Green synthesis of nanocrystalline α-Al2O3 powders by both wet-chemical and mechanochemical methods

2018 ◽  
Vol 32 (08) ◽  
pp. 1850109 ◽  
Author(s):  
Huiying Gao ◽  
Zhiyong Li ◽  
Peng Zhao
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Environmentally Benign ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Carbonate Hydroxide ◽  
Wet Chemical ◽  
Α Al2o3

Nanosized [Formula: see text]-Al2O3 powders were prepared with AlCl[Formula: see text]6H2O and NH4HCO3 as raw materials by both wet-chemical and mechanochemical methods, through the synthesis of the ammonium aluminum carbonate hydroxide (AACH) precursor followed by calcination. The environmentally benign starch was used as an effective dispersant during the preparation of nanocrystalline [Formula: see text]-Al2O3 powders. X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to characterize the precursor AACH and products. The results show that nanosized spherical [Formula: see text]-Al2O3 powders without hard agglomeration and with particle size in the range of 20–40 nm can be obtained by the two methods. Comparing the two “green” processes, the mechanochemical method has better prospects for commercial production.

Modification of polypropylene with nanosized α-Al2O3 powders prepared by the mechanochemical method

2018 ◽  
Vol 32 (25) ◽  
pp. 1850296 ◽  
Author(s):  
Huiying Gao ◽  
Zhiyong Li ◽  
Peng Zhao ◽  
Yankun Li ◽  
Zhenru Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Differential Scanning Calorimetric ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
Green Method ◽  
X Ray ◽  
Transmission Electron ◽  
Carbonate Hydroxide ◽  
Α Al2o3

Nanosized [Formula: see text]-Al2O3 powders were prepared by the mechanochemical method, with AlCl[Formula: see text]H2O and NH4HCO3 as raw materials, the environmentally friendly starch as an effective dispersant. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to characterize the ammonium aluminum carbonate hydroxide (AACH) precursor and products. The results show that nanosized spherical [Formula: see text]-Al2O3 powders without hard agglomeration and with particle size in the range of 20–40 nm can be obtained by this novel and green method. Then, polypropylene (PP)/nano [Formula: see text]-Al2O3 nanocomposites were prepared by melt blending in a mixer apparatus. The crystallization behavior and mechanical properties of PP/[Formula: see text]-Al2O3 nanocomposites were further investigated in this study. Wide-angle X-ray diffraction (WAXD) results show that a small amount of [Formula: see text]-crystal of PP forms after adding [Formula: see text]-Al2O3 nanoparticles. According to differential scanning calorimetric (DSC) measurement, the [Formula: see text]-Al2O3 nanoparticles make crystallization temperature of PP enhanced by acting as effective nucleating agents. The tensile strength and impact strength were both improved significantly with the addition of [Formula: see text]-Al2O3 nanoparticles through tensile and impact tests. Scanning electron microscopy (SEM) observation showed that the fracture surface became rougher and further confirmed the above result.

A novel green synthesis of γ-Al2O3 nanoparticles using soluble starch

2019 ◽  
Vol 33 (16) ◽  
pp. 1950182 ◽  
Author(s):  
Huiying Gao ◽  
Mengyao Zhang ◽  
Hua Yang ◽  
Zhiyong Li ◽  
Yankun Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Low Cost ◽  
Environmental Safety ◽  
Soluble Starch ◽  
Al2o3 Nanoparticles ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
Transmission Electron ◽  
Carbonate Hydroxide

In this research, nanocrystalline [Formula: see text]-[Formula: see text] powders have been synthesized by a novel mechanochemical method, through thermal decomposition of the ammonium aluminum carbonate hydroxide (AACH) precursor. The route involved using low-cost [Formula: see text] and [Formula: see text] as raw materials and environmental-friendly soluble starch as an effective dispersant. The precursor and product were characterized by simultaneous thermogravimetric and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that spherical [Formula: see text]-[Formula: see text] nanoparticles without hard agglomeration and with particle size in the range of 20–30 nm can be obtained. The crystallite size of products measured from XRD, SEM and TEM were in good agreement. This novel mechanochemical method combined with the use of environmentally benign starch has the advantages of simple operation, low calcination temperature and environmental safety, and will have good prospects for commercial production.

