scholarly journals Analysis of interdiffusion of Dy, Nd, and Pr in Mg

2001 ◽  
Vol 16 (11) ◽  
pp. 3287-3292 ◽  
Author(s):  
Y. Xu ◽  
L. S. Chumbley ◽  
G. A. Weigelt ◽  
F. C. Laabs
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
Intermetallic Phases ◽  
Diffusion Couples ◽  
X Ray ◽  
Diffusion Characteristics ◽  
Composition Profiles ◽  
Point Composition ◽  
Interdiffusion Coefficients ◽  
Scanning Electron

The diffusion characteristics of Mg–rare-earth diffusion couples were studied. Cylinders of pure Mg and rare earth (Dy, Nd, and Pr) were abutted and annealed at 500 °C for 100 h or 300 h. Point-by-point composition profiles were collected starting in pure Mg, across the diffusion zone, and ending in the pure rare earth, using energy dispersive x-ray spectroscopy with a scanning electron microscope. The intermetallic phases that resulted due to diffusion were identified and compared to existing phase diagrams, for which the data is limited. For each diffusion couple, a plot of concentration versus distance perpendicular to the original plane of contact was obtained and analyzed using the Boltzman–Matano method. The interdiffusion coefficients for each set of phases were then calculated. The results show that diffusion through the intermetallic phases is much slower than is expected in a solid solution.

scholarly journals Fabrication and Microstructure of Layers Containing Intermetallic Phases on Magnesium

2013 ◽  
Vol 13 (1) ◽  
pp. 99-102 ◽  
Author(s):  
R. Mola
Keyword(s):  
Solid Solution ◽  
Powder Mixture ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Vacuum Furnace ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Al Powder ◽  
Scanning Electron

Abstract Al- and Al/Zn-enriched layers containing intermetallic phases were deposited on the Mg substrate by heating the Mg specimens in contact with the powdered materials in a vacuum furnace. The Al-enriched surface layers were produced using Al powder, whereas the Al/Znenriched layers were obtained from an 80 wt.% Al + 20 wt.% Zn powder mixture. The microstructure and composition of the layers were analyzed by optical microscopy, scanning electron microscopy and X-ray diffraction. The results showed that the Al-enriched layer comprised an Mg17Al12 intermetallic phase and a solid solution of Al in Mg. The layer obtained from the Al+Zn powder mixture was composed of Mg-Al-Zn intermetalic phases and a solid solution of Al and Zn in Mg. Adding 20% of Zn into the Al powder resulted in the formation of a considerably thicker layer. Moreover, the hardness of the surface layers was much higher than that of the Mg substrate.

scholarly journals Phase Relations in the ZrO2-MgO-FeOx System: Experimental Data and Assessment of Thermodynamic Parameters

2021 ◽  
Author(s):  
Ivan Saenko ◽  
O. Fabrichnaya
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
Solid Solution ◽  
Thermodynamic Parameters ◽  
Spinel Phase ◽  
Experimental Investigations ◽  
X Ray ◽  
Heat Treated ◽  
Preliminary Phase ◽  
Scanning Electron

AbstractThermodynamic parameters were assessed for the MgO–FeOx system and combined with already available descriptions of ZrO2-FeOx and ZrO2-MgO systems to calculate preliminary phase diagrams for planning experimental investigations. Samples of selected compositions were heat treated at 1523, 1673 and 1873 K and characterized using x-ray and scanning electron microscopy combined with energy dispersive x-ray spectroscopy (SEM/EDX). Experiments indicated extension of cubic ZrO2 solid solution into the ternary system at 1873 K (75 mol.% ZrO2, 10 mol.% FeOx and 15 mol.% MgO) and limited solubility of 4 mol.% ZrO2 in spinel phase. Based on the obtained results thermodynamic parameters of C-ZrO2 and spinel phase were optimized.

Intermetallic Formation in the Aluminum–Copper System

2003 ◽  
Vol 10 (04) ◽  
pp. 677-683 ◽  
Author(s):  
E. B. Hannech ◽  
N. Lamoudi ◽  
N. Benslim ◽  
B. Makhloufi
Keyword(s):  
Electron Microscopy ◽  
Phase Diagram ◽  
Solid Solution ◽  
Intermetallic Layer ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Diffusion Couples ◽  
Intermetallic Formation ◽  
Parabolic Law ◽  
Scanning Electron

Intermetallic formation at 425°C in the aluminum–copper system has been studied by scanning electron microscopy using welded diffusion couples. Several Al–Cu phases predicted by the equilibrium phase diagram of the elements and voids taking place in the diffusion zone have been detected in the couples. The predominant phases were found to be Al 2 Cu 3 and the solid solution of Al in Cu, α. The growth of the intermetallic layer obeyed the parabolic law.

