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Quick Search     Adv Search   2015 Vol. 25, No. 06 Published: 2015-12-10   1 3D printing is changing the way we think ZONG Garrison DOI: 10.13228/j.boyuan.issn1006-6543.20150095 In the third industrial revolution and the “made in China 2025” plan environment and with strong 3D printing technology and application development, 3D printing is changing the way we think, including but not limited our thinking in the product design, research and development, manufacturing, sales, logistics, maintenance, and even the enterprise value chain. Seven thinking changes including free design, massive customized manufacturing, mechanical integration, technology complement, market driven, service platform, and collaborative innovation were discussed. 2015 Vol. 25 (06): 1-5 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 6 Study of silver powder used for silicon solar cell electronic paste ZHONG Jing-ming,,WANG Li-hui,,SHI Wen-feng,,ZHONG Xiang,,HA Min,,ZHENG Wei, DOI: 10.13228/j.boyuan.issn1006-6543.20150044 The market prospects, technical status and preparation methods of silver powder used in pastes for single-crystalline or polycrystalline silicon solar cells metallization were introduced. The characteristics of various preparation methods were analyzed. The problems existed in the silver powder industry and research were summarized, and the development trends were also discussed. 2015 Vol. 25 (06): 6-13 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 14 Effect of dispersant on the preparation of sub-micron spherical SiO2 particles LIU Wan-bin,SHAO Hui-ping,HUANG Xiao-hong,ZHENG Hang DOI: 10.13228/j.boyuan.issn1006-6543.20150060 The monodisperse submicron silica microspheres were successfully prepared by sol-gel method. Ammonia was used as catalyst, mixture of alcohol and water was employed as solvent, and silane coupling agent was used as surfactant. The influence of silane coupling agent dosage and the order added to the solution on particle size were studied. The morphology of the particles was characterized by scanning electron microscope （SEM）. The experimental results show that, under the reaction temperature of 20 ℃, ethyl orthosilicate concentration of 0.2-0.3 mol/L, and the dispersant of 0.075-0.125 mL added after the incubation reaction, the silica microspheres of 300-600 nm are prepared. And at room temperature of 20 ℃, ethyl orthosilicate concentration of 0.3 mol/L, 0.075-0.125 mL dispersant added after the incubation reaction, the silica particles grow up more easily to silica microspheres of about 600 nm. 2015 Vol. 25 (06): 14-17 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 18 Zinc powder production from secondary copper smelter flue dust by an alkaline method LI Qiang DOI: 10.13228/j.boyuan.issn1006-6543.20150018 A clean route was developed to convert flue dusts of secondary copper smelters into value-added products. The process consists of microwave-assisted alkaline leaching, purification and electrolysis. Initially, 83% (mass percent) Zn is dissolved in 200 g/L NaOH under microwave radiation (4 cycles of 30 s), whereas most of Cu is left in the residue. The rates of zinc recovery are significantly higher under microwave conditions as compared to those observed with conventional leaching. Furthermore, a better zinc selectivity and lower NaOH consumption are obtained. Then, the purification by adding zinc powders is carried out to reduce the Pb and Cu to low levels (lower than 100 mg/L). Subsequently, ultrafine Na2S are produced by electrolysis and the best performance occurrs at reaction temperature of 35 ℃, current density of 1 000-1 500 A/m2 with a solution composition of 30-40 g/L Zn2+ and 180-220 g/L NaOH. The products were characterized by SEM, XRD and Malvern laser particle size analyzer. The clean method also promises to treat other industrial wastes containing Zn due to its low cost and simple design. 2015 Vol. 25 (06): 18-24 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 25 Direct preparation of LaNi4Al hydrogen storage alloy by SOM process ZHAO Bing-jian,SI Xin-guo,YUAN Hui,LU Xiong-gang DOI: 10.13228/j.boyuan.issn1006-6543.20150027 A new process of solid oxygen-ion membrane process was used for the production of LaNi4Al alloy directly from La2O3-NiO-Al2O3 sintered pellet. Cathode and anode was separated from a yttria-stabilized zirconia tube in which only oxygen-ion was permeated so the voltage was as high as 3.8 V to achieve high deoxidization rate. The morphology, phase composition, corrosion of the sintered pellets in the molten salt were examined, the reduction mechanism was investigated by analyzing the phase constitution of the intermediate product. The results show that direct electrochemical reduction La2O3-NiO-Al2O3 sintered pellet to the LaNi4Al alloy by SOM process is feasible. At sintering temperature of 1 150 ℃, sintered pellet starts from LaAlO3 reacts with CaCl2 into LaOCl and Al, NiO is deoxidized into Ni, then reacting with LaOCl and Al into LaNi4Al. The current efficiency is 92.7%, the electrolysis energy consumption is as low as 3.55 kW·h/kg. It is concluded that SOM process has a bright future for industrial application because of its short process and high efficiency. 