Effect of Pressure Carbonization in Carbon/Carbon Composite Process (II)

1991 ◽  
Vol 251 ◽  
Author(s):  
H. Okamoto ◽  
T. Hosomura ◽  
K. Kosaka
Keyword(s):  
Iron Powder ◽  
Phenolic Resin ◽  
Carbon Composite ◽  
X Ray Diffraction ◽  
Micro Structure ◽  
Carbon Yield ◽  
X Ray ◽  
Effect Of Pressure ◽  
Heat Treated ◽  
Powder Addition

ABSTRACTWe have found that pressurized carbonization cause the increase of carbon yield and the improvement of micro structure In the case of pitch resin. While the effects of pressurized carbonization on phenolic resin are not obvious.In this study, carbonization and graphitization characteristics of phenolic resin were investigated experimentally. Phenolic resin specimens with and without iron powder addition were carbonized at the temperature of 650 °C under the pressure of atmospheric or 100MPa. Then each of them was heat-treated at the temperature of 1200, 1500 and 1900 °C respectively. Measurement of yield, density, x-ray diffraction and optical observation were carried out in the experiments. It is indicated from those results that pressurized carbonization of phenolic resin makes graphite crystallization progress and this effect is promoted by addition of iron powder.

A New Structural Model for Nongraphitic Carbons

1998 ◽  
Vol 31 (6) ◽  
pp. 910-916 ◽  
Author(s):  
Hideto Azuma
Keyword(s):  
Phenolic Resin ◽  
Structural Model ◽  
Nearest Neighbour ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
Diffraction Profile ◽  
X Ray ◽  
Heat Treated ◽  
Stacking Structure ◽  
Neighbour Interaction

A structural analysis using a new, simple model describing the stacking structure of nongraphitic carbons is presented. The model is based on the idea that there is only a nearest-neighbour interaction between carbon layers. The nearest-neighbour interaction is described by the distribution of interlayer dist-ances, which, assuming a linear conjugate of two independent Gaussian distributions, gives a good fit to the obtained X-ray diffraction profile of carbon. This model is applied to a heat-treated series of nongraphitizing carbons from phenolic resin. The result shows that the average interlayer distances are about 0.4 nm. The model allows the diffraction intensity from carbon layers and the scattering intensity due to the porous structure of the carbon samples to be differentiated.

Basic Properties of Woodceramics Made from Furane Resin/Bamboo Powder Composite

2010 ◽  
Vol 160-162 ◽  
pp. 1569-1574 ◽  
Author(s):  
Wei Hong Zhou ◽  
Yun Shui Yu ◽  
Xue Liang Xiong
Keyword(s):  
Electrical Resistivity ◽  
Apparent Density ◽  
Carbon Composite ◽  
Yield Ratio ◽  
Phase Identification ◽  
Strength Increase ◽  
X Ray Diffraction ◽  
Carbon Yield ◽  
X Ray ◽  
Bamboo Powder

A new woodceramics was developed by furane resin and bamboo powder. Microstructures and phase identification of woodceramics were performed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). The effect of content of furane resin on carbon yield ratio，dimension shrinkage，apparent density，comprehensive strength and volume electrical resistivity of woodceramics were investigated. The results show that the woodceramics is a kind of carbon/carbon composite composed by bamboo charcoal and glassy carbon, content of furane resin has a significant effect on the microstructure of woodceramics, but has a slight effect on the crystallinity of woodceramics. The carbon yield ratio, apparent density and comprehensive strength increase, and the dimension shrinkage and volume electrical resistivity decrease as the content of furane resin increases.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

scholarly journals Synthesis and Characterization of Lithium-Ion Conductive LATP-LaPO4 Composites Using La2O3 Nano-Powder

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3502
Author(s):  
Fangzhou Song ◽  
Masayoshi Uematsu ◽  
Takeshi Yabutsuka ◽  
Takeshi Yao ◽  
Shigeomi Takai
Keyword(s):  
Room Temperature ◽  
Conduction Mechanism ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Nano Powder ◽  
Powder Addition

