Morphology of Cobalt Oxalate Powders Prepared with Pulsed Electromagnetic Field

2015 ◽  
Vol 1088 ◽  
pp. 295-299
Author(s):  
Shu Jing Peng ◽  
Hui Ling Du ◽  
Li Dan Tang
Keyword(s):  
Electromagnetic Field ◽  
Fractal Dimension ◽  
Ammonium Oxalate ◽  
Pulsed Electromagnetic Field ◽  
Surface Fractal Dimension ◽  
X Ray ◽  
Box Counting ◽  
Surface Fractal ◽  
Cobalt Oxalate ◽  
Pulsed Electromagnetic

The spindle or spherical cobalt oxalate powders were prepared by conventional precipitation in the presence of pulsed electromagnetic field (PEMF). The morphology and phase structure were characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The aspect ratio and surface fractal dimension of cobalt oxalate aggregate were calculated using Image tool software and Differential Box Counting (DBC) algorithm. The results indicate that the products prepared from ammonium oxalate and cobalt chloride give rise to the formation of β-CoC2O4∙2H2O. With the increase of pulsed time, the morphology of cobalt oxalate sample varies periodically from rod-like to spheroidic. For the sample treated for 60 s, the degree of sphericity is the highest. The surface fractal dimension is 2.096 and the corresponding fractal form is tight type.

Morphology Control of Cobalt Oxalate Particles under the Action of Pulsed Electromagnetic Field

2011 ◽  
Vol 299-300 ◽  
pp. 554-557
Author(s):  
Hui Ling Du ◽  
Yan Jun Zhou ◽  
Jin Gang Qi ◽  
Jian Zhong Wang ◽  
Ai Min Liu
Keyword(s):  
Electromagnetic Field ◽  
Control Mechanism ◽  
Morphology Control ◽  
Pulsed Electromagnetic Field ◽  
Sem Images ◽  
X Ray ◽  
Phase Structures ◽  
Cobalt Oxalate ◽  
Pulsed Electromagnetic ◽  
Scanning Electron

It is very important for spheroidic metal cobalt powders production to control the morphology of cobalt oxalate powders precursor. The spheroidic cobalt oxalate powders were prepared by conventional precipitation when a pulsed electromagnetic field (PEMF) was introduced. Scanning electron microscopy (SEM) images and X-ray powder diffraction (XRD) were used to characterize morphologies and phase structures of the cobalt oxalate powders. The research results show that a pulsed electromagnetic field (PEMF) play a key role in the process of preparation of spheroidic cobalt oxalate powders. In addition, a possible morphology control mechanism was preliminarily discussed based on the effects of PEMF on the process of growth of cobalt oxalate particles.

Preparation of cobalt oxalate powders with the presence of a pulsed electromagnetic field

2010 ◽  
Vol 199 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Huiling Du ◽  
Jianzhong Wang ◽  
Bing Wang ◽  
Daqiang Cang
Keyword(s):  
Electromagnetic Field ◽  
Pulsed Electromagnetic Field ◽  
Cobalt Oxalate ◽  
Pulsed Electromagnetic

Synthesis of Spherical and Fine Cobalt Powders from Cobalt Oxalate

2015 ◽  
Vol 1088 ◽  
pp. 300-304
Author(s):  
Shu Jing Peng ◽  
Hui Ling Du ◽  
Bing Wang
Keyword(s):  
Electron Microscopy ◽  
Pulsed Electromagnetic Field ◽  
X Ray ◽  
Atomic Force ◽  
Fine Cobalt ◽  
Particle Size Analyzer ◽  
Cobalt Oxalate ◽  
Pulsed Electromagnetic ◽  
Average Size ◽  
Scanning Electron

Spherical and fine cobalt powders were prepared by thermal decomposition of cobalt oxalate precipitated in the presence of pulsed electromagnetic field (PEMF). The morphology and phase structure were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray powder diffraction (XRD). The aspect ratio was calculated by image tool software and the average size of cobalt particles was measured by laser particle size analyzer. The results indicate that both products prepared from cobalt oxalate with or without PEMF give rise to the formation of β-Co. The morphology of both products is similar to that of the precursors. The presence of PEMF plays an important role in formation of spherical and fine cobalt particles.

Pores in PAN-Based Carbon Fiber and Effects of Pore Defects on Mechanical Properties

2007 ◽  
Vol 546-549 ◽  
pp. 1665-1668 ◽  
Author(s):  
Zhong Hua ◽  
Ya Juan Zhong ◽  
Dong Feng Li
Keyword(s):  
Fractal Dimension ◽  
Carbon Fiber ◽  
Small Angle ◽  
Unit Volume ◽  
Fractal Theory ◽  
Surface Fractal Dimension ◽  
X Ray ◽  
X Ray Scattering ◽  
Surface Fractal ◽  
Ray Scattering

Specimens of polyacrylonitrile-based carbon fiber (PAN-CF) with different graphitization temperatures were investigated by small angle X-ray scattering (SAXS) and wide angle X-ray diffraction (WAXD). Based on SAXS intensity data and fractal theory, surface fractal dimension of the pore in PAN-CF was given by small angle X-ray scattering intensity method, the size of various pores and the bigger pore percentage of unit volume were calculated by Fankuchen gradual tangent method. The result indicatesd that the size and surface fractal dimension of the pores, the bigger pore percentage of unit volume increased with increasing graphitization temperature. This forms stress concentration easily, which leads to the decreasing of tensile strength.

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