New Method for Measuring the Viscosity of the Molten Amorphous Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 63-69
Author(s):  
Li Jun Cao ◽  
Jing Song Wang ◽  
Wei Sun ◽  
Jing Hua Wang ◽  
Hao Yan Sun
Keyword(s):  
Activation Energy ◽  
Amorphous Alloy ◽  
Rotating Cylinder ◽  
New Method ◽  
Molten Alloy ◽  
Exponential Relationship ◽  
Measurement Results ◽  
Cylinder Method ◽  
Covering Slag

A new method, covering slag technology combining rotating cylinder method, has been proposed in this paper for measuring the viscosity of the molten amorphous alloy, and the viscosity of molten Zr50Cu50 alloy was measured. Furthermore, the changes of viscous activation energy Ev were analyzed. The measurement results showed: the viscosity of molten Zr50Cu50 alloy increases with decreasing temperature in the range of 1373 to 1208K and there is an overall exponential relationship. Two discontinuous points on the curve of lnη ~1/T have been found. After analyzing the changes of viscous activation energy Ev , the microstructure of molten alloy could be changed. The viscosity of molten Zr50Cu50 alloy is three orders of magnitude higher than that of some other alloys which is closely related with the excellent GFA of Zr50Cu50 alloy.

Influence of Nb2O5 and basicity on the viscosity and structure of CaO-SiO2-Nb2O5-CeO2-CaF2 slag system

2020 ◽  
Vol 117 (3) ◽  
pp. 307
Author(s):  
Zhuang Ma ◽  
Zengwu Zhao ◽  
Wentao Guo ◽  
Zhi Wang
Keyword(s):  
Activation Energy ◽  
Slag System ◽  
Rotating Cylinder ◽  
Degree Of Polymerization ◽  
X Ray Diffraction ◽  
Structural Units ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Bayan Obo ◽  
Cylinder Method

In order to utilize niobium concentrate of Bayan Obo effectively, the effect of Nb2O5 and basicity on the viscosity of CaO-SiO2-Nb2O5-5.0 wt.% CeO2-5.0 wt.% CaF2 slag system was studied from 1653 to 1813 K in reducing atmosphere by rotating cylinder method. For the same condition, the as-quenched samples were investigated through X-ray diffraction and Raman spectroscopy. The results show that the viscosity, break temperature and activation energy of viscous flow decrease with the increase of Nb2O5 and basicity. Raman spectra show that the Nb4+ ions exist in the form of [NbO6] octahedron with different distortion and little [NbO4] tetrahedron in the slags. The Nb2O5 addition and basicity lower the degree of polymerization, where the complex Si-O network is depolymerized into simple structural units.

Discussion on Relationship between Viscosities of Molten Zr-Cu Based Alloys and their Glass Forming Ability

2011 ◽  
Vol 194-196 ◽  
pp. 1242-1246
Author(s):  
Jing Song Wang ◽  
Li Jun Cao ◽  
Jing Hua Wang ◽  
Hao Yan Sun ◽  
Shu You Huang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Rotating Cylinder ◽  
Glass Forming Ability ◽  
Vacuum Condition ◽  
Glass Forming ◽  
Amorphous Sample ◽  
Cylinder Method ◽  
The Relationship

The dynamic viscosities of molten Zr55Ni5Al10Cu30 and Zr50Cu50 alloys were measured by using rotating cylinder method under non-vacuum condition. According to the lnη~1/T curves, discontinuous changes were found and the activation energy was calculated. The activation energy of molten Zr55Ni5Al10Cu30 alloy is obviously larger than that of molten Zr50Cu50 alloy. Amorphous sample of Zr55Ni5Al10Cu30 with 3mm diameter was prepared successfully under non-vacuum condition, but there are crystallization phases in Zr50Cu50 amorphous sample with 2mm diameter. The relationship between viscosities of molten Zr-Cu based alloys and their glass forming ability (GFA) was discussed, and viscosities of molten Zr-Cu based alloys play an important role on their GFA.

