scholarly journals Synthesis of nearly spherical AlN particles by an in-situ nitriding combustion route

2020 ◽  
Author(s):  
Zhilei Wei ◽  
Kang Li ◽  
Bangzhi Ge ◽  
Chaowei Guo ◽  
Hongyan Xia ◽  
...  
Keyword(s):  
Particle Size ◽  
Combustion Temperature ◽  
High Efficiency ◽  
Raw Materials ◽  
Low Cost ◽  
Synthesis Method ◽  
Preparation Methods ◽  
Average Size ◽  
Micrometer Size

Abstract Spherical AlN powders with micrometer size have attracted great attention owing to their good fluidity and dispersity. However, the industrial preparation methods usually require high temperature and long soaking time, which lead to the high cost and limit the wide application of the products. Herein, nearly spherical AlN particles with the average size of 2.5 µm were successfully synthesized via an in-situ combustion synthesis method. The effect of N2 pressure, NH4Cl content and Al particle size on the combustion reaction procedure, phase composition and microstructure of the products was systematically investigated. The results showed that the decreased N2 pressure, increased NH4Cl content and Al particle size led to the decreasing of combustion temperature and speed, which further affected the morphology of the products. As a result, low N2 pressure (0.2 MPa), a small amount of NH4Cl (0.5 wt%) and fine Al particles (~ 2.5 µm) contributed to a moderate combustion temperature and facilitated the formation of nearly spherical AlN particles. In addition, based on the gas-releasing assisted quenching experiments and thermo-kinetic analysis, a two-step growth mechanism for the nearly spherical AlN particles was rationally proposed. The present method shows the advantages of low cost and high efficiency for preparing nearly spherical AlN particles, which can be used as raw materials for electronic substrates and fillers for packaging materials.

scholarly journals Synthesis of nearly spherical AlN particles by an in-situ nitriding combustion route

2021 ◽  
Vol 10 (2) ◽  
pp. 291-300
Author(s):  
Zhilei Wei ◽  
Kang Li ◽  
Bangzhi Ge ◽  
Chaowei Guo ◽  
Hongyan Xia ◽  
...  
Keyword(s):  
Particle Size ◽  
Combustion Temperature ◽  
High Efficiency ◽  
Raw Materials ◽  
Low Cost ◽  
Synthesis Method ◽  
Preparation Methods ◽  
Average Size ◽  
Micrometer Size

AbstractSpherical AlN powders with micrometer size have attracted great attention owing to their good fluidity and dispersity. However, the industrial preparation methods usually require high temperature and long soaking time, which lead to the high cost and limit the wide application of the products. Herein, nearly spherical AlN particles with the average size of 2.5 µm were successfully synthesized via an in-situ combustion synthesis method. The effect of N2 pressure, NH4Cl content, and Al particle size on the combustion reaction procedure, phase composition, and microstructure of the products was systematically investigated. The results showed that the decreased N2 pressure, increased NH4Cl content, and Al particle size led to the decreasing of combustion temperature and speed, which further affected the morphology of the products. As a result, low N2 pressure (0.2 MPa), a small amount of NH4Cl (0.5 wt%), and fine Al particles (∼2.5 µm) contributed to a moderate combustion temperature and facilitated the formation of nearly spherical AlN particles. In addition, based on the gas-releasing assisted quenching experiments and thermo-kinetic analysis, a two-step growth mechanism for the nearly spherical AlN particles was rationally proposed. The present method shows the advantages of low cost and high efficiency for preparing nearly spherical AlN particles, which can be used as raw materials for electronic substrates and fillers for packaging materials.

scholarly journals Synthesis of nearly spherical AlN particles by an in-situ nitriding combustion route

2020 ◽  
Author(s):  
Zhilei Wei ◽  
Kang Li ◽  
Bangzhi Ge ◽  
Chaowei Guo ◽  
Hongyan Xia ◽  
...  
Keyword(s):  
Particle Size ◽  
Combustion Temperature ◽  
High Efficiency ◽  
Raw Materials ◽  
Low Cost ◽  
Synthesis Method ◽  
Preparation Methods ◽  
Average Size ◽  
Micrometer Size

Abstract Spherical AlN powders with micrometer size have attracted great attention owing to their good fluidity and dispersity. However, the industrial preparation methods usually require high temperature and long soaking time, which lead to the high cost and limit the wide application of the products. Herein, nearly spherical AlN particles with the average size of 2.5 μm were successfully synthesized via an in-situ combustion synthesis method. The effect of N 2 pressure, NH 4 Cl content and Al particle size on the combustion reaction procedure, phase composition and microstructure of the products was systematically investigated. The results showed that the decreased N 2 pressure, increased NH 4 Cl content and Al particle size led to the decreasing of combustion temperature and speed, which further affected the morphology of the products. As a result, low N 2 pressure (0.2 MPa), a small amount of NH 4 Cl (0.5 wt%) and fine Al particles (~2.5 μm) contributed to a moderate combustion temperature and facilitated the formation of nearly spherical AlN particles. In addition, based on the gas-releasing assisted quenching experiments and thermo-kinetic analysis, a two-step growth mechanism for the nearly spherical AlN particles was rationally proposed. The present method shows the advantages of low cost and high efficiency for preparing nearly spherical AlN particles, which can be used as raw materials for electronic substrates and fillers for packaging materials.