Structural and Magnetic study of Al3+ doped Ni0.75Zn0.25Fe2-xAlxO4 nanoferrites

2013 ◽  
Vol 1506 ◽  
Author(s):  
L. Wang ◽  
B. K. Rai ◽  
S. R. Mishra
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Chemical Method ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Magnetic Dilution ◽  
Wet Chemical ◽  
Structural And Magnetic Properties

AbstractNanostructured Al3+ doped Ni0.75Zn0.25Fe2-xAlxO4 (x = 0.0,0.2,0.4,0.6,0.8, and 1.0) ferrites were synthesized via wet chemical method. X-ray diffraction, transmission electron microscopy, and magnetization measurements have been used to investigate the structural and magnetic properties of spinel ferrites calcined at 950 °C .With the doping of Al3+, the particle size of Ni0.75Zn0.25Fe2-xAlxO4 first increased to 47 nm at x = 0.4 and then decreased down to 37 nm at x = 1. Saturation magnetization decreased linearly with Al3+ due to magnetic dilution. The coercive field showed an inverse dependence on the particle size of ferrites.

scholarly journals A novel technique to synthesis of tenorite (CuO) nanoparticles from low concentration CuSO4 solution

2011 ◽  
Vol 47 (1) ◽  
pp. 73-78 ◽  
Author(s):  
E. Darezereshki ◽  
F. Bakhtiari
Keyword(s):  
Electron Microscopy ◽  
Decomposition Method ◽  
Raw Materials ◽  
Spherical Shape ◽  
Cuo Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Decomposition Method ◽  
Novel Technique ◽  
Transmission Electron

In this study CuO nanoparticles were prepared via direct thermal decomposition method using basic copper sulphates as wet chemically synthesized precursor which was calcined in air at 750?C for 2h. Samples were characterized by thermogravimetric (TG-DSC), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), infrared spectrum (IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD, EDS, and IR results indicated that the synthesized CuO particles were pure. The SEM and TEM results showed that the CuO nanoparticles were of approximate spherical shape, and 170?5 nm in size. Using this method, Cuo nanoparticles could be produced without using organic solvent, expensive raw materials, and complicated equipment.

Optical properties and energy transfer processes in Tb3+-doped ZnSe quantum dots

2021 ◽  
Author(s):  
Nguyen Ca ◽  
N. D Vinh ◽  
Phan Van Do ◽  
N. T. Hien ◽  
Xuan Hoa Vu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Chemical Method ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transfer Processes ◽  
Transmission Electron ◽  
Wet Chemical

Tb3+-doped ZnSe quantum dots (QDs) with Tb content in the range of 0.5 - 7% were successfully synthesized by a wet chemical method. X-ray diffraction (XRD) and transmission electron microscopy...

In situ x-ray study of the γ- to α-Al2O3 phase transformation during atmospheric pressure oxidation of NiAl(110)

2006 ◽  
Vol 21 (12) ◽  
pp. 3047-3057 ◽  
Author(s):  
A. Vlad ◽  
A. Stierle ◽  
N. Kasper ◽  
H. Dosch ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Orientation Relationship ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Oxidation In Air ◽  
Α Al2o3 ◽  
Underlying Substrate

The oxidation in air of NiAl(110) was investigated in the temperature range from 870 °C–1200 °C by in situ x-ray diffraction and transmission electron microscopy. Oxidation at 870 °C and 1 bar oxygen leads to the formation of an epitaxial layer of γ-alumina showing an R30° orientation relationship with respect to the underlying substrate. At oxidation temperatures between 950 °C and 1025 °C, we observed a coexistence of epitaxial γ- and polycrystalline δ-Al2O3. The α-Al2O3 starts to form at 1025 °C and the complete transformation of metastable phases to the stable α-alumina phase takes place at 1100 °C. The fcc-hcp martensitic-like transformation of the initial γ-Al2O3 to epitaxial α-Al2O3 was observed. X-ray diffraction and cross-section transmission electron microscopy proved the existence of a continuous epitaxial α-Al2O3 layer between the substrate and the polycrystalline oxide scale, having a thickness of about 150 nm. The relative orientation relationship between the epitaxial alumina and the underlying substrate was found to be NiAl(110) || α-Al2O3 (0001) and [110] NiAl || [1120].

