| 초록 |
Hydrogenation Disproportation Desorption Decombination(HDDR) technique as a efficiency method to obtain high performance NdFeB-type powders was first reported by Takeshita and Nakayama in 1989. Further more, a partial substitution of Co for Fe and the addition of Zr, Ga, Hf, Nb or Ta to the NdFeB alloy were found to be effective in improving the hard magnetic properties of HDDR treated NdFeB powders. In this research, the magnetic properties and the microstructures of HDDR magnet materials fabricated from the alloys with chemical composition of Nd14Fe62+xCo18-xB6.6Zr0.1Ga0.3 (x=0~9) have been investigated. The magnetic properties of the HDDR powders were measured by VSM(Vibration Sample Magnetometer) with the maximum magnetic field of 2 T. The microstructure of the HDDR powders was observed by X-ray diffraction. The variation of the magnetic properties of HDDR powders with HD temperature and DR temperature was studied. The results show that HD temperature and DR temperature affect the magnetic properties of HDDR magnet powders obviously. The magnetic properties of the Nd14Fe62Co18B6.6Zr0.1Ga0.3 alloy processed by the HD(2.5 hours, 860 ℃), DR(0.5 hours, 830 ℃) reach: Br = 8.59 KG, iHC = 12.26 KOe, (BH)max = 15.35 MGOe. |
