scholarly journals Synthesis, Polymorphism and Thermal Decomposition Process of (n-C4H9)4NRE(BH4)4 for RE = Ho, Tm and Yb

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1329
Author(s):  
Wojciech Wegner ◽  
Tomasz Jaroń
Keyword(s):  
Thermal Decomposition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Decomposition Products ◽  
Gaseous Products ◽  
Dsc Measurements ◽  
Unit Cells ◽  
Polymorphic Forms ◽  
Solid Decomposition ◽  
Derivatives Of

In total, three novel organic derivatives of lanthanide borohydrides, n-But4NRE(BH4)4 (TBAREB), RE = Ho, Tm, Yb, have been prepared utilizing mechanochemical synthesis and purified via solvent extraction. Studies by single crystal and powder X-ray diffraction (SC-XRD and PXRD) revealed that they crystalize in two polymorphic forms, α- and β-TBAREB, adopting monoclinic (P21/c) and orthorhombic (Pnna) unit cells, previously found in TBAYB and TBAScB, respectively. Thermal decomposition of these compounds has been investigated using thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) measurements, along with the analysis of the gaseous products with mass spectrometry (MS) and with analysis of the solid decomposition products with PXRD. TBAHoB and TBAYbB melt around 75 °C, which renders them new ionic liquids with relatively low melting points among borohydrides.

scholarly journals A Facile Synthesis and Characterization of Highly Crystalline Submicro-Sized BiFeO3

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3035
Author(s):  
Dovydas Karoblis ◽  
Diana Griesiute ◽  
Kestutis Mazeika ◽  
Dalis Baltrunas ◽  
Dmitry V. Karpinsky ◽  
...  
Keyword(s):  
Bismuth Ferrite ◽  
Cost Effective ◽  
Xrd Analysis ◽  
Synthetic Approach ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
Optimal Annealing Temperature ◽  
Synthesized Materials

In this study, a highly crystalline bismuth ferrite (BFO) powder was synthesized using a novel, very simple, and cost-effective synthetic approach. It was demonstrated that the optimal annealing temperature for the preparation of highly-pure BFO is 650 °C. At lower or higher temperatures, the formation of neighboring crystal phases was observed. The thermal behavior of BFO precursor gel was investigated by thermogravimetric and differential scanning calorimetry (TG-DSC) measurements. X-ray diffraction (XRD) analysis and Mössbauer spectroscopy were employed for the investigation of structural properties. Scanning electron microscopy (SEM) was used to evaluate morphological features of the synthesized materials. The obtained powders were also characterized by magnetization measurements, which showed antiferromagnetic behavior of BFO powders.

scholarly journals A Facile Method to Construct MXene/CuO Nanocomposite with Enhanced Catalytic Activity of CuO on Thermal Decomposition of Ammonium Perchlorate

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2457 ◽  
Author(s):  
Haifeng Zhao ◽  
Jing Lv ◽  
Junshan Sang ◽  
Li Zhu ◽  
Peng Zheng ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Ammonium Perchlorate ◽  
Photoelectron Spectra ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Improved Performance ◽  
Calcination Method

In this work, a mixing-calcination method was developed to facilely construct MXene/CuO nanocomposite. CuO and MXene were first dispersed in ethanol with sufficient mixing. After solvent evaporation, the dried mixture was calcinated under argon to produce a MXene/CuO nanocomposite. As characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectra (XPS), CuO nanoparticles (60–100 nm) were uniformly distributed on the surface and edge of MXene nanosheets. Furthermore, as evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the high-temperature decomposition (HTD) temperature decrease of ammonium perchlorate (AP) upon addition of 1 wt% CuO (hybridized with 1 wt% MXene) was comparable with that of 2 wt% CuO alone, suggesting an enhanced catalytic activity of CuO on thermal decomposition of AP upon hybridization with MXene nanosheets. This strategy could be further applied to construct other MXene/transition metal oxide (MXene/TMO) composites with improved performance for various applications.

Stress-Induced Crystal-to-Crystal Transformations in High-Density Polyethylene-Layered Silicate Nanocomposites: A Spectroscopic Study

2005 ◽  
Vol 59 (9) ◽  
pp. 1148-1154 ◽  
Author(s):  
Spiros Tzavalas ◽  
Vasilis G. Gregoriou
Keyword(s):  
High Density Polyethylene ◽  
Mechanical Strain ◽  
Layered Silicate ◽  
High Density ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Polyethylene Matrix ◽  
Dsc Measurements ◽  
Infrared Measurements ◽  
Ft Ir

High-density polyethylene (HDPE)–clay nanocomposites have been prepared using the melt intercalation technique. Organically modified montmorillonite at various loadings (0.5–7%) was used as a nanoadditive. Fourier transform infrared spectroscopy (FT-IR) was utilized for the first time to monitor the stress-induced crystal-to-crystal transformations of the polyethylene matrix with respect to the clay loading as well as to the degree of mechanical strain. In addition, polarized infrared measurements revealed information on both the orientation and the stress-induced distortion of the crystals. It was concluded that the crystal-to-crystal transformations are hindered by the presence of the clay, which also prevented the crystals from orienting even at low clay loadings (1%). Finally, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) measurements confirmed the presence of the stress-induced crystalline structures in agreement with the infrared measurements.

