Synthesis and Characterizations of Fe-based Metallic Glassy Systems
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
This thesis is a study of tailoring amorphous Fe-B-Si based alloy to produce bulk glassy rods by adding Nb. We have prepared rapid quenched thin ribbons (thickness ~12 µm) by melt spinning, and glassy rods of diameter ~1mm by Cu-mold casting based on compositions (Fe0.78B0.13Si0.9)100-xNbx (x=0, 4, 8, 12), and studied their different physical properties. The melt-spun ribbons are found to be X-ray amorphous, whereas some nano-crystallinity is observed in the case of rods. All the ribbons show high saturation magnetization and low coercivity, which are the desirable characteristics of a soft ferromagnet. These ribbons are thus suitable for designing high frequency transformers, and sensors from an applications point of view. With increasing Nb content their saturation magnetization, ferromagnetic Curie temperature, and resistivity are found to decrease as expected. The temperature dependence of electrical resistivity shows small positive temperature co-efficient that is expected for a metallic disordered material. We have also studied the modification of the properties on thermal annealing the (Fe0.78B0.13Si0.9)96 Nb4 ribbon at different temperatures in a neutral atmosphere.
Place, publisher, year, edition, pages
2011. , 40 p.
melt spun ribbon, soft magnetic properties, crystallization, Curie temperature, electrical resistivity
Other Materials Engineering
IdentifiersURN: urn:nbn:se:kth:diva-37395OAI: oai:DiVA.org:kth-37395DiVA: diva2:433678
Master of Science in Engineering - Materials Design and Engineering
2011-03-23, Red Room 127, Brinellvägen 23, SE-100 44, Stockholm, 10:15 (English)
Rao, K. Venkat, Professor
Rao, firstname.lastname@example.org, Professor