日本金属学会誌

J. Japan Inst. Metals, Vol. 73, No. 8 (2009),
pp. 636-642

Investigation on Structures of Mono-Sized Particles Prepared by Pulsated Orifice Ejection Method and the Critical Cooling Rate for Forming Glass Phase Structure

Ayako Miura, Wei Dong, Masahiro Fukue, Noriharu Yodoshi, Takamichi Miyazaki and Akira Kawasaki

Graduate School of Engineering, Tohoku University, Sendai 980-8579

Abstract:

Mono-sized [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4 alloy particles with desired particle size and high sphericity have been prepared by Pulsated Orifice Ejection Method (POEM). Each particle has uniform compositional distribution along with the same composition during processing. Phase transition of a particle from fully amorphous to amorphous/crystalline and then fully crystalline shows that the diameter of a single fully amorphous particle is less than 300 μm in Ar atmosphere and 700 μm in He atmosphere. The critical diameter of a fully amorphous phase particle shifts toward larger diameter with an increase in the initial melt temperature. The critical cooling rate to realize fully amorphous phase is estimated to be in the range of (700-900 K×s-1), which only depends on the initial melt temperature, irrespective of the atmospheres gases.


(Received 2009/3/13)

Keywords:

mono-sized particle, glass phase structure, crystallization, cooling rate, containerless solidification


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