Microwave hydrothermal synthesis of Nd-Fe-B permanent magnets

• Main Author: Chew, Wei Jie.
• Other Authors: Raju Vijayaraghavan Ramanujan
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Materials::Magnetic materials
• Online Access: http://hdl.handle.net/10356/35686
• Institution: Nanyang Technological University

A rapid synthesis of Nd2Fe14B nano powders was achieved by microwave irradiation to obtain oxide powders through varying microwave power and duration of microwave heating. The homogeneous oxide powders were then reacted with CaH2 through a reduction reaction at 700°C for 2hours, to obtain Nd-Fe-B powders. Under optimized conditions, the magnetic properties of Nd15Fe77B8 as reduced powder at 800W microwave power has achieved in the highest coercivity of 2946Oe and Ms= 102.17 emu/g with a crystallite size of 55.1nm. With microwave heating of 2.5minutes, Nd15Fe77B8 as reduced powder at 100W microwave power has the highest Ms of 105.7 emu/g and coercivity of 519.8Oe. This is a good technique to make nano composite material Nd-Fe-B/Fe exchanging-spring magnet, which are useful for many applications.