Synthesis of AlN Particles by Microwave-Assisted Urea Route

2016 ◽  
Vol 851 ◽  
pp. 191-195
Author(s):  
Jong Bin Ahn ◽  
Dong Soo Kim ◽  
Young Kook Kim ◽  
Jung Goo Lee
Keyword(s):  
Heat Treatment ◽  
Aluminum Chloride ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Mixed Solution ◽  
Organic Complex ◽  
Mixed Gas ◽  
Microwave Assisted ◽  
Gas Atmosphere ◽  
Mw Irradiation

Novel simple route to prepare AlN nanoparticles was proposed in this study. Aluminum nitride powder was synthesized by microwave-assisted urea route. Aluminum chloride was dissolved in ethanol and urea was added to this solution considering molar concentration with Aluminum chloride. The solution was heated under microwave (MW) irradiation from 60°C to 80°C for 5-10 minutes. And then heat treatment was performed in N2 atmosphere with various temperatures and time to obtain AlN particles. While microwave was irradiated to the mixed solution with Aluminum chloride, urea and ethanol, the solvent was eliminated and polymerization reaction was accelerated to formmetal-organic complex. AlN particles were successfully synthesized after heat treatment above 1600°C under N2 or N2-H2 mixed gas atmosphere in the molar ratio (urea/Aluminum chloride) of 6.

Microstructure of Yba2Cu3O7 Thick Films by Post Annealing of the Precursor by High Rate E-Beam Deposition On SrTiO3 Substrates

1999 ◽  
Vol 5 (S2) ◽  
pp. 832-833
Author(s):  
Lijun Wu ◽  
Yimei Zhu ◽  
M. Suenaga ◽  
R.L. Sabatini
Keyword(s):  
Heat Treatment ◽  
Electrical Power ◽  
Electron Beam Evaporation ◽  
High Rate ◽  
Phase Assemblage ◽  
Mixed Gas ◽  
Gas Atmosphere ◽  
Fabrication Procedure ◽  
Different Temperatures ◽  
Similar Phase

Recently, considerable efforts have been made in developing a fabrication procedure for YBa2 Cu3O7-δ superconducting films on a metallic substrate tape for electrical power applications. The central issue is to develop a method, which can produce the tape in sufficiently long lengths at a commercially viable cost. One possible approach is the so-called BaF2 post-deposition annealing process, which involves deposition of an unreacted mixture of a BaF2 -Y-Cu-O layer on a substrate by electron beam evaporation method, followed by heat-treatment of the layer in a mixed-gas atmosphere of a low partial pressure O2, saturated H2 O, and N2 . To fabricate thick and long films, it is important to understand the effects of the heat-treatment parameters on the. structure and the properties. Here, we report our structural analysis of the films annealed at different temperatures.The films annealed at 725°C, 750°C and 800°C have a similar phase assemblage which are composed ofYBa2 Cu3O7-δ and Y2O3, CuO and Ba-Ti-Sr-O precipitates, as shown in fig. la.

Kinetics of the C-Axis Aligned YBa2Cu3O7 Thick Film By a BaF2 Process

1998 ◽  
Vol 4 (S2) ◽  
pp. 670-671
Author(s):  
Lijun Wu ◽  
Yimei Zhu ◽  
V.F. Solovyov ◽  
H. Wiesmann ◽  
M. Suenaga
Keyword(s):  
Heat Treatment ◽  
Electron Beam ◽  
Electron Beam Evaporation ◽  
Metallic Substrate ◽  
Crucial Importance ◽  
Mixed Gas ◽  
Composite Tape ◽  
Gas Atmosphere ◽  
Kinetics Of ◽  
Made In

Over the last few years, considerable efforts have been made in developing fabrication processes for thick superconducting YBa2Cu3O7-δ film on a metallic substrate for electric power applications. Since these applications require the composite tape to be longer than 4-500m, any methods chosen need to be compatible with such length requirement. One possible approach is the so-called BaF2 process which involves deposition of a unreacted mixture of a BaF2-Y-Cu-O layer on a substrate by an electron beam evaporation method, followed by heat-treatment of the layer in a mixed-gas atmosphere of a low partial pressure O2, saturated H2O, and N2. Although it was shown previously that c-axis aligned films up to ∼ I m long can be produced under these conditions it is uncertain how thick the films can be made and this is of crucial importance as most applications require film thickness to be greater than ∼5μm to carry a large, dissipationless current.

scholarly journals Deep-Ultraviolet Transparent Conductive MWCNT/SiO2 Composite Thin Film Fabricated by UV Irradiation at Ambient Temperature onto Spin-Coated Molecular Precursor Film

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1348
Author(s):  
Hiroki Nagai ◽  
Naoki Ogawa ◽  
Mitsunobu Sato
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Heat Treatment ◽  
Uv Irradiation ◽  
Composite Thin Film ◽  
Precursor Film ◽  
Mixed Solution ◽  
Pencil Hardness ◽  
Strong Base ◽  
Deep Ultraviolet

