Synthesis and Structure of BxC1−x Intercalation Compounds with Heavy Alkali Metals (K, Rb, and Cs)

2000 ◽  
Vol 15 (6) ◽  
pp. 1409-1416
Author(s):  
L. Duclaux ◽  
F. Béguin ◽  
B. Ottaviani ◽  
S. Flandrois
Keyword(s):  
Alkali Metals ◽  
Liquid Ammonia ◽  
Stage Structure ◽  
Metal Vapor ◽  
Treatment Temperature ◽  
Intercalation Compounds ◽  
Host Material ◽  
Alkali Metal Vapor ◽  
Heat Treated ◽  
Pure Carbon

BxC1−x (x = 0.1 and 0.25) oriented platelets were intercalated with alkali metal vapor (M = K, Rb, Cs), giving first-stage M(B0.1C0.9)8 and M(B0.25C0.75)10. The presence of M(BxC1−x)5 dense domains interstratified in the first-stage structure were brought out from the 00.ℓ simulations. The presence of these domains is attributed to the acceptor electron effect of boron, which slightly enhances the intercalation rate as compared to pure carbon. Intercalation of Cs in liquid ammonia is improved using 1600 °C heat-treated B0.25C0.75 as a host material, and the composition Cs(B0.25C0.75)12 is reached after intercalation. In intercalation compounds of Cs in liquid ammonia obtained from heat-treated B0.25C0.75, as the heat-treatment temperature (HTT) was increased from 1600 to 2000 °C, the segregation of first stage was observed in two structures Cs(BxC1−x)8 and Cs(BxC1−x)10 with the respective 2 × 2 0° and 2.23 × 2.23 two-dimensional lattices of the cesium atoms. The presence of these two structures is assigned to the heterogeneity of the host material induced by the formation of B4C boron carbide domains and the consecutive boron elimination of the BxC1−x lamellar phase with increasing HTT.

scholarly journals Enhancing Graphene Retention and Electrical Conductivity of Plasma-Sprayed Alumina/Graphene Nanoplatelets Coating by Powder Heat Treatment

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 643
Author(s):  
Xiaoyu Wu ◽  
Shufeng Xie ◽  
Kangwei Xu ◽  
Lei Huang ◽  
Daling Wei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Structural Integrity ◽  
Ceramic Coatings ◽  
Treatment Temperature ◽  
Graphene Nanoplatelets ◽  
Structural Defects ◽  
Temperature Plasma ◽  
Heat Treated ◽  
Plasma Sprayed

Burning loss of graphene in the high-temperature plasma-spraying process is a critical issue, significantly limiting the remarkable performance improvement in graphene reinforced ceramic coatings. Here, we reported an effective approach to enhance the graphene retention, and thus improve the performance of plasma-sprayed alumina/graphene nanoplatelets (Al2O3/GNPs) coatings by heat treatment of agglomerated Al2O3/GNPs powders. The effect of powder heat treatment on the microstructure, GNPs retention, and electrical conductivity of Al2O3/GNPs coatings were systematically investigated. The results indicated that, with the increase in the powder heat treatment temperature, the plasma-sprayed Al2O3/GNPs coatings exhibited decreased porosity and improved adhesive strength. Thermogravimetric analysis and Raman spectra results indicated that increased GNPs retention from 12.9% to 28.4%, and further to 37.4%, as well as decreased structural defects, were obtained for the AG, AG850, and AG1280 coatings, respectively, which were fabricated by using AG powders without heat treatment, powders heat-treated at 850 °C, and powders heat-treated at 1280 °C. Moreover, the electrical conductivities of AG, AG850, and AG1280 coatings exhibited 3 orders, 4 orders, and 7 orders of magnitude higher than that of Al2O3 coating, respectively. Powder heat treatment is considered to increase the melting degree of agglomerated alumina particles, eventually leaving less thermal energy for GNPs to burn; thus, a high retention amount and structural integrity of GNPs and significantly enhanced electrical conductivity were achieved for the plasma-sprayed Al2O3/GNPs coatings.

scholarly journals Water Resistance and Creep Behavior of Heat-Treated Moso Bamboo Determined by the Stepped Isostress Method

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1264
Author(s):  
Teng-Chun Yang ◽  
Tung-Lin Wu ◽  
Chin-Hao Yeh
Keyword(s):  
Heat Treatment ◽  
Water Absorption ◽  
Creep Behavior ◽  
Heat Treatment Temperature ◽  
Water Resistance ◽  
Absorption Efficiency ◽  
Treatment Temperature ◽  
Moso Bamboo ◽  
Phyllostachys Pubescens ◽  
Heat Treated

The influence of heat treatment on the physico-mechanical properties, water resistance, and creep behavior of moso bamboo (Phyllostachys pubescens) was determined in this study. The results revealed that the density, moisture content, and flexural properties showed negative relationships with the heat treatment temperature, while an improvement in the dimensional stability (anti-swelling efficiency and anti-water absorption efficiency) of heat-treated samples was observed during water absorption tests. Additionally, the creep master curves of the untreated and heat-treated samples were successfully constructed using the stepped isostress method (SSM) at a series of elevated stresses. Furthermore, the SSM-predicted creep compliance curves fit well with the 90-day full-scale experimental data. When the heat treatment temperature increased to 180 °C, the degradation ratio of the creep resistance (rd) significantly increased over all periods. However, the rd of the tested bamboo decreased as the heat treatment temperature increased up to 220 °C.