2015 Vol. 25 (06): 25-29 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 30 Fabrication and mechanical properties of high performance 2024 aluminum alloy CAO Hui-qin,GUO Zhi-meng,YE An-ping,LUO Ji DOI: 10.13228/j.boyuan.issn1006-6543.20150082 High performance Al-Cu-Mg alloy was fabricated by high energy ball milling, nitrogen sintering and hot extrusion. The microstructure and mechanical properties of the material were investigated. Results show that the formation of liquid phase during sintering promotes the aluminum alloy densification. Relative density of 97.1% can be achieved after sintering. The 2024 aluminum alloy shows excellent mechanical properties after extrusion and T6 heat treatment. The ultimate tensile strength and yield strength are 612 MPa and 465 MPa, respectively, which is superior to those of conventional 2024 aluminum alloy. 2015 Vol. 25 (06): 30-35 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 36 Research of transition layer materials and its constitution used for medical X-ray tube rotating-anode target XIAO Li-peng,Lü Jian-gang DOI: 10.13228/j.boyuan.issn1006-6543.20150006 The conventional X-ray tube rotating-anode target is usually produced by CVD technology, in which the utilization rate of raw materials is less and the product performance is poor. Although the product performance can be greatly improved by powder metallurgy method, the great difference in compaction properties between tungsten powder and molybdenum powder results in a bad bonding strength, and leads subsequently to separate layers between tungsten and molybdenum during pressing, sintering and even X-ray working. A transition layer was used to increase the bonding strength between tungsten and molybdenum, thus improve the working performance of X-ray tube. 2015 Vol. 25 (06): 36-39 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 40 Self-propagating high-temperature synthesis of cathode material LiCoO2 SUN Bing-xue,CHEN Xiu-juan,MA Xiao-jie DOI: 10.13228/j.boyuan.issn1006-6543.20150016 Layered cathode material LiCoO2 was synthesized by self-propagating high-temperature synthesis. X-ray diffractometer and scanning electron microscope (SEM) were used to investigate the effects of heat-treatment temperature, heat-treatment time and the mole ratio of Li to Co on purity, crystal structure and microstructure of LiCoO2. The results show that the optimum conditions are as follows: molar ratio of Li to Co is 1.000∶1.000，molar ratio of C6H12N4 to Co is 1.0∶3.0，heat-treatment temperature is 800 ℃ and heat-treatment time is 1.5 h. Under the optimum condition, the percentage of LiCoO2 phase in the products is near to 100%, and the crystal has good layer structure. 2015 Vol. 25 (06): 40-47 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 48 Braking properties of Cu-Fe based powder metallurgy braking materials WANG Xiao-yang,,RU Hong-qiang DOI: 10.13228/j.boyuan.issn1006-6543.20150022 Using the cast steel as brake disc and Cu-Fe based powder metallurgy materials as braking materials to form a friction pair, the influence of braking speed (60-380 km/h) and braking pressure (0.3-0.5 MPa) on friction?coefficient,?braking temperature,?braking length and braking?torque of braking material was studied by using MM-1000Ⅱfriction and wear testing machine. The wear and the surface microstructure of the braking materials after braking test were analyzed. The results show that the friction coefficients of braking materials decrease with the increasing of braking speed. The increases in the braking pressure lead to the decreased braking distances and increased braking temperature. The wear mechanism of Cu-Fe based braking materials is mainly due to the fatigue wear, abrasive wear and oxidation wear at different braking speeds. 