Effect of the Neodymium Content on Mechanical Properties of the Electro-Brush Plated Nano-Al2O3/Ni Composite Coating

2012 ◽  
Vol 525-526 ◽  
pp. 277-280
Author(s):  
Guo Jin ◽  
Xiu Fang Cui ◽  
Er Bao Liu ◽  
Qing Fen Li
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Composite Coating ◽  
Nanoindentation Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Small Cracks ◽  
Scanning Electron

The effect of the neodymium content on mechanical properties of the electro-brush plated nanoAl2O3/Ni composite coating was investigated in this paper. The microstructure and phase structure were studied with scanning electron microscope (SEM) and X-ray diffraction (XRD). The hardness and abrasion properties of several coatings with different neodymium content were studied by nanoindentation test and friction / wear experiment. Results show that the coatings are much finer and more compact when the neodymium was added, and the hardness and abrasion property of the coatings with neodymium were improved obviously. Besides, the small cracks conduced by the upgrowth stress in the coatings were ameliorated when the rare earth neodymium was added. The improvement mechanism was further discussed.

Microstructure and Hydrogen Permeability of Duplex Phase M-ZrNi (M=V, Nb, Ta) Alloys

2006 ◽  
Vol 980 ◽  
Author(s):  
Kazuhiro Ishikawa ◽  
Naoshi Kasagami ◽  
Tomoyuki Takano ◽  
Kiyoshi Aoki
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
High Performance ◽  
Gas Flow ◽  
Hydrogen Permeation ◽  
Hydrogen Permeability ◽  
The Other ◽  
Cast State ◽  
X Ray ◽  
Scanning Electron

AbstractIn order to develop non-Pd based high performance hydrogen permeation alloys, microstructure, crystal structure and hydrogen permeability of duplex phase M-ZrNi (M=V and Ta) alloys were investigated using a scanning electron microscope, an X-ray diffractometer and a gas flow meter. These results were compared with those of Nb-ZrNi ones which have been previously published. The hydrogen permeation was impossible in the V-ZrNi alloys, because they were brittle in the as-cast state. On the other hand, duplex phase alloys consisting of the bcc-(Ta, Zr) solid solution and the orthorhombic ZrNi (Cmcm) intermetallic compound were formed and hydrogen permeable in the Ta-ZrNi system. The Ta40Zr30Ni30 alloy shows the highest value of hydrogen permeability of 4.1×10-8 [molH2m-1s-1Pa-0.5] at 673 K, which is three times higher than that of pure Pd.

Phase relationships in the Fe-rich region of the Ce–Nd–B–Fe quaternary system at 773 K

2021 ◽  
Vol 112 (9) ◽  
pp. 726-734
Author(s):  
Ketong Luo ◽  
Jianlie Liang ◽  
Jinming Zhu ◽  
Xuehong Cui
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Quaternary System ◽  
Continuous Solid Solution ◽  
Rich Region ◽  
Quaternary Compound ◽  
X Ray ◽  
Three Phase ◽  
Scanning Electron ◽  
Phase Relationships

Abstract The Fe-rich corner of the Ce–Nd–B–Fe quaternary system at 773 K has been experimentally investigated by means of X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy techniques. No quaternary compound was observed in this system. Ce2Fe14B and Nd2Fe14B were found to form the continuous solid solution (Ce,Nd)2Fe14B. Ce-Fe4B4 and NdFe4B4 also form the solid solution (Ce,Nd)-Fe4B4. The isothermal section consists of 8 three-phase regions and 2 four-phase regions.

scholarly journals Standard Hot Pressing as a Possible Solution to Obtain Dense K0.5Na0.5NbO3 Ceramic Doped by Er2O3 and Yb2O3

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4171 ◽  
Author(s):  
Paweł Rutkowski ◽  
Jan Huebner ◽  
Adrian Graboś ◽  
Dariusz Kata ◽  
Dariusz Grzybek ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Rare Earth ◽  
Phase Composition ◽  
Powder Mixture ◽  
Hot Pressing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasonic Methods ◽  
Scanning Electron

