Papers by Keyword: High Energy Ball Milling

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Authors: Shafiza Afzan Sharif, J.M. Juliewatty, W.A.W. Yusoff
Abstract: Pb (Zr0.52Ti0.48)O3, (PZT) powder has been synthesized using high energy ball milling technique. The synthesized powders were characterized using XRD, SEM, Density, Porosity and Impedance Analyzer. XRD patterns show that the perovskite phase of PZT can be formed from the mixture of starting material after milling for 40 h. The grain sizes of the powder have been estimated to be 1-3 μm. The relationship between the microstructure of the PZT samples and sintering temperature has been discussed. Dense PZT (> 95 % theoretical density) with excellent dielectric properties was obtained when the pellet are sintered at higher temperature with shorter soaking time. The results show that the sample sintered at 1100 °C /1 h yields a clearly uniform grain size with the highest dielectric constant.
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Authors: S. Triaa, L. Faghi, F. Otmane, F. Kali-Ali, M. Azzaz
Abstract: Nanomaterial Cr75Ni25 alloy with a mean crystallite size of 8.3 nm and microstrain of 1.23% after 48h of milling was synthesized by mechanical alloying using a high energy planetary ball milling. The morphological changes and particles size were investigated by scanning electron microscopy and laser diffraction. Magnetic results were measured by Foucault currants, coercive field and residual magnetisation. Structural change during ball milling was evaluated by X-ray diffraction. It was found that the paramagnetic Cr0.8Ni0.2 phase with bcc structure appears for 12 h of milling.
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Authors: Piyalak Ngernchuklin, Arjin Boonruang, Saengdoen Daungdaw, Nestchanok Yongpraderm
Abstract: Nowadays, the concept of harvesting energy from the environment, for example, thermal, wind, sun, vibration and human activities is much of interest. PZT is one of the materials which show an ability to harness vibration energy and then change to electrical energy. Therefore, the PZT (Pb(Zr0.53Ti0.47)O3) doped with 0.02 mol% BYF (Bi(Y0.7Fe0.3)O3) piezoelectric ceramics has been studied to improve the figure of merit (d33*g33). The PZT and BYF powder systems were prepared by solid state reaction with calcination temperature of 800 and 850 °C for 2 h, respectively. XRD results showed that both powders exhibited pure perovskite phase for PZT and single phase of BYF without pyrochlore phase. Then, the two calcined powders (PZT and BYF) were mixed according to the composition of 0.02 mol% BYF doped PZT by two different milling techniques called conventional ball-milling (CBM) and high energy ball-milling (HBM) for 10 h. The result showed that average particle size obtain from HBM was 1 µm which was smaller than from CBM shown up to a few microns in bimodal mode. The PZT-BYF-HBM ceramics showed higher physical and electrical properties but lower K value. Thus promoting to higher g33 which was equal to 36.89 * 10-3(Vm/N) and FOM was 11,632*10-15(m2/N), while PZT-BYF-CBM had g33 of 26.86* 10-3(Vm/N) and FOM at 8,016*10-15(m2/N), respectively.
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Authors: Siti Fairus Mohammad, Sufizar Ahmad, Hamimah Abdul Rahman, Andanastuti Muchtar
Abstract: In this study, samarium strontium cobaltite, Sm0.5Sr0.5CoO3−δ (SSC) and samarium doped ceria, Sm0.2 Ce0.8O1.9 (SDC) carbonate or (SDCC) was used as the new composite cathode powder materials. This composite cathode powder was prepared via high energy ball milling (HEBM) technique for LTSOFC application. Various weight percentages of SDCC ranging from 50 wt.% to 70 wt.% was chosen to be added with SSC powder. The prepared samples of SSC–CE55, SSC-CE64 and SSC-CE73 composite cathode powders were characterized by using TGA, XRD , FTIR in order to investigate their physical structural, morphological and chemical compatibility. Result shows that this new composite cathode powders obtained good thermal stability, chemical compatibility and exhibit no trace of dissimilar phase from both SSC and SDCC. The existence of carbonates layer in the SSC-SDCC composite cathodes powder has been verified by analysis of the FTIR spectra.
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Authors: Claudinei dos Santos, Alexandre Fernandes Habibe, Durval Rodrigues, José C. Minatti, Jefferson F.C. Lins, Luis Alberto dos Santos
Abstract: In this study, the effect of ball/powder ratios for grinding particles of a dental alloy consisting of 66%Co-28%Cr-6%Mo was investigated. Metal powders were obtained from SPEX mill, with tungsten carbide balls, setting the milling time to 60 minutes, 50% of volume of grinding vessel filled with powder and argon inert atmosphere. The ball/powder ratio was varied between 4:1, 6:1, 8:1, 10:1.The powders were characterized by XRD indicating Co as only crystalline phase present, which indicates that Cr and Mo enter into solid solution with the matrix Co. Measurement of crystallite size conducted using the Scherrer equation indicate the crystallite size about 10 to 6nm, due to the increase of the ball/powder ratio of 4:1 to 10:1. The morphology of the milled powders were analyzed by scanning electron microscopy (SEM) and indicate that the agglomerates created by the grinding process must have average sizes varying between 100μm and 200μm with the modification of the ball/powder.
