Sintering characteristics of Y–Ba–Cu–oxide–Agx superconductors

1999 ◽  
Vol 14 (11) ◽  
pp. 4148-4156 ◽  
Author(s):  
L. C. Pathak ◽  
S. K. Mishra ◽  
D. Bhattacharya ◽  
K. L. Chopra
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Weak Link ◽  
Sintering Atmosphere ◽  
X Ray ◽  
The Matrix ◽  
Apparent Activation Energies ◽  
Sintering Characteristics ◽  
Powder Compacts ◽  
Scanning Electron

The sintering characteristics of Y–Ba–Cu–oxide (YBCO)–Agx (x = 0 to 1.2) using thermomechanical analyzer were systematically investigated to understand the sintering mechanism of the metal superconductor composites. The addition of Ag was observed to lower the sintering temperatures, and the apparent densities of the sintered compacts increased with x from 0 to 0.6. A further increase of x above 0.6 decreased the apparent densities of the sintered compacts. The presence of Ag globules in the YBCO–Ag compacts was observed by scanning electron microscopy and energy dispersive x-ray spectroscopy. The apparent activation energies for sintering of the powder compacts were estimated and observed to vary between 900 to 2000 kJ/mol. The formation of AgOx by absorbing oxygen from YBCO and sintering atmosphere possibly controls the sintering and superconducting behavior. Incorporation of Ag into the matrix modifies the weak-link characteristics from superconductor–insulator– normal–superconductor (S–I–N–S) to superconductor–normal–superconductor (S–N–S) type.

Characteristics of Ni–Cr–Fe laser clad layers on EA4T steel

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744031
Author(s):  
Wenjing Chen ◽  
Hui Chen ◽  
Yongjing Wang ◽  
Congchen Li ◽  
Xiaoli Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cladding Layer ◽  
Metallurgical Bonding ◽  
The Matrix ◽  
Feeding Speed ◽  
Upper Bainite ◽  
Scanning Electron

The Ni–Cr–Fe metal powder was deposited on EA4T steel by laser cladding technology. The microstructure and chemical composition of the cladding layer were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The bonding ability between the cladding layer and the matrix was measured. The results showed that the bonding between the cladding layer and the EA4T steel was metallurgical bonding. The microstructure of cladding layer was composed of planar crystals, columnar crystals and dendrite, which consisted of Cr2Ni3, [Formula: see text] phase, M[Formula: see text]C6 and Ni3B phases. When the powder feeding speed reached 4 g/min, the upper bainite occurred in the heat affected zone (HAZ). Moreover, the tensile strength of the joint increased, while the yield strength and the ductility decreased.

scholarly journals The Influence of A Mo Addition on the Interfacial Morphologies and Corrosion Resistances of Novel Fe-Cr-B Alloys Immersed in Molten Aluminum

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Zicheng Ling ◽  
Weiping Chen ◽  
Weiye Xu ◽  
Xianman Zhang ◽  
Tiwen Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Probe ◽  
Molten Aluminum ◽  
Dendritic Structure ◽  
H13 Steel ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The influence of a Mo addition on the interfacial morphologies and corrosion resistances of novel Fe-Cr-B alloys in molten aluminum at 750 °C was systematically investigated using scanning electron microscopy, X-ray diffractometer, electron probe microanalysis, and transmission electron microscopy. The results indicated that Mo could not only strengthen the matrix but also facilitate the formation of borides. Furthermore, the microstructures of Mo-rich M2B boride changed from a local eutectic net-like structure to a typical coarse dendritic structure and a blocky hypereutectic structure with increasing Mo addition. This was true of the blocky Mo-rich M2B boride, rod-like Cr-rich M2B boride and the corrosion products, which had a synergistic effect on retarding of the diffusion of molten aluminum. Notably, the corrosion resistance of the Fe-Cr-B-Mo alloy, with an 8.3 wt.% Mo addition, was 3.8 times higher than that of H13 steel.

