Testing and Evaluation on Fractal Characteristic of Cementing Materials Powder

2011 ◽  
Vol 374-377 ◽  
pp. 1848-1853
Author(s):  
Ning Chen ◽  
Ming Tang ◽  
Jing Qi Li ◽  
Hong Liang Liu

The cement powder materials are evaluated by fractal theory. Fractal characteristic parameters are analysed and evaluated by the method of laser particle size analyzer, microscope, transmission electron microscope. In this paper, cement powder materials has good self-similarity. Fractal dimension of grading is tested and evaluated by laser particle size analyzer, fractal dimension of cluster is tested by microscope, fractal characteristic of particle distribution is tested by transmission electron microscope. Compared with traditional weight of screen residue and specific surface area, those methods are more careful. Fineness fractal parameters and activity of ultra fine fly ash and pulverized slag have good linear dependence relation that is evaluated by fractal dimensions. Fractal characteristics provide an important basis to further explore the inherent relation of cement powder materials and concrete material density effect.

2011 ◽  
Vol 295-297 ◽  
pp. 840-843
Author(s):  
Jian Hua Du ◽  
Yuan Yuan Li ◽  
Xiao Hui Zheng

Copper coated nano-SiO2 composite particles were prepared by mechanical milling technology. The effects of milling time on morphology, granularity, component and microstructure of the composite particles were characterized by scanning electronic microscope, laser particle size analyzer, energy depressives spectrometer and transmission electron microscope, respectively. Results showed that dendrite composite particles change to the flaky, and then to spherical ones with the milling time increasing. The particle size decreases firstly and then increases with the milling time increasing. The n-SiO2 particles disperse more homogeneously in the composite particles with the milling time increasing.


2010 ◽  
Vol 177 ◽  
pp. 32-36 ◽  
Author(s):  
An Rong Wang ◽  
Jian Li ◽  
Qing Mei Zhang ◽  
Hua Miao

Weak magnetic ZnFe2O4 nanoparticles were prepared by coprecipitation and treated with different concentrations of Fe(NO3)3 solution. Untreated and treated particles were studied using a vibrating sample magnetometer, transmission electron microscope, by X-ray diffraction, X-ray energy dispersive spectroscopy and X photoelectron spectroscopy. The results showed that, after treatment, the ZnFe2O4/γ-Fe2O3 forms disphase nanoparticles, with enlarged size, enhanced magnetic properties and with a surface parceled with Fe(NO3)3. The size of the particles and their magnetic properties are related to the concentration of the treatment solution. The particle size and magnetic properties could be controlled by controlling the concentration of treating solution, therefore nanoparticles can be more widely used.


2010 ◽  
Vol 434-435 ◽  
pp. 850-852
Author(s):  
Qi Wang ◽  
Bo Yin ◽  
Zhen Wang ◽  
Gen Li Shen ◽  
Yun Fa Chen

In present work, ceria microspheres were synthesized by template hydrothermal method. Crystalline form of the as-synthesized ceria microspheres was defined by X-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Dispersibility of ceria microspheres was comprehensively characterized using scanning electron microscope (SEM) observation and laser particle size analyzer. Furthermore, the ultraviolet light absorption performances of ceria microspheres with several different sizes were compared by ultraviolet visible spectrophotometer. The results showed that ceria microspheres presented excellent UV absorbent property and the size influence was remarkable.


2016 ◽  
Vol 10 (1) ◽  
pp. 35-40
Author(s):  
Yunasfi . ◽  
P. Purwanto ◽  
Mashadi .

Utilization of HEM (high energy milling) technique for growth of CNT (carbon nanotube) from graphite powders by using Ni as catalyst was carried out. Milling process performed on a mixture of graphite powder and nickel powder (Ni-C powders) with the ratio of weight percent of 98%: 2%, with a variation of milling time between 25 up to 75 hours. Characterization using PSA (Powder Size Analyzer), SAA (Surface Area Analyzer), TEM (Transmission Electron Microscope) and Raman Spectroscopy performed to obtain information about particle size, surface area, morphology and the structure bonding of the milled powder respectively. The analysis results of Ni-C powders using PSA and SAA showed the smallest particle size and biggest surface area obtained after milling process for 50 hours, i.e. 80 nm and 705 m2/g, respectively. TEM observations revealed formation of flat fibers which quantity increased with increasing milling time. This flattened fiber behave as an initiator for the growth of CNTs. Ni-C powder milling for 50 hours results more clearly show the growth of CNTs. Analysis by Raman Spectroscopy showed two bands at 1582 cm−1 as a peak of G band and at 1350 cm-1 as a peak of D band. These spectra are typical for sp2 structure. The position of G band peak is close to 1600 cm-1 as the evidence of a change to nano-crystalline graphite. The highest intensity of D band shown in the milling process for 50 hours, which indicates that this milling time produces more graphite-like structure compared to other conditions, and is predicted good for growing CNTs. AbstrakPemanfaatan teknik HEM (High Energy Milling) untuk penumbuhan CNT (carbon nanotube) dari serbuk grafit dengan menggunakan Ni sebagai katalis. Proses milling dilakukan terhadap campuran serbuk grafit dan serbuk nikel (serbuk Ni-C) dengan perbandingan berat 98% : 2%, dengan variasi waktu milling antara 25-75 jam. Karakterisasi menggunakan fasilitas PSA (Particle Size Analyzer), SAA (Surface Area Analyzer), dan TEM (Transmission Electron Microscope) serta Raman Spektroscopy yang masing-masingnya untuk mendapatkan informasi tentang ukuran partikel, luas permukaan dan morfologi serta struktur ikatan serbuk hasil milling. Hasil analisis serbuk Ni-C dengan PSA dan SAA menunjukkan ukuran partikel paling kecil dan luas permukaan paling besar diperoleh setelah proses milling selama 50 jam, masing-masing 80 nm dan 705 m2/g. Pengamatan TEM menunjukkan serbuk-serbuk berbentuk serat pipih dengan kuantitas yang meningkat dengan bertambahnya waktu milling. Serat pipih ini perupakan cikal bakal penumbuhan CNT. Serbuk Ni-C hasil milling menunjukkan penumbuhan CNT terlihat lebih jelas setelah milling selama 50 jam. Hasil analisis dengan Raman Spectroscopy memperlihatkan puncak G band pada bilangan gelombang 1582 cm−1 yang merupakan spektrum untuk struktur sp2 dari grafit dan puncak D band pada bilangan gelombang 1350 cm-1 yang mungkin merupakan deformasi struktur grafit. Posisi puncak G band mendekati 1600 cm-1 menjadi bukti perubahan ke grafit nano kristal. Intensitas D band tertinggi ditunjukkan oleh sistem komposit Ni-C hasil proses milling selama 50 jam dan hal ini sebagai indikasi bahwa proses milling selama 50 jam terhadap sistem komposit Ni-C lebih berstruktur mirip grafit (graphitic-like material) dibanding kondisi lainnya dan diprediksi bagus untuk menumbuhkan CNT. Dengan demikian, waktu milling yang optimal untuk penumbuhan CNT dari serbuk grafit dengan menggunakan Ni sebagai katalis adalah adalah 50 jam.  