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Authors: Juan Zhou, Yong Chen, Hong Mei Zhu, Xiang Fang Fan
Abstract: The microstructure and strain of gas atomization and water collection Fe73Si3B24 soft magnetic alloy powder treated by high energy ball milling were investigated via SEM and X-ray diffraction. And the magnetic properties of those powders were studied via VSM (Vibrating Sample Magnetometer). The results show that the atomization powders almost exhibited spheric or ellipsoidal shape. The averaged particle size was 104.94 μm. The main phases were composed of α-Fe (Si) and amorphous phase. As ball milling time went on, the interplanar space, amount of amorphous and crystal microstrain of the powders increased, while the grain size decreased. The peak for the (110) crystal plane of α-Fe (Si) phase widened, while the peaks for (200), (211) crystal planes weakened. These three peaks shifted towards to small angle direction. The saturation magnetic induction of treated powders was steady, and the coercivity of samples increased.
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Authors: Hui Qin Cao, Zhi Meng Guo, Wei Wei Yang, Ji Luo
Abstract: The fine and homogenous distribution of the SiC particles in Al metal matrix is basic prerequisite for improving the properties of the SiCp/Al composites. In this paper, the effects of high energy ball milling and ordinary ball milling on the spatial distribution of reinforcement of the SiCp/Al composites have been investigated. The result showed that high energy ball milling is the most effective method to get homogeneous distribution of SiC particles in Al matrix. There were many clusters of SiC particles in the composites fabricated by ordinary ball milling.
157
Authors: Jia Liang Luo, Shun Kang Pan, Zhen Zhong Wang, Zi Qiang Qiao, Li Chun Cheng
Abstract: The Nd7.69Fe92.31-xTix (x = 0, 4, 8, 12) alloy were prepared by arc smelting and high energy ball milling method. The morphology and phase structure of the powders were analyzed by Scanning Electron Microscope (SEM), X-ray diffraction (XRD) and the effect of the Ti content on microwave absorbing properties of the powders were measured by a vector network analyzer (VNA). The results reveal that the samples mainly consisted of Nd2Fe17 and α-Fe crystal structure. The minimum absorption peak frequency shifts to lower frequency region firstly and then shifts to higher frequency region with the increasing amount of Ti content. The minimum reflection loss of Nd7.69Fe84.31Ti8 powder is-31.35 dB and the bandwidth of R < -5 dB reach 3.6 GHz when the coating thickness is 2.0 mm. With the increasing of the coating thickness, the minimum reflectivity peak value of the Nd7.69Fe84.31Ti8 moves to lower frequency region and the minimum reflection loss increase firstly and then decrease. And the minimum reflection value of Nd7.69Fe84.31Ti8 alloy can reach to-38.74 dB (microwave absorption rate 99.99%) at 5.68 GHz, and the bandwidth of R < -10 dB reach 1.12 GHz with the best matching thickness of 2.2 mm.
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Authors: Qing Song Yong, Gui Ming Liu, Bin Li
Abstract: Using high energy ball milling method through changing the content (mass fraction) of alumina to sinter alumina particle dispersion reinforced copper matrix composites with different Al2O3 contents. The effects of alumina content on the microstructure and properties of the sintered body were studied by microstructure observation, relative density, electrical resistivity and hardness test. The results show that when the milling speed was 1400r/min, with the increase of the content of alumina, the relative density decreased, the electrical resistivity increased, the hardness increased first and then decreased. When the Al2O3 content was 1wt% the maximal relative density was 96.4% and the lowest electrical resistivity was 30.843 nΩ•m.
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Authors: Sheng Nan Zhang, Xiao Bo Ma, Ji Xing Liu, Jian Qing Feng, Cheng Shan Li, Ping Xiang Zhang
Abstract: FeSe superconducting bulks were prepared with high energy ball milling (HEBM) aided sintering process, within which process, tetragonal β-FeSe superconducting phase could be formed directly with one step sintering process, and the formation of hexagonal δ-FeSe non-superconducting phase was effectively avoided. The influences of HEBM time on the sintering process of FeSe bulks were systematically investigated. With different HEBM time, the phase composition and morphology of precursor powders changed correspondingly, which thus influenced the final phase composition and superconducting properties of FeSe superconducting bulks. Due to the formation of FeSe bulks with larger tetragonal phase content and higher superconducting transition temperature, HEBM time of 6.0 h was recognized as the optimal parameter. Shorter HEBM time could lead to the insufficient decrease of particle size and low density. While longer HEBM time caused the formation of amorphous hexagonal δ-FeSe, which crystallized during sintering process. Thus no more tetragonal FeSe could be obtained. The FeSe superconducting bulk with the critical temperature Tc(onset) of 8.0 K was obtained with the HEBM time of 6 h, and sintering temperature of 700 oC for 12 h.
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