Crystallization and Phase Transformation of ZrO2-SiO2 Gels

1990 ◽  
Vol 180 ◽  
Author(s):  
Xiaoming Li ◽  
P.F. Johnson
Keyword(s):  
Phase Transformation ◽  
Gravimetric Analysis ◽  
Acetate Solution ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
X Ray ◽  
Zirconium Acetate ◽  
The Stability ◽  
T Phase ◽  
Initial Crystallization Temperature

ABSTRACTPure SiO2, ZrO2 and SiO2−ZrO2 gels have been prepared by hydrolysis and gelation of tetraethylorthosilicate (TEOS) and zirconium acetate solution. The crystallization and phase transformation of SiO2 and ZrO2 in these gels have been followed up to 1450°C using differential thermal analysis (DTA), thermal gravimetric analysis (TGA) and X-ray diffraction analysis (XRD). The crystallization and phase transformation behavior of SiO2 or ZrO2 is quite different in different gel systems. It was found that in pure SiO2 gel, the cristobalite phase was precipitated out at about 1000°C. In the pure ZrO2 system, tetragonal (t−) phase zirconia was crystallized at about 430°C, t-ZrO2 crystals grew three dimensionally and the activation energy for growth was calculated as about 365 kJmol−1. But in the SiO2-ZrO2 system, the presence of ZrO2 suppressed the crystallization of SiO2 , and SiO2 increased the initial crystallization temperature and the stability of t-ZrO2.

Phase Transformation Behavior and Stability of LiNiO 2 Cathode Material for Li‐Ion Batteries Obtained from In Situ Gas Analysis and Operando X‐Ray Diffraction

ChemSusChem ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2240-2250 ◽  
Author(s):  
Lea de Biasi ◽  
Alexander Schiele ◽  
Maria Roca‐Ayats ◽  
Grecia Garcia ◽  
Torsten Brezesinski ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Cathode Material ◽  
Gas Analysis ◽  
Li Ion Batteries ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
X Ray ◽  
Phase Transformation Behavior ◽  
Li Ion

Thermal and Chemical Stability of Micron Aluminum Powders Subjected to Gaseous Water

2016 ◽  
Vol 712 ◽  
pp. 241-245
Author(s):  
Sergey V. Zmanovskiy ◽  
Alexander M. Gromov ◽  
Valentina V. Smirnova ◽  
Vadim F. Petrunin ◽  
Jin Chun Kim
Keyword(s):  
Room Temperature ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Aluminum Powders ◽  
X Ray ◽  
The Stability ◽  
Heating Up ◽  
The Impact ◽  
Thermal And Chemical Stability ◽  
Composition Of Products

The paper studies the impact of gaseous water on the stability of micron aluminum powders in time at room temperature using the method of gravimetric analysis. The stability was studied using methods of thermal analysis during heating up to 1200 °С in air. The composition of products was analyzed using X-ray diffraction analysis. It was found out that the stability of micron aluminum powders depends on partial pressure of water vapor: the increase of pressure results in decreased stability of powders. The work gives recommendations for storing micron aluminum powders.

Study of the Phases of Mg-Zn-La Magnesium Alloys at 150°C

2013 ◽  
Vol 750-752 ◽  
pp. 679-682 ◽  
Author(s):  
Ming Li Huang ◽  
Li Na Dong ◽  
Ying Ling Wang ◽  
Li Wei Quan
Keyword(s):  
Phase Equilibrium ◽  
Lattice Structure ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Binary Solid Solution ◽  
Two Phase ◽  
X Ray ◽  
The Difference ◽  
The Stability ◽  
T Phase

Alloys with different compositions in Mg-rich corner of Mg-Zn-La system at 150°C were prepared, and the phase equilibrium in Mg-Zn-La alloys were determined by scanning electron microscopy (SEM), electron probe microanalysis based on energy dispersive X-ray spectroscopy (EPMA-EDS) and X-ray diffraction (XRD). The stability, compositions and lattice structures of the intermetallic compounds of Mg-Zn-La alloys were identified. The results show that, there exists a ternary compound (T-phase) with constant La (about 8at%) and the changed ratio of Mg/Zn in the Mg-rich corner of Mg-Zn-La system. Though the ratio of (Mg, Zn)/La of T-phase is close to that of Mg/La of Mg12La, the T-phase was not the binary solid solution of Mg12La because of the difference of the lattice structure. It also reveals that T-phase is a stable phase, and it is in two-phase equilibrium of T-phase+Mg at 150°C.