Deep-ultraviolet (DUV) light-transparent conductive composite thin films, consisting of dispersed multiwalled carbon nanotubes (MWCNTs) and SiO2 matrix composites, were fabricated on a quartz glass substrate. Transparent and well-adhered amorphous thin films, with a thickness of 220 nm, were obtained by weak ultraviolet (UV) irradiation (4 mW cm−2 at 254 nm) for more than 6 h at 20−40 °C onto the precursor films, which were obtained by spin coating with a mixed solution of MWCNT in water and Si(IV) complex in ethanol. The electrical resistivity of MWCNT/SiO2 composite thin film is 0.7 Ω·cm, and transmittance in the wavelength region from DUV to visible light is higher than 80%. The MWCNT/SiO2 composite thin film showed scratch resistance at pencil hardness of 8H. Importantly, the resistivity of the MWCNT/SiO2 composite thin film was maintained at the original level even after heat treatment at 500 °C for 1 h. It was observed that the heat treatment of the composite thin film improved durability against both aqueous solutions involving a strong acid (HCl) and a strong base (NaOH).

Microwave Assisted Synthesis of Schiff Bases: A Green Approach

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Mousumi Chakraborty ◽  
Sanjay Baweja ◽  
Sunita Bhagat ◽  
TejpalSingh Chundawat
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Mass Spectra ◽  
Molar Ratio ◽  
Microwave Assisted Synthesis ◽  
Schiff’S Bases ◽  
Microwave Assisted ◽  
Green Approach ◽  
Schiff's Bases ◽  
Effects Of Temperature

Abstract In the present study Schiff’s bases are synthesized by the conventional as well as by microwave irradiation. Excellent yield within short reaction time is obtained using microwave irradiation along with other advantages like mild reaction condition, non-hazardous and safer environmental conditions. The effects of temperature, reactant molar ratio, and microwave power variation on yield are observed. Mathematical model has been developed using matlab software to obtain the yield as a function of microwave power. Kinetic study of the reaction has also been attempted. Schiff’s bases structures are confirmed by IR, 1HNMR, Mass Spectra and elemental analysis.

Synthesis of Nanoscale γ-Fe2O3 Powders with Hydrates via Microwave-Assisted Heat Treatment

2021 ◽  
Author(s):  
Han-Sol Yun ◽  
So-Young Shin ◽  
Kwon-Jin Park ◽  
Chun-Yeol You ◽  
Nam-Hee Cho
Keyword(s):  
Heat Treatment ◽  
Microwave Assisted

scholarly journals Enzymatic synthesis and characterization of novel terpolymers from renewable sources

2019 ◽  
Vol 91 (3) ◽  
pp. 397-408
Author(s):  
Diana Aparaschivei ◽  
Anamaria Todea ◽  
August E. Frissen ◽  
Valentin Badea ◽  
Gerlinde Rusu ◽  
...  
Keyword(s):  
Polymerization Reaction ◽  
Molar Ratio ◽  
Condensation Polymerization ◽  
Average Molecular Mass ◽  
New Class ◽  
Platform Chemicals ◽  
Starting Point ◽  
Reaction Cycles ◽  
Methylene Group

Abstract 2,5-Furandicarboxylic acid and itaconic acid are both important biobased platform chemicals and their terpolymer with 1,6-hexanediol (HDO) can be the starting point for a new class of reactive polyesters, with important applications. The green synthetic route developed in this study involves a biocatalytic condensation polymerization reaction of dimethyl furan-2,5-dicarboxylate (DMFDC) and dimethyl itaconate (DMI) with HDO in toluene at 80°C, using commercial immobilized lipases from Candida antarctica B. In the best conditions, the formed polymer product was isolated with more than 80% yield, containing about 85% terpolymer with average molecular mass of about 1200 (Mn, calculated from MALDI-TOF MS data) and 15% DMFDC_HDO copolymer. Considering the higher reactivity of DMFDC, the composition of the synthesized polymer can be directed by adjusting the molar ratio of DMFDC and DMI, as well as by extending the reaction time. Structural analysis by NMR demonstrated the regioselective preference for the carbonyl group from DMI adjacent to the methylene group. The biocatalyst was successfully reused in multiple reaction cycles.

scholarly journals Deep Eutectic Solvent-Based Microwave-Assisted Extraction of Baicalin from Scutellaria baicalensis Georgi

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Hui Wang ◽  
Xiaodi Ma ◽  
Qibin Cheng ◽  
Xiaoli Xi ◽  
Liwei Zhang
Keyword(s):  
Maximum Yield ◽  
Deep Eutectic Solvent ◽  
Extraction Yield ◽  
Scutellaria Baicalensis ◽  
Molar Ratio ◽  
Extraction Temperature ◽  
Microwave Assisted Extraction ◽  
Scutellaria Baicalensis Georgi ◽  
Microwave Assisted ◽  
Assisted Extraction

