Formation of Co-Fe-TM-B (TM=Ti,Zr) Amorphous Powders by Mechanical Alloying and Their Magnetic Properties

• Main Authors: Hsing-Ching Li, 李星慶
• Other Authors: Hsin-Ming Wu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/kd3hk6

碩士 === 大同大學 === 材料工程學系(所) === 95 === In this study, amorphous Co-Fe-TM-B powders were synthesized by mechanical alloying (MA). The composition investigated were Co62-XFeXTM8B30 with TM=Ti, Zr and X equal to 0, 5, 10, 15, 20 and 25. The X-ray diffraction results indicate that the amounts of Fe in the powder mixtures significantly affect the time to reach amorphization by MA technique. The higher the Fe content the longer the amorphization. For a fixed amount of Fe, the time to reach amorphization for the Co-Fe-Zr-B system is shorter than that for the Co-Fe-Ti-B system. The thermal analysis results showed that Co-Fe-Zr-B powders have better glass forming ability than the Co-Fe-Ti-B powders. The supercooled liquid regions of the Co-Fe-Zr-B powders vary from 46 to 58℃ and the largest reduced glass transition temperature in these powders (corresponding to Co47Fe15Zr8B30 composition) is 0.50. For the Co-Fe-Ti-B alloys, their supercooled liquid regions vary from 38 to 42℃ and the largest reduced glass transition temperature in these alloys (corresponding to Co57Fe5Zr8B30 composition) is 0.43. For the magnetic property of these alloys, it was found that the amounts of Fe in the powder mixtures affect the saturation magnetization profoundly. The measured saturation magnetization increases with the increase in Fe for both Co-Fe-Ti-B and Co-Fe-Zr-B alloys. It was determined that for each 1 at% increase in Fe substitution for Co, saturation magnetization increase by 1.17 emu/g in Co-Fe-Ti-B alloys and 0.63 emu/g in Co-Fe-Zr-B alloys. The saturation magnetization of Co-Fe-Ti-B alloys and Co-Fe-Zr-B alloys were in the range of 93~124 emu/g and 92~110 emu/g, respectively. The measured intrinsic coercivity of Co-Fe-Ti-B alloys and Co-Fe-Zr-B alloys were in the range of 68~97 Oe and 58~66 Oe, respectively.