The Gamma to Alpha Transformation in Thin Film Alumina

1984 ◽  
Vol 41 ◽  
Author(s):  
E. M. Clausen ◽  
J. J. Hren
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Thermal History ◽  
Starting Material ◽  
X Ray Diffraction ◽  
Transition Alumina ◽  
X Ray ◽  
Aluminum Hydroxides ◽  
Transitional Forms ◽  
Diffraction Patterns

AbstractMany forms of low temperature alumina have been identified [1]. These are collectively referred to as transitional forms. The particular form depends strongly on the starting material (e.g., hydrated, thermally oxidized, alkoxide, etc.), the impurities present, and on thermal history. Although different forms of transition alumina are sometimes referred to as phases, none can be considered a true polymorph of corundum, i.e., α-alumina. Transformations from one form to another which occur upon heating are not reversible, although they are quite reproducible [2]. These different transitional structures are therefore considered to comprise different states of reordering. Figure 1 is a compendium of powder x-ray diffraction patterns from all known transitional aluminas and several aluminum hydroxides [3]. It i.s obvious that there are several crystallographic spacings which are nearly common to all forms.

scholarly journals Deep learning for visualization and novelty detection in large X-ray diffraction datasets

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Lars Banko ◽  
Phillip M. Maffettone ◽  
Dennis Naujoks ◽  
Daniel Olds ◽  
Alfred Ludwig
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Artificial Intelligence ◽  
Deep Learning ◽  
Novelty Detection ◽  
Structural Similarity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Post Hoc

AbstractWe apply variational autoencoders (VAE) to X-ray diffraction (XRD) data analysis on both simulated and experimental thin-film data. We show that crystal structure representations learned by a VAE reveal latent information, such as the structural similarity of textured diffraction patterns. While other artificial intelligence (AI) agents are effective at classifying XRD data into known phases, a similarly conditioned VAE is uniquely effective at knowing what it doesn’t know: it can rapidly identify data outside the distribution it was trained on, such as novel phases and mixtures. These capabilities demonstrate that a VAE is a valuable AI agent for aiding materials discovery and understanding XRD measurements both ‘on-the-fly’ and during post hoc analysis.

Apparent Activation Energy in Low Temperature Aging of Y-TZP Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 100-103
Author(s):  
Qi Fei Xie ◽  
Cheng Wang ◽  
Qing Feng Zan ◽  
Li Min Dong
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Apparent Activation Energy ◽  
Coordinate Systems ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Temperature Aging ◽  
Diffraction Patterns ◽  
Straight Lines ◽  
Temperature Aging

Apparent activation energy in low temperature aging of two kinds of Y-TZP ceramic was studied in this paper. The ceramics were processed into small pieces, and aging in 100°C, 110°C, 120°C, 130°C and 140°C respectively. The content of monoclinic phase was calculated by X-ray diffraction patterns and the microstructure was scanned by SEM. According to MAJ law and Arrhenius formation, straight lines were fitted in coordinate systems of ln (ln (1/(1 − f )))-ln t and ln b-1/T, and the kinetic parameters of low temperature aging of Y-TZP ceramic were calculated according to these lines. The results revealed that grain size significantly affected apparent activation energy of Y-TZP ceramics.

X-ray Diffraction and Modelling Studies of Multilayer SnO2 Thin Film Gas Sensors

1995 ◽  
Vol 403 ◽  
Author(s):  
L. E. Depero ◽  
C. Perego ◽  
L. Sangaletti ◽  
G. Sberveglieri
Keyword(s):  
Thin Film ◽  
Orthorhombic Phase ◽  
Sno2 Thin Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modelling Studies ◽  
Cation Coordination ◽  
Diffraction Patterns ◽  
Two Phases ◽  
The Relationship

AbstractStructural studies have been carried out on SnO2 multilayer thin film grown by the Rheotaxial Growth and Thermal Oxidation method on A120 3 substrates. A preliminary analysis of the X-ray diffraction patterns shows that, in addition to the Sn0 2 cassiterite phase, a strong contribution from an orthorhombic Sn02 phase is present.In the case of the 3-layer film, the orthorhombic phase is structurally and microstructurally stable after an annealing up to 32 h at 400 'C. The cation coordination is similar to that found in cassiterite, but the chains of edge-sharing [SnO6]8- octahedra run in a zig-zag fashion along the [100] direction, each straight unit containing four octahedra. The relationship between the two phases is discussed on the basis of structural simulations including twinning planes in the crystal structure.

Low Temperature Preparation of y‐bA‐cU‐0 Films by Omcvd

1989 ◽  
Vol 169 ◽  
Author(s):  
Taiji Tsuruoka ◽  
Ryodo Kawasaki ◽  
Hitoshi Abe ◽  
Susumu Shibata
Keyword(s):  
Low Temperature ◽  
Deposition Rate ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Low Temperature Preparation ◽  
Zero Resistance ◽  
Diffraction Patterns ◽  
Temperature Preparation

AbstractBy using N2O for oxygen source, Y‐Ba‐Cu‐O films prepared at 650” C on the SrTiO3 substrates showed zero resistance at 79K. The deposition rate of Y‐Ba‐Cu‐0 films on MgO(l00) substrates by using N2O gas was nearly half of that using 02 gas. X‐ray diffraction patterns of Y‐Ba‐Cu‐0 films grown on SrTiO3(100) and MgO(l00) substrates indicate c‐axis orientation.

CuAl2 Intermetallic Hydrogen Evaluation after Mechanical Activation of Powders

2014 ◽  
Vol 793 ◽  
pp. 127-134 ◽  
Author(s):  
J. Luis López-Miranda ◽  
Tiberio A. Reyes-Hernández ◽  
Ares G. Hernández-Torres ◽  
J.R. Romero-Romero ◽  
R. Pérez ◽  
...  
Keyword(s):  
Mechanical Activation ◽  
Chemical Reaction ◽  
Room Temperature ◽  
Hydrogen Generation ◽  
Hydrogen Release ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminum Hydroxides ◽  
Mechanical Attrition ◽  
Diffraction Patterns

Water vapor in the air affects aluminum based intermetallic compounds to form hydrogen. We take advantage of this fact to explore the amount of hydrogen obtained from CuAl2 intermetallic after its mechanical attrition activation. For this propose, CuAl2 intermetallic alloy was first produced by conventional casting methods and then subjected to mechanical milling processing. After the mechanical activation of the CuAl2 powders, a chemical reaction between them and water was carried out at room temperature including additives such as CaO, Al and NaCl. The amount of hydrogen release was correlated with other phases produced after the chemical reaction. X-ray diffraction patterns and scanning electron microscopy studies indicates that these phases were aluminum hydroxides and cupper oxides. According to these studies, a significant presence of oxide and hydroxide products occurred in the samples with NaCl additions, indicating best capability for hydrogen generation.

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