2015 Vol. 25 (06): 48-52 [Abstract] ( 1 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 53 Experimental study on fusion bonding of TiC-TiB2 ceramic to Ti-6Al-4V alloy MA Tao,MA Jun-peng,QU Wei-liang,FU Jiu-chang DOI: 10.13228/j.boyuan.issn1006-6543.20150025 Based on using combustion synthesis to obtain high-temperature TiC-TiB2 ceramic in ultra-high gravity field, the fusion bonding of TiC-TiB2 ceramic to Ti alloy was achieved. Microstructure of the bonding of the ceramic to Ti alloy illustrates that in the super thermal vacuum resulted from the combustion synthesis of TiC-TiB2 and ultra-high gravity field, partial fusion on the surface of Ti alloy and inter-diffusion between the ceramic and Ti alloy are the reason for the achievement of the fusion bonding with constitutional gradient, where fine TiB2 platelets are embedded in the matrix of Ti alloy alternating with Ti-enriched carbides. And a linear decrease of Vickers hardness from the ceramic to Ti alloy in the bonding area is found. 2015 Vol. 25 (06): 53-56 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 57 Microstructure and performance of WC-12Co coating prepared by APS LIU An-qiang,,ZHU Hong-bin,,YUAN Jian-peng,,HOU Wei-ao, DOI: 10.13228/j.boyuan.issn1006-6543.20150043 WC-12Co coating was deposited on steel 45 by atmospheric plasma spraying (APS) process. The microstructure and phase composition of the coating were analyzed by SEM and XRD, respectively; microhardness tester and universal tester were used to measure the microhardness and bonding strength of the coating, respectively; the friction and wear resistance of the coating were examined using SRV-Ⅳ friction wear tester. The results indicate that, the WC-12Co coating is dense and uniform, only a small amount of WC decomposes during spraying process and small amount of W2C and Co3W3C phases are observed in the coating. The coating exhibits high mechanical properties, the average bonding strength is 50.63 MPa, the surface micro-hardness of the coating is 85.7 HR15N, and the micro-hardness of cross section is 1 053.8 HV0.3, respectively. Compared with the 304 stainless steel, WC-12Co coating exhibits excellent wear resistance. Abrasive wear is the major wear mechanism for the coating from room temperature to 300 ℃. 2015 Vol. 25 (06): 57-61 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 62 Research status on preparation of vanadium carbide nanopowder HU Wen-meng,ZHAO Zhi-wei,CHEN Fei-xiao,WANG Ming-chao DOI: 10.13228/j.boyuan.issn1006-6543.20150015 The excellent performance and research progress of vanadium carbide powders at home and abroad were summarized. Four main preparation methods (carbothermal reduction, gas phase reduction, precursor and mechanical alloying methods) for vanadium carbide powders were introduced in detail. The advantages, disadvantages and the latest research progress of each preparation method were also introduced. Finally, the development prospects of vanadium carbide nanopowders were prospected. 2015 Vol. 25 (06): 62-65 [Abstract] ( 2 ) HTML (1 KB)  PDF  (0 KB)  ( 2 ) 66 Research status on SiC and Si hybrid particle reinforced Al matrix composites HAN Hui-hui,WANG Ai-qin,,XIE Jing-pei DOI: 10.13228/j.boyuan.issn1006-6543.20150012 Due to the precipitation of Si particles in the preparation process SiC particle reinforced aluminum matrix composites containing Si, the composite turns into SiC and Si hybrid particle reinforced composites. SiC and Si hybrid particle reinforced aluminum matrix composites have high specific strength and stiffness, good wear resistance and fatigue resistance, good dimensional stability, lightweight and other excellent properties. It is widely used in aviation, aerospace, electronic appliances industries. The research status on SiC and Si hybrid particle reinforced aluminum matrix composites and several preparation methods of the composites were introduced. The defects existing in the microstructure and influencing factors of composite performance were analyzed. The application prospect of SiC and Si particle reinforced aluminium matrix composites was also proposed. 2015 Vol. 25 (06): 66-71 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 1 ) 72 Effects of press on the quality of bonded NdFeB magnets QIN Wan-zhong DOI: 10.13228/j.boyuan.issn1006-6543.20150019 Mould pressing is the most important preparation method for bonded NdFeB magnets. Characteristics of bonded NdFeB magnets were analyzed. Based on experimental research and lots of production practices, the important effects of die structure, press structure and compacting actions on magnets quality were introduced. The key techniques for controlling the quality of bonded NdFeB magnets were also summarized. 2015 Vol. 25 (06): 72-75 [Abstract] ( 0 ) HTML (1 KB)  PDF  (0 KB)  ( 2 )

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