Properties of various sintered rare earth-cobalt permanent magnets between -60° and +200°C

The temperature dependency of remanence, intrinsic and induction coercivity, energy product and loop squareness of sintered rare earth-cobalt permanent magnets was studied. High-energy magnets having room-temperature energy products of 19-30 MGOe were characterized with view toward their use in air-borne electrical machinery. The temperature variation of the commonly used design parameters is reported for six types of commercial magnets based on SmCo5, (Sm, Pr)Co5and modified Sm2Co17, which had been fabricated by three common field-pressing methods. Demagnetization curves were measured at four temperatures, from -60°C to +200°C. This paper identifies the magnet types by nominal composition and pressing geometry; it briefly discusses the methods of measurement and it reports detailed magnetic property data of value to the magnet user.