Observation on the Structure of Ordered Mesoporous Materials at High Temperature via In Situ X-Ray Diffraction

2010 ◽  
Vol 132 ◽  
pp. 29-37
Author(s):  
Chun Fang Zhou ◽  
Jian Hua Zhu
Keyword(s):  
High Temperature ◽  
Mesoporous Materials ◽  
Pore Wall ◽  
Short Paper ◽  
Structure Variation ◽  
Ordered Mesoporous Materials ◽  
In Situ Xrd ◽  
Mesoscopic Structure ◽  
Xrd Patterns

This short paper reports the direct observation of the structure variation of mesoporous silica at temperatures higher than 600 oC by use of an in situ XRD technique. The mesostructure of SBA-15 or other mesoporous materials such as MCM-41 became almost invisible when the temperature rose to above 600 oC, but recovered or partially recovered once the temperature decreased. Contrarily, the characteristic XRD patterns of zeolites such as ZSM-5 kept unchangeable under the same conditions. On the basis of comparative experiments performed on various mesoporous samples, it is inferred that the reversible variation of XRD patterns probably originates from the thermal shock of the pore wall, not from the permanent collapse of the mesoscopic structure in these samples. This observation indicates the special features of SBA-15 at high temperature.

An In Situ XRD Technique For Annealing Investigations

1994 ◽  
Vol 38 ◽  
pp. 757-762
Author(s):  
D.E. Koylman ◽  
S.C. Axtel ◽  
B.W. Robertson
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Copper Powder ◽  
Diffraction Data ◽  
Particle Growth ◽  
Annealing Behavior ◽  
In Situ Xrd ◽  
Analysis Technique ◽  
Fourier Analysis Technique

Abstract An in situ XRD technique employing a diffractometer equipped with a high temperature camera was used to investigate the annealing behavior of nanoerystalline copper powder produced by mechanical milling. Specimens were annealed isothermally for 12 h at temperatures between 480 and 770 K. The diffraction data was analyzed using a single-profile Fourier analysis technique. The activation energy for diffracting particle growth was determined to be 0.45 eV/atom.

High Temperature XRD Studies of Selected Carbonate Minerals

1984 ◽  
Vol 28 ◽  
pp. 331-338 ◽  
Author(s):  
S. S. Iyengar ◽  
P. Engler ◽  
M. W. Santana ◽  
E. R. Wong
Keyword(s):  
High Temperature ◽  
Thermal Behavior ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
In Situ Xrd ◽  
Natural Minerals ◽  
High Temperature Xrd ◽  
Analytical Reagent ◽  
Thermal Analysis Techniques

Thermal analysts have exploited the sensitivity of carbonate mineral decomposition to furnace atmosphere as a diagnostic tool for identifying and quantifying these minerals in mixtures and solid solutions (1-3). However, thermal analysis techniques alone cannot reveal information about the reaction products after each thermal event. In-situ high temperature x-ray diffraction is one technique that can identify these products. Using this technique, Kissinger et al. (4) identified the reaction products of the thermal decomposition of reagent grade FeCO3 (siderite) and MgCO3 (magnesite). However, the thermal behavior of analytical reagent grade carbonates differs from natural minerals (1). Milodowski and Morgan (5) used in-situ XRD to investigate the thermal behavior of the dolomite-ankerite series.

scholarly journals Understanding Thermodynamic and Kinetic Stabilization of FeNiZr via Systematic High-Throughput In Situ XRD Analysis

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 482
Author(s):  
Efraín Hernández-Rivera ◽  
Sean J. Fudger ◽  
B. Chad Hornbuckle ◽  
Anthony J. Roberts ◽  
Kristopher A. Darling
Keyword(s):  
Statistical Approach ◽  
Xrd Analysis ◽  
Quantitative Information ◽  
Transfer Model ◽  
In Situ Xrd ◽  
Flow Through ◽  
Xrd Patterns ◽  
Powder Compacts