scholarly journals Polymer-Assisted Modification of Metal-Organic Framework MIL-96 (Al): Influence on Particle Size, Crystal Morphology and Perfluorooctanoic Acid (PFOA) Removal

2020 ◽  
Author(s):  
Luqman Hakim Mohd Azmi ◽  
Daryl R. Williams ◽  
Bradley P. Ladewig
Keyword(s):  
Particle Size ◽  
Crystal Morphology ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Synthesis Method ◽  
Perfluorooctanoic Acid ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Metal Organic ◽  
Organic Framework

<div><b>Abstract</b></div><div>A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve >200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.<br></div>

scholarly journals Polymer-Assisted Modification of Metal-Organic Framework MIL-96 (Al): Influence on Particle Size, Crystal Morphology and Perfluorooctanoic Acid (PFOA) Removal

2020 ◽  
Author(s):  
Luqman Hakim Mohd Azmi ◽  
Daryl R. Williams ◽  
Bradley P. Ladewig
Keyword(s):  
Particle Size ◽  
Crystal Morphology ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Synthesis Method ◽  
Perfluorooctanoic Acid ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Metal Organic ◽  
Organic Framework

<div><b>Abstract</b></div><div>A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve >200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.<br></div>

scholarly journals Network of Palladium-Based Nanorings Synthesized by Liquid-Phase Reduction Using DMSO-H2O: In Situ Monitoring of Structure Formation and Drying Deformation by ASEM

2020 ◽  
Vol 21 (9) ◽  
pp. 3271 ◽  
Author(s):  
Takuki Komenami ◽  
Akihiro Yoshimura ◽  
Yasunari Matsuno ◽  
Mari Sato ◽  
Chikara Sato
Keyword(s):  
Surface Tension ◽  
Liquid Phase ◽  
Aqueous Solutions ◽  
Critical Point ◽  
Synthesis Method ◽  
Three Dimensional ◽  
In Situ Monitoring ◽  
Critical Point Drying ◽  
Micrometer Size

We developed a liquid-phase synthesis method for Pd-based nanostructure, in which Pd dissolved in dimethyl sulfoxide (DMSO) solutions was precipitated using acid aqueous solution. In the development of the method, in situ monitoring using atmospheric scanning electron microscopy (ASEM) revealed that three-dimensional (3D) Pd-based nanonetworks were deformed to micrometer-size particles possibly by the surface tension of the solutions during the drying process. To avoid surface tension, critical point drying was employed to dry the Pd-based precipitates. By combining ASEM monitoring with critical point drying, the synthesis parameters were optimized, resulting in the formation of lacelike delicate nanonetworks using citric acid aqueous solutions. Precipitation using HCl acid aqueous solutions allowed formation of 500-nm diameter nanorings connected by nanowires. The 3D nanostructure formation was controllable and modifiable into various shapes using different concentrations of the Pd and Cl ions as the parameters.

Clinical Trial of a Novel Starch-Based Adhesive Bandages for Medical Dressing

2020 ◽  
Vol 990 ◽  
pp. 96-100
Author(s):  
Sittiporn Punyanitya ◽  
Banyong Khantawa ◽  
Sakdiphon Thiansem ◽  
Rungsarit Koonawoot ◽  
Phanlob Chankachang ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Medical Devices ◽  
Raw Materials ◽  
Low Cost ◽  
International Standards ◽  
Preparation Methods ◽  
Safety And Efficacy ◽  
Plastic Components ◽  
Adhesive Bandage ◽  
Novel Starch

A typical adhesive bandage comprises of four main parts; the backing is often made of plastic; the adhesive sheet is usually plastic; the adhesive is commonly acrylate; the absorbent pad is often made of cotton. This adhesive bandages are made from starch based adhesive and natural paper, which have no plastic components. A starch-based adhesive bandages are tested on 100 volunteers and the result shows good performances with high confident of safety and efficacy. The raw materials and preparation methods are low cost, easily reproducible and eco-friendly, according to the international standards of medical devices regulation.

scholarly journals In situ recombination junction between p-Si and TiO2enables high-efficiency monolithic perovskite/Si tandem cells

2018 ◽  
Vol 4 (12) ◽  
pp. eaau9711 ◽  
Author(s):  
Heping Shen ◽  
Stefan T. Omelchenko ◽  
Daniel A. Jacobs ◽  
Sisir Yalamanchili ◽  
Yimao Wan ◽  
...  
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Atomic Layer ◽  
Optical Losses ◽  
Layer Deposition ◽  
Solar Electricity ◽  
The Cost ◽  
Recombination Junction ◽  
Processing Steps

