Extraction of boron Fe8B2 ribbons by annealing under hydrogen flow

2004 ◽  
Vol 120 ◽  
pp. 55-59
Author(s):  
G. Saage ◽  
S. Roth ◽  
J. Eckert ◽  
L. Schultz
Keyword(s):  
Melt Spinning ◽  
Extraction Process ◽  
Metal Alloys ◽  
Heating Rates ◽  
Hydrogen Flow ◽  
Transition Metal Alloys ◽  
Amorphous Ribbons ◽  
Target Composition ◽  
Flowing Hydrogen ◽  
And Diffusion

Transition metal alloys often are difficult to be prepared as ribbons by conventional methods. If boron is added to these alloys, amorphous ribbons may be prepared by melt spinning. These amorphous ribbons have a better workability than their crystalline counterparts. However, the composition is different from the target composition. Upon annealing treatments in flowing hydrogen the boron may be extracted and the ribbon crystallizes. Thermodynamically the extraction of boron proceeds by the reaction of hydrogen with the borides formed during the crystallization of the ribbons. In order to investigate this extraction in more detail Fe8B2 amorphous ribbons were used. Thermogravimetric measurements were made at three different heating rates which permit to develop a thermokinetic description of the extraction process, which is controlled by chemical reactions and diffusion. The description allows to calculate the degree of boron extraction for various annealing procedures.

Research of Crystallization Kinetics and Thermal Stability of W48.5Ni34Fe14.6B2.9 Amorphous Ribbons

2014 ◽  
Vol 789 ◽  
pp. 84-89 ◽  
Author(s):  
Wen Sheng Liu ◽  
Jia Jia Zhang ◽  
Yun Zhu Ma ◽  
Xiao Shan Ye
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Glass Transition ◽  
Crystallization Kinetics ◽  
Melt Spinning ◽  
Amorphous Structure ◽  
Heating Rates ◽  
Amorphous Ribbons ◽  
Kinetic Effects ◽  
Precipitated Phases

The W48.5Ni34Fe14.6B2.9 (wt.%) amorphous ribbons were prepared using melt spinning method. The crystallization kinetics of amorphous ribbons was investigated by differential scanning calorimeter (DSC) at different heating rates from 10 to 40 K/min. The activation energy of amorphous ribbons was simulated by Kissinger and Ozawa equations, respectively. The precipitated phases at different annealing temperatures were analyzed by X-ray diffraction (XRD). The results showed that the glass transition temperature (Tg), the crystallization temperature (Tx) and the peak temperature (Tp) were found to increase during enhancing heating rate, indicating the obvious kinetic effects of glass transition and crystallization. The consistency of values of the activation energy calculated by Kissinger and Ozawa equations suggested the good accuracy about experiment results. The specific temperatures of Tx and Tp detected by DSC and the deduced crystallization activation energy are generally higher than these of other amorphous alloys, which suggests a higher resistance to crystallization. The W48.5Ni34Fe14.6B2.9 alloy substantially remained at amorphous structure when annealed at 923K for 60 min, showing that the alloy possessed a higher thermal stability.

New developments in the ab initio determination of transition metal alloys phase diagram

1993 ◽  
Vol 90 ◽  
pp. 249-254 ◽  
Author(s):  
C Wolverton ◽  
M Asta ◽  
S Ouannasser ◽  
H Dreyssé ◽  
D de Fontaine
Keyword(s):  
Phase Diagram ◽  
Transition Metal ◽  
Ab Initio ◽  
Metal Alloys ◽  
New Developments ◽  
Transition Metal Alloys

Split-Off Narrowd-Band States aboveEFin Transition-Metal Alloys

1983 ◽  
Vol 51 (13) ◽  
pp. 1187-1190 ◽  
Author(s):  
F. U. Hillebrecht ◽  
J. C. Fuggle ◽  
G. A. Sawatzky ◽  
R. Zeller
Keyword(s):  
Transition Metal ◽  
Metal Alloys ◽  
Transition Metal Alloys

Spin glass and reentrant behavior in amorphous transition metal alloys Pd77.5-xCu5Si16.5Mx

1986 ◽  
Vol 54-57 ◽  
pp. 269-270
Author(s):  
J.A. Heller ◽  
G.V. Lecomte ◽  
E.F. Wassermann ◽  
D.M. Herlach
Keyword(s):  
Transition Metal ◽  
Spin Glass ◽  
Metal Alloys ◽  
Transition Metal Alloys
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