scholarly journals Design and use of a sapphire single-crystal gas-pressure cell for in situ neutron powder diffraction

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Raphael Finger ◽  
Nadine Kurtzemann ◽  
Thomas C. Hansen ◽  
Holger Kohlmann
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Gas Pressure ◽  
Sample Holder ◽  
Pressure Cell ◽  
Hydrogen Deuterium ◽  
Sapphire Single Crystal ◽  
Deuterium Gas

A sapphire single-crystal gas-pressure cell without external support allowing unobstructed optical access by neutrons has been developed and optimized for elastic in situ neutron powder diffraction using hydrogen (deuterium) gas at the high-intensity two-axis diffractometer D20 at the Institut Laue-Langevin (Grenoble, France). Given a proper orientation of the single-crystal sample holder with respect to the detector, parasitic reflections from the sample holder can be avoided and the background can be kept low. Hydrogen (deuterium) gas pressures of up to 16.0 MPa at 298 K and 8.0 MPa at 655 K were tested successfully for a wall thickness of 3 mm. Heating was achieved by a two-sided laser heating system. The typical time resolution of in situ investigations of the reaction pathway of hydrogen (deuterium) uptake or release is on the order of 1 min. Detailed descriptions of all parts of the sapphire single-crystal gas-pressure cell are given, including materials information, technical drawings and instructions for use.

ChemInform Abstract: In situ Neutron Powder Diffraction on Intermediate Hydrides of MgPd3in a Novel Sapphire Gas Pressure Cell.

ChemInform ◽  
2010 ◽  
Vol 41 (9) ◽  
Author(s):  
Holger Kohlmann ◽  
Nadine Kurtzemann ◽  
Richard Weihrich ◽  
Thomas Hansen
Keyword(s):  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Gas Pressure ◽  
Pressure Cell

scholarly journals A double-walled sapphire single-crystal gas-pressure cell (type III) for in situ neutron diffraction

2022 ◽  
Vol 55 (1) ◽  
Author(s):  
Raphael Finger ◽  
Thomas C. Hansen ◽  
Holger Kohlmann
Keyword(s):  
Neutron Diffraction ◽  
Single Crystal ◽  
Ambient Pressure ◽  
Functional Materials ◽  
Gas Pressure ◽  
Elastic Neutron ◽  
Type Iii ◽  
Pressure Cell ◽  
Sapphire Single Crystal

In situ neutron diffraction is an important characterization technique for the investigation of many functional materials, e.g. for hydrogen uptake and release in hydrogen storage materials. A new sapphire single-crystal gas-pressure cell for elastic neutron scattering has been developed and evaluated; it allows conditions of 298 K and 9.5 MPa hydrogen pressure and 1110 K at ambient pressure. The pressure vessel consists of a sapphire single-crystal tube of 35 mm radius and a sapphire single-crystal crucible as sample holder. Heating is realized by two 100 W diode lasers. It is optimized for the D20 diffractometer, ILL, Grenoble, France, and requires the use of a radial oscillating collimator. Its advantages over earlier sapphire single-crystal gas-pressure cells are higher maximum temperatures and lower background at low and high diffraction angles. The deuterium uptake in palladium was followed in situ for validation, proving the potential of the type-III gas-pressure cell for in situ neutron diffraction on solid–gas reactions.

scholarly journals Validation of a Sapphire Gas-Pressure Cell for Real-Time In Situ Neutron Diffraction Studies of Hydrogenation Reactions

2021 ◽  
Vol 5 (3) ◽  
pp. 22
Author(s):  
Raphael Finger ◽  
Thomas C. Hansen ◽  
Holger Kohlmann
Keyword(s):  
Neutron Diffraction ◽  
Single Crystal ◽  
Real Time ◽  
Hydrogen Pressure ◽  
Gas Pressure ◽  
Single Crystal Sample ◽  
Sample Holder ◽  
Pressure Cell ◽  
Hydrogenation Reactions