Effects of Reductive Conditions on the Electrochemical Properties of LiFePO4/C Derived by Fe3+ Sources

2014 ◽  
Vol 1081 ◽  
pp. 313-317
Author(s):  
Yan Wen Lu ◽  
Yu Ge ◽  
Yue Feng Tang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raw Materials ◽  
Thermal Method ◽  
X Ray Diffraction ◽  
Sintering Atmosphere ◽  
X Ray ◽  
Electrochemical Capacity ◽  
One Step ◽  
Scanning Electron

A one-step carbon thermal method was used to prepare LiFePO4/C particles by using normal Fe2O3, LiH2PO4and sucrose as raw materials. The effect of H2content in the sintering atmosphere of N2on the morphology and the electrochemical performance were investigated. LiFePO4/C materials were characterized by X-ray diffraction, scanning electron microscopy and the elemental analyzer. The results show that the precursor sintering under the atmosphere of 8%H2+N2exhibits the highest electrochemical capacity (162.3 mAh/g at 0.1C) .

Preparation and Photoluminescent Properties of Polystyrene Encapsulated SrAl2O4:Eu2+,Dy3+ Nanocrystals

2013 ◽  
Vol 538 ◽  
pp. 197-200 ◽  
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Properties ◽  
Phase Morphology ◽  
X Ray ◽  
Weight Percentage ◽  
Deep Blue ◽  
The Matrix ◽  
Pl Spectrum ◽  
Scanning Electron

Polystyrene encapsulated phosphors SrAl2O4:Eu2+,Dy3+ were prepared by dispersing the phosphors into the matrix of polystyrene. The phase, morphology and optical properties of the polystyrene encapsulated phosphors were characterized with X-ray diffractometry, scanning electron microscopy and photoluminescence (PL) spectroscopy, respectively. It has been observed that both the PL spectrum and the luminescent color of the polystyrene encapsulated phosphors can be dramatically modified although the phosphorescence of the polystyrene encapsulated phosphors is not affected. Tunable photoluminescent colors from green to deep-blue are expected for the polystyrene encapsulated phosphors by the control of the weight percentage of the phosphors in the composites.

scholarly journals Magnetic nanowires (Fe, Fe-Co, Fe-Ni) – magnetic moment reorientation in respect of wires composition

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Beata Kalska-Szostko ◽  
Urszula Wykowska ◽  
Dariusz Satuła
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Strong Dependence ◽  
Magnetic Nanowires ◽  
Deposition Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ni Alloy ◽  
The Matrix ◽  
Scanning Electron

Abstract Magnetic nanowires of Fe, Fe-Co, and Fe-Ni alloy and layered structure were prepared by electrochemical alternating current (AC) deposition method. The morphology of the nanowires in and without the matrix was studied by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. The wires either show strong dependence on the combination of elements deposition (alloy or layered) or chemical composition (Co or Ni). The magnetic properties of the nanostructures were determined on the basis of Mössbauer spectroscopy (MS).

Effect of Ca on Microstructure and Properties of Mg-Al-Si Alloys

2011 ◽  
Vol 194-196 ◽  
pp. 1369-1373 ◽  
Author(s):  
Chun Xiang Xu ◽  
Hui Ju ◽  
Yang Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Chinese Script ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ca Addition ◽  
The Matrix ◽  
Morphology Modification ◽  
Scanning Electron

Effect of Ca addition on the morphology modification in Mg-7Al-0.8Zn-0.2Mn-1Si (AS71) alloys has been investigated using X-ray diffraction (XRD), optical microscopy (OM), and scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and various testing machines. The results show that when adding 0.1 wt% Ca, a small fraction of Mg2Si change from Chinese script type to polygonal type; with the Ca addition up to 0.3 wt%, edges and angles of polygonal type Mg2Si phase are changed; further increase in Ca addition, the morphology of Mg2Si is changed to strip-like or spot-like one. Meanwhile, the addition of Ca results in the morphology of β- Mg17Al12 phase changing from discontinuous net-like to dispersive island-like. Ca exists as solid-soluting atomic in the matrix with small Ca addition while in the form of CaSi2 with large Ca addition. Optimal mechanical properties can be achieved when Ca addition is 0.3 wt%.

