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

Abstract

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 SmCo <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> , (Sm, Pr)Co <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> and modified Sm <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Co <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</inf> , 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.