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

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.

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

Molecules ◽

10.3390/molecules25225236 ◽

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.

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In Situ Synchrotron X-ray Absorption Experiments and Modelling of the Growth Rates of Electrochemically Deposited ZnO Nanostructures

MRS Proceedings ◽

10.1557/proc-1017-dd12-16 ◽

2007 ◽

Vol 1017 ◽

Cited By ~ 2

Author(s):

Bridget Ingham ◽

Benoit N. Illy ◽

Jade R. Mackay ◽

Stephen P. White ◽

Shaun C. Hendy ◽

...

Keyword(s):

Growth Rates ◽

High Resolution Electron Microscopy ◽

Ex Situ ◽

X Ray ◽

Deposition Parameters ◽

Wide Range ◽

Electrochemically Deposited ◽

Electrochemical Current ◽

X Ray Absorption

AbstractZnO is known to produce a wide variety of nanostructures that have enormous scope for optoelectronic applications. Using an aqueous electrochemical deposition technique, we are able to tightly control a wide range of deposition parameters (Zn2+ concentration, temperature, potential, time) and hence the resulting deposit morphology. By simultaneously conducting synchrotron x-ray absorption spectroscopy (XAS) experiments during the deposition, we are able to directly monitor the growth rates of the nanostructures, as well as providing direct chemical speciation of the films. In situ experiments such as these are critical to understanding the nucleation and growth of such nanostructures.Recent results from in situ XAS synchrotron experiments demonstrate the growth rates as a function of potential and Zn2+ concentration. These are compared with the electrochemical current density recorded during the deposition, and the final morphology revealed through ex situ high resolution electron microscopy. The results are indicative of two distinct growth regimes, and simultaneous changes in the morphology are observed.These experiments are complemented by modelling the growth of the rods in the transport-limited case, using the Nernst-Planck equations in 2 dimensions, to yield the growth rate of the volume, length, and radius as a function of time.

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Laser-heating system for high-pressure X-ray diffraction at the Extreme Conditions beamline I15 at Diamond Light Source

Journal of Synchrotron Radiation ◽

10.1107/s1600577518013383 ◽

2018 ◽

Vol 25 (6) ◽

pp. 1860-1868 ◽

Cited By ~ 7

Author(s):

Simone Anzellini ◽

Annette K. Kleppe ◽

Dominik Daisenberger ◽

Michael T. Wharmby ◽

Ruggero Giampaoli ◽

...

Keyword(s):

Light Source ◽

Laser Heating ◽

Theoretical Data ◽

Heating System ◽

Ex Situ ◽

X Ray Diffraction ◽

X Ray ◽

Wide Range ◽

Diamond Anvil

In this article, the specification and application of the new double-sided YAG laser-heating system built on beamline I15 at Diamond Light Source are presented. This system, combined with diamond anvil cell and X-ray diffraction techniques, allows in situ and ex situ characterization of material properties at extremes of pressure and temperature. In order to demonstrate the reliability and stability of this experimental setup over a wide range of pressure and temperature, a case study was performed and the phase diagram of lead was investigated up to 80 GPa and 3300 K. The obtained results agree with previously published experimental and theoretical data, underlining the quality and reliability of the installed setup.

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Pressure acid leaching of nickel laterite ores: anin situdiffraction study of the mechanism and rate of reaction

Journal of Applied Crystallography ◽

10.1107/s002188980502813x ◽

2005 ◽

Vol 38 (6) ◽

pp. 927-933 ◽

Cited By ~ 19

Author(s):

Ian C. Madsen ◽

Nicola V. Y. Scarlett ◽

Barry I. Whittington

Keyword(s):

Acid Leaching ◽

Negative Temperature ◽

Ex Situ ◽

Nickel Laterite ◽

X Ray ◽

Laterite Ores ◽

Wide Range ◽

Processing Plants ◽

Pressure Acid Leaching

This paper outlines the use of an innovative system for thein situinvestigation of hydrothermal reactions by X-ray diffraction. The key features are the use of: (i) a purpose-built capillary reaction vessel which allows close emulation of the conditions present in mineral processing plants; (ii) MoKα radiation, to ensure that the X-ray beam penetrates through the capillary, and (iii) an Inel CPS120 position-sensitive detector, to enable simultaneous collection of a wide range (120° 2θ) of diffraction data. The pressure acid leaching (PAL) of nickel laterite ores is used to illustrate the capabilities of this system, with a particular focus on the PAL of saprolite in strong H2SO4at 493 K. Saprolitic ore, which largely consists of serpentine mineral phases [(Mg,Fe,Ni,Al)3(Si,Al)2O5(OH)4], undergoes a number of mineralogical changes during both the acid leaching reaction and subsequent cooling, thus making it difficult to examine accurately using traditional post-reactionex situtechniques. In particular, kieserite (MgSO4.H2O), which forms during leaching, has a negative temperature coefficient of solubility, causing it to dissolve on cooling. Thein situtechnique described in this paper allows the direct observation of kieserite formation during the saprolite PAL at 493 K and its dissolution upon cooling to ambient temperature.

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

10.26434/chemrxiv.5459653 ◽

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 (AlF3)(LiF)x 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/(cm2 cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH3)3 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/(cm2 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 AlF3 and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF3)(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 (AlF3)(LiF)x 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 (AlF3)(LiF)x alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF3)(LiF)x alloy film was measured as σ = 7.5 × 10-6 S/cm.</div>

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.89-91.503 ◽

2010 ◽

Vol 89-91 ◽

pp. 503-508 ◽

Cited By ~ 1

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.

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

MRS Proceedings ◽

10.1557/proc-1027-d07-04 ◽

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.

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Bioencapsulation in Sol-Gel Glasses

MRS Proceedings ◽

10.1557/proc-519-171 ◽

1998 ◽

Vol 519 ◽

Cited By ~ 9

Author(s):

L. Bergogne ◽

S. Fennouh ◽

J. Livage ◽

C. Roux

Keyword(s):

Sol Gel ◽

Porous Silica ◽

Silica Matrix ◽

Whole Cells ◽

The Past ◽

Wide Range ◽

Activity Of Enzymes ◽

Gel Glasses ◽

Micro Organisms

AbstractBioencapsulation in sol-gel materials has been widely studied during the past decade. Trapped species appear to retain their bioactivity in the porous silica matrix. Small analytes can diffuse through the pores allowing bioreactions to be performed in-situ, inside the sol-gel glass. A wide range of biomolecules and micro-organisms have been encapsulated. The catalytic activity of enzymes is used for the realization of biosensors or bioreactors. Antibody-antigen recognition has been shown to be feasible within sol-gel matrices. Trapped antibodies bind specifically the corresponding haptens and can be used for the detection of traces of chemicals. Even whole cells are now encapsulated without any alteration of their cellular organization. They can be used for the production of chemicals or as antigens for immunoassays.

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