Study and review of permanent magnets for electric vehicle propulsion motors

A study of permanent magnets (PM) was performed in support of the DOE/NASA electric and hybrid vehicle program. PM requirements for electric propulsion motors are analyzed, design principles and relevant properties of magnets are discussed. Available PM types are reviewed. For the needed high-grade magnets, design data, commercial varieties and sources are tabulated, based on a survey of vendors. Economic factors such as raw material availability, production capability and cost are analyzed, especially for cobalt and the rare earths. Extruded Mn-Al-C magnets from Japan were experimentally characterized. Dynamic magnetic data for the range -50 deg to +150 deg C and some mechanical properties are reported. The state of development of the important PM material families is reviewed. Feasible improvements or new developments of magnets for electric vehicle motors are identified

Testing of the permanent magnet material Mn-Al-C for potential use in propulsion motors for electric vehicles

The development of Mn-Al-C permanent magnets is reviewed. The general properties of the material are discussed and put into perspective relative to alnicos and ferrites. The commercial material now available is described by the manufacturer's data. The traction motor designer's demands of a permanent magnet for potential use in electric vehicle drives are reviewed. From this, a list of the needed specific information is extracted. A plan for experimental work is made which would generate this information, or verify data supplied by the producer. The results of these measurements are presented in the form of tables and graphs. The tests determined magnetic design data and some mechanical strength properties. Easy axis hysteresis and demagnetization curves, recoil loops and other minor loop fields were measured over a temperature range from -50 C to +150 C. Hysteresis loops were also measured for three orthogonal directions (the easy and 2 hard axes of magnetization)

Low carbon technology performance vs infrastructure vulnerability: Analysis through the local and global properties space

Renewable energy technologies, necessary for low-carbon infrastructure networks, are being adopted to help reduce fossil fuel dependence and meet carbon mitigation targets. The evolution of these technologies has progressed based on the enhancement of technology-specific performance criteria, without explicitly considering the wider system (global) impacts. This paper presents a methodology for simultaneously assessing local (technology) and global (infrastructure) performance, allowing key technological interventions to be evaluated with respect to their effect on the vulnerability of wider infrastructure systems. We use exposure of low carbon infrastructure to critical material supply disruption (criticality) to demonstrate the methodology. A series of local performance changes are analyzed; and by extension of this approach, a method for assessing the combined criticality of multiple materials for one specific technology is proposed. Via a case study of wind turbines at both the material (magnets) and technology (turbine generators) levels, we demonstrate that analysis of a given intervention at different levels can lead to differing conclusions regarding the effect on vulnerability. Infrastructure design decisions should take a systemic approach; without these multilevel considerations, strategic goals aimed to help meet low-carbon targets, that is, through long-term infrastructure transitions, could be significantly jeopardized

INVESTIGATIONS OF PERMANENT MAGNET ALLOYS BASED ON COBALT AND CERIUM MISCHMETAL

L'auteur est arrivé à produire de grands champs coercitifs compris entre 4 000 et 5 000 Oe avec des poudres d'alliage MMCo5, où MM est un mischmétal riche en cérium. Ces résultats sont obtenus après broyage, traitement à l'acide et zinguage par diffusion. On a étudié le durcissement obtenu par précipitation dans MMCo5-xCux. On a obtenu à ce jour les valeurs MHc = 4 320 Oe et Mr/Mp = 0,98 pour x = 2. Ainsi MMCo5 et MMCo3Cu2 sont des matériaux intéressants pour fabriquer des aimants permanents relativement économiques du type RCo5.The intrinsic coercivity of powders of MMCo5 (MM = cerium mischmetal) could be raised to values between 4 000 and 5 000 Oe by ballmilling, an acid treatment and zinc diffusion coawfing, alternatively. The precipitation hardening of MMCo5-xCux was studied and optimized. MHc = 4 320 Oe and Mr/Mp = 0.98 were achieved for x = 2. MMCo5 and MMCo3Cu2 are thus attractive choices for relatively inexpensive permanent magnet materials of the RCo5 type

MICROSTRUCTURE AND MAGNETIC AFTEREFFECT IN BULK-HARDENED RARE EARTH-COBALT-COPPER BASE PERMANENT MAGNET ALLOYS

Dans le composé SmCo3,5CuFe0,5, le durcissement magnétique dû à la précipitation du cuivre a été étudié. Les propriétés magnétiques sont liées à la structure microscopique et à la dimension des particules. L'aftereffect magnétique est reporté pour différents états métallurgiques du composé.The magnetic hardening of SmCo3.5CuFe0.5 by a precipitation heat treatment has been studied, and the magnetic properties are related to microstructure and the particle size. Observations of the magnetic aftereffect in CeCo3.5CuFe0.5 in different. metallurgical states are reported