共搜索到21203条信息,每页显示10条信息,共2121页。用时:0小时0分0秒343毫秒
低温固相反应合成NiFe2O4尖晶石纳米粉张志刚,姚广春,马佳,华中胜东北大学材料与冶金学院摘 要:以FeSO4.7H2O,NiSO4.6H2O和NaOH为原料,NaCl为分散剂,在室温下充分研磨反应制备前驱体,然后将前驱体进行煅烧得到NiFe2O4尖晶石纳米粉.重点研究了分散剂含量,煅烧温度和保温时间对粉体粒度和形貌的影响.利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对所得产物进行表征.结果表明:添加20%(质量分数)NaCl制得的前驱体在800℃下煅烧1.5h得到的纳米粉分布均匀,颗粒呈球形并且晶型完整单一,平均粒径约为75nm.关键词:NiFe2O4尖晶石;纳米粉;低温;固相反应;分散剂;......
煅烧温度与柠檬酸用量对镍铁氧体结构与吸波性能的影响陈鑫,刘祥萱,刘渊,郭磊,张红聘第二炮兵工程大学603教研室摘 要:采用溶胶-凝胶法制备了立方晶系尖晶石型NiFe2O4镍铁氧体微粉.采用X射线衍射仪,扫描电镜和矢量网络分析仪对粉末的结构,形貌以及电磁波吸收性能进行了表征,研究了煅烧温度及柠檬酸用量对其形貌结构和电磁损耗性能的影响.结果表明,粉体粒径随煅烧温度的升高而增大,随柠檬酸用量增加先减小后增大.样品微波吸收性能随煅烧温度的升高而增加,吸收峰随柠檬酸用量的增加向低频移动.电磁波反射率小于-10dB的频宽可达3.0GHz,最小反射率为-21.7dB.关键词:NiFe2O4铁氧体;溶胶-凝胶法;电磁性能;微波吸收性能;......
Microstructure and Tensile Behavior of a Nano-Structured Al-Fe Based Alloy Tae-Yeub Ra1,Mok-Soon Kim2,Won-Yong Kim1,Jae-Sung Park2 (1.Advanced Materials R&D Center,Korea Institute of Industrial... specimen showed highe r value than extruded specimen over the whole strain rate region studied. Key words:microstructure; tensile deformation; A1-Fe based alloy; spray forming; extrusion; warm rolling......
铝电解用NiFe2O4尖晶石基惰性阳极马佳,姚广春,张啸,张志刚东北大学材料与冶金学院摘 要:采用高温固相合成法制备铝电解用NiFe2O4尖晶石基惰性阳极,利用球形模型研究了烧结时气孔的变化规律,并研究了烧结温度对其微观形貌和基本物理性能的影响.结果表明:烧结温度能显著改变NiFe2O4尖晶石基惰性阳极的性能;Fe2O3与NiO的反应属于自发反应,从热力学角度讲,该反应在常温下就可进行,而升高温度是为了满足动力学条件;当烧结温度从1150℃升高至1400℃,气孔率由30.41%降低到1.72%,抗弯强度由14.62MPa增加至71.94MPa.关键词:NiFe2O4尖晶石基惰性阳极;球形模型;烧结温度;气孔率;抗弯强度;......
on the quality and productivity. In order to protect the sink roll the carbide cermet and/or ceramic coatings were deposited on the surface of the sink roll. The WC-, Cr3 C2-cermet coatings were...-diffusion and inter-reaction of Zn, Al and elements in coating and corrosion behaviors of these coatings were investigated by XRD, SEM and EPMA etc. The corrosion mechanisms of the carbide cermet......
; Preparation and properties of pitch carbon based supercapacitor LIU Ye... curve results indicate that the carbon based supercapacitor using the self-made activated carbon as electrode materials shows the desired capacitance properties. In 1 mol/L Et4NBF4/AN electrolyte......
Effects of precoating and calcination on microstructure of 3D silica fiber reinforced silicon nitride based composites QI Gong-jin(齐共金), ZHANG Chang-rui(张长瑞), HU Hai-feng(胡海峰) State Key...: Three-dimensional silica fiber reinforced silicon nitride based composites were fabricated by preceramic polymer infiltration and pyrolysis method using perhydropolysilazane as a precursor......
J. Cent. South Univ. (2016) 23: 3183-3191 DOI: 10.1007/s11771-016-3384-6 Role based access control design using Triadic concept analysis Ch. Aswani Kumar1, S. Chandra Mouliswaran1, LI Jin-hai2, C.... Department of Computer Science, Periyar University, Salem, India Central South University Press and Springer-Verlag Berlin Heidelberg 2016 Abstract: Role based access control is one of the widely......
Effect of Si content on mechanical properties of Nb-Si based alloys with NbSS/ Nb5Si3 structure ZHENG Peng(郑 鹏), SHA Jiang-bo(沙江波), LIU Dong-ming(刘东明), GONG Sheng-kai(宫声凯), XU Hui-bin(徐惠彬) School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China Received 28 July 2006; accepted 15 September 2006 Abstract: In Nb-Si based......
......