Papers by Author: Xiao Nong Cheng

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Authors: Xiao Ying Wang, Yu Tao Zhao, Gang Chen, Song Li Zhang, Xiao Nong Cheng
Abstract: Mg2Si/AZ91D magnesium matrix composites are fabricated from AZ91D-Al2(SiO3)3 system by direct melt reaction method. The effects of the variation Al2(SiO3)3 addition contents to the microstructures and mechanical properties of the composites are investigated. The results show that the amounts of Mg2Si particles are increased and the structures of AZ91D magnesium alloy are refined with the Al2(SiO3)3 content increasing. When the additional content of Al2(SiO3)3 is 3wt.%, the tensile strength of the composite reaches 178.6MPa, which is increased by nearly 14.5% than that of AZ91D matrix alloy.
Authors: Xi Feng Zhang, Ke Wei Li, Ying Zhou, Xiao Nong Cheng
Abstract: To synthesize morphology- controlled nano- copper with excellent lubrication properties as lubricant’s additive, chemical reduction synthesis method was used coalescing in situ via liquid paraffin as resolvent and modification with polyethylene glycol (PEG-2000). The as- prepared Cu nanopieces with 35.59 nm average length and 21.03 nm average width were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The tribological behavior of Mobil 1 5W-30 lubricating oil with nano- Cu were measured by ball- on- disk UMT- Ⅱ tribometer and analyzed by SEM and EDS. It is found that the tribological performance of Mobil 1 5W- 30 with nano- Cu is improved, and the optimization addition is 0.4% (Cu wt) with the lowest friction coefficient.
Authors: Xue Yan, Xiao Nong Cheng, Xin Bo Yang, Cheng Hua Zhang
Abstract: ZrW2O8 was successfully synthesized via combustion method with (NH4)5H5[H2(WO4)6] ·H2O, ZrOCl2·8H2O, H3BO3, (NH2)2CO and HNO3. The best prescription of combustion synthesizing of ZrW2O8 was obtained. The linear thermal expansion coefficient of synthesized ZrW2O8 is -5.08×10-6oC-1 in the temperature range of 50-600oC. Different weight ratios of ZrW2O8 and ZrO2 were taken into account. Al2O3 was added into the composite during sintering to increase the density of the composites. When the weight ratio of ZrO2 to ZrW2O8 is 2, the composite with near zero thermal expansion can be obtained. 0.25 wt% Al2O3 can effectively increase the density of ZrO2/ZrW2O8 composites with slight influence on the thermal expansion property.
Authors: Dong Xu, Chen Zhang, Xiao Nong Cheng, Yuee Fan, Tao Yang, Hong Ming Yuan
Abstract: The CaCu3-xZnxTi4O12 (CCZTO) (x=0, 0.06, 0.1, 0.2) ceramics were prepared by Sol–gel method. The XRD pattern shows that crystal structure of the sample with no Zn is basically single-phase. The SEM results indicate that the samples have porous structures and the gain size decreases with the content of Zn increasing. The dielectric properties of CCZTO were analyzed by Agilent 4294A. The experimental results show that the dielectric constants are less than that in other papers reported obviously because of their mesoporous structures. With the little doping amount(x=0.06, 0.1), a sharp decrease happened in the dielectric constant (εr). The higher εr was found when x=0.2, but its dielectric loss (D) had greatly increased and frequency stability of dielectric property became worse. The uniformity of gains was put forward to explain the results which showed great impact on the dielectric constant.
Authors: Ya Bo Li, Fu Ming Wang, Xiao Nong Cheng
Abstract: Intergranular corrosion behavior of 00Cr12 ferritic stainless steels with different amounts cerium was evaluated. For this evaluation, electrochemical measurements - polarization curves - were obtained for tested materials, and optical microscope was used to observe corrosive microstructure. Experimental results shows: cerium reduces grain sizes and improves intergranular corrosion resistance of test materials. Through mechanism analysis: cerium reduces grain sizes, increases grain boundary density, therefore might improve distribution aspects of carbides and nitrides, chromium depletion situation near grain boundary would be improved, this work worth further study.
Authors: Qiang Liu, Xiao Nong Cheng, Huang Xia Fei
Abstract: TiO2 thin film containing SrFe12O19 powders on the surface of 316L stainless steel and NiTi alloy was prepared through sol-gel method and micro-magnetic field was established by the magnetization process applied on the coating. The coating film was characterized by x-ray diffraction (XRD) and the surface morphology of the coating was observed by scanning electron microscope (SEM). This blood compatibility thin film was evaluated by dynamic cruor time of blood test.The results show that dynamic cruor time of blood is prolonged by the micro-magnetic field of the thin film, indicating improved blood compatibility.
Authors: Dong Xu, Xiao Nong Cheng, Ming Song Wang, Li Yi Shi
Abstract: La2O3-doped ZnO-Bi2O3-based varistor ceramics were obtained by a solid reaction route, and the microstructure and electrical properties of the varistor ceramics were studied in this paper. The results showed with addition of 0-1.00mol% La2O3, La2O3-doped ZnO-based varistor ceramics were prepared in this paper with the voltage gradient of 77-503V/mm, the nonlinear coefficient of 2.4-36.8, and the leakage current of 0.09-494μA. The results also showed with addition of 0.08mol% La2O3, La2O3-doped ZnO-based varistor ceramics exhibit comparatively ideal comprehensive electrical properties. Such as the threshold voltage was 320V/mm, the nonlinear coefficient was 36.8 and the leakage current was 0.29μA. The doping of La2O3 affects the form and decomposition of the pyrochlore.
Authors: Cheng Hua Zhang, Jian Mei Pan, Xue Hua Yan, Xiao Nong Cheng, Gui Fang Xu, Yong Quan Gao
Abstract: A porous biomorphic woodceramic was prepared from bagasse powders infiltrated with the epoxy resin followed by sintering in vacuum. The microstructures and chemical structures of the woodceramics were studied by SEM and FTIR, respectively. The effect of the sintering temperature and content of bagasse on the carbon yield ratio, volume shrinkage ratio, and volume electrical resistivity of the woodceramics were studied. Experimental results show that the pores in woodceramics present the irregular distribution but the main structural features of the tracheidal cell structures are retained. The woodceramic is a carbon material containing C–O–C, C=C, C=O and C–H bonds. The carbon yield ratio of the woodceramics decreases with the increase of the content of bagasse. While the volume shrinkage ratio and volume electrical resistivity increase with the increase of the content of bagasse.
Authors: Xi Gui Cui, Cheng Yun Cui, Xiao Nong Cheng, Xiao Jing Xu, Jin Zhong Lu
Abstract: Temperature field during laser surface melting the pure Al was numerically simulated by the Laplace integral transform technique using the MathCAD software. The influences of laser power densities on the surface temperature of the pure Al were analyzed. Mathematical expressions for the temperature distribution of the heating and cooling process on the pure Al surface were obtained.
Authors: Juan Yang, Qin Qin Liu, Chuang Liang Zang, Xiao Nong Cheng
Abstract: Negative thermal expansion (NTE) material ZrWMoO8 was prepared by hydrothermal method. The phase structure and morphology of the obtained precursor and final product were examined by XRD and SEM, respectively. To study its negative thermal expansion property, two methods were utilized. One is based on the in-situ XRD results and the thermal expansion coefficient (CTE) was calculated by the cell parameters obtained at different temperatures. Another is based on the thermo-mechanical analysis (TMA) and the CTE was calculated by the length of ZrWMoO8 bar at different temperatures. The differences between these two methods were also discussed.
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