TY - GEN
T1 - Magnetic and physical properties of high melting rare earth-iron-boron magnet alloys with extrinsic sintering aids
AU - Oster, Nathaniel
AU - Anderson, Iver
AU - Tang, Wei
AU - Wu, Yaqiao
AU - Dennis, Kevin
AU - Kramer, Matthew
AU - McCallum, R. W.
PY - 2009
Y1 - 2009
N2 - Many common rare earth (RE)-iron-boron magnet alloys display a relatively low-melting (650-700°C) ternary eutectic. Nd-Fe-B is among these. The liquid formed from the eutectic promotes sintering of such particulate during processing of aligned, fully dense sintered magnets with a very high magnetic energy product. However, the coercivity and magnetic energy product rapidly decline at elevated temperatures. Several alternative RE-Fe-B magnet alloys that contain "heavy" rare earths, such as Dy-Fe-B, do not exhibit this low-melting eutectic and have better retention magnetic strength at high temperatures. Since the dominant RE2Fe14B phase in such particulate is a brittle intermetallic that melts much higher (about 1250°C), solid state sintering is difficult. This work tested Al as a possible extrinsic sintering aid system that could be added to magnet particulate that is dominated by heavy RE content. Magnetic properties of the sintered magnets were measured as a function of temperature, as well as microstructure and transverse rupture strength and compared to intrinsically (high temperature) sintered magnet compacts of the same alloy.
AB - Many common rare earth (RE)-iron-boron magnet alloys display a relatively low-melting (650-700°C) ternary eutectic. Nd-Fe-B is among these. The liquid formed from the eutectic promotes sintering of such particulate during processing of aligned, fully dense sintered magnets with a very high magnetic energy product. However, the coercivity and magnetic energy product rapidly decline at elevated temperatures. Several alternative RE-Fe-B magnet alloys that contain "heavy" rare earths, such as Dy-Fe-B, do not exhibit this low-melting eutectic and have better retention magnetic strength at high temperatures. Since the dominant RE2Fe14B phase in such particulate is a brittle intermetallic that melts much higher (about 1250°C), solid state sintering is difficult. This work tested Al as a possible extrinsic sintering aid system that could be added to magnet particulate that is dominated by heavy RE content. Magnetic properties of the sintered magnets were measured as a function of temperature, as well as microstructure and transverse rupture strength and compared to intrinsically (high temperature) sintered magnet compacts of the same alloy.
UR - http://www.scopus.com/inward/record.url?scp=84883335861&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:84883335861
SN - 9780981949611
T3 - Advances in Powder Metallurgy and Particulate Materials - 2009, Proceedings of the 2009 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2009
SP - 9117
EP - 9128
BT - Advances in Powder Metallurgy and Particulate Materials - 2009, Proceedings of the 2009 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2009
T2 - 2009 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2009
Y2 - 28 June 2009 through 1 July 2009
ER -