Study on Viscosity of Zr-Cu Alloys Based on Viscosity Measurement and Hirai Model

2011 ◽  
Vol 704-705 ◽  
pp. 1100-1105 ◽  
Author(s):  
Jing Song Wang ◽  
Shu You Huang ◽  
Li Jun Cao ◽  
Hao Yan Sun ◽  
Jing Hua Wang ◽  
...  
Keyword(s):  
Liquidus Temperature ◽  
Arrhenius Equation ◽  
Rotating Cylinder ◽  
Viscosity Data ◽  
Vacuum Melting ◽  
Temperature Relation ◽  
Cu Alloys ◽  
Cylinder Method ◽  
Covering Slag ◽  
The Relationship

In this paper, the viscosity of molten Zr50Cu50 alloy was measured by using NaF-CaF2 covering slag protection combining rotating cylinder method firstly under non-vacuum melting condition. The curve of viscosity and temperature was acquired stably in the temperature range from 1370K to the liquidus temperature (1208K). According the Arrhenius equation form, the viscosity-temperature relation of molten Zr50Cu50 alloy can be fit as the following equation: （1208K50 alloy can be calculated by the above equation in the range of 1370 to 1208K. The viscosity values of molten Zr50Cu50 alloy calculated by Hirai model are relatively small, so the corrected Hirai model was obtained by the measured viscosity data. The viscosities of molten Zr-Cu alloys can be expressed by the following corrected Hirai model: The viscosities of typical molten Zr-Cu alloys were calculated by the above corrected model. The results showed that the viscosities of Zr-Cu alloys are larger at the respective liquidus temperature. The fundamental data were provided for researching the relationship between viscosities of molten Zr-Cu alloys and amorphous form ability.

Viscosity Evaluation of Multi-phases Flux by Rotating Cylinder Method

2009 ◽  
Vol 95 (12) ◽  
pp. 807-812 ◽  
Author(s):  
Sohei Sukenaga ◽  
Shinichiro Haruki ◽  
Yoshinori Yamaoka ◽  
Noritaka Saito ◽  
Kunihiko Nakashima
Keyword(s):  
Rotating Cylinder ◽  
Cylinder Method

Pseudo-three-timescale approximation of exponentially modulated free-surface waves

2009 ◽  
Vol 625 ◽  
pp. 435-443 ◽  
Author(s):  
MARK A. KELMANSON
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Test Problem ◽  
Evolution Equations ◽  
Film Coating ◽  
Rotating Cylinder ◽  
New Method ◽  
Free Surface Waves ◽  
Numerical Integrations ◽  
Order Of Magnitude

A novel pseudo-three-timescale asymptotic procedure is developed and implemented for obtaining accurate approximations to solutions of an evolution equation arising in thin-film free-surface viscous flow. The new procedure, which employs strained fast and slow timescales, requires considerably fewer calculations than its standard three-timescale counterpart employing fast, slow and slower timescales and may readily be applied to other evolution equations of fluid mechanics possessing wave-like solutions exhibiting exponential decay in amplitude and variations in phase over disparate timescales. The new method is validated on the evolution of free-surface waves on a thin, viscous film coating the exterior of a horizontal rotating cylinder and is shown to yield accurate solutions up to non-dimensional times exceeding by an order of magnitude those of previous related studies. Results of the new method applied to this test problem are demonstrated to be in excellent agreement, over large timescales, with those of corroborative spectrally accurate numerical integrations.

THE RATE OF ADSORPTION OF SOME LOW BOILING GASES ON A MODIFIED SARAN CHARCOAL

1955 ◽  
Vol 33 (2) ◽  
pp. 344-351 ◽  
Author(s):  
J. R. Dacey ◽  
D. G. Thomas
Keyword(s):  
Activation Energy ◽  
Pore Structure ◽  
Temperature Variation ◽  
New Method ◽  
Adsorption Experiment ◽  
Vinylidene Chloride ◽  
Adsorption Of Nitrogen

