阳极弧等离子体制备镍纳米粉的性能表征

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.     

纳米银粉的微结构研究

采用阳极弧放电等离子体法成功制备了银纳米粉体，并利用X射线衍射（XRD）、透射电子显微镜（TEM）和选区电子衍射（SAED）对样品的形貌、晶体结构、粒度及其分布进行性能表征。利用静态表面吸附仪测试样品对N2的吸附-脱附等温线，依据BJH理论模型分析样品的孔结构；利用BET吸附公式计算出样品的比表面积。结果表明：所制备的银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，其粒度主要分布在10～50nm，平均粒度为26nm，比表面积为23．81m^2／g，呈规则的类球形分布。     

阳极弧等离子体制备镍纳米粉

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。     

非水溶液体系中晶种法制备球形银纳米颗粒

以丙三醇作溶剂,硝酸银为原料,聚乙烯吡咯烷酮(PVP)为分散剂,硼氢化钠为还原剂制备了银纳米晶种;以此银纳米粒子作为初级晶种,以丙三醇作溶剂和还原剂,通过升温提高丙三醇的还原性制备银纳米颗粒。研究分散剂种类、生长液银浓度、晶种加入量对银粉的影响,采用X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)对制备产物的结构、物相、形貌进行表征。结果表明,通过改变条件可以制备出分散性良好、粒径均匀的70 nm左右的球形银粉。     

约束弧等离子体制备碳包覆铁纳米颗粒的性能

采用约束弧等离子体技术制备碳包覆铁纳米颗粒,利用X射线衍射、透射电子显微镜、高分辨透射电子显微镜、X射线能量色散分析谱仪和N2吸附等测试手段对样品的化学成分、形貌、微观结构、比表面积和粒度等特征进行表征分析。结果表明：采用约束弧等离子体技术制备的碳包覆纳米金属颗粒具有明显的核？壳结构,内核金属为体心立方结构的铁,外壳为无定形碳。颗粒大多呈球形和椭球形,粒径分布在15～40nm范围内,平均粒径为30nm,内核粒径为18nm,外层碳的厚度为6～8nm,比表面积为24m2/g。     

DyFeO3纳米材料的制备及H2S敏感特性

采用柠檬酸溶胶-凝胶法制备了具有钙钛矿结构的稀土复合氧化物DyFeO3，X射线粉末衍射和透射电镜观察表明该材料为粒径约26nm的纳米颗粒，由于粒径的减小、表面积的增大而造成其晶体结构中呈现出一定的晶格畸变率。将材料制成气敏元件并测试了其对H2S，乙醇，CO，H2等多种气体的气敏特性，结果发现该材料对H2S有较高的灵敏度和选择性，因而有较高的实用价值。     

纳米金属Ni、纳米非晶合金Ni-P及Ni-B的制备及表征

运用化学镀方法制备纳米Ni、Ni-P及Ni-B粉末,并通过透射电子显微镜(TEM)和X射线衍射(XRD)等方法对纳米粉末的物相、组织形貌和粒度进行了测试表征.结果表明,纳米Ni粉末平均粒径为60 nm,面心立方晶体,粉末呈现球形;纳米Ni-P及Ni-B为非晶体,粉末呈现松散的聚集状态;纳米Ni-P及Ni-B粉体热稳定性较差,粒径分布较宽,分别为10～80 nm和30～50 nm;纳米Ni、Ni-P及Ni-B粉末纯度较高.     

碳包覆铜纳米颗粒的比表面积和孔结构

采用直流电弧放电等离子体技术制备碳包覆铜纳米颗粒,并对样品的形貌、晶体结构、粒度、比表面积和孔结构采用高分辨透射电子显微镜(HRTEM)、X射线衍射仪(XRD)和N_2吸-脱附等测试手段进行分析。结果表明:直流电弧等离子体技术制备的碳包覆铜纳米颗粒具有典型的核壳型结构,内核为面心立方的金属铜,外壳为石墨碳层。颗粒主要呈球形或椭球形,粒度相对比较均匀,分散性良好,粒径分布在20~100 nm范围内,平均粒径为50 nm,外壳碳层的厚度为10 nm。碳包覆铜纳米颗粒的等温吸附曲线属Ⅳ型,晶粒之间的孔隙以介孔为主,样品的BET比表面积为33 m~2/g,当量粒径为45 nm,与TEM和XRD测得的结果基本一致。BJH吸附累积总孔孔容与BJH吸附平均孔径分别为0.112 cm~3/g和13 nm。     