scholarly journals Structure Analysis and Properties of Unleaded Brasses

2015 ◽  
Vol 60 (1) ◽  
pp. 323-328 ◽  
Author(s):  
S. Rzadkosz ◽  
J. Kozana ◽  
A. Garbacz-Klempka ◽  
M. Piękoś
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Structure Analysis ◽  
Structure And Properties ◽  
X Ray ◽  
Ecological Characteristics ◽  
The Matrix ◽  
Scanning Electron

Abstract The analysis of brasses regarding their microstructure, mechanical properties and ecological characteristics has been presented. The influence of characteristic alloying elements contained in the brasses and the possibilities of replacing them with other elements have been assessed. The paper contains the results of studies on the influence of chosen additional elements shaping the structure and properties of unleaded alloys based on Cu-Zn system as the matrix. The research aimed at determining the mechanism and the intensity of influence of such additives as tellurium and bismuth. The microstructures were investigated with the help of light microscopy and scanning electron microscopy with X-ray microanalysis (SEM-EDS) for determining significant changes of the properties.

Intermetallic Particles-Induced Pitting Corrosion in 6061-T651 Aluminium Alloy

2011 ◽  
Vol 690 ◽  
pp. 389-392 ◽  
Author(s):  
Kalenda Mutombo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminium Alloy ◽  
Pitting Corrosion ◽  
Chloride Solution ◽  
Nacl Solution ◽  
X Ray ◽  
Intermetallic Particles ◽  
The Matrix ◽  
Scanning Electron

The polished 6061-T651 aluminium alloy was immersed in 3.5% NaCl solution with about 7 ppm dissolved oxygen. Scanning Electron Microscopy equipped with Energy dispersive X-ray Spectroscopy revealed the presence of Al-Si-Fe-containing particles that acted as cathodic sites and promoted the matrix dissolution. The effect of pH and chloride solution is assessed.

Synthesis and Study of 239Pu-Doped Ceramics Based on Zircon, (Zr,Pu)Sio4, and Hafnon, (Hf,Pu)SiO4

2000 ◽  
Vol 663 ◽  
Author(s):  
B.E. Burakov ◽  
E.B. Anderson ◽  
M.V. Zamoryanskay ◽  
M.A. Yagovkina ◽  
E.E. Strykanova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pressing Method ◽  
Optimal Amount ◽  
X Ray ◽  
Mass Losses ◽  
Ceramic Samples ◽  
The Matrix ◽  
Order Of Magnitude ◽  
Scanning Electron

ABSTRACTZircon, ZrSiO4, as well as its Hf-analogue hafnon, HfSiO4, have been proposed for use as durable Pu host phases for the immobilization of weapons grade Pu and other actinides. Four samples of Pu-doped ceramics based on the zircon and hafnon structures were synthesized through sintering in air using precursors containing 5-6 and 10 wt% 239Pu. Synthesized ceramic samples were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), microprobe method, MCC-1 leach test at 25 and 90°C. Inclusions of separated a PuO2phase in the matrix of zircon-based ceramic and presumably, (Pu,Hf)O2 phase in the hafnon-based ceramic were observed for samples obtained from precursors doped with 10 wt% Pu. No separated Pu-phases in significant amounts were identified in the matrices of both ceramics obtained from the precursors doped with 5-6 wt% Pu. It was found that normalized Pu mass losses (without correction on ceramic porosity) for samples doped with 10 wt% Pu which contain separated inclusions of PuO2 or (Pu,Hf)O2 after 14/28 days were approximately (in g/m2) - for zircon: 0.2/0.2 - at 90°C and 0.03/0.04 - at 25°C and for hafnon: 0.02/0.04 - at 90°C and 0.01/0.01 - at 25°C. The losses of Pu from samples doped with 5-6 wt% are 1-2 order of magnitude less. It was suggested that optimal amount of Pu which could be incorporated by zircon and hafnon lattices does not exceed 7 wt%. An important additional conclusion is that Pu- doped ceramic based on zircon or hafnon can be successfully fabricated excluding hot pressing method.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

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