scholarly journals Evolution of the phase composition of ZrB2-35MoSi2-15Al composite coating at annealing

2021 ◽  
Vol 2124 (1) ◽  
pp. 012016
Author(s):  
I Goncharov ◽  
M Kovaleva ◽  
M Yapryntsev ◽  
V Sirota
Keyword(s):  
Phase Composition ◽  
Zirconium Dioxide ◽  
Elevated Temperatures ◽  
Silicon Oxide ◽  
Composite Coatings ◽  
Molybdenum Disilicide ◽  
Carbon Composite ◽  
Carbon Composites ◽  
X Ray

Abstract In this article, new composite coatings ZrB2-35MoSi2-15Al were deposited on the surface of a carbon-carbon composite using a multi-chamber detonation accelerator. The evolution of the phase composition of ZrB2-35MoSi2-15Al coatings was analyzed with differential scanning calorimeter (DSC) and X-ray diffractometry (in situ HT-XRD) at temperatures from room temperature (∼ 25°C) to 1400°C (normal atmosphere and pressure). The coating before annealing according to X-ray diffractometry data is tetragonal (t-ZrO2) and monocline (m-ZrO2) zirconium dioxide, monocline silicon oxide (m-SiO2), hexagonal zirconium diboride (h-ZrB2), tetragonal molybdenum disilicide (t-MoSi2), cubic aluminum (c-Al) and cubic yttrium oxide (c-Y2O3). It was found that the coating crystallizes in m-ZrO2 at 460ºC, and then mullite with rhombic crystal lattice appears at 960ºC. When the temperature reaches 1050ºC the m-ZrO2, ZrSiO4, t-ZrO2, m-SiO2 and mullite phases formed in the coating. At 1400 º C, cubic zirconium dioxide appears in the coating. Experimental results can become the basis for the application of ceramic coating ZrB2-35MoSi2-15Al, which can improve the properties of carbon-carbon composites in an oxygen-containing environment at elevated temperatures.

An in situ microtomography apparatus with a laboratory x-ray source for elevated temperatures of up to 1000 °C

2021 ◽  
Vol 92 (3) ◽  
pp. 033704
Author(s):  
Rongqi Zhu ◽  
Zhaoliang Qu ◽  
Shuo Yang ◽  
Daining Fang
Keyword(s):  
Elevated Temperatures ◽  
X Ray

Residual Stress in Sputtered Silicon Oxycarbide Thin Films

2011 ◽  
Vol 1299 ◽  
Author(s):  
Ping Du ◽  
I-Kuan Lin ◽  
Yunfei Yan ◽  
Xin Zhang
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Elevated Temperatures ◽  
Silicon Oxide ◽  
Composite Films ◽  
Deposition Process ◽  
Silicon Oxycarbide ◽  
X Ray ◽  
Curvature Measurement ◽  
Film Substrate

ABSTRACTSilicon carbide (SiC) has received increasing attention on the integration of microelectro-mechanical system (MEMS) due to its excellent mechanical and chemical stability at elevated temperatures. However, the deposition process of SiC thin films tends to induce relative large residual stress. In this work, the relative low stress material silicon oxide was added into SiC by RF magnetron co-sputtering to form silicon oxycarbide (SiOC) composite films. The composition of the films was characterized by Energy dispersive X-ray (EDX) analysis. The Young’s modulus and hardness of the films were measured by nanoindentation technique. The influence of oxygen/carbon ratio and rapid thermal annealing (RTA) temperature on the residual stress of the composite films was investigated by film-substrate curvature measurement using the Stoney’s equation. By choosing the appropriate composition and post processing, a film with relative low residual stress could be obtained.

scholarly journals Nanoporous Iron Oxide/Carbon Composites through In-Situ Deposition of Prussian Blue Nanoparticles on Graphene Oxide Nanosheets and Subsequent Thermal Treatment for Supercapacitor Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 776 ◽  
Author(s):  
Alowasheeir Azhar ◽  
Yusuke Yamauchi ◽  
Abeer Enaiet Allah ◽  
Zeid A. Alothman ◽  
Ahmad Yacine Badjah ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Iron Oxide ◽  
Thermal Treatment ◽  
Prussian Blue ◽  
High Current Density ◽  
Carbon Composite ◽  
Hybrid Structure ◽  
Carbon Composites ◽  
Prussian Blue Nanoparticles

