ISSN 1005-3093
CN 21-1328/TG
Started in 1987

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    , Volume 34 Issue 8 Previous Issue    Next Issue
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    Structure and Thermoelectric Properties of Ag-doped SnSe Thin Films Deposited by Magnetron Sputtering
    LI Guipeng, SONG Guihong, HU Fang, DU Hao, YIN Lisong
    Chinese Journal of Materials Research, 2020, 34 (8): 561-568.  DOI: 10.11901/1005.3093.2020.021
    Abstract   HTML   PDF (3533KB) ( 250 )

    Ag-doped SnSe thermoelectric thin films were deposited by high vacuum magnetron sputtering using a powder sintered SnSe alloy target. The influence of Ag-doping on the surface and cross sectional morphology, phase composition and thermoelectric properties of the SnSe thin films were investigated by means of X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), as well as Seebeck coefficient/resistance analysis system LSR-3. The results show that the SnSe films are composed of SnSe phase of orthorhombic Pnma structure. The nano-sized Ag3Sn phase exists in the films with Ag-doping. Compared with the film without Ag-doping, the resistivity and absolute value of Seebeck coefficient of the SnSe films with Ag-doping decrease significantly. In a certain doping range, the more Ag-doping is, the smaller the resistivity and the absolute value of the Seebeck coefficient are. Although the absolute value of the Seebeck coefficient of undoped films is high and the resistivity is relatively large, so the power factor is small. For the film with 7.97% Ag (in atomic fraction), the power factor reaches the maximum at 280℃ due to higher Seebeck coefficient absolute value and appropriate resistivity, accordingly, the maximum power factor is about 0.93 mW·m-1·K-2 at 280℃, which is 40% higher than that of undoped films (PF=0.61 mW·m-1·K-2). In conclusion, the appropriate amount of Ag-doping can effectively improve the thermoelectric properties (power factor) of the SnSe thin films by magnetron sputtering.

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    Synthesis and Self-assembly Behavior of Amylose-chenodeoxycholic Acid Conjugates
    XIONG Xiaoqin, ZHANG Hongquan, FANG Chanyu
    Chinese Journal of Materials Research, 2020, 34 (8): 569-574.  DOI: 10.11901/1005.3093.2020.019
    Abstract   HTML   PDF (3798KB) ( 196 )

    Amylose-chenodeoxycholic acid conjugates (AMY-CDCA) were prepared using 1-ethyl-3-(3-dimethylaminopropyl)-carbonized diimine (EDC) /N-hydroxysuccinimide (NHS) cross-linking agents. The AMY-CDCA polymer was characterized by FTIR, 1H NMR and ultraviolet spectroscopy. It was shown that CDCA was successfully coupled to the amylose backbone with a molar substitution of 138.15 per 100 glucose units. Self-Assembled micelles were prepared from the AMY-CDCA polymer through dialysis method. The average particle size of the micelles measured by dynamic light scattering method is 224 nm, and the polydispersity index is 0.110. TEM images demonstrated that the micelles are of spherical shape with a core-shell structure. The critical micelle concentration is 2.8×10-3 mg/mL, which was determined using a probe fluorescence technique in the presence of pyrene. Additionally, Nile Red can be encapsulated and stabilized in the hydrophobic core of the micelles.

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    Preparation and Antibacterial Function of an Cu-bearing Chitosan Coating on Silicone Rubber Surface
    WANG Lirong, GUAN Hongyu, CHEN Shanshan, ZHANG Bingchun, YANG Ke
    Chinese Journal of Materials Research, 2020, 34 (8): 575-583.  DOI: 10.11901/1005.3093.2020.047
    Abstract   HTML   PDF (8022KB) ( 290 )