The pyrolysis at 300 °C. of vinylidene chloride monomer adsorbed on Saran charcoal alters the pore structure of the charcoal so that low boiling gases such as nitrogen are adsorbed slowly. The rates of adsorption of nitrogen, argon, and methane have been measured. They were found to vary with pressure and temperature, and from the temperature variation an activation energy may be calculated. A new method of determining this energy is described which involves changing the temperature during only one adsorption experiment.

scholarly journals A New Method to Extract Gate Bias-Dependent Parasitic Resistances in GaAs pHEMTs

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 266
Author(s):  
Ruirui Dang ◽  
Lijie Yang ◽  
Zhihao Lv ◽  
Chunyi Song ◽  
Zhiwei Xu
Keyword(s):  
Parameter Extraction ◽  
New Method ◽  
Small Signal ◽  
Gate Bias ◽  
Large Signal ◽  
S Parameter ◽  
Proposed Model ◽  
Measurement Results ◽  
Parasitic Parameter ◽  
Signal Models

Accurate large signal GaAs pHEMT models are essential for devices’ performance analysis and microwave circuit design. This, in turn, mandates precise small signal models. However, the accuracy of small signal models strongly depends on reliable parasitic parameter extraction of GaAs pHEMT, which also greatly influences the extraction of intrinsic elements. Specifically, the parasitic source and drain resistances, R s and R d , are gate bias-dependent, due to the two-dimensional charge variations. In this paper, we propose a new method to extract R s and R d directly from S-parameter measurements of the device under test (DUT), which save excessive measurements and complicated parameter extraction. We have validated the proposed method in both simulation and on-wafer measurement, which achieves better accuracy than the existing state-of-the-art in a frequency range of 0.5–40 GHz. Furthermore, we develop a GaAs pHEMT power amplifier (PA) to further validate the developed model. The measurement results of the PA at 9–15 GHz agree with the simulation results using the proposed model.

Effects of basicity and CaF2 on the viscosity of CaF2–CaO–SiO2 slag for electroslag remelting process

2019 ◽  
Vol 116 (6) ◽  
pp. 638 ◽  
Author(s):  
Yigui Lao ◽  
Yunming Gao ◽  
Fangjie Deng ◽  
Qiang Wang ◽  
Guangqiang Li
Keyword(s):  
Rotating Cylinder ◽  
Electroslag Remelting ◽  
Experimental Conditions ◽  
Ft Ir ◽  
Cylinder Method ◽  
The Fourier Transform ◽  
The Relationship ◽  
Complex Anions ◽  
Silicate Complex ◽  
Ft Ir Spectroscopy

Effects of the basicity and the CaF2 content on viscosity of CaF2–CaO–SiO2 slag with high CaF2 content for electroslag remelting process were investigated by the rotating cylinder method in the temperature ranging from 1773 to 1533 K. The relationship between the structure and the viscosity variation of the slag was also clarified by the Fourier transform infrared (FT-IR) spectroscopy of water-quenched slags. The results show that the viscosity gradually decreases with the increase in the basicity of the slag from 1 to 3 under the present experimental conditions. It is found that the CaO does not depolymerize all silicate complex anions for the slag with the basicity of 1 at 1773 K and there are still some bridging oxygens. With the increase in the basicity to 3, the silicate complex anions are almost completely depolymerized to simple ions. As the CaF2 content increases from 40 to 80 mass%, the viscosity of the slag decreases due to the dilution of CaF2 for the concentration of the silicate complex anions in unit volume of the slag. Moreover, the effect of the temperature on the viscosity is not remarkable. The activation energy of viscous flow exhibits the decrease from 40.4 to 26.7 kJ · mol−1 with the increase in the basicity from 1 to 3, and also the decrease from 66.6 to 31.0 kJ · mol−1 with the increase in the CaF2 content from 40 to 80 mass%.

scholarly journals A New Method for Producing Amorphous Alloy Wires

2010 ◽  
Vol 51 (8) ◽  
pp. 1495a-1495a
Author(s):  
Tao Zhang ◽  
Akihisa Inoue
Keyword(s):  
Amorphous Alloy ◽  
New Method
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