Controlled Synthesis of BaF2 Nanorods via Hydrothermal Microemulsion Method

2007 ◽  
Vol 121-123 ◽  
pp. 441-444
Author(s):  
Y.C. Chen ◽  
Y.G. Zhang
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Barium Chloride ◽  
Building Blocks ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
Microemulsion Method ◽  
X Ray ◽  
Transmission Electron ◽  
Microemulsion Droplet

BaF2 nanorods were synthesized by hydrothermal microemulsion method using sodium fluoride (NaF) and barium chloride (BaCl2) as the raw materials. The as-prepared products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results showed that the products were composed of BaF2 nanorods with diameters of 18-62 nm and lengths up to 1μm. A directed aggregation growth process mediated by the microemulsion droplet building blocks is proposed for the formation of BaF2 nanorods. Further work is in progress to evaluate the possibility of synthesizing other fluoride 1D nanostructures using a similar method.

Chemical Synthesis of Magnetic Fe3O4 Nanoparticles

2005 ◽  
Vol 475-479 ◽  
pp. 2275-2278 ◽  
Author(s):  
Rui Feng Yang ◽  
Yu Zhen Lv ◽  
Yahui Zhang ◽  
Chen Min Liu ◽  
Lin Guo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fe3o4 Nanoparticles ◽  
Solution Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Solution Method ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Surface Modified

Fe3O4 nanoparticles were simply prepared by a wet chemical solution method. In this method, poly (N-vinyl-2-pyrrolidone) (PVP) was used as surface modified reagent to control the shape of the product. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) were used to characterize the asprepared Fe3O4 nanoparticles. Furthermore, the magnetic properties of the sample were investigated by a VSM (vibrating sample magnetometer) technique.

HYDROTHERMAL SYNTHESIS OF POTASSIUM BISMUTH TITANATE NANOPARTICLES

2006 ◽  
Vol 05 (04n05) ◽  
pp. 663-669 ◽  
Author(s):  
GANGQIANG ZHU ◽  
HONGYAN MIAO ◽  
GUOQIANG TAN ◽  
YUN LIU ◽  
AO XIA
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Phase Composition ◽  
Bismuth Titanate ◽  
Raw Materials ◽  
Phase Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Potassium bismuth titanate nanoparticles were prepared by the hydrothermal method using Ti ( C 4 H 9 O )4 and Bi ( NO 3)3·5 H 2 O as raw materials in alkaline solution at temperatures of 160–200°C. The crystal phase, particle size, morphology and dispersion of the particles were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the particles with sizes of about 50–100 nm in diameter are well-dispersed K 0.5 Bi 0.5 TiO 3 (KBT) crystals of tetragonal structure, and the alkaline concentration and the temperature of solutions have great effects on the phase composition and morphology of the resultant particles. We could gain the KBT phase of high purity when the concentration of KOH is about 8–12 M and the reaction temperature is about 170–180°C.

scholarly journals Impact of Mg2+ and Zn2+ Addition on the Structural, Morphological, Physicochemical, Dielectric and Biological Properties of Hydroxyapatite

2021 ◽  
Author(s):  
Anandhan Narayanasamy ◽  
Panneerselvam Ramaswamy ◽  
Poonguzhali Ramaswamy ◽  
Amali Roselin Arockiam ◽  
Joseph Panneerdoss Issac ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Bone Growth ◽  
Chemical Precipitation ◽  
Biological Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Wet Chemical Precipitation

Abstract In the present work, the wet-chemical precipitation technique is employed to prepare Zinc/Magnesium doped hydroxyapatite (HAP). In doped HAP, the X-ray diffraction peak shifts to a higher angle because of the contraction of the lattice parameters along a - axis. The Raman peaks at 519, 440, 1464 cm-1 indicate the presence of Mg, Zn and CO32- in doped HAP respectively. The Field Emission Scanning Electron Microscopy (FESEM) measures the grain size of pure, 5% Zn and 5% Mg doped HAP, as 275, 510, and 251 nm respectively. Transmission Electron Microscopy (TEM) confirmed the morphological change in HAP. The X-ray photoelectron spectroscopy (XPS) identifies the presence of Mg2+ and Zn2+ in doped HAP. The dopant elevates the hardness and dielectric constant, so the strength and the bone growth of HAP increases. All the doped samples show excellent antibacterial, antifungal and antibiofilm activities than the pure HAP.

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