2020 ◽  
Vol 13 (04) ◽  
pp. 2050020
Author(s):  
Suihan Cui ◽  
Qingdong Ruan ◽  
Cuiqing Jiang ◽  
Tijun Li ◽  
Zheng Jin ◽  
...  

Li(NixMnyCoz)O2 cathode materials (NMC) have advantages such as the good Li ion diffusivity, stable reversible capacity, and environmental compatibility in spite of a low actual capacity. Although a double-layer lithium structure can be generated by pre-lithiation, the thickness is very small and the capacity improvement is limited. In this work, a series of Li([Formula: see text][Formula: see text][Formula: see text])O2 nanoparticles are prepared by the sol–gel method and centrifugation and the pre-lithiation process are monitored by transmission electron microscope (TEM). A double lithium structure of about 10 nanometers thick is produced on the NMC materials with different sizes. With decreasing NMC particle size, the proportion of the double-layer lithium structure increases and reaches 48% for a particle diameter of 100[Formula: see text]nm. The results reveal a viable means to improve the capacity of NMC materials in charging and discharging.


2013 ◽  
Vol 544 ◽  
pp. 135-138
Author(s):  
Fen Rong Yang ◽  
Kai Qi Liu ◽  
Bing Jun Wang ◽  
Xiao Hu Xie

With introducing briefly the refractory powder materials, the article analyzed the morphology and particle size distribution of commercial different size fraction corundum powder by scanning electron microscopy and laser particle size analyzer. The results showed that most of corundum powder particles were angular spherical, Their particle volume average diameters D(4,3) are greater than median grain sizes D50, and with the difference increasing the distribution curve symmetry becomes worse. Moreover, size frequency distribution curve presents slanting unimodal or bimodal pattern, not completely normal distribution. Besides those, particle size ranges are very wide, e.g. the D90 of 15 μ m is 30 times larger than D10. Therefore, using only the average particle diameter indicates the powder is not comprehensive. The parameters and the size distribution cure measured by laser particle size analyzer can be detailed and accurate to reflect actual powder particle size and distribution, so using them as the commercial corundum powder specification values will be important to enhance the effective utilization of the powder.


2014 ◽  
Vol 881-883 ◽  
pp. 1568-1571
Author(s):  
Zhi Qiang Ning ◽  
Ling Ling Zhang

The phase composition and particle size of the boron mud is investigated by X-ray diffractometry (XRD), scanning electron microscope (SEM) and laser particle size analyzer. The mainly phase composition of the boron mud are magnesite (MgCO3) and forsterite (Mg2SiO4). The mainly phase composition of the calcined boron mud are forsterite (Mg2SiO4) and a small amount magnesia (MgO). the sizes of the boron mud are about 2~6μm and a few of them are bigger and less than 10μm and the particle size of less than 10μm is about 60%.


ROTOR ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Hendri Van Hoten

The research is about analysis of Nano Sized Bioceramic Characterization Using Particle Size Analyzer (PSA). In the previous research, optimization of the parameters of making nano powders on Ball Mill machines using the Taguchi and ANOVA methods. The optimum parameters of the Taguchi Design analysis were grinding rate, grinding time and Ball Powder Ratio respectively 250 rpm, 3 hours and 1: 6. After that the characterization of the powder use a Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Powder size measurement use SEM tools obtained the smallest average size of 1.305 mm while using TEM tools showed the average size of the smallest powder between 50-100 nm. TEM test results were confirmed again using PSA. The results of the characterization using PSA showed that the particle size in the range 100-300 nm was approximately 80%


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