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阳极弧等离子体制备镍纳米粉 总被引:22,自引:3,他引:22
采用自行研制的实验装置,用阳极弧放电等离子体方法制备了高纯镍纳米粉末。利用X射线衍射(XRD)、透射电子显微镜(TEM)和相应选区电子衍射(ED)、BET吸附等对样品的成分、形貌、晶体结构、晶格常数、粒度及其分布、比表面积进行了分析。建立了关于金属超微粒产生过程的近似模型,分析了纳米粉的形成和生长机制,并对整个工艺过程影响纳米粉性能的各种工艺参数进行了理论探讨。结果表明:所制得的镍纳米粉纯度高,晶格结构与相应的致密体相同,为fcc相结构,平均粒径为47nm,粒径范围在20~70nm,比表面积为14.23m^2/g,呈规则的球形链状分布,并发现纳米晶体的晶格常数发生膨胀。 相似文献
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阳极弧等离子体制备镍纳米粉的机理研究 总被引:1,自引:0,他引:1
根据会属结晶的热力学和动力学理论,对采用阳极弧放电等离子体方法制备金属纳米粉的生长过程建立了一个近似的理论模型。研究了等离子体的产生、金属的蒸发、晶核的形成和生长机理。对影响纳米粉性能的各种工艺参数进行了理论分析。并利用X射线衍射(XRD)、透射电子显微镜(TEM)和相应选区电子衍射(ED)对样品的晶体结构、形貌、粒度及其分布进行表征。结果表明:采用阳极弧等离子体法制备的球形镍纳米粒予纯度高,晶格结构与相应的块体物质相同,为fcc结构的晶态,平均粒度为16nm,粒度范围分布在10nm~40nm。电源功率、电弧电流、气体压力及冷却温度是影响晶核的形成和生长的主要因素。通过适当调整各项工艺参数,可有效地控制粒子的粒度。 相似文献
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采用约束弧等离子体方法成功制备了高纯铝纳米粉末,利用X射线衍射(XRD)、透射电镜(TEM)和相应选区电子衍射(SAED)对样品的晶体结构、形貌、粒度进行性能表征。对约束弧等离子体方法制备金属纳米粉的形成和长大过程进行了分析,并对制备过程中工艺参数(气体种类和压力、电弧电流等)对纳米粉产率及粒度的影响规律进行了讨论。实验结果表明:本法所制备的铝纳米粉末的晶体结构为fcc结构的晶态,呈规则的球形。适当控制某些工艺参数就能制取粒径在20~100 nm的纳米粉,在其它工艺参数一定时,随着工作气压升高、电流强度的增加,产率和平均粒径都随之增大。 相似文献
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阳极弧等离子体制备镍纳米粉的性能表征 总被引:6,自引:0,他引:6
采用阳极弧放电等离子体方法成功制备了高纯镍纳米粉末;利用X射线衍射(XRD)、透射电子显微镜(TEM)和选区电子衍射(SAED)、BET吸附法测试手段对试样的成分、形貌、晶体结构、比表面积、粒度及其分布进行性能表征,并采用元素分析仪测定C,H,N含量,采用X射线能量色散分析谱仪(EDS)测定试样所含的元素及其相对含量,用红外吸收光谱(FT-1R)对结构组成进行定性分析.实验结果表明:本法所制备的镍纳米粉末的晶体结构与相应的块体材料基本相同,为fcc结构的晶态,平均粒径为47 nm,粒度范围分布在20 nm~70 nm,呈规则的球形链状分布,比表面积为14.23 m2/g,试样纯度高且具有很强吸附性. 相似文献
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基于双区域近似电弧模型的理论,研究了工艺参数对喷嘴出口处转移型焊接等离子弧的影响,给出了喷嘴出口处等离子电弧的伏安特性曲线,以及在不同离子气流速和喷嘴直径的条件下,电弧的弧柱半径及压力随焊接电流变化的曲线,并与试验数据进行比较,比较结果表明,计算结果与试验测量值吻合良好。同时还分析了喷嘴直径、钨极内缩量以及离子气流速在相应的焊接电流下对等离子弧功率与电弧力的影响,并绘出曲线图。研究结果表明,对于中小电流规范下的转移型等离子弧焊接,采用双区域近似电弧模型来研究喷嘴出口处等离子弧的特性是可行的,该模型计算简便,可为得到高质量等离子弧焊接的设计及生产提供理论基础。 相似文献
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为研究不同工艺参数对等离子弧增材制造镍基高温合金组织的影响,以脉冲等离子弧为热源、Inconel 718合金为成型材料,采用单一变量法分别研究了峰值电流、脉冲频率、焊接速度对成型层组织的影响。主要以光学显微镜、扫描电子显微镜和能谱分析等手段,从温度梯度、结晶速率的角度去考察不同工艺参数对组织形貌、大小和成分等影响规律。结果表明,随着峰值电流的增加,组织由细长的柱状枝晶转变为粗大的胞状枝晶,Laves相析出量增大;相反,随着焊接速度的增大,组织发生细化;脉冲频率过大或过小均能导致组织粗化。 相似文献
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研究铝阳极氧化工艺参数对冷封闭质量的影响.生产实践表明:阳极氧化采用温度为18~22℃、电流密度为1.1~1.35A/dm~2、硫酸浓度为160~195g/L、时间为25~35min,在控制好冷封闭工艺条件的前提下,可获得合格的封闭质量. 相似文献
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Ni nanopowders were successfully prepared in large quantities by anodic arc discharged plasma method with homemade experimental apparatus in inert gas. The particle size, microstructure and morphology of the particles were characterized via X-ray diffractometry (XRD), transmission electron microscopy (TEM) and the corresponding selected area electron diffractometry(SAED). The specific surface area and pore parameters were investigated by nitrogen sorption isotherms at 77 K with Brunauer-Emmett-Teller(BET) equation and