Sm-Co系焼結磁石の磁気特性に及ぼす残留炭素の影響 Influence of Residual Carbon on Magnetic Properties of Sintered Sm-Co Magnets
The addition of organic binder in a small amount improves the compressibility and compactibility of Sm-Co magnet alloy powders. However, impurity carbon which comes from the binder is thought to lower magnetic properties of the sintered magnets. In this study, the relationships between the resid-ual carbon content and magnetic properties in SmCo<SUB>5</SUB> and Zr containing Sm<SUB>2</SUB> Co<SUB>17</SUB> magnets have been studied varying the amount of the binder. Effects of thermal debinding atmosphere on binder removal have been also investigated. When the green compacts were debound in vacuum atmosphere, the carbon content of the magnets increased with increase of the binder addition, which decreased coercivities of the magnets markedly. It was observed that carbon forms SmCoC<SUB>2</SUB> and ZrC carbides in SmCo<SUB>5</SUB> and Sm<SUB>2</SUB>Co<SUB>17</SUB> magnets respectively. Thermal debinding treatment in hydrogen atmosphere was found to be very effective for removing the binder and reducing the carbon content in the mag-nets. In the binder addition ranges of the present study, the magnets produced through use of this debinding treatment have exhibited nearly the same magnetic properties as those of the magnets made from the powders without the binder.
粉体および粉末冶金 43(1), 66-71, 1996-01-15
Japan Society of Powder and Powder Metallurgy