Influence of Annealing Time on Microstructure of Ni-W Alloys

2013 ◽  
Vol 747-748 ◽  
pp. 613-618
Author(s):  
Qiao Zhang ◽  
Shu Hua Liang ◽  
Chen Zhang ◽  
Jun Tao Zou
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Grain Size ◽  
Grain Boundaries ◽  
Annealing Time ◽  
Single Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Grain Size ◽  
Scanning Electron

The as-cast Ni-W alloys with 15wt%W, 25wt%W and 30wt%W were annealed in hydrogen at 1100. The effect of the annealing time on the microstructure of Ni-W alloys was studied, and the phase constituents and microstructure of annealed Ni-W alloys were characterized by the X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that no any phase changed for Ni-15%W, Ni-25%W and Ni-30%W alloys annealed for 60 min, 90 min and 150 min, which were still consisted of single-phase Ni (W) solid solution. However, microstructure had a significant change after annealing. With increase of annealing time, the microstructure of Ni-15%W alloy became more uniform after annealing for 90 min, and the average grain size was 95μm, whereas the grain size of Ni-15%W alloy increased significantly after annealing for 150 min. For Ni-25%W and Ni-30%W, there was no obvious change on the grain size with increase of annealing time, and the amount of oxides at grain boundaries gradually reduced. After annealing for 150 min, the impurities at grain boundaries almost disappeared. Subsequently, the annealing at 1100 for 150 min was beneficial for the desired microstructure of Ni-25%W and Ni-30%W alloys.

Synthesis of Ti3Si0.4Al0.8C1.8 Solid Solution

2008 ◽  
Vol 368-372 ◽  
pp. 995-997
Author(s):  
Cui Wei Li ◽  
Hong Xiang Zhai ◽  
Yang Zhou ◽  
Shi Bo Li ◽  
Zhi Li Zhang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Lattice Parameters ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Scanning Electron

In this study, free Ti/Si/Al/C powder mixtures with molar ratio of 3:0.4:0.8:1.8 were heated in Argon with various schedules, in order to reveal the possibility for the synthesis of Ti3Si0.4Al0.8C1.8 solid solution powder. X-ray diffraction (XRD) was used for the evaluation of phase identities of the powder after different treatments. Scanning electron microscopy (SEM) was used to observe the morphology of the Ti3Si0.4Al0.8C1.8 solid solution. XRD results showed that predominantly single phase samples of Ti3Si0.4Al0.8C1.8 was prepared after heating at 1400oC for 5 min in Argon and the lattice parameters of Ti3Si0.4Al0.8C1.8 lay between those of Ti3SiC2 and Ti3AlC2.

Effects of V2O5 on the synthesis of Ba2Ti9O20 powders

2005 ◽  
Vol 20 (10) ◽  
pp. 2741-2744 ◽  
Author(s):  
Huixing Lin ◽  
Wei Chen ◽  
Lan Luo
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Eutectic Liquid ◽  
X Ray ◽  
Intermediate Phases ◽  
Phase Pure ◽  
Scanning Electron

Phase-pure Ba2Ti9O20 powders were made by doping 3 wt% of V2O5 to a Ba:Ti = 2:9 molar composition, and the effects of the dopant on the phase formation were investigated. The study shows that BaTiO3, BaTi2O5, and BaTi4O9 were the intermediate phases before the formation of Ba2Ti9O20 for samples with or without V2O5. However, with V2O5 doping, the temperature at which Ba2Ti9O20 occurred were lowered from 1150 to 1050 °C and single phase Ba2Ti9O20 powders was easily obtained at 1150 °C for 2 h. Microstructure of the powders was examined by field emission scanning electron microscopy. No evidence of V2O5–Ba2Ti9O20 solid-solution was found by x-ray diffraction and energy-dispersive spectroscopy. The benefit of V2O5 to facilitate the Ba2Ti9O20 synthesis is most probably due to a vanadium-containing eutectic liquid phase which accelerates the migration of reactant species.

