Sinter magnet based on Fe-Nd-B

US5194099A · kind A · utility

Assignees

• 501 Max-Planck-Gesellschaft zur Forderung der Wissenschaften E.V. · DE
• 502 Robert Bosch GmbH · DE

Inventors

• Friedrich Esper
• Waldemar Draxler · Markgröningen, DE
• Gunter Petzow · Echterdingen, DE
• Andreas Buchel · Stuttgart, DE
• Klaus-Dieter Durst · Stuttgart, DE
• Ernst-Theo Henig · Leonberg, DE
• Gerhard Schneider · Stuttgart, DE
• Helmut Kronmuller · Bad Marienberg, DE

Key dates

• Filing date: May 23, 1990
• Grant date: Mar 16, 1993
• Expiry date: May 23, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C32/0026
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A sinter magnet based on Fe-Nd-B with improved coercive field strength and reduced temperature dependency thereof consists of 25 to 50 wt. % Nd, 0.5 to 2 wt. % B, 0 to 5 wt. % Al, 0.5 to 3 wt. % O, remainder Fe and usual impurities and has an oxygen content which is adjusted by the addition of oxygen or of oxygen-containing compounds, especially of an Al and/or Nd oxide, before the dense sintering. It is obtainable by the melting together of the pure components with formation of a pre-alloy, pulverisation of the pre-alloy, alignment of the powder in a magnetic field and pressing to a green formed body, sintering at 1040.degree. to 1100.degree. C. and subsequent annealing at 600.degree. to 700.degree. C., whereby one adds the oxygen as Al or Nd oxide or via the grinding and/or sintering atmosphere.