Increasing the power conversion efficiency of silicon (Si) photovoltaics is a key enabler for continued reductions in the cost of solar electricity. Here, we describe a two-terminal perovskite/Si tandem design that increases the Si cell’s output in the simplest possible manner: by placing a perovskite cell directly on top of the Si bottom cell. The advantageous omission of a conventional interlayer eliminates both optical losses and processing steps and is enabled by the low contact resistivity attainable between n-type TiO2and Si, established here using atomic layer deposition. We fabricated proof-of-concept perovskite/Si tandems on both homojunction and passivating contact heterojunction Si cells to demonstrate the broad applicability of the interlayer-free concept. Stabilized efficiencies of 22.9 and 24.1% were obtained for the homojunction and passivating contact heterojunction tandems, respectively, which could be readily improved by reducing optical losses elsewhere in the device. This work highlights the potential of emerging perovskite photovoltaics to enable low-cost, high-efficiency tandem devices through straightforward integration with commercially relevant Si solar cells.

Preparation and Characterization of ß-Tricalcium Phosphate via Wet Mechanochemical Treatment

2008 ◽  
Vol 368-372 ◽  
pp. 1166-1168 ◽  
Author(s):  
Tao Yu ◽  
Jian Dong Ye
Keyword(s):  
Tricalcium Phosphate ◽  
Raw Materials ◽  
Low Cost ◽  
Synthesis Method ◽  
Particle Diameter ◽  
Mechanochemical Treatment ◽  
Mechanochemical Reaction ◽  
Ftir Analysis ◽  
Hydrogen Phosphate

In this work, a simple, reproducible and low-cost synthesis method for the preparation of ß-tricalcium phosphate (ß-TCP) was developed. ß-TCP was prepared via wet mechanochemical treatment using calcium oxide and calcium hydrogen phosphate as raw materials. XRD and FTIR analysis indicated that the as-treated precursor was non-stoichiometric, poorly-crystallized carbonated hydroxyapatite (CHA) resulting from the mechanochemical reaction, and the crystalline ß-TCP powder was obtained by calcining the precursor at 800°C for 2 hours. SEM observation showed that the addition of surfactants could eliminate the agglomeration of the powder and well-dispersive ß-TCP powder with a particle diameter between 0.1 and 2.0 2m can be obtained.

Study on the Preparation and Particle Size Control of Silica Sphere in a Sol-Gel Process

2013 ◽  
Vol 787 ◽  
pp. 52-57
Author(s):  
Ying Qiu ◽  
Shu Chun Hu ◽  
Jing Zhai ◽  
Zhi Jian Lin ◽  
Wen Feng Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Sol Gel ◽  
Size Control ◽  
Ammonia Concentration ◽  
Amorphous Structure ◽  
Silica Sphere ◽  
Sol Gel Process ◽  
Key Factor ◽  
Average Size

Silica sphere has wide applications not only in the field of physical chemistry dealing with dynamic behavior and stability of particulate systems, but also in industries including catalysts, ceramics, pigments, pharmacy, etc. However, the control on the particle size is a key factor in the preparation process of silica sphere. In this paper, silica sphere with uniform sphere morphology and amorphous structure was prepared by a sol-gel method, and the control of particle size was emphatically studied. The results showed that the particle size of the as-prepared silica sphere was obviously influenced by the raw materials concentration. The average size of the product increased from 0.66 μm to 0.90 μm when ethanol concentration increased from 7.14M to 9.55M, increased from 0.50 μm to 0.90 μm with the increase of ammonia concentration in the range of 1.88M to 2.36M, and increased from 0.47 to 0.90 μm while tetraethoxysilane concentration increased from 0.08M to 0.11M. Further study indicated that the silica particle size was also influenced by reaction temperature, it increased with the increase of temperature from 26°C to 28°C, and decreased with the further increase of temperature in the scope of 28°C to 32°C.

Simple Preparation of Well-Dispersed Nanosized α-Fe2O3

2014 ◽  
Vol 513-517 ◽  
pp. 78-81
Author(s):  
Yu Ping Tong ◽  
Chen Zheng ◽  
Chao Li Yu ◽  
Xin Yue Fang ◽  
Yong Qiang Zhang ◽  
...  
Keyword(s):  
Crystalline Phase ◽  
Raw Materials ◽  
Low Cost ◽  
Combustion Method ◽  
Absorption Peak ◽  
Broad Absorption ◽  
Broad Absorption Peak ◽  
Dispersed Particles ◽  
Simple Preparation ◽  
Average Size

Well-dispersed α-Fe2O3 nanocrystalline was prepared by a convenient self-propagation combustion method using low-toxic glycine as fuel, low-cost Fe (NO3)2·9H2O as raw materials. The XRD results indicate that the glycine doses have an important effect on the control of the average size and the order of the crystalline phase. The UV-vis results indicate that the α-Fe2O3 nanocrystals prepared by this method have a broad absorption peak whose center is at about 221 nm. TEM images revealed that the products were composed of well-dispersed particles with an average size about 35 nm.

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