Creation of an Icephobic Coating using Graphite Powder and PTFE Nanoparticles

2019 ◽  
Author(s):  
Joseph Gonzales ◽  
Hirotaka Sakaue
Keyword(s):  
Graphite Powder ◽  
Ptfe Nanoparticles

Employing Exfoliated Graphite as Novel Support Material for Heterogeneous Model Catalysts

2019 ◽  
Author(s):  
Moritz Wolf ◽  
Nico Fischer ◽  
Michael Claeys
Keyword(s):  
Surface Area ◽  
Graphite Powder ◽  
Model Catalysts ◽  
Model Systems ◽  
Exfoliated Graphite ◽  
Support Material ◽  
Heterogeneous Model ◽  
Support Materials ◽  
Metal Support Interaction ◽  
Catalyst Systems

<p>The inert nature of graphitic samples allows for characterisation of rather isolated supported nanoparticles in model catalysts, as long as sufficiently large inter-particle distances are obtained. However, the low surface area of graphite and the little interaction with nanoparticles result in a challenging application of conventional preparation routes in practice. In the present study, a set of graphitic carbon materials was characterised in order to identify potential support materials for the preparation of model catalyst systems. Various sizes of well-defined Co<sub>3</sub>O<sub>4</sub> nanoparticles were synthesised separately and supported onto exfoliated graphite powder, that is graphite after solvent-assisted exfoliation <i>via</i> ultrasonication resulting in thinner flakes with increased specific surface area. The developed model catalysts are ideally suited for sintering studies of isolated nano-sized cobaltous particles as the graphitic support material does not provide distinct metal-support interaction. Furthermore, the differently sized cobaltous particles in the various model systems render possible studies on structural dependencies of activity, selectivity, and deactivation in cobalt oxide or cobalt catalysed reactions.</p>

Dc arc emission analysis of rare earth metals and their oxides with sorption preconcentration of impurities

2018 ◽  
Vol 84 (11) ◽  
pp. 9-14
Author(s):  
E. S. Koshel ◽  
V. B. Baranovskaya ◽  
M. S. Doronina
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Analytical Signal ◽  
Graphite Powder ◽  
Atomic Emission ◽  
Standard Samples ◽  
Emission Analysis ◽  
Sorption Preconcentration ◽  
Sample Shape

The analytical capabilities of arc atomic emission determination of As, Bi, Sb, Cu, Te in rare earth metals (REM) and their oxides after preparatory group concentration using S,N-containing heterochain polymer sorbent are studied on a high-resolution spectrometer “Grand- Extra” (“WMC-Optoelectron-ics” company, Russia). Sorption kinetics and dependence of the degree of the impurity extraction on the solution acidity are analyzed to specify conditions of sorption concentration. To optimize the procedure of arc atomic emission determination of As, Bi, Sb, Cu, and Te various schemes of their sorption preconcentration and subsequent processing of the resulted concentrate with the addition of a collector at different stages of the sorption process have been considered. Graphite powder is used as a collector in analysis of rare earth oxides due to universality and relative simplicity of the emission spectrum. Conditions of analysis and parameters of the spectrometer that affect the analytical signal (mass and composition of the sample, shape and size of the electrodes, current intensity and generator operation mode, interelectrode spacing, wavelengths of the analytical lines) are chosen. The evaporation curves of the determinable impurities were studied and the exposure time of As, Bi, Sb, Cu, and Te in the resulted sorption concentrate was determined. Correctness of the obtained results was evaluated using standard samples of the composition and in comparisons between methods. The results of the study are used to develop a method of arc chemical-atomic emission analysis of yttrium, gadolinium, neodymium, europium, scandium and their oxides in a concentration range of n x (10-2 - 10-5) wt.%.

scholarly journals Injection Molding and Near-Complete Densification of Monolithic and Al2O3 Fiber-Reinforced Ti2AlC MAX Phase Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3632
Author(s):  
Sylvain Badie ◽  
Rimy Gabriel ◽  
Doris Sebold ◽  
Robert Vaßen ◽  
Olivier Guillon ◽  
...  
Keyword(s):  
Injection Molding ◽  
Graphite Powder ◽  
Max Phase ◽  
Powder Injection ◽  
Fiber Reinforced ◽  
Ceramic Fibers ◽  
Plasma Sintering ◽  
Molded Parts ◽  
Al2o3 Fiber ◽  
Induced Velocity

