Phase selection in precursor-derived yttrium aluminum garnet and related Al2O3–Y2O3 compositions

2005 ◽  
Vol 20 (4) ◽  
pp. 1017-1025 ◽  
Author(s):  
Ashutosh S. Gandhi ◽  
Carlos G. Levi
Keyword(s):  
Heat Treatment ◽  
Yttrium Aluminum Garnet ◽  
Lattice Parameter ◽  
Defect Structures ◽  
X Ray Diffraction ◽  
Phase Selection ◽  
X Ray ◽  
Yttrium Aluminum ◽  
Rich Side ◽  
Nitrate Solutions

Al2O3–Y2O3 powders were synthesized in the range of 25–55% Y2O3 by reverse coprecipitation of nitrate solutions. All starting powders were amorphous and formed primary yttrium aluminum garnet (YAG) upon crystallization. X-ray diffraction detected only garnet in compositions of 30–40% Y2O3 after heat treatment at 1250 °C. Compositions of 45–55% Y2O3 established a metastable YAG + Y4Al2O9 microstructure. The YAG phase field was metastably extended away from its stoichiometry, as indicated by a systematic increase in lattice parameter with Y2O3 content. Although some Al2O3 enrichment was achieved, YAG appears to tolerate greater off-stoichiometry on the Y2O3-rich side. Possible defect structures accommodating the solubility extension were examined. Phase selection results indicate that compositional inhomogeneity is not the only reason behind the appearance of hexagonal YAlO3, which is frequently reported during YAG synthesis.

Contribution of the hybrid component to the structure and properties of ceramics based on metastable phases Al2O3

2021 ◽  
pp. 127-136
Author(s):  
A. V. Maletsky ◽  
T. E. Konstantinova ◽  
D. R. Belichko ◽  
G. K. Volkova ◽  
V. V. Burkhovetsky
Keyword(s):  
Mechanical Properties ◽  
Yttrium Aluminum Garnet ◽  
Metastable Phase ◽  
Physical And Mechanical Properties ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Mutual Inhibition ◽  
X Ray ◽  
Tetragonal Lattice ◽  
Yttrium Aluminum

The paper presents results of the study of the effect of doping with yttrium oxide on ceramics of the composition (γ + θ) Al2O3 + nY2O3 (n = 0, 1, 2, 3 wt%), sintered at 1550°C for 2 h, from powders of the specified composition annealed at temperatures of 500 , 800, 1000°С. X-ray diffraction analysis established the formation in ceramics of yttrium aluminum garnet Y3Al5O12 (YAG) and a metastable phase of the same composition with a tetragonal lattice type in powders at temperatures above 1200°C. The effect of YAG on the physical and mechanical properties was established: high properties were demonstrated by ceramics of the composition α-Al2O3 + 2wt% Y2O3, obtained from a powder annealed at 1000°C. In addition, high physical and mechanical properties were observed in ceramics of the composition α-Al2O3 + 0wt% Y2O3, obtained from a powder annealed at 800°C. The effect of the so-called “mutual protection against crystallization” was discovered, which consists in the mutual inhibition of crystallization processes in powders of the Al2O3 – Y2O3 system.

Crystallization kinetics of yttrium aluminum garnet (Y3Al5O12)

2001 ◽  
Vol 16 (6) ◽  
pp. 1795-1805 ◽  
Author(s):  
Bradley R. Johnson ◽  
Waltraud M. Kriven
Keyword(s):  
Yttrium Aluminum Garnet ◽  
Three Dimensional ◽  
Constant Number ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Yttrium Aluminum ◽  
Temperature Transformation ◽  
Kinetics Of ◽  
Dimensional Crystal

The kinetics and pathways for crystallization of solid, amorphous, yttrium aluminum garnet (YAG) were studied using isothermal differential thermal analysis, x-ray diffraction, and transmission electron microscopy. The activation energy for crystallization was 437 KJ/mol and the measured Avrami exponent was 2.74, which corresponded to three-dimensional crystal growth with a constant number of nuclei. Time–temperature–transformation (T–T–T) curves were developed from the data to predict crystallization rates as a function of temperature. The crystallization pathway for YAG in this system is compared to others reported in the literature.

Study of Aluminium-Titanate Based Ceramics in Fe2O3-Al2O3-TiO2 System

2010 ◽  
Vol 659 ◽  
pp. 31-36
Author(s):  
Támas Korim
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Lattice Parameter ◽  
Self Healing ◽  
X Ray Diffraction ◽  
Repeated Heating ◽  
X Ray ◽  
Aluminium Titanate ◽  
Complete Solid Solution ◽  
Constructed Self

Solid solutions formed within the Al2O3-TiO2-Fe2O3 (Fe2xAl2(1-x)TiO5) system upon heat treatment were investigated by adjusting the substituting Fe3+ content in the range of x=0.0 to 1.0. X-ray diffraction phase analyses and lattice parameter determinations confirmed that substitution of Fe3+ ions within the aluminium titanate lattice was complete. For this complete solid solution, however, the trends observed for changes in d-spacing values indicated that there were certain discrete compositions to identify with Fe3+ substitution. Within these, Fe0.4Al1.6TiO5 and Fe1.6Al0.4TiO5 crystalline phases were investigated in detail and their X-ray diffraction cards were constructed. Self-healing effect occurring in repeated heating-cooling cycles in Fe3+ doped AT ceramics were proved; it was demonstrated that Fe3+ doped AT ceramics do not decompose even if exposed to repeated thermal shock.