LATP-based composite electrolytes were prepared by sintering the mixtures of LATP precursor and La2O3 nano-powder. Powder X-ray diffraction and scanning electron microscopy suggest that La2O3 can react with LATP during sintering to form fine LaPO4 particles that are dispersed in the LATP matrix. The room temperature conductivity initially increases with La2O3 nano-powder addition showing the maximum of 0.69 mS∙cm−1 at 6 wt.%, above which, conductivity decreases with the introduction of La2O3. The activation energy of conductivity is not largely varied with the La2O3 content, suggesting that the conduction mechanism is essentially preserved despite LaPO4 dispersion. In comparison with the previously reported LATP-LLTO system, although some unidentified impurity slightly reduces the conductivity maximum, the fine dispersion of LaPO4 particles can be achieved in the LATP–La2O3 system.

Investigations of Actinide Metals and Compounds under Pressure Provide Important Insights into Bonding and Chemistry

2003 ◽  
Vol 802 ◽  
Author(s):  
R. G. Haire ◽  
S. Heathman ◽  
T. Le Bihan ◽  
A. Lindbaum ◽  
M. Iridi
Keyword(s):  
Structural Changes ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Interatomic Distances ◽  
X Ray ◽  
Effect Of Pressure ◽  
Electronic Configurations ◽  
5F Electrons ◽  
Actinide Series ◽  
Alloys And Compounds

ABSTRACTOne effect of pressure on elements and compounds is to decease their interatomic distances, which can bring about dramatic perturbations in their electronic nature and bonding, which can be reflected in changes in physical and/or chemical properties. One important issue in the actinide series of elements is the effect of pressure on the 5f-electrons. We have probed changes in electronic behavior with pressure by monitoring structure by X-ray diffraction, and have studied several actinide metals and compounds from thorium through einsteinium. These studies have employed angle dispersive diffraction using synchrotron radiation, and energy dispersive techniques via conventional X-ray sources. The 5f-electrons of actinide metals and their alloys are often affected significantly by pressure, while with compounds, the structural changes are often not linked to the involvement of 5 f-electron. We shall present some of our more recent findings from studies of selected actinide metals, alloys and compounds under pressure. A discussion of the results in terms of the changes in electronic configurations and bonding with regard to the element's position in the series is also addressed.

PREPARATION OF ANTIMONY-PLATINUM SURFACE ALLOY ELECTRODE BY ATOM DIFFUSION IN THE SOLID PHASE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3999-4004
Author(s):  
HIROSHI MATSUI ◽  
KAZUFUMI WATANABE
Keyword(s):  
Diffraction Pattern ◽  
Low Temperatures ◽  
Solid Phase ◽  
Electrochemical Measurement ◽  
X Ray Diffraction ◽  
Platinum Surface ◽  
X Ray ◽  
Atom Diffusion ◽  
Heat Treated ◽  
Titanium Substrates

Antimony-platinum bilayers were prepared on titanium substrates by the two-step electrodeposition in the usual baths, and then surface alloys were formed by the atom diffusion in the solid phase. The simple antimony layer was little influenced by the substrate in both the measurements of X-ray diffraction and the i - E characteristic in a sulfuric acid solution. Regarding the bilayers, the catalytic activity in hydrogen evolution reaction was very sensitive to the presence of platinum, while the hydrogen adsorbability was quite insensitive. An interaction between antimony and platinum was confirmed by the appearance of a new dissolution wave in the electrochemical measurement and the occurrence of a new diffraction in the X-ray diffraction pattern after the heat-treatment of about 400°C. Although the new diffraction disagreed with any of the reported alloys, clear diffraction pattern of PtSb 2 alloy was observed, when the bilayers were heat-treated at about 600°C for one hour. Considering the penetration depth of X-ray, the alloying of antimony and platinum seems to occur also at low temperatures at least at the top surface.

