Published online by Cambridge University Press: 25 February 2011
Several ternary compounds of tetragonal structure and with the composition R2Fe14B have found an application as starting materials for permanent magnets. Several physical properties of R2Fe14B compounds will be discussed in relation to the modification in properties that can be obtained by substituting other elements for R, Fe or B. Also investigated is the extent to which it will be possible to find alternative materials differing in structure and composition from R2Fe14B. For this purpose the results obtained on 3d-rich ternaries based on well-known structure types will be reviewed. Included in this survey will be novel ternary intermetallics made by crystallization from the amorphous state. These compounds, though stable enough for applications, are actually metastable. They are not found in the corresponding equilibrium diagrams.