ESR and X-ray diffraction measurements of Nd substituted yttrium aluminum garnet films

2000 ◽  
Vol 300-301 ◽  
pp. 316-321 ◽  
Author(s):  
R. Jabłonski ◽  
J. Sarnecki ◽  
K. Mazur ◽  
J. Sass ◽  
J. Skwarcz
Keyword(s):  
Yttrium Aluminum Garnet ◽  
X Ray Diffraction ◽  
X Ray ◽  
Garnet Films ◽  
Yttrium Aluminum

Residual Stress Effects on Fatigue Crack Growth in Directionally Solidified YAG/Spinel Eutectics

2015 ◽  
Vol 752-753 ◽  
pp. 263-267 ◽  
Author(s):  
Serkan Abali
Keyword(s):  
Residual Stresses ◽  
Crack Growth ◽  
Yttrium Aluminum Garnet ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
Zone Method ◽  
X Ray ◽  
Stress Effects ◽  
Float Zone ◽  
Yttrium Aluminum

In this paper, yttrium aluminum garnet-magnesium aluminate spinel with good mechanical strength was fabricated by directional solidification, and its microstructure and mechanical properties were investigated. MgAl2O4-Y3Al5O12 eutectic rods were grown by a float zone method. The composition of the grown ingots was determined by the X-ray diffraction technique and electron probe microanalysis. The crack growth characteristics were examined in directionally solidified YAG/spinel eutectics. The residual stresses were determined in MgAl2O4/Y3Al5O12 eutectics using piezospectrosocopic probes. The crack growth behaviors show that residual stresses play a key role in the crack growth.

Low Temperature Phase Transformation Study in the Al2O3-Y2O3-Nb2O5 System

2014 ◽  
Vol 798-799 ◽  
pp. 90-94
Author(s):  
Eduardo de Sousa Lima ◽  
A.P.O. Santos ◽  
R.F. Cabral ◽  
J.I.N. Fortini ◽  
Jose B. de Campos
Keyword(s):  
Yttrium Aluminum Garnet ◽  
Rietveld Method ◽  
High Energy ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Yttrium Aluminum ◽  
Energy Ball ◽  
Transformation Study ◽  
Low Temperature Phase

The mechanical properties and creep resistance of the Al2O3 have been improved with the use of other oxide ceramics, among these the Y3Al5O12 (YAG - "yttrium aluminum garnet"), to obtain the Al2O3-YAG composite. The aim of this work is to study the effect of addition of Nb2O5 at low sintering temperatures of the composite, starting from the eutectic composition Al2O3-Y2O3. In this work, the compositions were produced by powder mixtures of Al2O3-Y2O3 and Al2O3-Y2O3-Nb2O5 using high energy ball milling. The green bodies were pressed at 70 MPa and sintered at 1000, 1100, 1200 and 1300°C for 2 h. The materials were characterized by shrinkage and X-Ray Diffraction (XRD) using the Rietveld method. The presence of Nb2O5 does not show any improve neither for the YAG phase formation nor for the shrinkage of the sintered samples in the temperature range studied.

Yttrium aluminum garnet Nanoparticles with low antisite Defects studied with neutron and X-ray diffraction

2012 ◽  
Vol 192 ◽  
pp. 366-370 ◽  
Author(s):  
Yuanhua Sang ◽  
Dehong Yu ◽  
Maxim Avdeev ◽  
Haiming Qin ◽  
Jiyang Wang ◽  
...  
Keyword(s):  
Yttrium Aluminum Garnet ◽  
X Ray Diffraction ◽  
X Ray ◽  
Yttrium Aluminum ◽  
Antisite Defects

Influence of Sulfate Ion on Phase and Dispersion of Y3Al5O12 Nanopowders with the Co-Crystallization Method

2018 ◽  
Vol 281 ◽  
pp. 3-8
Author(s):  
Meng Meng Hao ◽  
Zi Qing Zeng ◽  
Gui Fen Fan ◽  
Xiao Hong Wang ◽  
Wen Zhong Lu ◽  
...  
Keyword(s):  
Yttrium Aluminum Garnet ◽  
Decomposition Temperature ◽  
X Ray Diffraction ◽  
Sulfate Ion ◽  
Xrd Pattern ◽  
X Ray ◽  
Crystallization Method ◽  
Transmission Electron ◽  
Pure Phase ◽  
Yttrium Aluminum

Yttrium aluminum garnet Y3Al5O12 (YAG) nanopowders were synthesized from co-crystallized precursors of Y2(SO4)3, Al(NO3)3-Al2(SO4)3 and Y(NO3)3 with a three-layer core-shell structure. X-ray diffraction (XRD) pattern indicated that too much was detrimental to the synthesis of pure phase YAG because of the serious separation between Y2(SO4)3 and Al(NO3)3-Al2(SO4)3. Transmission electron microscopy (TEM) revealed that was beneficial for the dispersion of the powders owing to the high decomposition temperature of . The powders with the n()/n(Y3+) mole ratio of 1.5/3 calcined at 1050°C showed good sintering activity.

Synthesis of yttrium aluminum garnet by reverse strike precipitation

1992 ◽  
Vol 7 (3) ◽  
pp. 706-711 ◽  
Author(s):  
Prasad Apte ◽  
Harry Burke ◽  
Helen Pickup
Keyword(s):  
Yttrium Aluminum Garnet ◽  
Mixed Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phase Pure ◽  
Yttrium Aluminum ◽  
Different Temperatures

Yttrium aluminum garnet (YAG) powders were synthesized by normal and reverse strike precipitation from a mixed solution containing aluminum and yttrium nitrates. The precipitates were characterized by FTIR, DTA, and TGA techniques. The amorphous precipitates were crystallized under various atmospheres (air, argon, hydrogen) at different temperatures and the product analyzed by x-ray diffraction. Only reverse strike precipitation followed by crystallization in hydrogen consistently yielded phase pure YAG.

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