In-Situ Microstructure Characterization of Sintering of Controlled Porosity Materials

1994 ◽  
Vol 346 ◽  
Author(s):  
Helen M. Kerch ◽  
Harold E. Burdette ◽  
Rosario Gerhardt ◽  
Susan Krueger ◽  
Andrew J. Allen ◽  
...  
Keyword(s):  
Pore Size ◽  
Small Angle ◽  
Sintering Behavior ◽  
Quantitative Measurements ◽  
Angle Scattering ◽  
Size Evolution ◽  
Bimodal Pore Size Distribution ◽  
Controlled Porosity ◽  
Colloidal Gel

ABSTRACTThe isothermal sintering behavior of a colloidal gel with a well-characterized pore structure was studied using a newly commissioned in-situ small-angle neutron scattering furnace. The apparatus enables small-angle scattering measurements to be performed on monolithic samples during heat treatment in an oxidizing, reducing, or neutral environment at temperatures up to 1700°C. In-situ, quantitative measurements of the pore size evolution within a gel possessing a bimodal pore size distribution is discussed. Also reported is the in-situ measurement of the gel's surface area evolution which is an important microstructural parameter in understanding the sintering behavior of highly porous materials.

In-situ X-Ray Small Angle Scattering during the Crystallization of Amorphous Mg76Zn24

1986 ◽  
Vol 41 (9) ◽  
pp. 1123-1128 ◽  
Author(s):  
M. Schaal ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Phase Diagram ◽  
Amorphous Phase ◽  
Small Angle ◽  
Small Angle Scattering ◽  
Crystalline Phases ◽  
X Ray ◽  
Β Phase ◽  
Angle Scattering

By X-Ray small angle scattering the relaxation and crystallization of amorphous Mg76Zn24 was investigated in-situ. Radii of gyration of the different phases developing during the annealing of the sample were determined. By comparison of the small angle scattering results with DSC-results from the literature and the phase diagram the different phases could be identified. The crystallization of amorphous Mg76Zn24 is preceded by the formation of β-phase (Mg72Zn28)-like inhomogeneities in the amorphous phase. Further annealing leads to the final crystalline phases γ-MgZn and Mg.

Experimental Evidence of Super Densification of Adsorbed Hydrogen by in-situ Small Angle Neutron Scattering (SANS)

2011 ◽  
Vol 1334 ◽  
Author(s):  
Dipendu Saha ◽  
Lilin He ◽  
Cristian I. Contescu ◽  
Nidia C. Gallego ◽  
Yuri B. Melnichenko
Keyword(s):  
Neutron Scattering ◽  
Pore Size ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Hydrogen Gas ◽  
Necessary Condition ◽  
Adsorbed Hydrogen ◽  
Oak Ridge ◽  
Hydrogen Molecules

ABSTRACTEntrapping hydrogen molecules within the nanopores of solid adsorbents serves as a unique alternative for on-board storing of hydrogen for transportation purposes. The key advantage of the physisorption process for hydrogen storage is the higher density values achieved with the adsorbed gas, compared to that of the compressed phase, translating into higher storage capacities at lower pressures. The necessary condition for effective adsorption is the presence of narrow micropores of < 2 nm in width which provide the most suitable environment of hydrogen adsorption. Despite numerous theoretical calculations or indirect experimental estimations, there has not been a direct experimental measurement of the density of adsorbed hydrogen as a function of pressure and/or pore size. In the present study, we report on the use of in-situ small angle neutron scattering (SANS) to study the phase behavior of hydrogen confined in narrow micropores. We provide for the first time direct experimental measurements of the effect of pore size and pressure on hydrogen adsorbed on a polyfurfuryl alcohol-derived activated carbon (PFAC), at room temperature and pressures up to 207 bar. SANS studies were carried out at the General-Purpose Small-Angle Neutron Scattering spectrometer of the High Flux Isotope Reactor at Oak Ridge National Laboratory. The measurements covered the Q-range from 0.01 to 0.8 Å-1, covering the pores in the range of 9 to 34 Å of the PFAC material. Initial results suggest that the density of adsorbed hydrogen is higher than the density of bulk hydrogen gas and increases with decreasing pore size.

