Lateral Diffusion of Platinum Through Pt2Si in Pt/Si Couples

1982 ◽  
Vol 18 ◽  
Author(s):  
L. R. Zheng ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Electron Microprobe ◽  
Lateral Diffusion ◽  
Square Root ◽  
Diffusion Couples ◽  
X Ray ◽  
Temperature Range ◽  
Scanning Electron

Lateral diffusion couples formed by depositing platinum islands on silicon layers on Al2O3 were used in conjunction with scanning electron microprobe measurements to investigate the growth of platinum silicides in the temperature range 400–700 °C. The phase Pt2Si grows over a length of 4–30 μm with a rate proportional to the square root of time and an activation energy of approximately 1.3 eV. With samples containing 7 at.% Rh in the platinum, the growth rate of Pt2Si is reduced and the activation energy is increased to about 2.0 eV. In these Pt–7at.% Rh samples, electron-induced X-ray measurements indicate that rhodium remains in the original deposited region while both platinum and silicon diffuse in the formed Pt2Si region.

scholarly journals Chemical Stability of Ti3C2 MXene with Al in the Temperature Range 500–700 °C

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1979 ◽  
Author(s):  
Jing Zhang ◽  
Shibo Li ◽  
Shujun Hu ◽  
Yang Zhou
Keyword(s):  
Electron Microscopy ◽  
Chemical Stability ◽  
Metal Matrix ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Transmission Electron ◽  
Work First ◽  
Scanning Electron

Ti3C2Tx MXene, a new 2D nanosheet material, is expected to be an attractive reinforcement of metal matrix composites because its surfaces are terminated with Ti and/or functional groups of –OH, –O, and –F which improve its wettability with metals. Thus, new Ti3C2Tx/Al composites with strong interfaces and novel properties are desired. To prepare such composites, the chemical stability of Ti3C2Tx with Al at high temperatures should be investigated. This work first reports on the chemical stability of Ti3C2Tx MXene with Al in the temperature range 500–700 °C. Ti3C2Tx is thermally stable with Al at temperatures below 700 °C, but it reacts with Al to form Al3Ti and TiC at temperatures above 700 °C. The chemical stability and microstructure of the Ti3C2Tx/Al samples were investigated by differential scanning calorimeter, X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy.

Electron microprobe analyses of salt distribution in the halophyte Salicornia pacifica var. utahensis

1977 ◽  
Vol 55 (11) ◽  
pp. 1516-1523 ◽  
Author(s):  
D. J. Weber ◽  
H. P. Rasmussen ◽  
W. M. Hess
Keyword(s):  
Electron Microprobe ◽  
High Salt ◽  
Leaf Section ◽  
X Ray ◽  
Salt Ions ◽  
Palisade Cells ◽  
Salt Distribution ◽  
Photosynthetic Cells ◽  
Scanning Electron ◽  
Vascular Region

The halophyte Salicornia pacifica var. utahensis grows in the desert saline playa. The fused leaves form succulent stems and have apparently isolated tracheids in the palisade region as observed by scanning electron microscopy. Frozen shoots were fractured under liquid nitrogen and scanned for Na+, K+, and Cl− with an electron microprobe X-ray analyzer. In young shoots, the palisade cells were low in salts, and the spongy cells had higher concentrations. The salt in the spongy cells provides a high osmotic pressure permitting the plant to absorb more water from the soil. As the shoots matured, the concentration of salts increased in the spongy cells, and the amount of salt in the palisades also increased. The salt ions in the palisades were excluded from the organelles and were mainly present in the vacuoles. Eventually, the leaf section collapsed because of the high salt in the palisade and spongy cells, but the vascular region in the shriveled section continued to function. The sections adjacent to the dead shriveled section remained green and succulent. The salt tolerance appeared to be based on the exclusion of the salt from the photosynthetic cells and on the ability of the succulent stem to function even though sections were dead owing to high salt concentration.

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 .