X-Ray Diffraction Studies on Ti-Pd Shape Memory Alloys

2014 ◽  
Vol 783-786 ◽  
pp. 2517-2522
Author(s):  
Raju Arockiakumar ◽  
Madoka Takahashi ◽  
Satoshi Takahashi ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Phase Transformation ◽  
Shape Memory ◽  
Low Temperatures ◽  
Periodic Table ◽  
Room Temperature ◽  
Group Iv ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
X Ray ◽  
B2 Phase

The phase transformation behavior of Ti-50Pd-5x (x =Zr, Hf, V, Nb, Ta, Cr, Mo, W) (at.%) alloys was studied by X-ray diffraction measurements from room temperature to 800 oC. In all the alloys, B19 martensite was observed at room temperature and it transformed to B2 phase upon heating. In addition, peaks corresponding to formation of (Ti, x)2Pd3 phase was seen for all the alloys. However, the temperature of formation of (Ti, x)2Pd3, interestingly, varied with respect to the elements group from the periodic table. Elements except from group IV (Zr and Hf) have been identified to accelerate the formation of (Ti, x)2Pd3 phase even at low temperatures (~400 oC).

A Study of Rhombohedral Phase in Y2 O3 -Partially Stabilized Zirconia

1986 ◽  
Vol 78 ◽  
Author(s):  
Jukishige Kitano ◽  
Y. Mori ◽  
A. Ishitani ◽  
T. Masaki
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Hot Isostatic Pressing ◽  
Tetragonal Zirconia ◽  
Rhombohedral Phase ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
The Stability

ABSTRACTTetragonal to rhombohedral phase transformation was studied by X-ray diffraction technique on the ground surfaces of tetragonal zirconia polycrystals (Y-TZP) and partially stabilized zirconia (Y-PSZ) with 2.0 to 5.0 mol% Y2 O3 contents prepared by hot isostatic pressing. The rhombohedral phase increased with increase of Y2 O3 content from 2.0 to 5.0 mol%, and also with the increase of HIPing temperature from 1400 to 1600°C. The stability of the phase was also studied with regard to the surface finish and annealing. The subsequent heat treatment of the samples was found to promote the reverse rhombohedral to tetragonal transformation.

Stability of Superalloys Doped with Rare Earth Elements

2013 ◽  
Vol 586 ◽  
pp. 141-145
Author(s):  
Walenty Jasinski ◽  
Paweł Zawada
Keyword(s):  
Phase Transformation ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Thermal Processing ◽  
Microstructure Analysis ◽  
Hardness Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Hardness ◽  
The Stability

The stability of the microstructure and properties of the iron superalloys of the secondgeneration IN 519 (24% Cr, 24% Ni, 1.5% Nb) modified with 0.1 and 0.2 [wt.%] rare earthelements was investigated. The alloys underwent annealing at 825 oC for 10, 100 and 1000 h. Thefollowing techniques were used to evaluate the phase transformation: X-ray diffraction on crosssectionand isolates extracted from the as-cast and annealed alloys, microstructure analysis byoptical microscopy, hardness measurements by Brinell and nanoindentation with a Berkovich tipmethod. The analysis of changes in hardness distribution due to thermal processing of superalloyswas conducted with respect to the average hardness of matrix and phase precipitates.

Crystallization and Melting in Multilayered Structures

1987 ◽  
Vol 103 ◽  
Author(s):  
W. Sevenhans ◽  
H. Vanderstraeten ◽  
J. P. Locquet ◽  
Y. Bruynseraede ◽  
H. Homma ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Melting Temperature ◽  
Layered Structure ◽  
Broad Temperature Range ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Multilayered Structures ◽  
X Ray ◽  
Temperature Range ◽  
The Stability

ABSTRACTThe stability of Pb/Ge and Pb/C multilayers has been studied over a broad temperature range by x-ray diffraction experiments. In the Pb/Ge system an amorphous to microcrystalline phase transformation of the Ge-layers was already observed at ≃ 100 °C. This transition destroys the modulation structure and improves the Pb(111) texture. In the Pb/C multilayers, the layered structure was still present at temperatures higher than the melting temperature of Pb. Contrary to recent publications, no depression of the melting temperature of the two-dimensional Pb layers could be observed.

Fractionation of polymethylene chains: An electron crystallographic investigation

1986 ◽  
Vol 44 ◽  
pp. 794-795
Author(s):  
Douglas L. Dorset
Keyword(s):  
Cross Section ◽  
Binary Systems ◽  
Linear Chain ◽  
Pure Component ◽  
Organic Substrates ◽  
Crystallographic Investigation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Sizes ◽  
The Stability

A variety of linear chain materials exist as polydisperse systems which are difficultly purified. The stability of continuous binary solid solutions assume that the Gibbs free energy of the solution is lower than that of either crystal component, a condition which includes such factors as relative molecular sizes and shapes and perhaps the symmetry of the pure component crystal structures.Although extensive studies of n-alkane miscibility have been carried out via powder X-ray diffraction of bulk samples we have begun to examine binary systems as single crystals, taking advantage of the well-known enhanced scattering cross section of matter for electrons and also the favorable projection of a paraffin crystal structure posited by epitaxial crystallization of such samples on organic substrates such as benzoic acid.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

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