Improved corrosion and temperature behaviour of modified Nd-Fe-B magnets

• Published in: IEEE transactions on magnetics Vol. 26; no. 5; pp. 1930 - 1932
• Main Authors: Tenaud, P., Vial, F., Sagawa, M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.09.1990; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Atmosphere; Bars; Coercive force; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Corrosion; Exact sciences and technology; Magnetic properties and materials; Magnets; Metals. Metallurgy; Oxidation; Physics; Powders; Remanence; Temperature; Thermal degradation
• DOI: 10.1109/20.104574
• ISSN: 0018-9464

The characteristics of the high energy product NdFeB magnets obtained by the powder metallurgy route have been improved by appropriate vanadium additions. Specific combinations of V and Co lead to an intrinsic coercive force of about 1350 kA/m (17 kOe) in Dy-free magnets, without any large decrease of remanence. If 1.5-at.% Dy is added, load line down to -B/ mu H=0.5 can be achieved at 180 degrees C without irreversible losses. Corrosion resistance is improved by blocking the selective oxidation of the Nd-rich phase. As a consequence, organic-coated magnets are able to withstand 15 days at 115 degrees C-1.75 bars in a H/sub 2/O saturated atmosphere without any degradation. It is concluded that this set of new properties will enlarge the application fields of Nd-F-B permanent magnets.< >