共查询到18条相似文献,搜索用时 80 毫秒
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高能球磨法制备聚合物—氧化铁纳米复合材料 总被引:5,自引:0,他引:5
采用高能球磨法制备聚合物-氧化铁的米复合材料,平均粒径为10nm,Mossbauer测量显示有超微磁性,XRD测试与Mossbauer谱参数都证明有纳米α-Fe2O3微晶生成。 相似文献
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高能球磨法制备纳米晶Zn铁氧体 总被引:12,自引:0,他引:12
用高能球磨法制备了纳米晶Zn铁氧体。通过样品的Moessbauer谱及XRD谱的测定,研究了纳米晶的形成过程。结果表明:球磨的3hα-Fe2O3即与ZnO发生机械化学反应生成Zn铁氧体,这种反应是通过先形成α-Fe2O3-ZnO固溶体而进行的。制得的纳米晶铁氧体有一定的晶格畸变。 相似文献
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氧化铝高能球磨时机构力化学效应研究 总被引:8,自引:0,他引:8
研究了氧化铝在高能球磨过程中机械力化学效应的变化,机械力化学效应因子随球磨时间的变化可分为三个阶段;第一阶段主要是晶粒尺寸减小和显微应变增加同时进行;第二阶段主要是有效温度系数的增加;第三阶段主要是点阵膨胀至饱和。用溶解法比较了球磨前后氧化铝的活性,发现经球磨后,氧化铝在盐酸中的溶解活化能由18kJ/mol降至4kJ/mol,表面活化层增厚。 相似文献
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主要研究了以纯镍粉(99.99%)为原料,采用高能球磨法制备纳米镍体材料。球磨得到的试样的平均晶粒尺寸在20.8~26.5nm;不同球料比的试样的显微硬度均存在一个相同的规律,即随着球磨时间的延长,显微硬度呈现出周期性硬化、软化趋势,且随着球磨的继续进行将最终趋于一个稳定值状态;平均显微硬度与晶粒尺寸之间也符合正Hall-Petch关系。 相似文献
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采用高能球磨法制备了W-TiC纳米复合粉体,分别采用无水乙醇、四氯化碳和甲苯作为球磨液体介质,并改变液体介质比,研究其对复合粉体球磨过程的影响,并对球磨后粉体的晶粒尺寸、晶格畸变、颗粒形貌以及比表面积进行测定和分析讨论。结果表明,球磨过程中适量的液体介质可以有效地改善粉体团聚、结块以及黏壁现象,提高出粉率。粉体的比表面积随着液体介质比的增加先增大后减小,无水乙醇的液体介质比为2时,球磨后粉体的比表面最大(2.3m2/g),颗粒形状近似于球形,平均粒径100nm,每个颗粒为多晶结构;液体介质的种类对粉体比表面影响较小;添加液体介质对粉体的晶粒细化有利。 相似文献
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高能球磨中促进粉体细化的主要因素研究 总被引:1,自引:1,他引:1
高能球磨技术作为一种制备包括纳米粉体在内的多种亚稳相材料的有效方法,已获得广泛应用.通常可以添加过程处理剂或在低温下球磨来抑制球磨过程中的冷焊,促使粉末细化.利用外加物理能场辅助高能球磨,使物理能与机械能协同作用到粉末,也是提高高能球磨效率的一种有效途径.根据不同条件下Fe粉的球磨细化结果,分析了高能球磨中过程处理剂、低温和外加能场辅助等主要促进粉体细化的因素及其作用.研究表明,采用等离子体辅助球磨仅仅10h,铁粉颗粒就被细化到了100nm.这种高的细化效率是因为等离子体辅助球磨中,等离子体对粉体产生的热爆效应和热应力的协同作用使粉体更易细化. 相似文献
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Mulas G. Monagheddu M. Cocco G. Cutrufello M. G. Ferino I. Rombi E. 《Journal of Materials Synthesis and Processing》2000,8(5-6):385-391
Amorphous powders prepared by mechanical alloying were tested as heterogeneous catalysts in the 4-methylpentan-2-ol conversion into its dehydration and dehydrogenation products. The reaction was performed both in a conventional fixed-bed flow microreactor and in a modified milling vial used as a mechanochemical batch reactor. In the thermal catalytic tests several amorphous alloys, CuM (M = Ti, Zr, Hf), PdZr, and CuPdZr were employed as catalysts. Pretreatment conditions and catalytic runs induced different structural evolution in the tested systems. A correspondence was observed between structural modifications and catalytic properties. The mechanochemical trials were performed over a-Cu40Hf60 powders. Conversion and selectivity results were found to depend on the impact energy. The determination of the milling dynamics parameters allowed evaluation of the mechanochemical activity and comparison of, on an absolute basis, the results of the catalytic trials performed by the two techniques. 相似文献
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Meng Ning Jiajun Wen Zhihua Duan Xiaoguo Cao Guojian Qiu Minglu Zhang Xiaoji Ye Zhenghui Li Haiyan Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(34):2301975
Oxygen doping is an effective strategy for constructing high-performance carbon anodes in Na ion batteries; however, current oxygen-doped carbons always exhibit low doping levels and high-defect surfaces, resulting in limited capacity improvement and low initial Coulombic efficiency (ICE). Herein, a stainless steel-assisted high-energy ball milling is exploited to achieve high-level oxygen doping (19.33%) in the carbon framework. The doped oxygen atoms exist dominantly in the form of carbon-oxygen double bonds, supplying sufficient Na storage sites through an addition reaction. More importantly, it is unexpected that the random carbon layers on the surface are reconstructed into a quasi-ordered arrangement by robust mechanical force, which is low-defect and favorable for suppressing the formation of thick solid electrolyte interfaces. As such, the obtained carbon presents a large reversible capacity of 363 mAh g−1 with a high ICE up to 83.1%. In addition, owing to the surface-dominated capacity contribution, an ultrafast Na storage is achieved that the capacity remains 139 mAh g−1 under a large current density of 100 A g−1. Such good Na storage performance, especially outstanding rate capability, has rarely been achieved before. 相似文献
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以TiO2、Al、C(石墨)为原料,首先采用高能球磨引导铝热反应合成了Al2O3-TiC纳米复合粉体,然后采用放电等离子体烧结纳米复合粉体制备了Al2O3-TiC复合材料.结果表明,在氩气氛围下高能球磨3h后,原料粉末就发生了铝热反应,合成的Al2O3-TiC复合粉体粒子尺寸大约在100nm左右.采用SPS技术在1450℃保温4min烧结的试样致密度达99.6%,并且结构精细(大部分晶粒<1μm),两相分布比较均匀,有较好的力学性能和电导性能,抗弯强度为650+21MPa,硬度为19.1±0.2GPa,断裂韧性为4.5±0.2MPa·m1/2,电导率为2.3828×105Ω-1.m-1. 相似文献
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以TiO2、Al、C(石墨)为原料,首先采用高能球磨引导铝热反应合成了Al2O3-TiC 纳米复合粉体,然后采用放电等离子体烧结纳米复合粉体制备了Al2O3-TiC复合材料.结果表明,在氩气氛围下高能球磨3h后,原料粉末就发生了铝热反应,合成的Al2O3-TiC复合粉体粒子尺寸大约在100nm左右.采用SPS技术在1450℃保温4min烧结的试样致密度达99.6%,并且结构精细(大部分晶粒<1μm),两相分布比较均匀,有较好的力学性能和电导性能,抗弯强度为650±21MPa.,硬度为19.1±0.2GPa,断裂韧性为4.5±0.2MPa·m1/2,电导率为2.3828×105Ω-1·m-1. 相似文献