Hardening of Selective Laser Melted M2 Steel

2021 ◽  
Author(s):  
Mei Yang ◽  
Yishu Zhang ◽  
Haoxing You ◽  
Richard Smith ◽  
Richard D. Sisson
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
Cutting Tools ◽  
High Speed Steel ◽  
High Hardness ◽  
Steel Part ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Near Net Shape

Abstract Selective laser melting (SLM) is an additive manufacturing technique that can be used to make the near-net-shape metal parts. M2 is a high-speed steel widely used in cutting tools, which is due to its high hardness of this steel. Conventionally, the hardening heat treatment process, including quenching and tempering, is conducted to achieve the high hardness for M2 wrought parts. It was debated if the hardening is needed for additively manufactured M2 parts. In the present work, the M2 steel part is fabricated by SLM. It is found that the hardness of as-fabricated M2 SLM parts is much lower than the hardened M2 wrought parts. The characterization was conducted including X-ray diffraction (XRD), optical microscopy, Scanning Electron Microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to investigate the microstructure evolution of as-fabricated, quenched, and tempered M2 SLM part. The M2 wrought part was heat-treated simultaneously with the SLM part for comparison. It was found the hardness of M2 SLM part after heat treatment is increased and comparable to the wrought part. Both quenched and tempered M2 SLM and wrought parts have the same microstructure, while the size of the carbides in the wrought part is larger than that in the SLM part.

scholarly journals Effect of pressure on a mixed valence FeiiFeiii2complex

2014 ◽  
Vol 70 (a1) ◽  
pp. C901-C901
Author(s):  
Solveig Madsen ◽  
Jacob Overgaard ◽  
Bo Iversen
Keyword(s):  
Phase Transition ◽  
Hydrogen Bond ◽  
Mixed Valence ◽  
Hydrogen Bond Network ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Pressure ◽  
Bond Network ◽  
Fe Sites ◽  
Cyano Groups

Intramolecular electron transfer (ET) in mixed valence (MV) oxo-centered [FeiiFeiii2O(carboxylate)6(ligand)3]·solvent complexes is highly dependent on temperature, on the nature of the ligands, and on the presence of crystal solvent molecules [1]. Whereas the effects of temperature, crystal solvent, and ligand variation on the details of the ET have been explored thoroughly, the effect of pressure is less well described [2]. The effect of pressure on the ET in MV Fe3O(cyanoacetate)6(water)3has been investigated with single crystal X-ray diffraction and Mössbauer spectroscopy. Previous multi-temperature studies have shown that at room temperature the ET between the three Fe sites is fast and the observed structure of the Fe3core is a perfectly equilateral triangle [3]. Cooling the complex below 130 K induces a phase transition as the ET slows down. Below 120 K the Fe3core is distorted due to the localization of the itinerant electron on one of the three Fe sites in the triangle (the complex is then in the valence trapped state). The valence trapping is complete within a temperature interval of just 10 K. The abruptness of the transition has been attributed to the extended hydrogen bond network involving water ligands and cyano groups, promoting intermolecular cooperative effects. The high-pressure X-ray diffraction data show that there is a 900flip of half the cyano groups at 3.5 GPa, which dramatically changes the hydrogen bond network. At a slightly higher pressure, a phase transition is found to occur. The five single crystals investigated all broke into minor fragments at the transition; however triclinic unit cells, similar to the low temperature unit cell, could be indexed from selected spots. Additional evidence that the complex is valence trapped comes from high pressure Mössbauer spectra measured above the phase transition (4 GPa). The relationship between valence trapping and the structural changes will in this work be highlighted using void space and Hirshfeld surface analysis.

scholarly journals Pengaruh Suhu Kalsinasi terhadap Karakteristik Komposit Forsterit-Karbon Tersintesis dalam Medium Gas Argon

2020 ◽  
Vol 16 (2) ◽  
pp. 12
Author(s):  
Solihudin Solihudin ◽  
Haryono Haryono ◽  
Atiek Rostika Noviyanti ◽  
Muhammad Rizky Ridwansyah
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Rice Husk ◽  
Energy Dispersive Spectroscopy ◽  
Carbon Composite ◽  
X Ray Diffraction ◽  
Argon Gas ◽  
X Ray ◽  
Scanning Electron