This work reports the successful preparation of nanoporous iron oxide/carbon composites through the in-situ growth of Prussian blue (PB) nanoparticles on the surface of graphene oxide (GO) nanosheets. The applied thermal treatment allows the conversion of PB nanoparticles into iron oxide (Fe2O3) nanoparticles. The resulting iron oxide/carbon composite exhibits higher specific capacitance at all scan rates than pure GO and Fe2O3 electrodes due to the synergistic contribution of electric double-layer capacitance from GO and pseudocapacitance from Fe2O3. Notably, even at a high current density of 20 A g−1, the iron oxide/carbon composite still shows a high capacitance retention of 51%, indicating that the hybrid structure provides a highly accessible path for diffusion of electrolyte ions.

MICROSTRUCTURE AND WEAR RESISTANCE OF IN-SITU SYNTHESIZED TiB2–TiC/Fe COMPOSITE COATING BY LASER CLADDING

2020 ◽  
pp. 2050046
Author(s):  
TIANWEI YANG ◽  
ZHAOHUI WANG ◽  
SHIHAI TAN ◽  
FU GUO
Keyword(s):  
Wear Resistance ◽  
Laser Cladding ◽  
Composite Coatings ◽  
X Ray Diffraction ◽  
Mixed Powder ◽  
X Ray ◽  
Material Surfaces ◽  
Metallurgical Bonding ◽  
Steel Surfaces

To increase the strength and wear resistance of material surfaces, various combinations of B4C and 80TiFe powder were mixed into a Fe60 self-fluxing alloy powder; the composite coatings reinforced by TiB2–TiC were successfully prepared on Q235 steel surfaces by laser cladding. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to study the microstructure and chemical and phase composition. Microhardness and wear testers were used to investigate the mechanical properties. The results show that the interfaces of composite coatings and substrate materials are excellent for metallurgical bonding. The block-like TiB2 particles and flower-like TiC particles are uniformly distributed in the cladding coating. When the mass fraction of the mixed powder is 30%, the average microhardness of the coating is approximately 1100 HV[Formula: see text], which is 50% higher than that without the mixed powder, and demonstrates the best wear with a performance twice as better as that of the substrate.

Transformation of ferrihydrite to hematite: anin situinvestigation on the kinetics and mechanisms

2008 ◽  
Vol 72 (1) ◽  
pp. 217-220 ◽  
Author(s):  
H. P. Vu ◽  
S. Shaw ◽  
L. G. Benning
Keyword(s):  
High Resolution ◽  
Growth Mechanism ◽  
Elevated Temperatures ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Time Resolved ◽  
X Ray ◽  
Resolution Electron ◽  
Stage Process

AbstractThe kinetics and mechanisms of the transformation of 2-line ferrihydrite (FH) to hematite (HM), in the presence of Pb at elevated temperatures and high pH condition, were elucidated using synchrotron-based,in situenergy dispersive X-ray diffraction (EDXRD). The time-resolved diffraction data indicated that HM crystallization occurred via a two-stage process. Based on the EDXRD data, combined with high-resolution electron microscopic images, an aqueous-aided 2D growth mechanism is proposed for both HM crystallization stages.

In situ sulfur deposition route to obtain sulfur–carbon composite cathodes for lithium–sulfur batteries

2014 ◽  
Vol 2 (12) ◽  
pp. 4316-4323 ◽  
Author(s):  
W. G. Wang ◽  
X. Wang ◽  
L. Y. Tian ◽  
Y. L. Wang ◽  
S. H. Ye
Keyword(s):  
Reversible Capacity ◽  
Carbon Composite ◽  
Cycle Performance ◽  
Carbon Composites ◽  
Stable Cycle ◽  
Sulfur Deposition ◽  
Composite Cathodes ◽  
Lithium Sulfur Batteries ◽  
Lithium Sulfur

Sulfur–carbon composites were prepared by an in situ sulfur deposition route developed for the heterogeneous nucleation of sulfur into nanopores of conductive carbon black (CCB) by fumigation of Na2S4/CCB powder with HCl. The sulfur–carbon composites demonstrate enhanced reversible capacity and stable cycle performance.

