THE EFFECT OF Fe CONTENT ON THE TEMPERATURE DEPENDENT MAGNETIC PROPERTIES OF Sm(Co,Fe,Cu,Zr), AND SmCo5 SINTERED MAGNETS AT 450 "C

Abstract

The magnetic properties of SmCos, Sm(Cob,l.Feo.tl CU0.06Zr0.02)7.6, sintered magnets have been measured up to 350, 400 and 450 C. For a fixed temperature range, the irreversible loss of Sm(Co,Fe,Cu,Zr), magnets has been found to increase with increasing Fe content. Despite the high B, obtained at 2S°C, a magnet must have a low irreversible loss of induction to retain a high magnetization after thermal cycling. Compromis- ing the B, of 11.3 kG obtained at 25 C and the irreversible loss of 1.9% after thermal cycling to 450 OC, a magnet with the composition of the Sm(Cobal.Feo.2lCu0.06 Zr0.03)~.6 was found to exhibit the highest retained magnetiza tion among the magnets studied. This magnet also exhibited the highest H,, (2.8 kOe) and BH,,, (6.7 MGOe) at 450 'C among all magnets studied. The reversible temperature coefficients of induction of Sm(Co,Fe,Cu,Zr)z sintered magnets were found to be about - 0.03 to -0.04 Oh PC, while those of SmCoS magnet were about -