<p>Komposit forsterit-karbon merupakan salah satu material modifikasi dari forsterit yang berpotensi memiliki sifat isolator panas baik. Karbon dalam komposit dapat mengisi cacat titik pada kristal forsterit. Arang sekam padi (residu gasifikasi) mengandung SiO2 amorf dan karbon yang tinggi. Penelitian ini bertujuan menentukan pengaruh suhu kalsinasi dalam medium gas inert (dengan pengaliran gas argon) terhadap karakteristik komposit forsterit-karbon dari arang sekam padi dan magnesium karbonat. Metode penelitian meliputi preparasi arang sekam padi hasil gasifikasi, dan sintesis forsterit-karbon. Proses sintesis komposit forsterit karbon dilakukan dengan cara mencampurkan arang sekam padi dengan kalium karbonat pada rasio mol magmesium terhadap silikon sebesar 2 : 1 kemudian dikalsinasi dengan suhu divariasikan (700, 800, 900, dan 1000 oC). Selanjutnya sampel hasil sintesis dikarakterisasi dengan Fourier-transform infrared (FTIR), X-ray diffraction (XRD), dan scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). Hasil karakterisasi dengan FTIR dan XRD diperoleh kesimpulan bahwa forsterit mulai terbentuk pada suhu kalisiasi 800 oC dan sempurna pada suhu 1000 oC, karenanya komposit yang terbentuk pada 1000 oC dimungkinkan sebagai forsterit-karbon, di mana unsur-unsur yang terkandung ditunjukkan oleh SEM-EDS.</p><p> </p><p><strong>The Effect of Calcination Temperature on the Characteristics of Forsterite-Carbon Composites Synthesized in Argon Gas Medium</strong>. Forsterite-carbon composite is one of the material modifications of forsterite, which potentially has a good heat insulation property. Carbon in composites can fill point defects in forsterite crystals. Rice husk charcoal, as gasification residues, contains high amorphous SiO2 and carbon. This study aims to determine the effect of temperature on the calcination of a mixture of rice husk charcoal and magnesium carbonate under an inert gas (argon gas) on the characteristics of the forsterite-carbon composite produced. The experimental research performed includes the preparation of gasified rice husk charcoal and the synthesis of the carbon-forsterite composite. The synthesis process of the carbon-forsterite composites was carried out by mixing rice husk charcoal with potassium carbonate at a mole ratio of magnesium to silicon of 2 : 1. The mixture was then calcined with varying temperatures (700, 800, 900, and 1000 °C). Furthermore, the synthesized sample was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The FTIR and XRD analysis show that the forsterites began to form at a calcination temperature of 800 °C and perfectly formed at a temperature of 1000 °C; therefore, the composite formed at 1000 °C is possible as forsterite-carbon, in which the contained elements were indicated by SEM-EDS.</p>

scholarly journals Construction and Mechanism of Bacterial Cellulose With High Carbon Yield By a Stretching Orientation Method

2021 ◽  
Author(s):  
Wenjing Jiang ◽  
Zhenlin Jiang ◽  
Xin Fan ◽  
Min Zhu
Keyword(s):  
Bacterial Cellulose ◽  
Low Cost ◽  
X Ray Diffraction ◽  
High Carbon ◽  
Carbon Yield ◽  
X Ray ◽  
Graphitization Degree ◽  
Low Field ◽  
Orientation Method ◽  
Environmentally Friendly Method

Abstract Bacterial cellulose (BC)decomposes easily and the carbon residue rate is low. These factors critically restrict its application in fabricating cellulosic carbon materials. Therefore, in this paper, a simple and facile method to improve the BC carbon yield is proposed based on the stretching orientation of BC. By controlling the degree of BC deformation, the orientation and crystallinity of the BC can be adjusted, thereby sensitively affecting the graphitization degree and carbon yield of carbonized BC. Samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Raman scattering, and low-field nuclear magnetic resonance (LNMR). The results indicated that when the pre-stretched strain was 40%, the crystallinity and graphitization degree of BC improved, and the carbon yield increased significantly in comparison to that of untreated BC. Thus, a low-cost, facile, and environmentally friendly method of increasing the carbon yield of BC was developed in this study.

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