Processing and Characterizations of Bi2O3/BaTiO3 Ceramic

2013 ◽  
Vol 802 ◽  
pp. 7-11 ◽  
Author(s):  
Wanwilai C. Vittayakorn ◽  
Dondanai Banjong ◽  
Naratip Vittayakorn
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Single Phase ◽  
Sintering Temperature ◽  
Secondary Phase ◽  
Dielectric Characteristics ◽  
X Ray ◽  
Synthesis Conditions ◽  
Average Grain Size ◽  
Scanning Electron

The objective of this work is to provide the process for making BaTiO3-based ceramics by adding bismuth oxide (Bi2O3) into the system. The attention is also focused on synthesis conditions, where sintering temperature exhibits a pronounced effect on phase formation, density, microstructure and dielectric properties of BaTiO3 ceramics doped with different contents of Bi2O3 nanoparticles. The phases of BaTiO3-based ceramics have been prepared by solid state reaction using different Bi2O3 amount and characterized by X-ray diffractometry, Archimedes’s method, scanning electron microscopy and dielectric spectroscopy. The results show that single phase of BaTiO3 with no evidence of secondary phase forms in all samples. Abnormal grain growth was found in pure BaTiO3 ceramic with 37.30 µm of average grain size. After added Bi2O3 nanoparticles into system, the grain size significantly decreases and the sintering temperature of BaTiO3-based ceramics efficiently reduces without degrading the dielectric characteristics.

A Study of Natural Metamict Yttrium Niobate as Analogue of Actinide Ceramic Waste Form

2014 ◽  
Vol 1665 ◽  
pp. 313-318 ◽  
Author(s):  
Cao Qiuxiang ◽  
Anton I. Isakov ◽  
Liu Xiaodong ◽  
Sergey V. Krivovichev ◽  
Boris E. Burakov
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Single Phase ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Original Sample ◽  
X Ray Diffraction ◽  
Average Chemical Composition ◽  
X Ray ◽  
Scanning Electron

ABSTRACTNatural metamict mineral found as large (1-3 cm in size) homogeneous grains (as assumed, former single crystals), was investigated by X-ray powder diffraction (pXRD), high-temperature pXRD, scanning electron microscopy (SEM) and electron microprobe analysis (EMPA). The average chemical composition obtained by EMPA is (wt. %): Nb2O5 – 42.6; Ta2O5 – 4.4; TiO2 – 9.2; UO3 – 4.4; ThO2 – 1.0; MnO – 1.3; FeO – 19.4; Y2O3 – 16.6.The untreated (original) sample is X-ray amorphous. The sample remained amorphous after annealing at 400 °C for 1 hour. The sample became almost fully crystalline after annealing at 700 °C for 1 hour with an X-ray diffraction pattern similar to that of Fe-columbite (ICCD: 01-074-7356). Further annealing at 1000 °C and higher temperatures caused changes in the phase composition of the sample. It was proposed that under self-irradiation a single-phase U-Th-bearing solid solution, based on monocrystalline Y-niobate, became metamict but remained homogeneous without evidence of solid solution destruction. However, this metamict solid solution is unstable under thermal treatment and recrystallization.

Impedance Spectroscopy of Nanocrystalline Y-Stabilized Tetragonal Zirconia

1997 ◽  
Vol 500 ◽  
Author(s):  
P. Mondal ◽  
H. Hahn
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
High Resolution ◽  
Impedance Spectroscopy ◽  
Grain Boundaries ◽  
Tetragonal Zirconia ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

ABSTRACTImpedance Spectroscopy, X-Ray Diffraction and High Resolution Scanning Electron Microscopy have been used to study the effect of extremely fine grain size on electrical properties such as dc-conductivity and activation energies in nanocrystalline Y-stabilized tetragonal zirconia. The samples were prepared from powders produced by the Inert Gas condensation method. X-Ray Diffraction was used to characterize phase and average grain size of the sample. In addition, grain size and microstructure of the sample was examined using High Resolution Scanning Electron Microscopy. With Impedance Spectroscopy relaxations of O−2-ions in the lattice and in the grain boundaries could be resolved. The dc-conductivities of the lattice and the grain boundaries were deduced from the data. The activation energies for ac- and dc-conductivity of the lattice and grain boundary relaxation are reported.

Synthesis of Single-Phase Nanocrystalline YIG by Co-Precipitation: The Influence of pH Value of Precursor Solution and Calcinating

2011 ◽  
Vol 311-313 ◽  
pp. 1294-1299 ◽  
Author(s):  
Liang Zheng ◽  
Hui Zheng ◽  
Jiang Xia Deng ◽  
Zhi Hua Ying ◽  
Jun Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Single Phase ◽  
Ph Value ◽  
Precursor Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
Influence Of Ph ◽  
Scanning Electron

Single-phase nanocrystalline YIG powders have been successfully synthesized through chemical co-precipitation methods. The influence of pH value of the precursor solution and calcinating conditions (temperatures ranging from 700 to 900°C and times ranging from 0.5 to 12 hours) on the purity and grain size of the single-phase nanocrystalline YIG powders were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) technique. The results show that a pure single-phase YIG powder was obtained as the pH value of precursor solution above 10 and the YIG grain grows bigger as calcinating temperature and time increased. Finally, the optimal condition to form single-phase nanocrystalline YIG with the smallest grain size is calcinating at 750°C for 7 hours.