Near-net shape components composed of monolithic Ti2AlC and composites thereof, containing up to 20 vol.% Al2O3 fibers, were fabricated by powder injection molding. Fibers were homogeneously dispersed and preferentially oriented, due to flow constriction and shear-induced velocity gradients. After a two-stage debinding procedure, the injection-molded parts were sintered by pressureless sintering at 1250 °C and 1400 °C under argon, leading to relative densities of up to 70% and 92%, respectively. In order to achieve near-complete densification, field assisted sintering technology/spark plasma sintering in a graphite powder bed was used, yielding final relative densities of up to 98.6% and 97.2% for monolithic and composite parts, respectively. While the monolithic parts shrank isotropically, composite assemblies underwent anisotropic densification due to constrained sintering, on account of the ceramic fibers and their specific orientation. No significant increase, either in hardness or in toughness, upon the incorporation of Al2O3 fibers was observed. The 20 vol.% Al2O3 fiber-reinforced specimen accommodated deformation by producing neat and well-defined pyramidal indents at every load up to a 30 kgf (~294 N).

scholarly journals Structural disorder of graphite and implications for graphite thermometry

Solid Earth ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 223-231 ◽  
Author(s):  
Martina Kirilova ◽  
Virginia Toy ◽  
Jeremy S. Rooney ◽  
Carolina Giorgetti ◽  
Keith C. Gordon ◽  
...  
Keyword(s):  
Irreversible Process ◽  
Carbonaceous Material ◽  
Graphite Powder ◽  
Structural Disorder ◽  
Structural Order ◽  
Active Tectonic ◽  
Graphite Structure ◽  
Tectonic Settings ◽  
Host Rocks ◽  
Crystalline Graphite

Abstract. Graphitization, or the progressive maturation of carbonaceous material, is considered an irreversible process. Thus, the degree of graphite crystallinity, or its structural order, has been calibrated as an indicator of the peak metamorphic temperatures experienced by the host rocks. However, discrepancies between temperatures indicated by graphite crystallinity versus other thermometers have been documented in deformed rocks. To examine the possibility of mechanical modifications of graphite structure and the potential impacts on graphite thermometry, we performed laboratory deformation experiments. We sheared highly crystalline graphite powder at normal stresses of 5 and 25  megapascal (MPa) and aseismic velocities of 1, 10 and 100 µm s−1. The degree of structural order both in the starting and resulting materials was analyzed by Raman microspectroscopy. Our results demonstrate structural disorder of graphite, manifested as changes in the Raman spectra. Microstructural observations show that brittle processes caused the documented mechanical modifications of the aggregate graphite crystallinity. We conclude that the calibrated graphite thermometer is ambiguous in active tectonic settings.

scholarly journals The Surface Modification of Graphite Powder by Direct Fluorination(II). The Effect of Fluorination Temperature.

1994 ◽  
pp. 605-612
Author(s):  
Yong-bo CHONG ◽  
Hiroyuki IDOGAWA ◽  
Makoto KURONUMA ◽  
Fumiyuki YAMADA ◽  
Nobuatsu WATANABE
Keyword(s):  
Surface Modification ◽  
Graphite Powder ◽  
Direct Fluorination

R-55 Rodent Repellent: Effect on Germination in Douglas-fir and Western Hemlock.

1972 ◽  
Vol 2 (3) ◽  
pp. 256-263 ◽  
Author(s):  
D. G. W. Edwards ◽  
Patricia E. Olsen
Keyword(s):  
Graphite Powder ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Repellent Effect ◽  
Dry Storage

Coating Douglas-fir and western hemlock seeds with R-55, a rodent repellent, seriously reduced normal germination. Acidifying the latex sticker, or adding graphite powder, had no effect. If seeds were coated first with latex, more R-55 could be applied without significantly increasing germination losses. Both stratification and dry storage of R-55 coated seeds increased germination losses. Treatment differences detected by normal germination percentages were also reflected in germination values. Observations based on total (normal + abnormal) germination obscured the effects of the various coatings.

Phase Studies in WC-Stainless Steel AISI 347 Hardmetal System with Graphite Addition

2014 ◽  
Vol 1024 ◽  
pp. 239-242
Author(s):  
Zuhailawati Hussain ◽  
Emee Marina Salleh ◽  
Tran Bao Trung ◽  
Zainal Arifin Ahmad
Keyword(s):  
Stainless Steel ◽  
Powder Mixture ◽  
Milled Powder ◽  
Graphite Powder ◽  
Planetary Mill ◽  
Argon Atmosphere ◽  
Maximum Hardness ◽  
Steel Container ◽  
Steel Aisi ◽  
Stainless Steel Aisi

In this study, WC-stainless steel AISI 347 hardmetal system was produced to replace WC-Co hardmetal which uses the expensive, toxic and depleted resource Co. WC, stainless steel AISI 347 and graphite powder mixture were milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Carbon was added in amounts ranging from 0 wt% until 4 wt% into the composition to avoid unwanted η (Fe3W3C) phase. As-milled powder was compacted at 300 MPa and sintered in a tube furnace at 1350°C. ɳ phase was detected in compositions with 0 and 1 wt% C addition. For 2 wt% C addition, no η (Fe3W3C) phase formation was identified. However, the η phase was detected for compositions containing 3 and 4 wt% C. Maximum hardness was achieved due to the absence of η phase.

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