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.

Microstructure and Phase Composition of (Ce, Mg)-PSZ Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1194-1196
Author(s):  
Zhi Ping Shen ◽  
Shu Cai ◽  
Zhen Dong
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Monoclinic Phase ◽  
Processing Method ◽  
Nanoporous Structure ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
Heat Treated

Magnesia, ceria partially stabilized zirconia (Ce,Mg)-PSZ ceramics with net shape microstructure are prepared using a processing method similar to that of conventional Mg-PSZ ceramics, then heat-treated at 1500°C for different time. Microstructure and phase composition of (Ce, Mg)-PSZ samples with different amount of CeO2 doped were investigated using SEM and X-ray diffraction. The addition of CeO2 could impede the formation of monoclinic phase and inhibit the growth of cubic grains. A microstructure with net-shape cubic grains, in which tetragonal precipitates interweave to a nanoporous structure is obtained by adding 4∼8 mol% CeO2 in 10mol% MgO doped zirconia matrix and then heat treatment at 1500°C for different time. The precipitate morophology might be related with the addition of CeO2 and the heat treatment temperatures.

Microstructure & Phase Transformation in Rapidly Solidified V-Ga Alloys

1986 ◽  
Vol 80 ◽  
Author(s):  
M. W. Park ◽  
S. H. Whang ◽  
S. Karmarkar ◽  
D. Divecha
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Grain Refinement ◽  
Rapid Solidification ◽  
Rapid Quenching ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapidly Solidified ◽  
A15 Phase

AbstractThe A15 Phase forming V-Ga alloys were processed into ribbons and foils by rapid solidification techniques. Microstructures and phase transformation in these alloys by rapid solidification and succeeding heat treatment were investigated by x-ray diffraction and TEM. It is shown that equilibrium A15 phases can readily be suppressed by rapid quenching in these alloys. A significant grain refinement resulting from the rapid solidification also was observed. Microhardnesses of these alloys as a function of Ga concentration were determined.

Study on the Law of Phrase Transformation of High-Carbon Matrix Steel 4Cr-3Mo-3V-2W

2011 ◽  
Vol 284-286 ◽  
pp. 1610-1614
Author(s):  
Shun Sang Na ◽  
Jian Sha Chen ◽  
Chao Fu ◽  
Guo Tao Zhang ◽  
Qian Xu
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Phase Analysis ◽  
Carbon Matrix ◽  
Residual Austenite ◽  
X Ray Diffraction ◽  
High Carbon ◽  
X Ray ◽  
Metallographic Observation ◽  
Alloy Carbide

The study on the phase transformation law of High-Carbon Matrix steel 4Cr-3Mo-3V-2W-Ni-Nb, which is processed in different heat treatment, is conducted by means of metallographic observation, hardness determination and phase analysis conducted with the help of X-ray diffraction. The results indicate what is as follow: through quenching at 970°C, the main precipitations of alloy carbide are V4WC5, Cr7C3 and Fe3W3C at 200~300°C, V4WC5 and Cr7C3 at 400°C, V4WC5 and Cr7C3 at 500°C, V4WC5, Cr7C3 and Mn23C6 at 600°C. The transformation of residual austenite is thorough completed above 400 °C and the cause of secondary hardening is the precipitation of V4WC5 and V4C2.67.

scholarly journals Структурные особенности замещенного феррита стронция Sr-=SUB=-1-x-=/SUB=-La-=SUB=-x-=/SUB=-FeO-=SUB=-3-delta-=/SUB=-: I. Sr-=SUB=-2-=/SUB=-LaFe-=SUB=-3-=/SUB=-O-=SUB=-9-delta-=/SUB=-

2021 ◽  
Vol 63 (10) ◽  
pp. 1648
Author(s):  
В.Д. Седых ◽  
О.Г. Рыбченко ◽  
Н.В. Барковский ◽  
А.И. Иванов ◽  
В.И. Кулаков
Keyword(s):  
Heat Treatment ◽  
Diffraction Analysis ◽  
Rhombohedral Phase ◽  
Structural Features ◽  
Structure Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Treatment Conditions ◽  
Valence States

