scholarly journals Selenium-iodide: A low melting point eutectic semiconductor

2018 ◽  
Vol 113 (24) ◽  
pp. 242103 ◽  
Author(s):  
L. F. Voss ◽  
J. W. Murphy ◽  
Q. Shao ◽  
R. A. Henderson ◽  
C. D. Frye ◽  
...  
Keyword(s):  
Melting Point ◽  
Melting Point Eutectic

Entire Symmetric Structure Inchworm-Type Piezoelectric Linear Actuator

2011 ◽  
Vol 480-481 ◽  
pp. 1061-1064 ◽  
Author(s):  
Hong Zhuang Zhang ◽  
Jiang Tian Shi ◽  
De Xin Sun
Keyword(s):  
Melting Point ◽  
Magnesium Alloy ◽  
Tensile Stress ◽  
Liquid Film ◽  
Solidification Process ◽  
Solidification Cracking ◽  
Necessary Condition ◽  
Welding Joint ◽  
Solidification Cracks ◽  
Melting Point Eutectic

The feature of the hot cracks of the welding joint of the MIG welded magnesium alloy AZ91D was studied systematically. The result indicates that the weld of the magnesium alloy displays a high cracking susceptibility. The cracks are mainly formed on the centerline of the weld and in the arc crater at the end of the weld. These cracks propagate along the α-Mg grain boundary, and they belong to the solidification cracking. These solidification cracks are resulted by the joint function of the low melting point liquid film in the weld and the tensile stress suffered by the weld metal during the solidification process. The low melting point liquid film is the internal cause to form the solidification cracks, while the tensile stress is a necessary condition. Limiting the amount of the low melting point eutectic and decreasing the tensile stress of the welding joint are two effective methods to improve the solidification cracking susceptibility of the Mg alloy weld.

Thermodynamics and Kinetic Considerations behind the Growth of AlN Whiskers Synthesized by Carbothermal Reduction

2007 ◽  
Vol 280-283 ◽  
pp. 1403-1408 ◽  
Author(s):  
Ren Li Fu ◽  
He Ping Zhou ◽  
Ke Xin Chen ◽  
José Maria F. Ferreira
Keyword(s):  
Melting Point ◽  
Liquid Phase ◽  
Carbothermal Reduction ◽  
Solid Phase ◽  
Dominant Role ◽  
Kinetic Studies ◽  
Synthesis Temperature ◽  
Screw Dislocations ◽  
Melting Point Eutectic ◽  
Kinetics Of

AlN whiskers have been successfully synthesized by carbothermal reduction. The thermodynamics and growth kinetics of AlN whiskers were studied at 1600°C using CaCO3 as a catalyst. The research indicated that AlN whiskers are more easily nucleated from the liquid phase than at the surface of solid phase. AlN whiskers are nucleated by VLS mechanism and the liquid, which plays a dominant role in the VLS mechanism, is formed by Al-Ca interphases, such as CaO×2Al2O3 and CaO×6Al2O3. Kinetic studies suggest that the catalyst reacts with Al2O3 to form a low melting point eutectic (1390°C). The liquid phase formed at this low melting point eutectic provides good conditions for nucleation of AlN whiskers. At the synthesis temperature, the liquid phase vaporizes, thus creating suitable conditions for the subsequent growing of whiskers by the VLS mechanism. This growing mechanism conforms to thermodynamics and a lot of proof indicates that screw dislocations play an important role in the process of the whiskers' formation.

scholarly journals Deposits in Gas-fired Rotary Kiln for Limonite Magnetization-Reduction Roasting: Characteristics and Formation Mechanism

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 764 ◽  
Author(s):  
Xianghui Fu ◽  
Zezong Chen ◽  
Xiangyang Xu ◽  
Lihua He ◽  
Yunfeng Song
Keyword(s):  
Melting Point ◽  
Liquid Phase ◽  
Formation Mechanism ◽  
Rotary Kiln ◽  
Coal Ash ◽  
Binder Phase ◽  
Reduction Roasting ◽  
Key Factor ◽  
Liquefaction Temperature ◽  
Melting Point Eutectic

The formation mechanism of deposits in commercial gas-fired magnetization-reduction roasting rotary kiln was studied. The deposits ring adhered on the kiln wall based on the bonding of low melting point eutectic liquid phase, and the deposit adhered on the air duct head by impact deposition. The chemical composition and microstructure of the deposits sampled at different locations varied slightly. Besides a small amount of quartz and limonite, main phases in the deposits are fayalite, glass phase and magnetite. The formation of the deposits can be attributed to the derivation of low melting point eutectic of fine limonite and coal ash, and the solid state reaction between them. Coal ash, originated from the reduction coal, combining together with fine limonite particles, results in the accumulation of deposits on the kiln wall and air duct. Fayalite, the binder phase, was a key factor for deposit formation. The residual carbon in limonite may cause an over-reduction of limonite and produce FeO. Amid the roasting process, SiO2, originated from limonite and coal ash, may combine with FeO and reduce the liquefaction temperature, therewith liquid phase generates at high temperature zone, which can significantly promote the growth of deposits.