The role of kinetically and thermodynamically driven microstructural evolution on FeNiZr was explored through in situ XRD analysis. A statistical approach based on log-likelihoods and composite link model was used to fit and extract important data from the XRD patterns. Best practices on using the statistical approach to obtained quantitative information from the XRD patterns was presented. It was shown that the alloyed powder used in the current study presents more thermodynamic stability than previously reported ball-milled powders. Based on hardness values, it was shown that mechanical strength is expected to be retained at higher processing temperatures. Lastly, a 2-dimensional heat transfer model was used to understand heat flow through the powder compacts.

High temperature in-situ XRD of plasma sprayed HA coatings

Biomaterials ◽  
2002 ◽  
Vol 23 (2) ◽  
pp. 381-387 ◽  
Author(s):  
S.W.K. Kweh ◽  
K.A. Khor ◽  
P. Cheang
Keyword(s):  
High Temperature ◽  
In Situ Xrd ◽  
Plasma Sprayed

In Situ XRD Studies of ZnO/GaN Mixtures at High Pressure and High Temperature: Synthesis of Zn-Rich (Ga1−xZnx)(N1−xOx) Photocatalysts

2010 ◽  
Vol 114 (4) ◽  
pp. 1809-1814 ◽  
Author(s):  
Haiyan Chen ◽  
Liping Wang ◽  
Jianming Bai ◽  
Jonathan C. Hanson ◽  
John B. Warren ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Synthesis ◽  
In Situ Xrd ◽  
High Temperature Synthesis ◽  
Xrd Studies

scholarly journals Structural degradation of tungsten sandwiched in hafnia layers determined by in-situ XRD up to 1520 °C

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gnanavel Vaidhyanathan Krishnamurthy ◽  
Manohar Chirumamilla ◽  
Surya Snata Rout ◽  
Kaline P. Furlan ◽  
Tobias Krekeler ◽  
...  
Keyword(s):  
High Temperature ◽  
Morphological Changes ◽  
Temperature Stability ◽  
Xrd Analysis ◽  
Vapor Pressures ◽  
High Temperature Stability ◽  
Layer System ◽  
In Situ Xrd ◽  
Radiative Power

AbstractThe high-temperature stability of thermal emitters is one of the critical properties of thermophotovoltaic (TPV) systems to obtain high radiative power and conversion efficiencies. W and HfO2 are ideal due to their high melting points and low vapor pressures. At high temperatures and given vacuum conditions, W is prone to oxidation resulting in instantaneous sublimation of volatile W oxides. Herein, we present a detailed in-situ XRD analysis of the morphological changes of a 3-layer-system: HfO2/W/HfO2 layers, in a high-temperature environment, up to 1520 °C. These samples were annealed between 300 °C and 1520 °C for 6 h, 20 h, and 40 h at a vacuum pressure below 3 × 10–6 mbar using an in-situ high-temperature X-ray diffractometer, which allows investigation of crucial alterations in HfO2 and W layers. HfO2 exhibits polymorphic behavior, phase transformations and anisotropy of thermal expansion leads to formation of voids above 800 °C. These voids serve as transport channels for the residual O2 present in the annealing chamber to access W, react with it and form volatile tungsten oxides. An activation energy of 1.2 eV is calculated. This study clarifies the limits for the operation of W-HfO2 spectrally selective emitters for TPV in high-temperature applications.

The reaction of amorphous Ni-Nb films with Si in the presence of a native SiO2 layer

1990 ◽  
Vol 48 (4) ◽  
pp. 664-665
Author(s):  
N. Rozhanski ◽  
A. Barg
Keyword(s):  
High Temperature ◽  
Crystallization Temperature ◽  
Diffusion Barriers ◽  
Sio2 Layer ◽  
Si Substrate ◽  
Cross Sectional ◽  
Plan View ◽  
Temperature Range ◽  
Sputter Deposited

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

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