Preparation of rare earth based permanent magnet by sol-gel followed by reduction-diffusion method

• Main Author: Muhammad Khairi Uda.
• Other Authors: Raju Vijayaraghavan Ramanujan
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Materials; DRNTU::Engineering::Materials::Nanostructured materials; DRNTU::Engineering::Materials::Magnetic materials; DRNTU::Engineering::Materials::Metallic materials::Alloys
• Online Access: http://hdl.handle.net/10356/38600
• Institution: Nanyang Technological University

Nanomaterials with attractive properties are the focus of current research. Nanostructure magnetic materials are expected to have interesting magnetic properties. The magnetic properties of magnetic material are determined to a great extent by the composition, phases present. The main objective of this project is the synthesis, characterization and property evaluation of cobalt substituted Nd-Fe-B magnets. The motivation arises from the need to increase coercivity and saturation magnetization in order to produce high energy product permanent magnets. In this work cobalt substituted Nd-Fe-B magnets were synthesized by sol-gel process followed by reduction-diffusion using calcium hydride as reducing agent. The magnetic properties, phase analysis and structure of these nanoparticles were determined by VSM, XRD and SEM. In this project, cobalt of 10 to 100 atomic wt% were substituted to iron in the Nd2Fe14B compound. The effect of different percentages of Co substitution on the magnetic properties is studied. It was observed, through Rietveld analysis that the lattice parameters were indeed increased with cobalt substitution. This proves that the cobalt is entering the lattice site. Sol-gel indeed proven to be a successful technique to substitute Fe by Co yielding Nd-Fe-Co-B magnetic materials.