    In order to solve the infection caused by the indwelling catheter, an anti-infective Cu-bearing chitosan coating was prepared on the silicone rubber surface. But it is difficult to prepare a coating on the surface of silicone rubber due to its biological inertness. Therefore, chemical grafting was used to activate the silicone rubber by the dopamine pretreatment, which provides abundant functional groups on the activated silicone rubber surface. The surface morphology and surface properties of the silicone rubber after surface activation pretreatment were characterized by the active functional groups. Onto which, subsequently, the Cu-bearing chitosan coating could be chemically grafted, and then the surface morphology was compared for the coatings before and after immersion test. The effectiveness of pretreatment process was assessed by the bonding force between the functionalized coating and the silicone rubber. It follows that the abundant functional groups offered by the pretreatment on the activated silicone rubber surface may be beneficial for enhancing the adhesive strength of the functionalized coating to the silicon rubber. Thereby, the Cu-bearing chitosan coating makes the silicone rubber catheter have good antibacterial function.

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    Hydrothermal Synthesis and Electrochemical Performance of Co3O4@CNTs Composite Film
    LIU Zhijun, LI Zhifeng, WANG Chunxiang, XIE Guangming, HUANG Qingyan, ZHONG Shengwen
    Chinese Journal of Materials Research, 2020, 34 (8): 584-590.  DOI: 10.11901/1005.3093.2020.042
    Abstract   HTML   PDF (3741KB) ( 212 )

    A facile and effective method has been developed for synthesis of Co3O4/carbon nanotube film (Co3O4@CNTs) composites as anode materials in LIBs. With 5-sulfosalicylic acid and glutaric acid as chelation and oxidation reagents, the CoSO4 can be directly oxidized into nanoscale Co3O4 under hydrothermal conditions. Co3O4/carbon nanotube film (Co3O4@CNTs) composites can be easily synthesized and the Co3O4 particles are tightly attached to carbon nanotubes via the same process. The electrochemical test results show that the composites film has higher discharge specific capacity and excellent rate performance. At 0.2C rate the initial discharge specific capacity can be up to 1712.5 mAh·g-1, the discharge specific capacity is still about 1128.9 mAh·g-1 after 100 cycles. At 1C rate the discharge specific capacity of 527.8 mAh·g-1 is still maintained after 100 cycles. The excellent performance is due to the synergistic combination of Co3O4 and CNTs. The highly dispersed Co3O4 expands the contact area between the active material and the electrolyte, and CNTs can form the conductive network to increase the electron conductivity, thus improve the cycle performance of Co3O4 anode materials.

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    One Step Hydrothermal Preparation of SnO2@C Composite and Its Lithium Storage Performance
    LI Lingfang, ZENG Bin, YUAN Zhipeng, FAN Changling
    Chinese Journal of Materials Research, 2020, 34 (8): 591-598.  DOI: 10.11901/1005.3093.2019.604
    Abstract   HTML   PDF (7663KB) ( 195 )

    Two kinds of SnO2@C composite were successfully prepared by a facile and cost-effective method through one-pot hydrothermal treatment of a mixture of Sn4+, and different carbohydrates (glucose and starch). The composition and microstructure of resultants were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), N2 Adsorption-desorption method and Transmission Electron Microscope (TEM). The electrochemical performance as anode material for lithium-ion batteries was confirmed by galvanostatic charge-discharge test and Cyclic Voltammetry (CV) method. Results show that the pyrolytic carbon derived from carbohydrate precursors forms a stable composite structure with 4~5 nm SnO2 nanocrystals. The large volume variation of SnO2 during the Li+ insertion-extraction process is effectively alleviated by the buffering effect of carbon matrix. Whatsmore, small SnO2 nanoparticles can also effectively reduce this volume change, improving the electrode structural stability and electrochemical properties. Because the degree of order of glucose pyrolytic carbon is higher than that of starch pyrolytic carbon, correspondingly its composite shows better cycle and rate performance, which can stably release >400 mAh/g specific capacity at high current density of 2 A/g.