scholarly journals A Robust Recovery of Ni From Laterite Ore Promoted by Sodium Thiosulfate Through Hydrogen-Thermal Reduction

2021 ◽  
Vol 9 ◽  
Author(s):  
Shoujun Liu ◽  
Chao Yang ◽  
Song Yang ◽  
Zhongliang Yu ◽  
Zhao Wang ◽  
...  
Keyword(s):  
Melting Point ◽  
Sodium Thiosulfate ◽  
Thermal Reduction ◽  
Metal Salts ◽  
Reduction Roasting ◽  
Alkali Metal Salts ◽  
Ni Content ◽  
Element Migration ◽  
Melting Point Eutectic ◽  
Laterite Ore

Laterite ore is one of the important sources of nickel (Ni). However, it is difficult to liberate Ni from ore structure during reduction roasting. This paper provided an effective way for a robust recovery of Ni from laterite ore by H2 reduction using sodium thiosulfate (Na2S2O3) as a promoter. . It was found that a Ni content of 9.97% and a Ni recovery of 99.24% were achieved with 20 wt% Na2S2O3 at 1,100°C. The promoting mechanism of Na2S2O3 in laterite ore reduction by H2 was also investigated. The thermogravimetric results suggested the formation of Na2Mg2SiO7, Na2SO3, Na2SO4, and S during the pyrolysis of laterite with Na2S2O3, among which the alkali metal salts could destroy the structures of nickel-bearing silicate minerals and hence release Ni, while S could participate in the formation of the low-melting-point eutectic phase of FeS-Fe. The formation of low-melting-point phases were further verified by the morphology analysis, which could improve the aggregation of Ni-Fe particles due to the capillary forces of FeS-Fe as well as the enhanced element migration by the liquid phase of sodium silicates during reduction.

scholarly journals Thermal, Viscoelastic and Surface Properties of Oxidized Field’s Metal for Additive Microfabrication

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7392
Author(s):  
Rosendo Zamora ◽  
Juan Martínez-Pastor ◽  
Félix Faura
Keyword(s):  
Melting Point ◽  
Contact Angles ◽  
Metal Alloys ◽  
Liquid Metal Coolant ◽  
Two Phase ◽  
Drop Shape ◽  
Analysis Techniques ◽  
Wetting Properties ◽  
Melting Point Eutectic ◽  
Metal Coolant

Field’s metal, a low-melting-point eutectic alloy composed of 51% In, 32.5 Bi% and 16.5% Sn by weight and with a melting temperature of 333 K, is widely used as liquid metal coolant in advanced nuclear reactors and in electro–magneto–hydrodynamic two-phase flow loops. However, its rheological and wetting properties in liquid state make this metal suitable for the formation of droplets and other structures for application in microfabrication. As with other low-melting-point metal alloys, in the presence of air, Field’s metal has an oxide film on its surface, which provides a degree of malleability and stability. In this paper, the viscoelastic properties of Field’s metal oxide skin were studied in a parallel-plate rheometer, while surface tension and solidification and contact angles were determined using drop shape analysis techniques.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

The observation of nano-voids in Au thin films

1987 ◽  
Vol 45 ◽  
pp. 366-367
Author(s):  
William Krakow
Keyword(s):  
Thin Films ◽  
Melting Point ◽  
Present Author ◽  
Stacking Faults ◽  
Damage Threshold ◽  
Ionic Species ◽  
Rare Gases ◽  
Chain Defects ◽  
Vacancy Chains ◽  
Au Thin Films

It has long been known that defects such as stacking faults and voids can be quenched from various alloyed metals heated to near their melting point. Today it is common practice to irradiate samples with various ionic species of rare gases which also form voids containing solidified phases of the same atomic species, e.g. ref. 3. Equivalently, electron irradiation has been used to produce damage events, e.g. ref. 4. Generally all of the above mentioned studies have relied on diffraction contrast to observe the defects produced down to a dimension of perhaps 10 to 20Å. Also all these studies have used ions or electrons which exceeded the damage threshold for knockon events. In the case of higher resolution studies the present author has identified vacancy and interstitial type chain defects in ion irradiated Si and was able to identify both di-interstitial and di-vacancy chains running through the foil.

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