scholarly journals Low-Melting Manganese (II)-Based Ionic Liquids: Syntheses, Structures, Properties and Influence of Trace Impurities

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3764 ◽  
Author(s):  
Peppel ◽  
Geppert-Rybczyńska ◽  
Neise ◽  
Kragl ◽  
Köckerling
Keyword(s):  
Surface Tension ◽  
Ionic Liquids ◽  
Structural Information ◽  
Measured Temperature ◽  
X Ray Diffraction ◽  
Trace Impurities ◽  
Scanning Calorimetry ◽  
Magnetic Ionic Liquids ◽  
Dsc Measurements ◽  
Density Dynamic

The synthesis of more than 10 new magnetic ionic liquids with [MnX4]2− anions, X = Cl, NCS, NCO, is presented. Detailed structural information through single-crystal X-ray diffraction is given for (DMDIm)[Mn(NCS)4], (BnEt3N)2[Mn(NCS)4], and {(Ph3P)2N}2[Mn(NCO4)]·0.6H2O, respectively. All compounds consist of discrete anions and cations with tetrahedrally coordinated Mn (II) atoms. They show paramagnetic behavior as expected for spin-only systems. Melting points are found for several systems below 100 °C classifying them as ionic liquids. Thermal properties are investigated using differential scanning calorimetry (DSC) measurements. The physicochemical properties of density, dynamic viscosity, electrolytic conductivity, and surface tension were measured temperature-dependent of selected samples. These properties are discussed in comparison to similar Co containing systems. An increasing amount of bromide impurity is found to affect the surface tension only up to 3.3%.

Glass Forming Ability and Crystallization Kinetics of Al-Mg-Ni-La Metallic Glasses

2014 ◽  
Vol 960-961 ◽  
pp. 161-164 ◽  
Author(s):  
Juan Mu ◽  
Hai Feng Zhang
Keyword(s):  
Crystallization Kinetics ◽  
Glass Forming Ability ◽  
Continuous Heating ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
Dsc Measurements ◽  
Mg Addition ◽  
Kinetics Of ◽  
Thermal Stability Of

Glass forming ability and crystallization kinetics of Al-Mg-Ni-La alloys have been investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The maximum thickness achievable in glasses of Al76Mg11Ni8La5and Al69Mg18Ni8La5ribbons were 200 and 120 μm, respectively. The crystallization temperature and peak temperature indicated by DSC measurements displayed dependence on the heating rate during continuous heating, and were coincident with Lanoka’s relationship. The activation energies for the crystallization reactionExwere obtained from the Kissinger’s equation. The results show the Mg addition is beneficial to the thermal stability of the amorphous phase.

scholarly journals Deformation induced martensite characterization in Fe-30%Ni-5%Cu alloy

2012 ◽  
Vol 48 (2) ◽  
pp. 259-264 ◽  
Author(s):  
E. Güler ◽  
M. Güler
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Dsc Measurements ◽  
Cu Alloy ◽  
The Face ◽  
Xrd Techniques ◽  
Scanning Electron

Deformation induced martensite properties were examined according to existing martensite morphology, crystallography and formation temperatures for different prior austenite homogenization conditions in Fe-30%Ni-5%Cu alloy. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques were employed to investigation. Scanning electron microscope observations showed elongated deformation induced martensite morphology in the austenite phase of alloy. As well, after deformation martensite start temperatures (Ms) were determined as -101?C and -105?C from DSC measurements for different homogenization conditions. In addition, X-ray diffraction analysis revealed the face centred cubic (fcc) of austenite phases and body centred cubic (bcc) deformation induced martensite phases for all studied samples.

The Relationship between Phase Structure and Melting Characteristics of High Cesium Content KF-CsF-AlF3 Aluminum Flux

2013 ◽  
Vol 634-638 ◽  
pp. 2909-2915 ◽  
Author(s):  
Fang Jie Cheng ◽  
Jun Xiang Yang ◽  
Hai Wei Zhao ◽  
Guan Xing Zhang ◽  
Jun Lan Huang ◽  
...  
Keyword(s):  
Solid Phase ◽  
Chemical Elements ◽  
Eutectic Reaction ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Decomposition Products ◽  
Melting Characteristics ◽  
The Common ◽  
The Relationship

The melting curves of high cesium content KF-CsF-AlF3 flux samples prepared by the wetting synthesis method were measured by differential scanning calorimetry (DSC), and the effect of the flux compositions on the melting characteristics was analyzed and summarized. Existing phases of every representation sample was identified by X-ray diffraction (XRD), meanwhile, the morphology and chemical elements of the typical flux samples were analyzed by scanning electron microscope (SEM) and energy spectrum analysis (EDS), respectively. The results indicated that solid phase decomposition first occurred in the common phase Cs2AlF5 for all the flux samples at 420°C; one of the decomposition products, Cs3AlF6 take the eutectic reaction with the Cs2KAlF6 at about 450°C; the flux samples containing phase CsAl2F7 or Cs2KAl3F12 have the e5 and e1 eutectic reaction at 471°C and 525°C, respectively, and their liquidus increased correspondingly. The liquidus for regionⅠflux samples is about 450°C and with a narrow melting range, which would make them good substrates for aluminum alloy middle temperature brazing.

