scholarly journals Reaction Sintering of Ca3Co4O9 with BiCuSeO Nanosheets for High-Temperature Thermoelectric Composites

2021 ◽  
Author(s):  
Richard Hinterding ◽  
Desiree Rieks ◽  
Patrick A. Kißling ◽  
Lukas Steinbach ◽  
Nadja C. Bigall ◽  
...  
Keyword(s):  
Ceramic Composites ◽  
Reaction Sintering ◽  
X Ray Diffraction ◽  
Large Power ◽  
Thermogravimetric Analyses ◽  
X Ray ◽  
High Seebeck Coefficient ◽  
Heating Up ◽  
Thermal Stability Of

AbstractCeramic composites composed of oxide materials have been synthesized by reaction sintering of Ca3Co4O9 with BiCuSeO nanosheets. In situ x-ray diffraction and thermogravimetric analyses of the compound powders were conducted to understand the phase transformations during heating up to 1173 K. Further thermogravimetric analyses investigated the thermal stability of the composites and the completion of reaction sintering. The microstructure of the formed phases after reaction sintering and the composition of the composites were investigated for varying mixtures. Depending on the amount of BiCuSeO used, the phases present and their composition differed, having a significant impact on the thermoelectric properties. The increase of the electrical conductivity at a simultaneously high Seebeck coefficient resulted in a large power factor of 5.4 $$\mu $$ μ W cm−1 K−2, more than twice that of pristine Ca3Co4O9.

scholarly journals Characterization of the Interface Between the Bulk Glass Forming Alloy Zr41Ti14Cu12Ni10Be23 with Pure Metals and Ceramics

2000 ◽  
Vol 15 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Jan Schroers ◽  
Konrad Samwer ◽  
Frigyes Szuecs ◽  
William L. Johnson
Keyword(s):  
Sessile Drop ◽  
Bulk Glass ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Glass Forming ◽  
Processing Times ◽  
Thermal Stability Of

The reaction of the bulk glass forming alloy Zr41Ti14Cu12Ni10Be23 (Vit 1) with W, Ta, Mo, AlN, Al2O3, Si, graphite, and amorphous carbon was investigated. Vit 1 samples were melted and subsequently solidified after different processing times on discs of the different materials. Sessile drop examinations of the macroscopic wetting of Vit 1 on the discs as a function of temperature were carried out in situ with a digital optical camera. The reactions at the interfaces between the Vit 1 sample and the different disc materials were investigated with an electron microprobe. The structure and thermal stability of the processed Vit 1 samples were examined by x-ray diffraction and differential scanning calorimetry. The results are discussed in terms of possible applications for composite materials.

scholarly journals Intermetallic/Ceramic Composites Synthesized from Al–Ni–Ti Combustion with B4C Addition

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 873
Author(s):  
Chun-Liang Yeh ◽  
Chih-Yao Ke
Keyword(s):  
Combustion Velocity ◽  
Ceramic Composites ◽  
The Other ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
Reaction Systems ◽  
X Ray ◽  
High Temperature Synthesis ◽  
In Situ Formation

The fabrication of intermetallic/ceramic composites by combustion synthesis in the mode of self-propagating high-temperature synthesis (SHS) was investigated in the Al–Ni–Ti system with the addition of B4C. Two reaction systems were employed: one was used to produce the composites of xNiAl–2TiB2–TiC with x = 2–7, and the other was used to synthesize yNi3Al–2TiB2–TiC with y = 2–7. The reaction mechanism of the Al–Ni–Ti system was strongly influenced by the presence of B4C. The reaction of B4C with Ti was highly exothermic, so the reaction temperature and combustion velocity decreased due to increasing levels of Ni and Al in the reactant mixture. The activation energies of Ea = 110.6 and 172.1 kJ/mol were obtained for the fabrication of NiAl- and Ni3Al-based composites, respectively, by the SHS reaction. The XRD (X-ray diffraction) analysis showed an in situ formation of intermetallic (NiAl and Ni3Al) and ceramic phases (TiB2 and TiC) and confirmed no reactions taking place between Ti and Al or Ni. The microstructure of the product revealed large NiAl and Ni3Al grains and small TiB2 and TiC particles. With the addition of TiB2 and TiC, the hardness of NiAl and Ni3Al was considerably increased and the toughness was also improved.

scholarly journals “PdO vs. PtO”—The Influence of PGM Oxide Promotion of Co3O4 Spinel on Direct NO Decomposition Activity

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 62 ◽  
Author(s):  
Gunugunuri K. Reddy ◽  
Torin C. Peck ◽  
Charles A. Roberts
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Decomposition ◽  
Single Element ◽  
X Ray Diffraction ◽  
X Ray ◽  
Promotional Effect ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Thermal Stability Of

Direct decomposition of NO into N2 and O2 (2NO→N2 + O2) is recognized as the “ideal” reaction for NOx removal because it needs no reductant. It was reported that the spinel Co3O4 is one of the most active single-element oxide catalysts for NO decomposition at higher reaction temperatures, however, activity remains low below 650 °C. The present study aims to investigate new promoters for Co3O4, specifically PdO vs. PtO. Interestingly, the PdO promoter effect on Co3O4 was much greater than the PtO effect, yielding a 4 times higher activity for direct NO decomposition at 650 °C. Also, Co3O4 catalysts with the PdO promoter exhibit higher selectivity to N2 compared to PtO/Co3O4 catalysts. Several characterization measurements, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR), and in situ FT-IR, were performed to understand the effect of PdO vs. PtO on the properties of Co3O4. Structural and surface analysis measurements show that impregnation of PdO on Co3O4 leads to a greater ease of reduction of the catalysts and an increased thermal stability of surface adsorbed NOx species, which contribute to promotion of direct NO decomposition activity. In contrast, rather than remaining solely as a surface species, PtO enters the Co3O4 structure, and it promotes neither redox properties nor NO adsorption properties of Co3O4, resulting in a diminished promotional effect compared to PdO.