A gas-pressure cell, based on a leuco-sapphire single-crystal, serving as a pressure vessel and sample holder, is presented for real time in situ studies of solid-gas hydrogenation reactions. A stainless steel corpus, coated with neutron absorbing varnish, allows alignment for the single-crystal sample holder for minimizing contributions to the diffraction pattern. Openings in the corpus enable neutron scattering as well as contactless temperature surveillance and laser heating. The gas-pressure cell is validated via the deuteration of palladium powder, giving reliable neutron diffraction data at the high-intensity diffractometer D20 at the Institut Laue-Langevin (ILL), Grenoble, France. It was tested up to 15.0 MPa of hydrogen pressure at room temperature, 718 K at ambient pressure and 584 K at 9.5 MPa of hydrogen pressure.

Metal hydride formation in palladium and palladium rich intermetallic compounds studied by in situ neutron diffraction

2013 ◽  
Vol 28 (S2) ◽  
pp. S242-S255 ◽  
Author(s):  
H. Kohlmann ◽  
N. Kurtzemann ◽  
T. C. Hansen
Keyword(s):  
Intermetallic Compounds ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Gas Pressure ◽  
Type Structure ◽  
Sapphire Crystal ◽  
Direct Reaction ◽  
Β Phase ◽  
In Situ Neutron Diffraction

In order to investigate the hydrogenation of intermetallic compounds, a gas pressure cell for in situ neutron powder diffraction based on a sapphire crystal tube was constructed. By proper orientation of the single crystal Bragg peaks of the container material can be avoided, resulting in a very low diffraction background. Using a laser heating and gas pressure controller, the hydrogenation (deuteration) of palladium and palladium rich intermetallics was studied in real time up to 8 MPa gas pressure and 700 K. Crystal structure parameters of palladium deuterides could be obtained under various deuterium gas pressures, corresponding to compositional ranges of 0.04≤x≤0.11 for the α-phase and 0.52≤x≤0.72 for the β-phase at 446 K. In situ neutron powder diffraction of the deuteration of a thallium lead palladium intermetallic Tl1-xPbxPd3 shows two superstructures of the cubic closest packing (ccp) to transform independently into a AuCu3 type structure. This proves a direct reaction to the deuterium filled AuCu3 type structure instead of a reaction cascade involving different ccp superstructures and thus gives new insights into the reaction pathways of palladium rich intermetallic compounds.

scholarly journals Air-heated solid–gas reaction setup for in situ neutron powder diffraction

2019 ◽  
Vol 52 (4) ◽  
pp. 761-768 ◽  
Author(s):  
Jakob Voldum Ahlburg ◽  
Emmanuel Canévet ◽  
Mogens Christensen
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Time Resolution ◽  
Temperature Stability ◽  
Sample Volume ◽  
Industrial Applications ◽  
Neutron Powder Diffraction ◽  
Advanced Materials ◽  
Air Gun

The design and function of a reduction furnace, specially designed for solid–gas in situ monochromatic angular dispersive neutron powder diffraction, is presented. The functionality is demonstrated by performing a reduction experiment of CoFe2O4 nanoparticles at the instrument DMC at SINQ. Heating is provided by an air gun, allowing the sample to reach temperatures in the range of 300–973 K within less than 5 min. The setup is based on a single-crystal sapphire tube with one end closed. A φ scan of the tube reveals its single-crystal nature, through strong single-crystal reflections, while the remaining background is very low, uniform and flat. CoFe2O4 was reduced using a time resolution of 8 min and a sample volume of ∼2 cm3. By means of sequential Rietveld refinement of the in situ neutron diffraction data, a two-step reduction mechanism was discovered: CoFe2O4 → Co0.33Fe0.67O → CoFe2. The setup offers high temperatures, fast temperature stability, large sample volumes and respectable time resolution. The setup has proven to be ideal to carry out investigations of advanced materials under realistic conditions. The ability to investigate real materials in real time under realistic conditions may be a significant advantage for scientific investigations as well as for industrial applications.

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