Bonded thin cylinder magnets using Sm-Fe-N anisotropic powder
Anisotropic bonded Sm-Fe-N thin cylinder magnets have been developed by an injection-molding technology using unsaturated polyester resin, because thin and high-performance magnets are needed in order to downsize the motor. A special point for forming was a control of the rate of shrinkage. A multioriented cylinder magnet of 0.8 mm thickness was made by an insertion forming an aluminum column of 18.4 mm diameter and 18 mm height. A radial-oriented cylinder magnet of 15 mm outer diameter, 16 mm height, and 0.5 mm thickness was also made.
Progress of Sm-Fe-N Anisotropic Magnets
A reduction and diffusion method (R/D) is used to make a mother alloy of Sm-Fe-N anisotropic magnets. Reduction of 0.5wt% of samarium content compared to the conventional powder increases magnetization. Milling condition and surface treatment improve the squareness of demagnetization curve, the aging property and the heat resistance. The maximum energy product of 292 kJ/m3 is obtained with the powder. High coercive force is maintainable even if the powder is exposed for 300h in 80 °C 90%RH. The maximum energy product of 141 kJ/m3 is obtained with an injection molded anisotropic magnet. The aging property estimated by irreversible flux loss is comparable to the conventional MQP-B magnets. The heat resistance temperature (T−5%) at which die initial irreversible flux loss becomes −5% is 125-more than 150 °C for Sm-Fe-N magnets and 150–170 °C for hybrid magnets. The magnetic properties of bonded HDDR Nd-Fe-B magnet were improved by substituting for Nd-Fe-B powder with Sm-Fe-N powder. A new technology to make anisotropic bonded Sm-Fe-N thin cylinder magnets by an injection molding using unsaturated polyester (UP) resin was developed.
Magnetic properties of Sm-Fe-N thick film magnets prepared by the aerosol deposition method
This paper describes magnetic properties of Sm-Fe-N films prepared by an aerosol deposition method. The films with thickness of 3-45 /spl mu/m were obtained by the deposition within 10 min and the deposition rate was estimated as approximately 2-10 /spl mu/m/min. The Sm-Fe-N films showed relatively high micro Vickers hardness in the range from 500 to 700. The remanence of the Sm-Fe-N films was approximately 0.4 T, which was lower than that of initial host powders. However, almost of all samples showed higher coercivities around 1.8 T.