Abstract: Novel permanent magnets of Sm.sub.2 Co.sub.17 type crystal structure are provided herein. The magnets preferably have samarium, cobalt, iron, copper and zirconium in specified amounts. They have superior magnetic properties, including maximum energy product, intrinsic coercivity and second quadrant loop squareness. The compositions of the magnets can be expressed by a general formula ?Co.sub.a Fe.sub.b Cu.sub.c Zr.sub.d !.sub.e Sm. Preferred embodiments, wherein a is about 0.6 to about 0.7, b is about 0.2 to about 0.3, c is about 0.06 to about 0.07, d is about 0.02 to about 0.03, and e is about 7.2 to about 7.4, have unexpectedly high maximum energy product, high intrinsic coercive force and squareness. Processes for producing the improved alloy are also provided.

Abstract: Novel permanent magnets of Sm.sub.2 Co.sub.17 type crystal structure are provided herein. The magnets preferably have samarium, cobalt, iron, copper and zirconium in specified amounts. They have superior magnetic properties, including maximum energy product, intrinsic coercivity and second quadrant loop squareness. The compositions of the magnets can be expressed by a general formula [Co.sub.a Fe.sub.b Cu.sub.c Zr.sub.d ].sub.e Sm. Preferred embodiments, wherein a is about 0.6 to about 0.7, b is about 0.2 to about 0.3, c is about 0.06 to about 0.07, d is about 0.02 to about 0.03, and e is about 7.2 to about 7.4, have unexpectedly high maximum energy product, high intrinsic coercive force and squareness. Processes for producing the improved alloy are also provided.