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    Thermal Decomposition Dynamics of Nylon 66 and Its Composites
    MIAO Yuezhen, WANG Xintong, XIE Mengshu, QI Kezhen, CHU Zengze, SUN Qiuju
    Chinese Journal of Materials Research, 2020, 34 (8): 599-604.  DOI: 10.11901/1005.3093.2019.570
    Abstract   HTML   PDF (3065KB) ( 334 )

    The thermal decomposition curves of nylon 66 (PA66) and two kinds of glass fiber reinforced nylon 66 composites (GF/PA) were measured by thermogravimetric analyzer, and the thermal decomposition kinetics of PA66 and GF/PA were investigated by the Kissinger method and Crane method. The results showed that the thermal decomposition reaction order of PA66, GF/PA-1 and GF/PA-2 were 0.949, 0.912 and 0.921, respectively, which were all consistent with first-order reactions with thermal decomposition activation energy of 218.65 kJ/mol, 121.81 kJ/mol and 132.23 kJ/mol, respectively. These results demonstrated that the incorporation of glass fiber reduced the thermal decomposition activation energy of PA66. In addition, by the same heating rate, the temperature corresponding to the maximum thermal decomposition rate for the two kinds of GF/PA was obviously lower than that for PA66, indicating that although glass fiber improved the performance of PA66, but accelerated the thermal decomposition process of PA66, and there was also a "wick effect".

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    Effect of Dy Addition on Glass-forming Ability and Mechanical Properties of Cu50Zr46Al4 Bulk Metallic Alloy
    LI Dongmei, TAN Liming, ZHAO Qing, XIE Hanxi, YU Peng, XIA Lei
    Chinese Journal of Materials Research, 2020, 34 (8): 605-610.  DOI: 10.11901/1005.3093.2020.063
    Abstract   HTML   PDF (3891KB) ( 156 )

    A series of Cu50-xZr46Al4Dyx(x=0~4) alloys is prepared by copper mold casting based on Cu50Zr46Al4 bulk metallic glass (BMG). The effect of Dy addition on the glass forming ability and mechanical properties of Cu50-xZr46Al4Dyx alloy was investigated through thermodynamics and mechanical experiments. It is found that 1%~2% (atomic fraction) Dy addition can significantly improve the thermal stability of Cu50-xZr46Al4Dyx, and the glass forming ability of the alloy. The strength and plastic deformation ability of the alloy can be improved effectively by proper Dy addition. The influence of Dy addition on the glass forming ability and mechanical properties of Cu50-xZr46Al4Dyx is also discussed.

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    Dynamic Recrystallization Behavior and Kinetics Model of a New Developed Austenitic Heat Resistant Steel CHDG-A
    CHENG Xiaonong, GUI Xiang, LUO Rui, XU Guifang, YUAN Zhizhong, ZHOU Yuseng, GAO Pei
    Chinese Journal of Materials Research, 2020, 34 (8): 611-620.  DOI: 10.11901/1005.3093.2019.567
    Abstract   HTML   PDF (17052KB) ( 176 )

    The deformation behavior and microstructural evolution of a new developed austenitic heat resistant steel CHDG-A were investigated by hot compression tests with strain rate in the range of 0.01-10 s-1 at 900~1100℃. The results show that either increasing the deformation temperature or decreasing the strain rate, the flow stress level reduces remarkably. Accurate constitutive equations were established between peak stress and deformation parameters, i.e., temperature and strain rate by the regression analysis of sine hyperbolic function. The hot deformation activation energy of CHDG-A was calculated to be 515.618 kJ/mol. From the deformed microstructures it is found that dynamic recrystallization (DRX) is the principal softening mechanism during hot working. The DRX process may initiate from nucleus formed at bulging out of grain-boundaries, which can be promoted by the increase of temperature and the decrease of strain rate. The values of peak stress, critical stress, peak strain and critical strain for DRX were determined from the true strain-true stress curves and their equations related to the Zener-Hollomon parameter were obtained. The critical strain and corresponding stress for DRX can be expressed through the parameter Z. The critical ratios of εc/εp and σc/σp are also identified, which are 0.52 and 0.98, respectively. Moreover, the DRX kinetics for CHDG-A can be represented in the form of Avrami equation, and the predicted volume fraction of new grains based on the developed model agrees well with the experimental results.