Barrett-Joyner-Halenda (BJH) method. The chemical compositions were determined by X-ray energy dispersive spectrometry(XEDS) and element analysis. The experimental results indicate that this method is convenient and effective, and the nanopowders with uniform size, higher purity, weakly agglomerated and spherical chain shape are gotten. The crystal structure of the samples is FCC structure as the bulk materials, the particle size distribution ranges from 20 to 70 nm, and the average particle size is about 46 nm obtained by TEM and confirmed by XRD and BET results. The specific surface area is 14.23 m^2/g, specific pore volume is 0.09 cm^3/g and average pore diameter is 23 nm. 相似文献
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Copper nanopowders were successfully prepared by anodic arc discharging plasma method with home-made experimental apparatus.The effects of various processing parameters on the particle size of Cu nanopowders were investigated in the process,and the optimum processing parameters were obtained.In addition,the morphology,crystal structure,particle size distribution of the nanopowders were characterized via X-ray diffraction(XRD),transmission electron microscopy(TEM)and the corresponding selected area electron diffraction(SAED).The experimental results show that the crystal structure of the samples is the same fcc structure as that of the bulk materials.The processing parameters play a major role in controlling the particle size.The particle size increases with the increase of the arc current or gas pressure. 相似文献
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在G型喷嘴下,利用SprayWatch-2i喷涂粒子速度、温度测试仪在线测量粒子的飞行参数,研究了等离子喷涂工艺参数对喷涂粒子速度和温度的影响,并对等离子喷涂氧化锆粉末的主要工艺参数进行优化分析。在诸因素中.气体流量对粒子速度和温度的影响最为显著,随着主气流量的增加,粒子速度有所增加。 相似文献
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Z.Q.Wei H.X.Qiao J.F.Dai W.J.Feng Q.Wang P.X.Yan 《金属学报(英文版)》2005,18(3):209-216
Pure Ni nanopowders were successfully prepared by the method of anodic arc discharged plasma with homemade experimental apparatus. The particle size, mircostructure and morphology of the particles by this process were characterized via X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED); The specific surface area and pore parameters were investigated by multi-point full analysis of nitrogen adsorption-desorption isotherms at 77K by BrunauerEmmett-Teller (BET) surface area analyzer; The chemical composition were determined by X-ray energy dispersive spectrometry (XEDS) equipped in SEM and element analyze instrument. The experiment results indicate that the samples by this method with high purity, the crystal structure of the particles is as same as the bulk material, is fcc structure, with average particle sizes about 47nm, ranging from 20 to 70nm, and distributed uniformly in spherical chain shapes, the specific surface areavis 14.23m^2/g, pore volume of pore is 0.09cm^3/g and average pore diameter is 23nm. 相似文献