SmCo5-Sm2Co17. Each has weakness. The present study sought to find new and better materials. The findings in this work are described in detail in 33 journal publications. About a third of the effort has been devoted to effecting improvements in existing materials which occur in the SmCo5 or Nd2Fe14B structures. Materials forming in the ThMn12 and LaCo13 structures were also studied. About half of the effort was devoted to developing a preparation scheme to form Fe 6N2, which is reported to have a theoretical energy product of - 200 MGOe. Fe16N2 has been formed but in the presence of large amounts of - Fe and - Fe-N alloy. The enlarged B value reported for Fe16N2 has been confirmed in the present study. (jg)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 28, 1994
- Accession Number
- ADA290749
Entities
People
- W. E. Wallace
Organizations
- Carnegie Mellon University