scholarly journals Preparation and thermal decomposition of solid state cinnamates of alkali earth metals, except beryllium and radium

1998 ◽  
Vol 23 (0) ◽  
pp. 91-98 ◽  
Author(s):  
Ana Glauce ZAINA CHIARETTO ◽  
Marco Aurélio da Silva CARVALHO FILHO ◽  
Nedja Suely FERNANDES ◽  
Massao IONASHIRO
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Solid State ◽  
General Formula ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Preparation And Thermal Decomposition ◽  
Derivative Thermogravimetry

Solid state compounds of general formula ML2.nH2O [where M is Mg, Ca, Sr or Ba; L is cinnamate (C6H5 -CH=CH-COO-) and n = 2, 4, 0.8, 3 respectively], have been synthetized. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC) and X-ray diffraction powder patterns have been used to characterize and to study the thermal stability and thermal decomposition of these compounds.

Polymorphic forms of bendamustine hydrochloride: crystal structure, thermal properties and stability at ambient conditions

2019 ◽  
Vol 75 (6) ◽  
pp. 933-941
Author(s):  
Pablo Gaztañaga ◽  
Ricardo Baggio ◽  
Daniel Roberto Vega
Keyword(s):  
Crystal Structure ◽  
Fusion Rule ◽  
Polymorphic Form ◽  
Heat Of Fusion ◽  
High Humidity ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Molecular Conformations ◽  
Polymorphic Forms

Crystallographic, thermal and stability analyses are presented of three different anhydrated forms of bendamustine hydrochloride [(I), (III) and (IV)] and a fourth, monohydrated one (II). Since form (I) presents the higher melting point and the higher heat of fusion, according to the `heat of fusion' rule it should be the most stable in thermodynamic terms [Burger & Ramberger (1979). Mikrochim. Acta, 72, 259–271], though it is unstable in high-humidity conditions. The monohydrate structure (II), in turn, dehydrates by heating and topotactically transform into anhydrate (III). This latter form appears as less stable than anhydrate (I), to which it is linked via a monotropic relationship. For these three different forms, the crystal structure has been determined by single crystal X-ray diffraction. The crystal structures and molecular conformations of forms (II) and (III) are quite similar, as expected from the topotactic transformation linking them; furthermore, under high-humidity conditions, form (III) shows changes compatible with a transformation into form (II) within 24 h. The crystal structure of form (I) is different from the other two. The remaining polymorphic form (IV) could only be obtained as a powder, from which its crystalline structure could not be determined. The relative thermodynamic stability of the different crystalline forms was determined by differential scanning calorimetry and thermogravimetrical studies, and their stability under different humidity conditions analysed.

1H and 13C NMR and Electrical Conductivity Studies on New Ionic Plastic Crystals of Tetraalkylammonium Tetraethylborate

2015 ◽  
Vol 70 (7) ◽  
pp. 521-528 ◽  
Author(s):  
Satoru Hirakawa ◽  
Hisashi Honda
Keyword(s):  
Electrical Conductivity ◽  
Weak Interactions ◽  
Entropy Change ◽  
Ionic Diffusion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Plastic Crystals ◽  
Line Shapes ◽  
Dsc Measurements ◽  
Cscl Type

AbstractEight plastic crystals of the types NEtxMe(4 − x)BEt4 and NEtyPr(4 − y)BEt4 (x=0–4, y=1–3) were found in a new region of ionic plastic crystals. In this area, globular cations and anions are assembled by weak interactions. Based on the results of solid-state 1H and 13C nuclear magnetic resonance (NMR) measurements, it was revealed that the ions performed isotropic reorientations in the NEtxMe(4–x)BEt4 crystals (x=0–4). Additionally, X-ray diffraction (XRD) of these compounds was able to identify the CsCl-type cubic structure. In contrast, the XRD reflections of NEtyPr(4−y)BEt4 (y=1–3) could be successfully fitted by distorted cubic lattices (trigonal symmetry). The NMR line shapes observed in these compounds were explained by overall molecular motions with large amplitudes (pseudo-isotropic reorientations). Differential scanning calorimetry (DSC) spectra of NEtyPr(4 − y)BEt4 (y=1–3) showed a low entropy change (ΔSmp) of 6–8 J K−1 mol−1 at the melting point. Ionic diffusion was identified by electrical conductivity measurements of NEtxMe(4 − x)BEt4 and NEtyPr(4–y)BEt4 (x=0–4, y=1–3). In the case of NPr4BEt4 crystals, ionic diffusion was also detected, although complex powder patterns and large ΔSmp values were observed by XRD and DSC measurements, respectively.

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