Modification of clays with styrenic ionic liquid by Synthesis of in-situ Polystyrene Nanocomposite

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Mohammad Galehassadi ◽  
Fatemeh Hosseinzadeh ◽  
Mehrdad Mahkam
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Transmission Electron ◽  
Insitu Polymerization ◽  
Thermal Stability Of

Abstract Nanocomposites of polystyrene (PS) was prepared with new styrenic ionic liquid, N-(4-vinyl benzyl)-(N,N-dimethylamino) pyridinium chloride[VBMAP], surfactants used as organic modifications for the clays. Sodium montmorillonite (Na-MMT) was successfully modified by [VBMAP] to become OMMT through cation exchange technique which is shown by the increase of basalspacing of clay by XRD. The composite material based on polystyrene and organo-modified montmorillonite (OMMT) was prepared by insitu polymerization and characterized. The morphology of the polymer/clay hybrids was evaluated by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and scanning electron microscopy (SEM), showing good overall dispersion of the clay. The thermal stability of the polymer/clay nanocomposites were enhanced, as evaluated by thermogravimetric analysis.

In Situ X-Ray Diffraction Study of Thermal Stability of Cu and Cu-Zr Samples Processed by ECAP

2013 ◽  
Vol 753 ◽  
pp. 279-284 ◽  
Author(s):  
Radomír Kužel ◽  
Zdeněk Matěj ◽  
Miloš Janeček
Keyword(s):  
In Situ Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Abnormal Growth ◽  
Angular Pressing ◽  
Dislocation Densities ◽  
Diffraction Patterns ◽  
Number Of Passes ◽  
Thermal Stability Of

X-ray diffraction (XRD) studies of ECAP (equal-channel angular pressing) materials were performed after annealing and by in-situ measurements in XRD high-temperature chamber for samples prepared by different number of passes and number of revolutions, respectively. Main attention was given to Cu and Cu-Zr samples. Significant dependence on number of passes was found for ECAP samples. In-situ measurements were focused not only on temperature dependence but also on time evolution of the diffraction line profiles. Evaluation in terms of dislocation densities, correlation and crystallite size and its distribution was performed by our own software MSTRUCT developed for total powder diffraction pattern fitting. Abnormal growth of some grains with annealing is well-known for copper and leads to the creation of bimodal microstructure. Therefore a special care must be given to the evaluation and a model of two Cu components (larger and smaller crystallites) was fitted to the data if an indication of some crystallite growth appears either in the XRD line profile shape or in two-dimensional diffraction patterns.

scholarly journals Investigation of thermal stability of Cu/W multilayers by in situ X-ray diffraction

2016 ◽  
Vol 72 (a1) ◽  
pp. s418-s418 ◽  
Author(s):  
Claudia Cancellieri ◽  
Frank Moszner ◽  
Mirco Chiodi ◽  
Songhak Yoon ◽  
Daniel Ariosa ◽  
...  
Keyword(s):  
Thermal Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

scholarly journals Thermal and electrical properties of polyimide/PANI nanofiber composites prepared via in situ polymerization

2018 ◽  
Vol 36 (2) ◽  
pp. 283-287
Author(s):  
Aseel A. Kareem
Keyword(s):  
In Situ Polymerization ◽  
Composite Films ◽  
Nanocomposite Films ◽  
X Ray Diffraction ◽  
Nanofiber Composite ◽  
X Ray ◽  
Thermal And Electrical Properties ◽  
Ft Ir ◽  
Thermal Stability Of

Abstract Polyimide/polyaniline nanofiber composites were prepared by in situ polymerization with various weight percentages of polyaniline (PANI) nanofibers. X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR), proved the successful preparation of PANI nanofiber composite films. In addition, thermal stability of PI/PANI nanofiber composites was superior relative to PI, having 10 % gravimetric loss in the range of 623 °C to 671 °C and glass transition temperature of 289 °C to 297 °C. Furthermore, the values of the loss tangent tanδ and AC conductivity σAC of the nanocomposite films were notably higher than those of pure polyimide. The addition of 5 wt.% to 15 wt.% PANI nanofiber filler enhanced the activation energy of PI composites from 0.37 eV to 0.34 eV.

Preparation and Characterization of PET/MMT Nanocomposition Modified by MDI

2014 ◽  
Vol 904 ◽  
pp. 7-9
Author(s):  
Xiao Hua Gu ◽  
Xi Wei Zhang ◽  
Bao Yun Xu ◽  
Peng Zeng
Keyword(s):  
Thermal Stability ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
Organic Montmorillonite ◽  
Polymerization Method ◽  
Thermal Stability Of

In this paper, the diphenyl methane diisocyanate (MDI) was used to modify montmorillonoid (MMT) and got the organic montmorillonite (OMMT), which was used with the monomers of PET by in situ polymerization method to prepare PET/MMT nanocomposition. The OMMT was analyzed by the X ray diffraction (XRD) to test the change of the spacing layer. Dispersion of MMT in the PET/MMT nanocomposites were studied with XRD and SEM and by means of thermogravimetric analyzer (TGA) on the thermal stability of PET/MMT nanocomposites. The results showed that, MDI modified MMT successfully, and the compatibility of MMT and PET was increased .

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