scholarly journals [NiEn3](MoO4)0.5(WO4)0.5 Co-Crystals as Single-Source Precursors for Ternary Refractory Ni–Mo–W Alloys

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3272
Author(s):  
Polina S. Serebrennikova ◽  
Vladislav Y. Komarov ◽  
Aleksandr S. Sukhikh ◽  
Svetlana P. Khranenko ◽  
Andrey V. Zadesenets ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Carbon Nitride ◽  
Water Solution ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Decomposition Products ◽  
X Ray ◽  
Refractory Alloys ◽  
Thermal Decomposition Products ◽  
Heating Up

The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown.

scholarly journals Application of n-Dodecyltrimethylammonium Chloride for the Oxidation of Intermetallic Phases

2011 ◽  
Vol 66 (3) ◽  
pp. 230-238 ◽  
Author(s):  
Bodo Böhme ◽  
Stefan Hoffmann ◽  
Michael Baitinger ◽  
Yuri Grin
Keyword(s):  
Thermal Decomposition ◽  
Ionic Liquids ◽  
Redox Reactions ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Decomposition Products ◽  
X Ray ◽  
Thermal Decomposition Products ◽  
Dodecyltrimethylammonium Chloride

The thermal decomposition products of ionic liquids based on n-dodecyltrimethylammonium chloride (DTAC) were used for the preparation of the metastable allotrope Ge(cF136) by oxidation of Na12Ge17 in gas-solid reactions. This method of preparation provides a promising low-temperature route for the synthesis of intermetallic phases and elemental modifications. In order to explore the reaction mechanism, we investigated the thermal decomposition of DTAC as well as of the ionic liquids DTAC/MgCl2 and DTAC/AlCl3 by in-situ mass spectrometry and by powder X-ray diffraction. The results have revealed HCl, CH3Cl and 1-chlorododecane to act as oxidizing agents in the gas-solid redox reactions.

scholarly journals STUDY OF THERMAL DECOMPOSITION PRODUCTS OF NITROGEN-PHOSPHORUS-POTASSIUM FERTILIZERS BASED ON AMMONIUM NITRATE BY X-RAY DIFFRACTUON

2017 ◽  
Vol 61 (1) ◽  
pp. 72
Author(s):  
Konstantin G. Gorbovskiy ◽  
Alena S. Ryzhova ◽  
Andrey M. Norov ◽  
Denis A. Pagaleshkin ◽  
Valentina N. Kalinina ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Phosphoric Acid ◽  
Ammonium Nitrate ◽  
Confined Space ◽  
Decomposition Products ◽  
X Ray ◽  
Thermal Decomposition Products ◽  
Nitrogen Phosphorus ◽  
Thermal Stability Of

Complex mineral ammonium nitrate-based fertilizers are complex multicomponent salt systems possessing low thermal stability and prone to self-sustaining decomposition. This leads to the need to increase the requirements for fire and explosion safety in their manufacture, storage and transportation, caused by the fact that ammonium nitrate is a solid oxidant able to support a combustion, and its heating in confined space can lead to detonation. Components that make up such fertilizers can both reduce (phosphates and ammonium sulfate) and accelerate (chlorine compounds) decomposition of ammonium nitrate. Thus, the thermal stability of fertilizers based on ammonium nitrate largely depends on the ratio of the components that make up its composition or formed as a result of the chemical reaction. The simplest way to reduce the content of ammonium nitrate and increase the thermal stability of fertilizer without changing the content of essential nutrients is to increase the degree of phosphoric acid ammoniation. In this paper, the phase composition change of grade 22:11:11 nitrogen-phosphorus-potassium fertilizer obtained with different ammoniation degree in the process of thermal decomposition was studied by X-ray phase analysis. To obtain this fertilizer, wet-process phosphoric acid obtained sulfuric acid attack of the Khibin apatite concentrate by a hemihydrate method is used. It is shown that an increase in the ammoniation degree has a significant effect on the exothermic decomposition of ammonium nitrate and the amount of material that is released into the gas phase. The phases formed at each stage of the decomposition are determined.Forcitation:Gorbovskiy K.G., Ryzhova A.S., Norov A.M., Pagaleshkin D.A., Kalinina V.N., Mikhaylichenko A.I. Study of thermal decomposition products of nitrogen-phosphorus-potassium fertilizers based on ammonium nitrate by X-ray diffractuon. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 72-77

Kristallstruktur, thermische Zersetzung und Schwingungsspektrum von Ethylendiammonium-pentafluoromanganat(III), enH2MnF5 / Crystal Structure, Thermal Decomposition and Vibrational Spectrum of Ethylenediammonium-pentafluoromanganate(III), enH2MnF5

1992 ◽  
Vol 47 (6) ◽  
pp. 789-794 ◽  
Author(s):  
Ursula Bentrup ◽  
Ludger Schröder ◽  
Werner Massa
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Hydrogen Bonds ◽  
Vibrational Spectrum ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Decomposition Products ◽  
X Ray ◽  
Jahn Teller ◽  
Jahn Teller Effect

