Synthesis of Submicron AlON Powder by Wet Chemical Processing

2012 ◽  
Vol 624 ◽  
pp. 42-46 ◽  
Author(s):  
Fei Zhong Ma ◽  
Jing Xuan Lei ◽  
Ying Shi ◽  
Jian Jun Xie ◽  
Fang Lei
Keyword(s):  
Carbothermal Reduction ◽  
Single Phase ◽  
Preparation Method ◽  
Process Conditions ◽  
Chemical Processing ◽  
Particle Sizes ◽  
Synthetic Process ◽  
Median Particle ◽  
Wet Chemical ◽  
Partical Size

The single-phase Υ-AlON powders were synthesized from three different precursors: Υ-Al2O3+C, Al(OH)3+C, NH4Al(OH)2CO3+C at 1750°C by carbothermal reduction and nitridation . The effects of aluminium source and synthetic process conditions on the characteristic of Υ-AlON powders were investigated in order to optimize the preparation method. It was revealed that the wet chemical processing was helpful to reduce partical size. The median particle sizes (d50) of AlON powders synthesized from different precusors were 15.33 μm, 2.886 μm, 405.6 nm, respectively.

Synthesis of ZnO Nanoparticles via Simple Wet-Chemical Routes

2013 ◽  
Vol 699 ◽  
pp. 133-137 ◽  
Author(s):  
Byeong Woo Lee ◽  
Jin Heui Koo ◽  
Tae Suk Lee ◽  
Yun Hae Kim ◽  
Jae Suk Hwang
Keyword(s):  
Single Phase ◽  
Hydrothermal Process ◽  
Processing Parameters ◽  
Zinc Nitrate ◽  
Precursor Concentration ◽  
Precipitation Process ◽  
Process Conditions ◽  
Crystallite Sizes ◽  
Zno Powders ◽  
Wet Chemical

Zinc oxide (ZnO) powders were synthesized by a simple precipitation and a hydrothermal process at the temperature range RT-100°C. In precipitation process, the powders were formed by mixing aqueous solutions of zinc nitrate with NaOH aqueous solution under controlled process conditions such as precursor concentration, reaction pH and temperature. Single phase ZnO particles can be easily synthesized in lower precursor concentration, higher reaction pH and temperature. The powders synthesized at room temperature exhibited plates, rods or pointed multipod morphologies depending on the concentration and pH. ZnO crystallites synthesized by hydrothermal process consisted mostly of well developed large or elongated crystallites of plates or rods in shape. The results reveal that the ZnO crystallite sizes and shapes would be efficiently controllable by changing the processing parameters of the preparation processes.

Synthesis and Evaluation of Hollow-Tubular ZnO by Wet Chemical Method

2007 ◽  
Vol 124-126 ◽  
pp. 571-574
Author(s):  
Hideaki Murase ◽  
Shoichiro Shio ◽  
Atsushi Nakahira
Keyword(s):  
Chemical Process ◽  
Aging Process ◽  
Chemical Method ◽  
Room Temperature ◽  
Single Phase ◽  
Chemical Processing ◽  
Wet Chemical Method ◽  
High Transparency ◽  
Wet Processing ◽  
Wet Chemical

In this study, morphology control of ZnO was performed by a wet chemical processing without templates at room temperature. In special, the effect of aging time and pH of this wet processing on ZnO morphologies was in detail investigated. As a result, products composed of a single phase of ZnO with a unique morphology like a hollow tube were obtained. Then, it was found that an aging process played an important role on controlling morphology of ZnO during this wet chemical process. Furthermore, it was found that this hollow-tubular ZnO had a high transparency.

Thermodynamical Calculations and Experimental Confirmation about the Mg-Al-Spinel Reaction Path in the Sol-Gel-Process

2006 ◽  
Vol 317-318 ◽  
pp. 135-138 ◽  
Author(s):  
Wilfried Wunderlich ◽  
Krupathi Vishista ◽  
Francis D. Gnanam ◽  
Daniel Doni Jayaseelan
Keyword(s):  
Thermal Analysis ◽  
Reaction Path ◽  
Sol Gel ◽  
Chemical Processing ◽  
Aluminium Isopropoxide ◽  
Spinel Formation ◽  
Sol Gel Process ◽  
Wet Chemical ◽  
Enthalpy Data ◽  
Good Agreement