Crystal Chemistry and Phase Equilibrium Studies of the Bao(baco3)‐r2o3‐cuo Systems. V. Melting Relations in ba2(y,nd,eu)cu3o6+x

1989 ◽  
Vol 169 ◽  
Author(s):  
Winnie Wong‐Ng ◽  
Lawrence P. Cook ◽  
Michael D. Hill ◽  
Boris Paretzkin ◽  
E.R. Fuller
Keyword(s):  
Electron Microscopy ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Equilibrium Studies ◽  
X Ray ◽  
Helium Gas ◽  
Ionic Size ◽  
Differential Thermogravimetric Analysis ◽  
Melting Relations ◽  
Scanning Electron

AbstractThe influence of the ionic size of the lanthanides R on melting relations of Ba2RCu3O6+x, where R=Y, Eu and Nd, was studied and compared with that of a high Tc superconductor mixed‐lanthanide phase Ba2(Y.75Eu.125Nd 125)Cu3O6+xThese materials have been characterized by a variety of methods including differential thermogravimetric analysis (DTA), scanning electron microscopy (SEM) with energy dispersive X‐ray spectroscopy (EDX) and X‐ray powder diffraction. Single phase samples of Ba2(Y.75Eu.125Nd.125)Cu3O6+x were annealed at 1004, 1040, 1052, 1060, 1078, 1107 and 1160°C and quenched into a helium gas container cooled by liquid nitrogen. The SEM micrographs of these samples showed the progressive chnages in features of the microstructures from sintering and grain growth through melting and then recrystallization from the melt. The addition of the SEM technique in conjunction with X‐ray diffraction has been helpful in the study of phase equilibria in this system.

The Synthesis of Cu0.81Ni0.19 Intermetallics by Mechanical Alloying

2012 ◽  
Vol 496 ◽  
pp. 379-382
Author(s):  
Rui Song Yang ◽  
Ming Tian Li ◽  
Chun Hai Liu ◽  
Xue Jun Cui ◽  
Yong Zhong Jin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Milling Time ◽  
Elemental Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scherrer Equation ◽  
Scanning Electron

The Cu0.81Ni0.19 has been synthesized directly from elemental powder of nickel and copper by mechanical alloying. The alloyed Cu0.81Ni0.19 alloy powders are prepared by milling of 8h. The grain size calculated by Scherrer equation of the NiCu alloy decreased with the increasing of milling time. The end-product was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM)

Light Burning Condition of Preparing Dolomite Clinker Using Natural Dolomite

2018 ◽  
Vol 281 ◽  
pp. 156-162
Author(s):  
Wang Nian Zhang ◽  
Xi Tang Wang ◽  
Zhou Fu Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Burning Temperature ◽  
X Ray ◽  
Temperature Range ◽  
Scanning Electron

The influence of the light burning temperature on the sintering property of nature dolomite has been investigated by two-step sintering process in the temperature range 1500 °C to 1600 °C. The resulting bulk densities and apparent porosities of the sintered dolomite samples were examined, and analyzing the sintered dolomite by scanning electron microscopy and X-ray diffraction were performed. The results showed light burned at 850 °C for 3 h, the main phases of the dolomite with 3-5 grain size were MgO, CaO and little CaCO3, and then fired at 1600 °C,the density of sintering dolomite reached to 3.38 g/cm3, the apparent property was 1.2 %, the size of MgO grain up to 3.75 μm . However when dolomite light burned at 1050 °C for 3 h, the main phases were MgO and CaO, and then fired at 1600 °C,the density of sintering dolomite only was 3.30 g/cm3, the apparent property was 2.3 %, the size of MgO only was 3.05 μm .

The Effects of Al-Ca Compounds on Grain Refinement of Mg-Ca Alloys

2011 ◽  
Vol 686 ◽  
pp. 348-354 ◽  
Author(s):  
Shu Tao Xiong ◽  
Fu Sheng Pan ◽  
Bin Jiang ◽  
Xiao Ke Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Grain Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metallic Compound ◽  
Scanning Electron ◽  
Main Factor

In the present work, Al-Ca metallic compound was prepared in Mg-Ca alloys and the effects of Al-Ca metallic compound and different Al/Ca values on the grain refinement of Mg-Ca alloys were investigated by scanning electron microscopy and X-ray diffraction, and the mechanism of grain refinement of Mg-Ca alloys was discussed. The results showed that the grain size of Mg-0.5Ca alloy was obviously reduced from 550μm to 230μm due to the addition of Al. Al2Ca phase existed in these alloys and its morphology evolved from granular to rod-like. It is regarded as the main factor for the grain refinement.

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