Effect of Heat Treatment on the Microstructure and Property of TiAl Alloys Prepared by Gas Atomization Powders

2013 ◽  
Vol 747-748 ◽  
pp. 497-501
Author(s):  
Na Liu ◽  
Zhou Li ◽  
Guo Qing Zhang ◽  
Hua Yuan ◽  
Wen Yong Xu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Tial Alloy ◽  
Lamellar Microstructure ◽  
Treatment Temperature ◽  
Gas Atomization ◽  
Thermally Induced ◽  
Heat Treated ◽  
Fine Duplex ◽  
Step Heat Treatment

Powder metallurgical TiAl alloy was fabricated by gas atomization powders, and the effect of heat treatment temperature on the microstructure evolution and room tensile properties of PM TiAl alloy was investigated. The uniform fine duplex microstructure was formed in PM TiAl based alloy after being heat treated at 1250/2h followed by furnace cooling (FC)+ 900/6h (FC). When the first step heat treatment temperature was improved to 1360/1h, the near lamellar microstructure was achieved. The ductility of the alloy after heat treatment improved markedly to 1.2% and 0.6%, but the tensile strength decreased to 570MPa and 600MPa compared to 655MPa of as-HIP TiAl alloy. Post heat treatment at the higher temperature in the alpha plus gamma field would regenerate thermally induced porosity (TIP).

Study on Alkali-Metal Vapor Removal for High-Temperature Cleaning of Coal Gas

2005 ◽  
Vol 19 (4) ◽  
pp. 1606-1610 ◽  
Author(s):  
Yili Li ◽  
Jian Li ◽  
Yuquan Jin ◽  
Youqing Wu ◽  
Jinsheng Gao
Keyword(s):  
High Temperature ◽  
Alkali Metal ◽  
Metal Vapor ◽  
Coal Gas ◽  
Alkali Metal Vapor

Changes in Microstructure of Biomedical Co-Cr-Mo-C Alloys with Solution Treating and Aging

2010 ◽  
Vol 89-91 ◽  
pp. 377-382 ◽  
Author(s):  
S. Mineta ◽  
Shigenobu Namba ◽  
Takashi Yoneda ◽  
Kyosuke Ueda ◽  
Takayuki Narushima
Keyword(s):  
Solution Treatment ◽  
Heating Time ◽  
Treatment Temperature ◽  
Vacuum Furnace ◽  
Solution Treatment Temperature ◽  
Precipitate Dissolution ◽  
Heat Treated ◽  
M23c6 Type ◽  
Type Carbide ◽  
Time Required

Microstructural changes occurring in biomedical Co-Cr-Mo alloys with three carbon levels due to solution treatment and aging were investigated. Ingots of Co-Cr-Mo alloys with three different carbon levels were prepared by vacuum furnace melting; their chemical composition was Co-28Cr-6Mo-xC (x = 0.12, 0.25 and 0.35 mass%). Precipitates were electrolytically extracted from as-cast and heat-treated alloys. An M23C6 type carbide and a phase were detected as precipitates in as-cast Co-28Cr-6Mo-0.12C alloy, and an M23C6 type carbide and an  phase (M6C-M12C type carbide) were detected in as-cast Co-28Cr-6Mo-0.25C and Co-28Cr-6Mo-0.35C alloys. Only the M23C6 type carbide was detected during solution treatment. Complete precipitate dissolution occurred in all the three alloys after solution treatment. The holding time required for complete precipitate dissolution increased with increasing carbon content and decreasing solution treatment temperature. Complete precipitate dissolution occurred in the Co-Cr-Mo-C alloys solution treated at 1523 K for 43.2 ks; they were then subjected to aging from 873 to 1473 K for a heating time up to 44.1 ks after complete precipitate dissolution in solution treatment at 1523 K for 43.2 ks. The M23C6 type carbide with a grain size of 0.1–3 m was observed after aging. A time-temperature-precipitation diagram of the M23C6 type carbide formed in the Co-28Cr-6Mo-0.25C alloy was plotted.

Reactions of aliphatic halides with solutions of alkali metals in liquid ammonia: I. Experiments with alkyl halides

2010 ◽  
Vol 81 (12) ◽  
pp. 1033-1052 ◽  
Author(s):  
A. Beverloo ◽  
M. C. Dieleman ◽  
P. E. Verkade ◽  
K. S. de Vries ◽  
B. M. Wepster
Keyword(s):  
Alkali Metals ◽  
Liquid Ammonia ◽  
Alkyl Halides

Enhancement of optical properties of poly (9,9′-di-n-octylfluorenyl-2,7-diyl) in conjugated polymer/TiO2 nanocomposites

2014 ◽  
Vol 92 (9) ◽  
pp. 1021-1025 ◽  
Author(s):  
Bandar Ali Al-Asbahi ◽  
Mohammad Hafizuddin Haji Jumali
Keyword(s):  
Optical Properties ◽  
Conjugated Polymer ◽  
Emission Spectra ◽  
Treatment Temperature ◽  
Nanocomposite Films ◽  
Glass Substrates ◽  
Solution Blending ◽  
Heat Treated ◽  
Blending Method ◽  
Splitting Energy

The influence of colloidal TiO2 nanoparticle contents on the optical properties of poly (9,9′-di-n-octylfluorenyl-2,7-diyl) conjugated polymer (PFO) has been investigated. The solution blending method was used to prepare homogenous PFO/TiO2 nanocomposite. The nanocomposite films were prepared on glass substrates using the spin-coating technique. The films were divided into two groups, the first was left to dry at room temperature while the second was heat-treated at 120 °C for 1 h. Absorption and emission spectra showed that the PFO existed in α- and β-phases morphology having monomeric, excimeric, and double excimeric states. In addition, both spectra revealed that TiO2 contents and heat treatment temperature extended the conjugation length of PFO. Finally, emission spectra for both cases exhibited decreasing in the line width of zero-phonon emission spectra and increasing in the vibronic splitting energy, upon increment of the TiO2, led to a significant increase in π-electron delocalization and lower degree in chain disorder.

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