The aim of this research is, to clarify which route the sol-gel-process is taking in the case of a Al-Mg-spinel slurry, in particular, whether the hydrolysis reaction or the spinel formation is faster and which of the intermediate hydroxide phases Al(OH)3, and Mg(OH)2, or MgO and Al2O3 or MgAl2O4H2O are formed during the spinel formation. The spinel-alloy was produced using the polymeric route during wet chemical processing. Aluminium-isopropoxide was hydrolyzed in order to form the boehmite-sol and then the same amount of magnesia was added and mixed. This sol precipitated as boehmite (AlOOH) and brucite (Mg(OH)2) after ageing for 12h as confirmed by differential thermal analysis (DTA), and differential thermal gravity (DTG) measurements. After that, the powders were subsequently annealed at 900oC for 3h in air and observed by TEM. Calculations using thermodynamic enthalpy data are in good agreement with the experiments and can be used to predict reaction paths in other system as well.

Physico-Chemical Characterization of Alumina Sols Prepared From Aluminum Alcoxides

1986 ◽  
Vol 73 ◽  
Author(s):  
William L. Olson
Keyword(s):  
Room Temperature ◽  
Gel Filtration ◽  
Chemical Characterization ◽  
Process Conditions ◽  
Chemical Processing ◽  
Rotary Evaporation ◽  
Physico Chemical ◽  
Elution Curves ◽  
Alumina Sol

ABSTRACTAlumina sols derived from aluminum sec-butoxide (Yoldas) were characterized. The distribution of the polymer sizes within the sol, determined by gel filtration chromatography (GFC), was found to be dramatically affected by small changes in the chemical processing or preparative procedure. Aging the sol at room temperature for two weeks produced no significant change in the GFC elution curves of the alumina sol. Sols with a “milky” appearance were found to exhibit a wider distribution of polymers by GFC than transparent sols. Rotary evaporation of the sol followed by redissolution of the residue was found to change the polymer size distribution described by the gel filtration elution curves. These observations coupled with 27Al NMR spectroscopy and viscometry measurements were used to elucidate the effects of process conditions and aging on the molecular structure of the sol.

Relationship of Electrical Properties and Partical Size of Piezoelectric Ceramics Fabricated by Digital Light Processing 3D Printing

2021 ◽  
Author(s):  
Kai Liu ◽  
Jiaming Hu ◽  
Yusheng Shi ◽  
Chenyang Zhou ◽  
Yunfei Sun ◽  
...  
Keyword(s):  
Particle Size ◽  
Electrical Properties ◽  
3D Printing ◽  
Piezoelectric Sensor ◽  
Piezoelectric Ceramics ◽  
Particle Sizes ◽  
Digital Light Processing ◽  
Relationship Of ◽  
Partical Size ◽  
Functional Ceramics

Abstract To improve electrical properties of BaTiO3 piezoelectric ceramics fabricated by 3D printing, effects of particle sizes was investigated on rheological and curing properties of ceramic slurries, electrical properties of BaTiO3 fabricated by Digital Light Processing 3D printing method. It was found that the curing ability of ceramic slurries decreased first and then increased with the increase of particle size from 136 nm to 1486 nm, while the viscosity of the slurries kept decreasing. When the particle size in a range of submicron, the grain size of sintered ceramics decreased from 13.27 μm to 6.84 μm as particle size increasing. Immediately, the relative density, piezoelectric constant, relative permittivity and remanent polarization of sintered ceramics were measured and it turns out to reach 95.32%, 161.4 pC/N, 1512 and 7.59 uC/cm2 respectively while using the BaTiO3 powder with particle sizes of 993 nm. Finally, a cellular structural BaTiO3 ceramics was fabricated by using optimized powder and process parameters and packaged as a piezoelectric sensor, showing a good function of force-electricity conversion. These results demonstrated the feasibility of fabricating high-quality functional ceramics with designed geometry by Digital Light Processing.

scholarly journals Features of Waste Chemical Processing Germanium Concentrates

2020 ◽  
Author(s):  
Igor Nikolaevich Tanutrov ◽  
Marina Nikolaevna Sviridova
Keyword(s):  
Chemical Properties ◽  
Average Diameter ◽  
Toxic Waste ◽  
High Temperature Treatment ◽  
High Dispersion ◽  
Chemical Processing ◽  
Particle Sizes ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