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    Electrochemical Performance of Li1.2Mn0.54Ni0.13Co0.13O2 Lithium-enriched Cathode Materials Coated with Al2O3
    ZUO Cheng, DU Yunhui, ZHANG Peng, WANG Yujie, Cao Haitao
    Chinese Journal of Materials Research, 2020, 34 (8): 621-627.  DOI: 10.11901/1005.3093.2019.579
    Abstract   HTML   PDF (3949KB) ( 204 )

    Li1.2Mn0.54Ni0.13Co0.13O2 lithium-rich manganese-based cathode materials were prepared by sol-gel method, then coated with Al2O3 by uniform precipitation method, which further characterized by means of XRD, TEM and electrochemical properties analysis. Results show that the coated material still has the layered structure as its original status, Al2O3 was uniformly coated on the surface of the Li1.2Mn0.54Ni0.13Co0.13O2 particles to form a nano-scale coating. The initial discharge capacity of the Li1.2Mn0.54Ni0.13Co0.13O2 powder coated with 0.7% Al2O3 was 251.3 mAh/g under the condition of 0.1 C and 2.0~4.8 V. The first coulombic efficiency is 76.1%, and the capacity retention rate is 92.9% after 100 cycles., and the coating also effectively suppresses the voltage decay during the cycle. The proper amount of Al2O3 coating can effectively improve the electrochemical performance of the cathode material.

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    Deformation Mechanism of Nanoscale Polycrystalline α-Silicon Carbide Based on Molecular Dynamics Simulation
    SHI Yuanji, CHEN Xianbing, WU Xiujuan, WANG Hongjun, GUO Xunzhong, LI Junwan
    Chinese Journal of Materials Research, 2020, 34 (8): 628-634.  DOI: 10.11901/1005.3093.2019.600
    Abstract   HTML   PDF (16155KB) ( 265 )

    Based on the molecular dynamics method, Vashishta potential function was used to study the plastic deformation mechanism of polycrystalline α-silicon carbide matrix under the action of nano indentation in terms of the effect of grain boundary and temperature. The load displacement curve was analyzed, and the change of atomic failure and migration path in the deformation area was described by identifying the deformation structure. As the contact load increased the amorphous phase transformation occurred in the contact zone and expanded to the crystal interior, which was blocked by the grain boundary. With the increase of the load, the grain boundary as the source of 1/2<110> perfect dislocation emission will slip at high stress level. In addition, with the increase of temperature the bearing capacity of SiC polycrystal decreases, especially the plastic deformation occurs inside the material, the dislocation grows from the grain boundary to the inside of the crystal, and finally forms 'U-shaped' dislocation ring.

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    Preparation of 316L Stainless Steel Products by Fused Deposition Model 3D-printing and Effect of La on Morphology and Distribution of Precipitates
    CAI Guodong, CHENG Xiyun, WANG Dian
    Chinese Journal of Materials Research, 2020, 34 (8): 635-640.  DOI: 10.11901/1005.3093.2019.591
    Abstract   HTML   PDF (12283KB) ( 350 )

    The hot melt feedstock was prepared with micron 316L stainless steel powder and wax based binder. The green body was formed by 3D printing, and the final product was formed by degreasing and sintering. Through the performance characterization and test of the final product, the feasibility of this forming method has been verified. Aiming at relieving the irregular morphology of precipitates and the emerge of inclusions on grain boundaries of the prepared products, the influence of rare earth La on the deposition has been explored. Based on the microporous structure formed by degreasing of the green body, a method of adding La via liquid phase has been proposed. The results show that 316L stainless steel products can be prepared by FDM type 3D printing, trace rare earth La can be added to the green body via liquid phase addition method, and the mass ratio of 0.3% LaCl3 can significantly improve the microstructure and distribution characteristics of final products after sintering.

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