Single crystals of enH2MnF5 (en = ethylenediamine) have been prepared from aqueous HF solution and the crystal structure was determined by X-ray diffraction: space group Cccm, Z = 16, a = 1710.5(4), b = 1799.2(4), c = 847.8(2) pm, R/wR = 0.040/0.028 for 977 reflections. The structure consists of kinked [MnF5]2-- chains built by MnF6 octahedra sharing trans vertices (angles Mn-F-Mn 161.2 and 157.8°). The bridging Mn-Fax bonds are strongly elongated by the Jahn-Teller effect (mean Mn-Fax 215.4, Mn-F 183.8 pm). Each of the enH22+ cations is connected to four anionic chains by hydrogen bonds forming a 3 D network. Thermal decomposition occurs between 200 and 380 °C in two steps giving finally MnF2. The IR spectra of enH2MnF5 and its decomposition products are reported.

On the infra-red spectrum and thermal decomposition products of thaumasite, Ca3H2(CO3/SO4)SiO4.13H2O

1968 ◽  
Vol 36 (283) ◽  
pp. 1003-1011 ◽  
Author(s):  
G. N. Kirov ◽  
C. N. Poulieff
Keyword(s):  
Thermal Decomposition ◽  
Amorphous State ◽  
Ir Absorption ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Decomposition Products ◽  
Infra Red ◽  
Thermal Decomposition Products ◽  
Diffraction Patterns ◽  
Composite Nature

SummaryThe infra-red spectrum of untreated thaumasite Ca3H2(CO3/SO4)SiO4.13H2O, as well as the spectra and X-ray diffraction patterns of thaumasite heated in air at 200, 360, 550, 725, 800, 900, and 1150° C were investigated. The release of CO2 and H2O upon heating was followed. It was established that thaumasite changes between 200 and 550° C to a glass-like, amorphous state. Ca2SiO4-polymorphs and anhydrite are formed upon heating at temperatures up to 800° C. From 900° C calcium silicosulphate and anhydrite are the thermal decomposition products. These results are used in the assignment of the IR-absorption bands under 1400 cm−1 of untreated thaumasite, which are shown to be of a composite nature, i.e. attributable to overlapping vibrations of both sulphate and silicate tetrahedra.

scholarly journals Thermal Stability and Decomposition Products of P-Doped Ferrihydrite

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4113
Author(s):  
Gabriela Pieczara ◽  
Maciej Manecki ◽  
Grzegorz Rzepa ◽  
Olaf Borkiewicz ◽  
Adam Gaweł
Keyword(s):  
Thermal Stability ◽  
Room Temperature ◽  
Thermal Transformation ◽  
X Ray Diffraction ◽  
Decomposition Products ◽  
X Ray ◽  
Molar Ratios ◽  
P Content ◽  
Heating Up ◽  
Transformation Processes

This work aimed to determine the effect of various amounts of P admixtures in synthetic ferrihydrite on its thermal stability, transformation processes, and the properties of the products, at a broad range of temperatures up to 1000 °C. A detailed study was conducted using a series of synthetic ferrihydrites Fe5HO8·4H2O doped with phosphates at P/Fe molar ratios of 0.2, 0.5, and 1.0. Ferrihydrite was synthesized by a reaction of Fe2(SO4)3 with 1 M KOH at room temperature in the presence of K2HPO4 at pH 8.2. The products of the synthesis and the products of heating were characterized at various stages of transformation by using differential thermal analysis accompanied with X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy. Coprecipitation of P with ferrihydrite results in the formation of P-doped 2-line ferrihydrite. A high P content reduces crystallinity. Phosphate significantly inhibits the thermal transformation processes. The temperature of thermal transformation increases from below 550 to 710–750 °C. Formation of intermediate maghemite and Fe-phosphates, is observed. The product of heating up to 1000 °C contains hematite associated with rodolicoite FePO4 and grattarolaite Fe3PO7. Higher P content greatly increases the thermal stability and transformation temperature of rodolicoite as well.

Interfacial properties of GaSb/InAs superlattices

1993 ◽  
Vol 51 ◽  
pp. 826-827
Author(s):  
M. E. Twigg ◽  
B. R. Bennett ◽  
J. R. Waterman ◽  
J. L. Davis ◽  
B. V. Shanabrook ◽  
...  
Keyword(s):  
Gaas Substrate ◽  
Molecular Beam ◽  
Infrared Detector ◽  
Interfacial Properties ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
X Ray ◽  
Short Period ◽  
High Optical Absorption

Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an extensive set of GaSb/InAs superlattices grown on an GaSb buffer, which, in turn had been grown on a (100) GaAs substrate. Through appropriate shutter sequences, the interfaces were directed to assume either an InSb-like or GaAs-like character. These superlattices were then studied with a variety of ex-situ probes such as x-ray diffraction and Raman spectroscopy. These probes confirmed that, indeed, predominantly InSb-like and GaAs-like interfaces had been achieved.

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