In order to increase the extraction of germanium in the technology of production of germanium concentrates, as well as finding ways to eliminate the accumulation of toxic waste using modern techniques and equipment, the physical and chemical properties of waste chemical processing of germanium concentrates (OHGC) of two domestic enterprises were experimentally studied. The main components of OHGC are: sulphate hemihydrate CaSO4·0.5H2O and hypochlorite Ca(OCl)2 calcium. The moisture content of the sludge amounted to 30–50 %. The content of germanium in the cakes of both companies is in the range of 0.20 and 0.27 %, respectively, indicating the feasibility of recovery in the Ge. At the same time, the samples of cakes differ significantly in the content of impurities, which depends on the types of raw materials in the preparation of concentrates. Granulometric composition of cakes is characterized by high dispersion. With an average diameter of 12 μm, all particle sizes are in the range of 0.5-15 μm. The distribution of particle sizes is shifted in interval of 0–15 μm, and the area of the particles less than 3 μm is not more than 10 %. The high dispersion of the cake is reflected in the specific surface area, which is 23.7 m2/g. Thermographic study found that the heating of the sample cake is accompanied by two endothermic effects of dehydration at 110 and 145–168 ∘C calcium sulfate and hypochloride semihydrate with corresponding weight loss of 13.1 and 12.9 %. The presence of toxic impurities (arsenic, zinc and lead), as well as chlorine, presents significant challenges for the development of disposal technology with the extraction of germanium. Assuming that the undiscovered part of the germanium in the concentrate is compounds or solid solutions with silicon dioxide, an effective technology should include their reagent high temperature treatment. Keywords: waste, germanium concentrate, chemical processing, waste, physical and chemical properties

Synthetic Processes via Complex Precursors of Rare Earth Manganites with the Perovskite and its Related Structures

2004 ◽  
Vol 449-452 ◽  
pp. 725-728 ◽  
Author(s):  
A. Shimono ◽  
Hirohisa Sato ◽  
K. Kawada-Wada ◽  
Yasuo Ito ◽  
Naoki Kamegashira
Keyword(s):  
Rare Earth ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Rare Earth Complex ◽  
Normal Process ◽  
Composition Region ◽  
Synthetic Process ◽  
Reaction Method ◽  
X Ray ◽  
Rare Earth Manganites

A development of synthetic process via rare earth complex precursors was applied to a formation of rare earth manganites which can not be easily formed by conventional (normal) process. Several compounds of rare earth manganites with various structures were successfully synthesized by this method and their crystal structures were identified by powder X-ray diffractometry. Both of the orthorhombic and rhombohedral LaMnO3phases were prepared. LnMn2O5phase was more easily prepared by this method than by another method. The solid solution of (Sr,La)2MnO4phase for various compositions were tried to prepare a single phase, especially for a composition region Sr/La ratio < 1. since this phase is normally formed for only region of Sr/La ratio .. 1 by the solid state reaction method.

Microfluidic paper-based analytical devices fabricated by low-cost photolithography and embossing of Parafilm®

Lab on a Chip ◽  
2015 ◽  
Vol 15 (7) ◽  
pp. 1642-1645 ◽  
Author(s):  
Ling Yu ◽  
Zhuan Zhuan Shi
Keyword(s):  
Low Cost ◽  
Chemical Processing ◽  
Wet Chemical

The combination of photolithography-patterning and embossing of a Parafilm® can fabricate microfluidic paper-based analytical devices (μPADs) without the use of a wax printer, cutter plotter and wet-chemical processing of paper.

Influence of Powder Particle Size of Slurries on Mechanical Properties of Porous Hydroxyapatite Ceramics

2005 ◽  
Vol 284-286 ◽  
pp. 365-368 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Particle Sizes ◽  
Wet Milling ◽  
Median Particle Size ◽  
Powder Characteristics ◽  
Median Particle

The effect of different particle sizes on the flexural strength and microstructure of three different types of hydroxyapatite (HAp) powders was studied. The powder characteristics of laboratory synthesized HAp powder (Lab1 and Lab2) were obtained through a wet milling method, and the median particle size and the specific surface area of powders are different with the dryness period. The median particle sizes of Lab1 and Lab2 are 0.34 µm and 0.74 µm, and the specific surface areas of Lab1 and Lab2 are 38.01 m2/g and 19.77 m2/g. The commercial HAp had median particle size of 1.13 µm and specific surface area of 11.62m2/g. The different powder characteristics affected the slip characteristics, and the flexural strength and microstructure of the sintered porous HAp bodies are also different. The optimum value for the minimum viscosity in these present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were investigated. The flexural strengths of the porous HAp ceramics prepared by heating at 1200°C for 3 hrs in air were 17.59 MPa for Lab1 with a porosity of 60.48％, 10.51 MPa for Lab2 with a porosity of 57.75％, and 3.92 MPa for commercial HAp with a porosity of 79.37％.

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