The structural features and Fe valence states in the substituted strontium ferrite Sr2/3La1/3FeO3-δ (or Sr2LaFe3O9-δ) have been studied for different synthesis and heat treatment conditions by X-ray diffraction analysis and Mossbauer spectroscopy. A series of annealing of Sr2LaFe3O9-δ in vacuum ((10-3 Torr) in the temperature range of 400 - 650оС allowed us to trace the structure evolution from rhombohedral phase (Sr2LaFe3O9) to orthorhombic one (Sr2LaFe3O8) over the formation of intermediate multiphase states and the redistribution of Fe valence states as well.

Pitfalls of local and quantitative phase analysis in partially stabilized zirconia

2012 ◽  
Vol 45 (6) ◽  
pp. 1136-1144 ◽  
Author(s):  
Stefan Martin ◽  
Harry Berek ◽  
Christos G. Aneziris ◽  
Ulrich Martin ◽  
David Rafaja
Keyword(s):  
Phase Transformation ◽  
Phase Analysis ◽  
Tetragonal Zirconia ◽  
Quantitative Phase Analysis ◽  
Local Concentration ◽  
Stabilized Zirconia ◽  
Concentration Gradients ◽  
Continuous Transition ◽  
Partially Stabilized Zirconia ◽  
Quantitative Phase

The addition of selected elements into the host structure of ZrO2stabilizes the tetragonal and cubic phases of zirconia, which are, in their undoped binary form, only stable at high temperatures. From the crystallographic point of view, the increasing amount of the stabilizer causes a continuous transition of the tetragonal zirconia to its cubic modification. In partially stabilized zirconia, local concentration gradients of the stabilizer are frequently present as a consequence of the production process, which results in a coexistence of zirconia domains having different degrees of tetragonality. The presence of the local concentration gradients in such samples and the continuous nature of the phase transformation are features important for many technological applications, but their analysis is not straightforward. Furthermore, these features complicate the quantitative phase analysis in partially stabilized zirconia. For the example of zirconia partially stabilized by magnesium, this contribution illustrates the capabilities and limitations of X-ray and electron backscatter diffraction. In particular, the ability of these experimental methods to reveal the gradual lattice distortion that is associated with the cubic to tetragonal phase transformation in zirconia and the reliability of the quantitative phase analysis are discussed. In this context, it is shown to what extent the choice of the microstructure model influences the result of the phase analysis.

Effect of Fe on Phase Transformation of Low Temperature Cu-Al-Mn Memory Alloy

2011 ◽  
Vol 687 ◽  
pp. 474-479
Author(s):  
Kun Peng Zhu ◽  
Ning Hu ◽  
Fu Shun Liu
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Sharp Increase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fe Content ◽  
Heat Treated ◽  
Scanning Electron ◽  
Al Matrix ◽  
Fe Addition

The influence of Fe addition on the phase transformation and the microstructure of Cu67Al27-XMn6FeXshape memory alloys are investigated by means of electrical resistivity, X-ray diffraction, scanning electron microscopy and microhardness test. It was shown that the Ms (Martensitic start transformation) temperature of the 850°C heat-treated alloy exhibit a sharp increase as Fe content increases, by comparison with the alloy without heat-treatment. For example, after 850°C heat-treatment, the Ms temperature of the alloy increases from 52K to 135K when Fe is added from 0 at.% to 1.5 at.%. The microstructure of as-homogenized Cu67Al27-XMn6FeXalloys consists of Cu3Al matrix, γ2(Cu9Al4) and α (Cu) phases. Fe element was distributed in precipitates and matrix.