Deep eutectic solvents (DESs) have attracted significant attention as green media for the extraction and separation of natural compounds from Chinese medicine. In this study, a hydrophobic DESs-based microwave-assisted extraction (MAE) was successfully used to efficiently extract baicalin from Scutellaria baicalensis Georgi. Firstly, DecA: N4444-Cl (DES-1 , molar ratio 1 : 2) was screened and selected as the most appropriate DES by comparing the extraction yield in different hydrophobic DESs. Based on the extraction yield of baicalin, response surface methodology (RSM) was employed to model and optimize the parameters (extraction temperature, liquid-solid ratio, and extraction time). Furthermore, the maximum yield of 106.96 mg·g−1 was achieved under optimum conditions in DES-containing aqueous solutions (33 vol% water content), which reached a similar level that was conducted using the pharmacopoeia procedure (104.94 mg·g−1). These results indicated that the proposed method is an excellent alternative for the extraction of baicalin.

scholarly journals Effects of Various Mixed Metal Chlorides- AlCl3 in TiCl4/MgCl2/THF Catalytic System on Ethylene Polymerization

2015 ◽  
Vol 14 (2) ◽  
pp. 12
Author(s):  
Nittaya Sudsong ◽  
Wanna Phiwkliang ◽  
Bunjerd Jongsomjit ◽  
Piyasan Praserthdam
Keyword(s):  
Catalytic System ◽  
Ethylene Polymerization ◽  
Catalyst System ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Metal Chlorides ◽  
Mixed Metal ◽  
Icp Analysis ◽  
Co Addition

In this research, the modification of TiCl4/MgCl2/THF catalyst system with various metal chlorides was investigated on ethylene polymerization. Experimentally, metal chlorides (CaCl2, FeCl2 and ZnCl2) were simultaneously introduced different with TiCl4/MgCl2/THF catalyst. ICP analysis was used to determine the total amount of each metal in the catalyst. For polymerization reaction, TEA was used as cocatalyst and hexane was used as a medium solvent. The Al/Ti molar ratio was 140. The activity result of Ca-Al, Zn-Al and Fe-Al was 979, 1009 and 1476 kgPE/molTi.h, respectively. The coaddition of AlCl3 and FeCl2 in TiCl4/MgCl2/THF catalyst system exhibited the highest activity. It suggested that the co-addition of AlCl3 and FeCl2 has higher electronegativity (EN) and the radius of Fe2+ is closer to Mg2+ resulting in an increased efficiency of the THF removal. This result led to improve the catalyst performance.

scholarly journals Selective oxidation of tool steel surfaces under a protective gas atmosphere using inductive heat treatment

2018 ◽  
Vol 190 ◽  
pp. 14003
Author(s):  
S. Schöler ◽  
D. Yilkiran ◽  
D. Wulff ◽  
F. Özkaya ◽  
K. Möhwald ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Selective Oxidation ◽  
Tool Steel ◽  
Metal Forming ◽  
Sliding Wear ◽  
Wear Behaviour ◽  
Gas Atmosphere ◽  
Steel Surfaces ◽  
Protective Gas ◽  
Sliding Wear Behaviour

For the realization of liquid lubricant free forming processes different approaches are conceivable. The priority program 1676 “Dry forming - Sustainable production through dry machining in metal forming” addresses this issue in the context of metal forming processes. The present study reports results from one subproject of the priority program that employs selective oxidization of tool steel surfaces for the implementation of a dry sheet metal deep drawing process. Within the present study, specimen surfaces of the tool steel (1.2379) were heat-treated to optimize their tribological properties with respect to sliding wear behaviour in contact with drawn sheet metal (DP600+Z). The heat treatment was designed to result in the formation of selective oxide layers that can act as friction reducing separation layers. The heating setup employed an inductive heating under protective gas atmosphere. Selective oxidation was realized by controlling the residual oxygen content. Specifically, the specimens were heated in the near-surface region just above the annealing temperature, thus avoiding the degradation of mechanical properties in the bulk. Evaluation of hardness along cross-sections of each specimen revealed suitable initial temperatures for the inductive heat treatment. Oxide layer systems were analyzed regarding their tribological sliding wear behaviour after selective oxidation, as well as their morphology and chemical composition before and after the sliding wear tests.

Preparation and Research of Skeletal Pt-C Compounds

2018 ◽  
Vol 937 ◽  
pp. 83-87 ◽  
Author(s):  
Xin Ling Hu ◽  
Ying Jiang Qian ◽  
Dong Xu Li ◽  
Xiao Min Chen
Keyword(s):  
Optical Properties ◽  
Synthesis Method ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Excellent Performance ◽  
Electrical And Optical Properties ◽  
Cermet Material ◽  
New Synthesis ◽  
New Ideas ◽  
New Type

Platinum matrix composite is a new type of functional pottery material, which has excellent mechanical, electrical and optical properties. Due to the complexity of the synthesis method and the expensive equipment, the development of cermet material is extremely slow, so that the method to solve the problem is urgently needed. In view of the excellent performance of the Pt-C compounds, by hydrothermal method and high temperature roasting method, a new synthesis method for the composite is proposed using melamine and four platinum chloride at 60 °C by the polymerization reaction with a molar ratio of 20:1. The synthetic of Pt-C compounds provides a new synthesis method and new ideas and at the same time the Pt-C compounds has excellent performance, showing the excellent applications in machining.

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