Microstructure and Properties of Laser Cladding Cu-TiB2 Composite Coating on Copper

2012 ◽  
Vol 512-515 ◽  
pp. 639-642 ◽  
Author(s):  
Xiao Qin Guo ◽  
Jing Bo Chen ◽  
Xin Fang Zhang ◽  
Yong Kai Wang ◽  
Rui Zhang
Keyword(s):  
Laser Cladding ◽  
Coating Layer ◽  
Composite Coatings ◽  
Copper Substrate ◽  
Bonding Interface ◽  
X Ray ◽  
Cladding Layer ◽  
Metallurgical Bonding ◽  
Tib2 Particles

Cu-TiB2 composite coatings were in-situ synthesized on the copper substrate by using a Nd: YAG laser. The microstructure of the coating and the bonding interface between the laser cladding layer and the substrate were studied by X-ray and SEM. The microhardness and the wear resisting property were tested. The results show that the TiB2 particles were well-proportioned and spherical existing in the coating layer, the bonding interface between the layer and substrate was metallurgical bonding. The microhardness reaches HV450 and the wear resistance is about 10 times as much as that of Cu substate.

scholarly journals X Preparation and Characterization of Carbon-Based Composite Nanofibers for Supercapacitor

2017 ◽  
Vol 17 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Dawei Gao ◽  
Lili Wang ◽  
Chunxia Wang ◽  
Yuping Chang ◽  
Pibo Ma
Keyword(s):  
Carbon Nanotubes ◽  
Phase Composition ◽  
Electron Microscope ◽  
Surface Area ◽  
Composite Nanofibers ◽  
Carbon Composite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Abstract Polyacrylonitrile (PAN)/Co(OAc)2/carbon nanotubes (CNTs) composite nanofibers were fabricated via electrospinning with N,N-dimethylformamide (DMF) as solvent, and by carbonization and activation of the above precursor nanofibers, porous carbon composite nanofibers were successfully obtained. Scanning electron microscope, X-ray diffraction, ASAP 2020, and Solartron 1470 were used to characterize the surface morphology, the phase composition, specific surface area, and electrochemical property of the nanofibers, respectively. The result showed that some of the fibers were broken after sintering, and the surface area and pore volume of the porous C/Cu/CNTs were 771 m2/g and 0.347 cm3/g, respectively. The specific capacitance of the composite nanofibers reached up to 210 F/g at the current density of 1.0 A/g. Its energy density and power density were 3.1 Wh/Kg and 2,337 W/Kg, respectively, at the current of 0.5 and 5 mA.

Hydration of Synthetized Clinker Phases C3S and C3A with Metakaolin in Isothermal Conditions

2015 ◽  
Vol 1124 ◽  
pp. 23-30 ◽  
Author(s):  
Martin Boháč ◽  
Radoslav Novotný ◽  
Jiří Másilko ◽  
Tomáš Opravil ◽  
František Šoukal ◽  
...  
Keyword(s):  
Phase Composition ◽  
Heat Flow ◽  
Isothermal Calorimetry ◽  
X Ray Diffraction ◽  
Early Hydration ◽  
X Ray ◽  
Calorimetric Measurements ◽  
Flow Development ◽  
Cementitious Systems

Heat flow development during initial hydration of fresh pastes based on mixtures of pure clinker phases C3S and C3A with metakaolin was investigated by means of isothermal calorimetry. Phase composition development was examined by "in situ" X-ray diffraction technique. Obtained results from calorimetric measurements and X-ray diffraction were correlated with recent studies in field of hydration of cementitious systems. The effect of co-sintering of clinker phases on early hydration was characterized by isothermal calorimetry.

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