Thermal stability of ternary compounds in the Cu-Li-Sn system and phase transition of the Cu6Sn5 electrode: First-principles calculations and experiment

2019 ◽  
Vol 783 ◽  
pp. 44-54 ◽  
Author(s):  
Fan Zhang ◽  
Shuhong Liu ◽  
Jianchuan Wang ◽  
Yong Du ◽  
Weibin Zhang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
First Principles ◽  
First Principles Calculations ◽  
Ternary Compounds ◽  
Thermal Stability Of

Reaction mechanism of metal and pyrite under HPHT conditions and improvement of the properties

2022 ◽  
Author(s):  
Yao Wang ◽  
Dan Xu ◽  
Shan Gao ◽  
Qi Chen ◽  
Dayi Zhou ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Pressure ◽  
Reaction Mechanism ◽  
First Principles ◽  
Room Temperature ◽  
First Principles Calculations ◽  
Mine Wastewater ◽  
Al Addition ◽  
Thermal Stability Of ◽  
Pyrite Tailings

Abstract Pyrite tailings are the main cause of acid mine wastewater. An idea was put forward to more effectively use pyrite, and it was modified by exploiting the reducibility of metal represented by Al under high-pressure and high-temperature (HPHT) conditions. Upon increasing the Al addition, the conductivity of pyrite were effectively improved, which is nearly 734-times higher than that of unmodified pyrite at room temperature. First-principles calculations were used to determine the influence of a high pressure on the pyrite lattice. The high pressure increased the thermal stability of pyrite, reduced pyrite to high-conductivity Fe7S8 (pyrrhotite) by Al, and prevented the formation of iron. Through hardness and density tests the influence of Al addition on the hardness and toughness of samples was explored. Finally the possibility of using other metal-reducing agents to improve the properties of pyrite was discussed.

scholarly journals Simultaneous tuning of the magnetic anisotropy and thermal stability of $$\alpha ^{''}$$-phase Fe$$_{16}$$N$$_{2}$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
D. Odkhuu ◽  
S. C. Hong
Keyword(s):  
Thermal Stability ◽  
Magnetic Anisotropy ◽  
First Principles ◽  
Alpha Phase ◽  
Formula Unit ◽  
First Principles Calculations ◽  
A Value ◽  
Valence Electrons ◽  
Re Elements ◽  
Thermal Stability Of

AbstractSimultaneously enhancing the uniaxial magnetic anisotropy ($$K_u$$ K u ) and thermal stability of $$\alpha ^{''}$$ α ′ ′ -phase Fe$$_{16}$$ 16 N$$_{2}$$ 2 without inclusion of heavy-metal or rare-earth (RE) elements has been a challenge over the years. Herein, through first-principles calculations and rigid-band analysis, significant enhancement of $$K_u$$ K u is proposed to be achievable through excess valence electrons in the Fe$$_{16}$$ 16 N$$_{2}$$ 2 unit cell. We demonstrate a persistent increase in $$K_u$$ K u up to 1.8 MJ m$$^{\text {-}3}$$ - 3 , a value three times that of 0.6 MJ m$$^{\text {-}3}$$ - 3 in $$\alpha ^{''}$$ α ′ ′ -Fe$$_{16}$$ 16 N$$_{2}$$ 2 , by simply replacing Fe with metal elements with more valence electrons (Co to Ga in the periodic table). A similar rigid-band argument is further adopted to reveal an extremely large $$K_u$$ K u up to 2.4 MJ m$$^{\text {-}3}$$ - 3 in (Fe$$_{0.5}$$ 0.5 Co$$_{0.5}$$ 0.5 )$$_{16}$$ 16 N$$_{2}$$ 2 obtained by replacing Co with Ni to Ga. Such a strong $$K_u$$ K u can also be achieved with the replacement by Al, which is isoelectronic to Ga, with simultaneous improvement of the phase stability. These results provide an instructive guideline for simultaneous manipulation of $$K_u$$ K u and the thermal stability in 3d-only metals for RE-free permanent magnet applications.

scholarly journals Synthesis and photocatalytic properties of Sn–TiO2 nanomaterials

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060018
Author(s):  
E. M. Bayan ◽  
T. G. Lupeiko ◽  
L. E. Pustovaya ◽  
M. G. Volkova
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
Sol Gel ◽  
Rutile Phase ◽  
Photocatalytic Properties ◽  
Light Activation ◽  
X Ray ◽  
Tio2 Nanomaterials ◽  
Visible Light Activation ◽  
Thermal Stability Of

Sn-doped TiO2 nanomaterials were synthesized by sol–gel method. It was shown the phase compositions and phase transitions change with the introduction of different tin amounts (0.5–20[Formula: see text]mol.%). X-ray powder diffraction was used to study the effect of different tin amounts on the anatase–rutile phase transition. It was found that the introduction of ions increases the thermal stability of anatase modifications. The material’s photocatalytic activity was studied in reaction with a model pollutant (methylene blue) photodegradation under UV and visible light activation. The best photocatalytic properties were shown for material, which contains 5[Formula: see text]mol.% of Sn.

scholarly journals The thermal stability of FAPbBr3 nanocrystals from temperature-dependent photoluminescence and first-principles calculations

RSC Advances ◽  
2020 ◽  
Vol 10 (72) ◽  
pp. 44373-44381
Author(s):  
Xiaozhe Wang ◽  
Qi Wang ◽  
Zhijun Chai ◽  
Wenzhi Wu
Keyword(s):  
First Principles ◽  
First Principle ◽  
First Principles Calculations ◽  
Temperature Dependent ◽  
Time Resolved ◽  
First Principle Calculations ◽  
Steady State Time ◽  
Time Resolved Photoluminescence ◽  
Thermal Stability Of ◽  
Temperature Dependent Photoluminescence

The thermal properties of FAPbBr3 perovskite nanocrystals (PNCs) is investigated by use of temperature-dependent steady-state/time-resolved photoluminescence and first-principle calculations.

Orbital change manipulation metal–insulator transition temperature in W-doped VO2

2015 ◽  
Vol 17 (17) ◽  
pp. 11638-11646 ◽  
Author(s):  
Xinfeng He ◽  
Yijie Zeng ◽  
Xiaofeng Xu ◽  
Congcong Gu ◽  
Fei Chen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Infrared Spectroscopy ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
First Principles ◽  
Insulator Transition ◽  
First Principles Calculations ◽  
Orbital Structure ◽  
Metal Insulator Transition ◽  
Metal Insulator

Using ultraviolet-infrared spectroscopy and first principles calculations, it is revealed that changes in the orbital structure can regulate the W-doped VO2 phase transition temperature.

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