In this study, the influence of the addition of rare earth oxides on the phase composition and density of KNN piezoelectric ceramics was investigated. The initial powders of Na2CO3 and K2CO3 were dried at 150 °C for 2 h. Then, a powder mixture for synthesis was prepared by adding a stoichiometric amount of Nb2O5 and 5 and 10 wt % overabundance of Na2CO3. All powders were mixed by ball-milling for 24 h and synthesized at 950 °C. The phase composition of the reaction bed was checked by means of X-ray diffraction (XRD). It had an appearance of tetragonal and monoclinic K0.5Na0.5NbO3 (KNN) phases. Then, 1 and 2 wt % of Er2O3 and Yb2O3, were added to the mixture. Green samples of 25 mm diameter and 3 mm thickness were prepared and sintered by hot pressing at 1000 °C for 2 h under 25 MPa pressure. The final samples were investigated via scanning electron microscopy (SEM)-energy-dispersive X-ray spectroscopy (EDS), XRD, Rietveld, and ultrasonic methods. Phase analysis showed tetragonal and orthorhombic KNN phases, and a contamination of (K2CO3·1.5H2O) was present. The obtained KNN polycrystals had a relative density above 95%. Texturing of the material was confirmed as a result of hot pressing.

Interaction between Two Ni-Base Alloys and Ceramic Moulds

2013 ◽  
Vol 747-748 ◽  
pp. 765-771 ◽  
Author(s):  
Jian Sheng Yao ◽  
Ding Zhong Tang ◽  
Xiao Guang Liu ◽  
Cheng Bo Xiao ◽  
Xin Li ◽  
...  
Keyword(s):  
Solid Solution ◽  
Interface Reaction ◽  
Vapour Phase ◽  
Optical Microscope ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Reaction Surfaces

The interfacial reactions between ceramic moulds and DZ417G and DZ125 superalloys were investigated. The microstructure and composition of the interface region were observed by optical microscope, X-ray diffraction and scanning electron microscope with energy dispersive spectroscopy. The results showed that (Al1-xCrx)2O3solid solution phase with pink color was formed from the dissolution of Cr2O3and Al2O3and vapour phase, which was transferred to the reaction surfaces. The reaction layer thicknesses of DZ417G and DZ125 alloys were about in the range of 40-50μm. The interface reaction product between DZ417G alloy and ceramic mould was TiO2and the product between DZ125 alloy and ceramic mould was HfO2.

Effect of Synthesis Conditions and Actinide Contents on Phase Composition of Actinide Bearing Ceramics

2003 ◽  
Vol 807 ◽  
Author(s):  
A. G. Ptashkin ◽  
S. V. Stefanovsky ◽  
S. V. Yudintsev ◽  
S. A. Perevalov
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Phase Composition ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Reducing Conditions ◽  
Dispersive System ◽  
Scanning Electron

ABSTRACTPu-bearing zirconolite and pyrochlore based ceramics were prepared by melting under oxidizing and reducing conditions at 1550 °C. 239Pu content in the samples ranged between ∼10 and ∼50 wt.%. Phase composition of the ceramics and Pu partitioning were studied using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive system (SEM/EDS). Major phases in the samples were found to be the target zirconolite and pyrochlore as well as a cubic fluorite structure oxide. Normally the Pu content in the Pu host phases was 10–12 wt.%. This corresponds to the Pu content recommended for matrices for immobilization of excess weapons plutonium. At higher Pu content (up to 50 wt.%) additional phases, such as a PuO2-based cubic fluorite-structured solid solution, perovskite, and rutile were found.

Detection of Intermetallic Compounds in a Mg-5Al-3Ca-0.7Sr-0.2Mn Magnesium Alloy

2013 ◽  
Vol 197 ◽  
pp. 137-142 ◽  
Author(s):  
Tomasz Rzychoń ◽  
Janusz Szala ◽  
Tomasz Kukiełka
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Magnesium Alloy ◽  
Light Microscopy ◽  
Diffraction Analysis ◽  
Intermetallic Compounds ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

In this paper the results of microstructural investigations and methodology of detection of intermetallic compounds were reported. The microstructural investigations included the light microscopy, scanning electron microscopy, chemical microanalysis and X-ray diffraction analysis. It was found that the microstructure of Mg-5Al-3Ca-0.7Sr-0.2Mn alloy consists of α-Mg, (Mg,Al)2Ca, Al3Mg13(Sr,Ca), Mg2Ca and Al2Ca intermetallic phases. The correct detection of these phases requires the high magnifications and a large number of measurements fields.

Sign in / Sign up

Export Citation Format

Share Document