Chemical Interaction of Phosphates MII2P4O12 with Melted MICl or MINO3 (MI – Li, Na, K; MII – Mg, Co, Ni, Zn)

2015 ◽  
Vol 230 ◽  
pp. 297-302 ◽  
Author(s):  
Oksana V. Livitska ◽  
Nataliya Yu. Strutynska ◽  
Igor V. Zatovsky ◽  
Nikolay S. Slobodyanik
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ftir Spectroscopy ◽  
Powder Diffraction ◽  
Diffuse Reflectance ◽  
Chemical Interaction ◽  
Crystalline Phases ◽  
X Ray ◽  
Temperature Range ◽  
Scanning Electron

The interaction in the systemsMII2P4O12-MICl (MINO3) (MI– Li, Na, K;MII– Mg, Co, Ni, Zn) was investigated in temperature range 1073-673 K. The conditions of formation phosphates: Li3PO4,MIMIIPO4(MI– Na, K), Na4MII3(PO4)2P2O7, Na9Co3(PO4)5have been established. Obtained crystalline phases have been investigated using X-ray powder diffraction, Diffuse reflectance, Raman and FTIR spectroscopy and scanning electron microscopy methods.

Ge Diffusion in SnTe Crystal

1998 ◽  
Vol 527 ◽  
Author(s):  
O.E. Kaportseva ◽  
L.V. Yashina ◽  
V.B. Bobruiko ◽  
D.V. Safonov ◽  
V.F. Kozlovsky ◽  
...  
Keyword(s):  
Activation Energy ◽  
Lattice Constant ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Layer By Layer ◽  
X Ray ◽  
Temperature Range

ABSTRACTThis work is devoted to the study of Ge diffusion in crystalline Sn1-δTe1+8 with δ=0.0065±0.0008 in temperature range T=878-973 K by electron probe microanalysis and layer by layer X-ray analysis. For the latter lattice constant dependence on composition was determined: a(Å)=a(SnTe)-(0.368±0.008)× where 0<×<0. 1. Activation energy was found to be about 1.3 eV, much less than in the case of Ge diffusion in PbTe.

ADDITION OF ETHYL RADICALS TO ETHYLENE

1957 ◽  
Vol 35 (7) ◽  
pp. 588-594 ◽  
Author(s):  
J. A. Pinder ◽  
D. J. Le Roy
Keyword(s):  
Activation Energy ◽  
Reaction Zone ◽  
Addition Reaction ◽  
Steric Factor ◽  
Square Root ◽  
Temperature Range ◽  
Ethyl Radical ◽  
Ethyl Radicals

The addition of ethyl radicals to ethylene has been studied in the temperature range 58° to 123 °C. The radicals were produced by the mercury photosensitized decomposition of hydrogen in the presence of ethylene, and the rate of the addition reaction was measured in terms of the rate of formation of n-hexane by the combination of ethyl and butyl radicals. Corrections were made for the non-uniformity of radical concentrations in the reaction zone. Assuming a negligible activation energy for the combination of two ethyl radicals, the activation energy for the addition reaction is 5.5 kcal. per mole; the steric factor, relative to the square root of the steric factor for ethyl radical combination, is 5.0 × 10−5.

scholarly journals An XRD, SEM and TG study of a uranopilite from Australia

2006 ◽  
Vol 70 (3) ◽  
pp. 299-307 ◽  
Author(s):  
R.L. Frost ◽  
M.L. Weier ◽  
G.A. Ayoko ◽  
W. Martens ◽  
J. Čejka
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Northern Territory ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Evolved Gas ◽  
X Ray ◽  
Temperature Range ◽  
Step Over ◽  
Scanning Electron