Evidence of Highly Localized Failure within Core−Shell Toughening Particles from in-Situ Small-Angle Scattering

2001 ◽  
Vol 34 (19) ◽  
pp. 6708-6718 ◽  
Author(s):  
Michele Sferrazza ◽  
Jane Crawshaw ◽  
Athene M. Donald ◽  
Theyencheri Narayanan
Keyword(s):  
Small Angle ◽  
Small Angle Scattering ◽  
Core Shell ◽  
Angle Scattering ◽  
Localized Failure

X-ray transparent proton-exchange membrane fuel cell design for in situ wide and small angle scattering tomography

2019 ◽  
Vol 437 ◽  
pp. 226906 ◽  
Author(s):  
Isaac Martens ◽  
Antonis Vamvakeros ◽  
Raphael Chattot ◽  
Maria V. Blanco ◽  
Miika Rasola ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Small Angle ◽  
Proton Exchange Membrane ◽  
Small Angle Scattering ◽  
Proton Exchange ◽  
Cell Design ◽  
X Ray ◽  
Angle Scattering ◽  
Exchange Membrane

scholarly journals A new ultrasonic transducer sample cell for in situ small-angle scattering experiments

2018 ◽  
Vol 89 (1) ◽  
pp. 015111 ◽  
Author(s):  
Sudipta Gupta ◽  
Markus Bleuel ◽  
Gerald J. Schneider
Keyword(s):  
Small Angle ◽  
Ultrasonic Transducer ◽  
Small Angle Scattering ◽  
Sample Cell ◽  
Angle Scattering

A Small Angle Neuitron Scattering Investigation of Compacted Nanophase TiO2 and Pd

1989 ◽  
Vol 166 ◽  
Author(s):  
J. E. Epperson ◽  
R. W. Siegel ◽  
J. W. White ◽  
J. A. Eastman ◽  
Y. X. Liao ◽  
...  
Keyword(s):  
Cross Sections ◽  
Small Angle ◽  
Structural Parameters ◽  
Scattering Data ◽  
Bulk Materials ◽  
Angle Scattering ◽  
Gas Atmosphere ◽  
Nanophase Materials ◽  
Thin Disks

ABSTRACTNanocrystalline compacts of TiO2 and Pd were prepared by first condensing the Ti or Pd vapors in an inert gas atmosphere. The Ti was oxidized in situ to TiO2. Samples were prepared by scraping off and compacting the nanophase materials into thin disks. The small angle neutron scattering was measured in the as-prepared condition and after isothermal anneals of up to 23 hrs at 550°C for the TiO2 and up to 3.3 hrs at 300°C for the Pd. Scattering data were obtained in absolute cross sections. Integrated small angle scattering and maximum entropy methods were used in estimating the structural parameters. The results are interpreted in terms of a model which consists of nanometer sized grains of the materials separated by boundary regions which are, on average, much less dense than the respective bulk materials; 21% for the TiO2 and about 56% for Pd. However, the boundary regions contain voids or pores, which contribute to these density decrements. Possible sources of error are discussed.

scholarly journals Small-angle scattering for beginners

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Cedric J. Gommes ◽  
Sebastian Jaksch ◽  
Henrich Frielinghaus
Keyword(s):  
Small Angle ◽  
Small Angle Scattering ◽  
X Rays ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Time Resolved ◽  
Characterization Methods ◽  
Angle Scattering

Many experimental methods are available for the characterization of nanostructures, but most of them are limited by stringent experimental conditions. When it comes to analysing nanostructures in the bulk or in their natural environment – even as ordinary as water at room temperature – small-angle scattering (SAS) of X-rays or neutrons is often the only option. The rapid worldwide development of synchrotron and neutron facilities over recent decades has opened unprecedented possibilities for using SAS in situ and in a time-resolved way. But, in spite of its huge potential in the field of nanomaterials in general, SAS is covered far less than other characterization methods in non-specialized curricula. Presented here is a rigorous discussion of small-angle scattering, at a technical level comparable to the classical undergraduate coverage of X-ray diffraction by crystals and which contains diffraction as a particular case.

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