scholarly journals In-Situ Synthesis and Characterization of Nanocomposites in the Si-Ti-N and Si-Ti-C Systems

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5236
Author(s):  
Maxime Balestrat ◽  
Abhijeet Lale ◽  
André Vinícius Andrade Bezerra ◽  
Vanessa Proust ◽  
Eranezhuth Wasan Awin ◽  
...  
Keyword(s):  
Amorphous Materials ◽  
Structural Evolution ◽  
Ammonia Nitrogen ◽  
Ex Situ ◽  
Mechanistic Study ◽  
X Ray ◽  
Modified Polymer ◽  
Amorphous Network ◽  
The Matrix

The pyrolysis (1000 °C) of a liquid poly(vinylmethyl-co-methyl)silazane modified by tetrakis(dimethylamido)titanium in flowing ammonia, nitrogen and argon followed by the annealing (1000–1800 °C) of as-pyrolyzed ceramic powders have been investigated in detail. We first provide a comprehensive mechanistic study of the polymer-to-ceramic conversion based on TG experiments coupled with in-situ mass spectrometry and ex-situ solid-state NMR and FTIR spectroscopies of both the chemically modified polymer and the pyrolysis intermediates. The pyrolysis leads to X-ray amorphous materials with chemical bonding and ceramic yields controlled by the nature of the atmosphere. Then, the structural evolution of the amorphous network of ammonia-, nitrogen- and argon-treated ceramics has been studied above 1000 °C under nitrogen and argon by X-ray diffraction and electron microscopy. HRTEM images coupled with XRD confirm the formation of nanocomposites after annealing at 1400 °C. Their unique nanostructural feature appears to be the result of both the molecular origin of the materials and the nature of the atmosphere used during pyrolysis. Samples are composed of an amorphous Si-based ceramic matrix in which TiNxCy nanocrystals (x + y = 1) are homogeneously formed “in situ” in the matrix during the process and evolve toward fully crystallized compounds as TiN/Si3N4, TiNxCy (x + y = 1)/SiC and TiC/SiC nanocomposites after annealing to 1800 °C as a function of the atmosphere.

In Situ Studies of the Processing of Sol-Gel Produced Amorphous Materials Using Xanes, Saxs and Curved Image Plate XRD

1999 ◽  
Vol 590 ◽  
Author(s):  
DM Pickup ◽  
G Mountjoy ◽  
RJ Newport ◽  
ME Smith ◽  
GW Wallidge ◽  
...  
Keyword(s):  
Amorphous Materials ◽  
Sol Gel ◽  
Heat Treatments ◽  
Silica Gels ◽  
Ex Situ ◽  
High Count ◽  
X Ray ◽  
Image Plate ◽  
Wide Range

ABSTRACTSol-gel produced mixed oxide materials have been extensively studied using conventional, ex situ structural techniques. Because the structure of these materials is complex and dependent on preparation conditions, there is much to be gained from in situ techniques: the high brightness of synchrotron x-ray sources makes it possible to probe atomic structure on a short timescale, and hence in situ. Here we report recent results for mixed titania- (and some zirconia-) silica gels and xerogels. Titania contents were in the range 8–18 mol%, and heat treatments up to 500°C were applied. The results have been obtained from intrinsically rapid synchrotron x-ray experiments: i) time-resolved small angle scattering, using a quadrant detector, to follow the initial stages of aggregation between the sol and the gel; ii) the use of a curved image plate detector in diffraction, which allowed the simultaneous collection of data across a wide range of scattering at high count rate, to study heat treatments; and iii) x-ray absorption spectroscopy to explore the effects of ambient moisture on transition metal sites.

In Situ Structural Evolution of Steel-Based MMC by High Energy X-Ray Diffraction and Comparison with Micromechanical Approach

2013 ◽  
Vol 768-769 ◽  
pp. 313-320 ◽  
Author(s):  
Guillaume Geandier ◽  
Moukrane Dehmas ◽  
Mickael Mourot ◽  
Elisabeth Aeby-Gautier ◽  
Sabine Denis ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Coefficient Of Thermal Expansion ◽  
Hydrostatic Stress ◽  
Structural Evolution ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
The Matrix

In situ high energy X-ray diffraction synchrotron was used to provide direct analysis of the transformation sequences in steel-based matrix composite (MMC) reinforced with TiC particles. Evolution of the phase fractions of the matrix and TiC particles as well as the mean cell parameters of each phase were determined by Rietveld refinement from high energy X-ray diffraction (ID15B, ESRF, Grenoble, France). In addition, some peaks were further analysed in order to obtain the X-ray strain during the cooling step. Non-linear strain evolutions of each phase are evidenced, which are either associated with differences in the coefficient of thermal expansion (CTE) between matrix and TiC particle or to the occurrence of phase transformation. Micromechanical calculations were performed through the finite element method to estimate the stress state in each phase and outline the effects of differences in CTE and of volume change associated with the matrix phase transformation. The calculated results led to a final compressive hydrostatic stress in the TiC reinforcement and tensile hydrostatic stress in the matrix area around the TiC particles. Besides, the tendencies measured from in situ synchrotron diffraction (mean cell parameters) matched with the numerical estimates.

Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

2017 ◽  
Author(s):  
Younghee Lee ◽  
Daniela M. Piper ◽  
Andrew S. Cavanagh ◽  
Matthias J. Young ◽  
Se-Hee Lee ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Atomic Layer ◽  
Mass Gain ◽  
Alloy Film ◽  
Ex Situ ◽  
X Ray ◽  
Layer Deposition ◽  
Ion Conducting ◽  
Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH<sub>3</sub>)<sub>3</sub> as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF<sub>3</sub> and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF<sub>3</sub>)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film was measured as σ = 7.5 × 10<sup>-6</sup> S/cm.</div>

STRUCTURAL EVOLUTION OF EXCEPTIONALLY IRON-DEFICIENT HEMATITE NANOCRYSTALS AS OBSERVED BY IN SITU SYNCHROTRON X-RAY DIFFRACTION

2019 ◽  
Author(s):  
Si Athena Chen ◽  
◽  
Peter Heaney ◽  
Jeffrey E. Post ◽  
Peter J. Eng ◽  
...  
Keyword(s):  
Structural Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Deficient

In Situ X-Ray Diffraction Investigations during Diffusion Anneals of Ni-Cu Thin Film Diffusion Couples

2010 ◽  
Vol 89-91 ◽  
pp. 503-508 ◽  
Author(s):  
J. Sheng ◽  
U. Welzel ◽  
Eric J. Mittemeijer
Keyword(s):  
Thermal Stresses ◽  
Stress Generation ◽  
Ex Situ ◽  
Diffusion Annealing ◽  
X Ray Diffraction ◽  
Individual Layer ◽  
X Ray ◽  
Bilayer System ◽  
Stress Changes

The stress evolution during diffusion annealing of Ni-Cu bilayers (individual layer thicknesses of 50 nm) was investigated employing ex-situ and in-situ X-ray diffraction measurements. Annealing at relatively low homologous temperatures (about 0.3 - 0.4 Tm) for durations up to about 100 hours results in considerable diffusional intermixing, as demonstrated by Auger-electron spectroscopy investigations (in combination with sputter-depth profiling). In addition to thermal stresses due to differences of the coefficients of thermal expansion of layers and substrate, tensile stress con-tributions in the sublayers arise during the diffusion anneals. The obtained stress data have been discussed in terms of possible mechanisms of stress generation. The influence of diffusion on stress development in the sublayers of the diffusion couple during heating and isothermal annealing was investigated by comparing stress changes in the bilayer system with corresponding results obtained under identical conditions for single layers of the components in the bilayer system. The specific residual stresses that emerge due to diffusion between the (sub)layers in the bilayer could thereby be identified.

In situ synchrotron small- and wide-angle X-ray study on the structural evolution of Kevlar fiber under uniaxial stretching

RSC Advances ◽  
2016 ◽  
Vol 6 (85) ◽  
pp. 81552-81558 ◽  
Author(s):  
Xiaoyun Li ◽  
Feng Tian ◽  
Ping Zhou ◽  
Chunming Yang ◽  
Xiuhong Li ◽  
...  
Keyword(s):  
Structural Evolution ◽  
Wide Angle ◽  
Uniaxial Stretching ◽  
X Ray ◽  
Kevlar Fiber

In situ SAXS and WAXS study on the structural evolution and mechanism of two different Kevlar fibers during stretching.

Structural evolution of NASICON-type Li1+xAlxGe2−x(PO4)3 using in situ synchrotron X-ray powder diffraction

2016 ◽  
Vol 4 (20) ◽  
pp. 7718-7726 ◽  
Author(s):  
Dorsasadat Safanama ◽  
Neeraj Sharma ◽  
Rayavarapu Prasada Rao ◽  
Helen E. A. Brand ◽  
Stefan Adams
Keyword(s):  
Solid Electrolyte ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Structural Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nasicon Type ◽  
Precursor Glass

In situ synchrotron X-ray diffraction study of the synthesis of solid-electrolyte Li1+xAlxGe2−x(PO4)3 (LAGP) from the precursor glass reveals that an initially crystallized dopant poor phase transforms into the Al-doped LAGP at 800 °C.

In situ X-ray Scattering Study of the Formation of Au Nano Crystals During Thermal Annealing

2007 ◽  
Vol 1027 ◽  
Author(s):  
Do Young Noh ◽  
Ki-Hyun Ryu ◽  
Hyon Chol Kang
Keyword(s):  
Thermal Annealing ◽  
Bragg Reflection ◽  
Ex Situ ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Au Thin Films ◽  
Ray Scattering

AbstractThe transformation of Au thin films grown on sapphire (0001) substrates into nano crystals during thermal annealing was investigated by in situ synchrotron x-ray scattering and ex situ atomic force microscopy (AFM). By monitoring the Au(111) Bragg reflection and the low Q reflectivity and comparing them with ex situ AFM images, we found that polygonal-shape holes were nucleated and grow initially. As the holes grow larger and contact each other, their boundary turns into Au nano crystals. The Au nano crystals have a well-defined (111) flat top surface and facets in the in-plane direction.

In-situ X-ray tomographic imaging study of gas and structural evolution in a commercial Li-ion pouch cell

2022 ◽  
Vol 520 ◽  
pp. 230818
Author(s):  
Wenjia Du ◽  
Rhodri E. Owen ◽  
Anmol Jnawali ◽  
Tobias P. Neville ◽  
Francesco Iacoviello ◽  
...  
Keyword(s):  
Structural Evolution ◽  
Imaging Study ◽  
Tomographic Imaging ◽  
X Ray ◽  
Li Ion
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