0000000000181414
AUTHOR
K. Ishizaki
Microwave-induced electromigration in multicomponent metallic alloys
The crystallization of amorphous FeCoCuZrAlSiB alloy ribbons during microwave heating was investigated in situ using time-resolved X-ray powder diffraction. The formation of the nanocrystalline α-(Fe,Co)(SiAl) phase during the primary crystallization stage is followed by the crystallization of the residual glassy matrix. Scanning electron microscopy analysis after microwave exposure reveals the formation of nanosized hillocks evenly distributed over the ribbon surfaces. Local chemical composition analysis by energy-dispersive spectroscopy shows that the surface clusters are enriched in Cu and Al. The occurrence of this typical electromigration effect imposes a strong restriction on the dura…
Rapid nanocrystallization of soft-magnetic amorphous alloys using microwave induction heating
The crystallization of Fe73Nb3Cu1Si16B7 alloy during microwave heating was investigated in situ using synchrotron radiation powder diffraction. The phase transformation comprises a primary nanocrystallization stage and a final microcrystallization step. We provide evidence for a strong enhancement of the transformation kinetics. Microwave heating occurs as a result of both ohmic and magnetic losses induced by eddy currents, which defines a volumetric microwave induction heating process. Nanocrystallization is completed within 5 s, while full crystallization is achieved in less than 10 s.
Nanocrystallization of amorphous alloys using microwaves:In situtime-resolved synchrotron radiation studies
Important energy and time savings can be achieved with the thermal treatment of materials by replacing conventional heating methods with microwave heating. The nano- crystallization of Co-Fe-W-B amorphous alloy powders under microwave irradiation was followed for the first time by in situ time-resolved synchrotron radiation powder diffraction. It is shown that even a very short exposure to the electromagnetic field (single pulse microwave application) typically of the order of a few seconds is sufficient to obtain the bulk nano- crystalline state. A metastable high-temperature Co-W-B orthorhombic phase forms during the microwave heating, which gradually transforms to the tetragonal Co2B sta…