AbstractA uranopilite from The South Alligator River, Northern Territory, Australia, has been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) with EDAX attachment, and thermogravimetry in conjunction with evolved gas mass spectrometry. The XRD shows that the mineral is a pure uranopilite with few if any impurities. The SEM images show that the uranopilite consists of elongated crystals, up to 50μm long and 5 μm wide. Thermogravimetry combined with mass spectrometry shows that dehydration occurs at ∼31°C resulting in the formation of metauranopilite. The first dehydration step over 20–71°C corresponds to a decrease of 5.4 wt.%, equivalent to 6.076 H2O. The second dehydration step, over the temperature range 71 –162.4°C corresponds to a decrease of 4.7 wt.%, equivalent to 5.288 H2O, making a total of 11.364 moles of H2O, close to 12 H2O for uranopilite.Dehydroxylation takes place over the temperature range 80–160°C. The loss of sulphate occurs at higher temperatures in two steps at 622 and 636°C. A mass loss also occurs at 755°C, accounted for by evolved oxygen.

Metallography and Corrosion Product Studies on Archaeological Bronze Fragments from the Qu Cun Site

1996 ◽  
Vol 462 ◽  
Author(s):  
W. T. Chase ◽  
Quanyu Wang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Corrosion Product ◽  
Electron Microprobe ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Western Zhou ◽  
Future Work ◽  
Scanning Electron

ABSTRACTThe authors studied a suite of fragments of corroded bronzes from the Tienma-Qu Cun site, a Western Zhou city and cemetery complex dating from ca. 1000 to ca. 650 B.C‥ Conventional metallographic techniques were used along with scanning electron microscope, electron microprobe and x-ray diffraction. The bronzes are very varied in structure and composition. Most are cast, moderate-tin bronzes, but some are high or low in tin or lead. A few show a worked and annealed structure, and some of the cast bronzes were also heat treated (possibly by use as cooking pots). corrosion patterns also vary greatly, from almost uncorroded to total mineralization. Periodic and esquential corrosion phenomena were detected, as well as patination applied when the bronzes were made. We had hoped to be able to ascertain the causes of the different penetration of corrosion in these samples, but that must remain for future work.

Elektrotransportversuche mit epitaktischen Goldschichten

1979 ◽  
Vol 34 (10) ◽  
pp. 1196-1202
Author(s):  
W. Kleinn ◽  
H. Hübner
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Electron Microscope ◽  
Temperature Gradient ◽  
Transmission Electron Microscope ◽  
Direct Current ◽  
Gold Films ◽  
Temperature Range ◽  
Transmission Electron ◽  
Current Densities

Abstract Electrotransport Experiments with Epitaxial Gold Films Electrotransport in gold films of 60 nm thickness grown epitaxially onto hot (100) NaCl substrate is determined from the growth rate of voids forming in the temperature gradient in short specimens observed in the transmission electron microscope while loaded with direct current densities of several 106 A/cm2 . For the temperature range 631 -1214 K an activation energy (1,19 ± 0,05) eV is found.

A Combined Scanning Electron Microscope/Electron Microprobe Analyzer

1968 ◽  
Vol 26 ◽  
pp. 368-369
Author(s):  
V.G. Macres ◽  
O. Preston ◽  
N.C. Yew ◽  
R. Buchanan
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Microprobe ◽  
High Performance ◽  
Electron Gun ◽  
Objective Lens ◽  
Condenser Lens ◽  
X Ray ◽  
Low X ◽  
Scanning Electron

The instrument described here is the Materials Analysis Company Model 400S combined scanning electron microscope/electron micro-probe analyzer. It was designed specifically to incorporate the most advanced features of a high performance electron microprobe analyzer with those of a medium resolution (1000A°) scanning electron microscope. The high effective x-ray take-off angle of the instrument (38.5°) offers low x-ray absorption, and thus allows the analysis of fairly rough specimens. The large depth of focus of the scanned electron images further enhances the capability of examining rough specimens.The electron-optical column comprises a triode electron gun, double condenser lens and objective lens. The electron gun uses a conventional hairpin filament, autobiased Wehnelt cylinder and anode. An externally controlled filament/Wehnelt cylinder height adjustment is provided for optimizing gun performance at all operating potentials. The double condenser lens is unitized and has two lens regions and a common energizing coil.

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