In Situ Synchrotron X-Ray Diffraction Study of the Cubic to Rhombohedral Phase Transformation in Ln6 WO12 (Ln = Y,Ho,Er,Yb)

2012 ◽  
Vol 96 (3) ◽  
pp. 987-994 ◽  
Author(s):  
Zlatomir D. Apostolov ◽  
Pankaj Sarin ◽  
Ryan P. Haggerty ◽  
Waltraud M. Kriven
Keyword(s):  
Phase Transformation ◽  
Diffraction Study ◽  
Rhombohedral Phase ◽  
X Ray Diffraction ◽  
X Ray

Nitriding of Zirconia by Irradiation with NdrYAG Laser Beam

1995 ◽  
Vol 397 ◽  
Author(s):  
S. Fujitsu ◽  
M. Sawai ◽  
K. Kawamura ◽  
H. Hosono
Keyword(s):  
Laser Beam ◽  
Mass Spectroscopy ◽  
Nd:Yag Laser ◽  
Zirconium Nitride ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
Secondary Ion

ABSTRACTThe surface of partially stabilized zirconia ceramics was irradiated by a Nd:YAG laser in various atmospheres. Zirconia strongly absorbed YAG's laser beam and changed its chemistry and microstructure. The change of color of zirconia into gold was due to the formation of zirconium nitride (ZrN) observed on the irradiated surface in air, nitrogen or ammonia, which was confirmed by X-ray diffraction and secondary ion mass spectroscopy. The observed ZrN phase was 10-20 um in thickness at the irradiated area by the direct beam. The adhesion between formed ZrN and YSZ substrate was very weak.

The Effects of Composition and Sintering Conditions on Zirconia Toughened Alumina (ZTA) Nanocomposites

2010 ◽  
Vol 93-94 ◽  
pp. 695-698 ◽  
Author(s):  
H. Esfahani ◽  
Ali Nemati ◽  
E. Salahi
Keyword(s):  
Tetragonal Zirconia ◽  
Al2o3 Nanoparticles ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Constant Composition ◽  
X Ray ◽  
Different Temperatures ◽  
Lattice Network ◽  
Diffraction Patterns ◽  
Zirconia Toughened Alumina

Zirconia Toughened Alumina (ZTA) Nanocomposites were prepared using Nano sized Zirconia (ZrO2) powders doped with 3% mol of yttria (Y2O3) nanopowders. Diffusion of α-alumina (Al2O3) nanoparticles as well as yttria into the Zirconia lattice network drives monoclinic – tetragonal martensitic transformation. Zirconia toughened alumina (ZTA) composites containing different amount of partially stabilized Zirconia (PSZ) 5, 10, 15 and 20% mol, were prepared via wet mixing and axial pressing. After sintering at different temperatures,1450, 1550 and 1650 °C, phase change in the samples were monitored. X-ray diffraction patterns showed that at constant composition, tetragonal zirconia was increased by temperature increasing due to intensification of diffuse coefficient of alumina and yttria in the system. At constant temperature, remained monoclinic zirconia was increased with Zirconia content increasing.

Temperature Effect on Chicken Egg Shell Investigated by XRD, TGA and FTIR

2008 ◽  
Vol 55-57 ◽  
pp. 333-336 ◽  
Author(s):  
Kittisakchai Naemchanthara ◽  
S. Meejoo ◽  
Wandee Onreabroy ◽  
Pichet Limsuwan
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Ir Spectroscopy ◽  
Water Absorption ◽  
Calcium Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Egg Shell ◽  
Anadara Granosa

The main purpose of this work is to study the structure of Anadara granosa shell sample and its structural transformation upon heat treatments. The sample was ground and characterized as powder throughout this work. Structural identifications of all samples were characterized, and determined qualitatively by using X-ray diffraction, IR spectroscopy and thermogravimetry measurement (TGA). It was found that the specimen is made of aragonite, a common phase of CaCO3 mineral. The powder sample was annealed at specific temperatures over the range of 200°C - 900°C and the effects of heat treatment on the structure of Anadara granosa shell samples were studied. The results show that aragonite transforms to calcite at the temperatures between 200°C and 400°C and completely becomes calcite between 400-500°C. Then, the calcite transforms to calcium oxide at the temperatures between 500°C - 900°C. The exact structures and quantities of phase at different annealing temperatures were studied by Rietveld refinement. In our study, we also used IR spectroscopy and TGA to study the effect of water absorption of the samples on the phase transformation.

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