约束弧等离子体制备铝纳米粉体工艺

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。     

热注入法制备银纳米颗粒及其结构表征

采用热注入法,以AgNO_3为前躯体、乙二醇为还原剂,聚乙烯吡咯烷酮为稳定剂和分散剂,制备银纳米颗粒。利用透射电子显微镜(TEM)、X射线衍射(XRD)仪和紫外-可见光分光光度计(UV-Vis)对产物银颗粒的尺寸形貌、晶体结构以及光学性能进行表征,同时根据Mie散射理论对消光谱进行模拟计算。结果表明,同传统的一步化学还原法相比,利用热注入法制备的银纳米颗粒粒径分布更加均匀,分散性更好。所制备的银颗粒呈类球形,粒度约为20 nm,其共振吸收谱线同模拟计算的结果基本符合。     

Preparation and particle size characterization of Cu nanoparticles prepared by anodic arc plasma

1. Introduction Metal nanoparticles exhibit novel physical and chemical properties owing to the small size effect, surface effect, quantum size effect, and quanta tun-nel effect [1-4]. In recent years, the research and de-velopment for metal nanoparticles have attracted significant interest and is still the subject of intense investigation owing to their intriguing properties and various potential applications [5-7]. Because the properties depend strongly on the details of particle size, speci…     

Preparation and particle size characterization of Cu nanopartides prepared by anodic arc plasma

Copper nanoparticles were successfully prepared in large scale by means of anodic arc discharging plasma method in inert atmosphere. The particle size, specific surface area, crystal structure, and morphology of the samples were characterized by X-ray diffraction （XRD）, BET equation, transmission electron microscopy （TEM）, and the corresponding selected area electron diffraction （SAED）. The experimental results indicate that the crystal structure of the samples is fcc structure the same as that of the bulk materials. The specific surface area is 11 m^2/g, the particle size distribution is 30 to 90 nm, and the average particle size is about 67 nm obtained from TEM and confirmed from XRD and BET results. The nanoparticles with uniform size, high purity, narrow size distribution and spherical shape can be prepared by this convenient and effective method.     

Growth mechanism of Cu nanopowders prepared by anodic arc plasma

1 Introduction In recent years, the research and development for metal nanopowders has attracted significant interest and it is still the subject of intense investigation owing to their intriguing properties and extensive prospects [1-5]. Metal nanopowder…     

Preparation and characterization of Ni nanopowders prepared by anodic arc plasma

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.     

PARTICLE SIZE AND MICROSTRUCTURE OF Ni NANOPOWDERS PREPARED BY ANODIC ARC PLASMA

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.     

机械活化对铟铁酸锌溶解动力学及物化性质的影响

以人工合成的高纯度铟铁酸锌为研究对象,采用搅拌球磨对其进行机械活化。以锌的浸出率为评价指标,研究不同活化试样在硫酸溶液中的浸出特性和溶解动力学,并利用X射线衍射仪、扫描电镜、激光粒度分析仪和比表面积分析仪分别考察机械活化对铟铁酸锌晶体结构、颗粒形貌、粒度和比表面积的影响。结果表明:机械活化使铟铁酸锌的物化性质发生明显改变,并由此提高了铟铁酸锌的反应活性。经机械活化30和60 min后,铟铁酸锌与硫酸反应的表观活化能由未活化时的76.4 kJ/mol分别降至58.6和51.8 kJ/mol,表观反应级数也由原来的0.79分别降至0.62和0.59。未活化铟铁酸锌的酸溶过程受化学反应控制,活化后则为混合控制。     

阳极弧等离子体制备镍纳米粉的机理研究

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。     

Obtaining YSZ nanoparticles by the sol–gel method with sucrose and pectin as organic precursors

Production of yttria-stabilized zirconia (YSZ) nanoparticles with the sol–gel method using new organic precursors: sucrose and pectin, which are abundant and cost effective, is described. Different analyses of the produced nanoparticles are presented. The crystal structure is analyzed by X-ray diffraction (XRD). The sintering process is studied by thermal analysis (TA), and suggestions are made for processes responsible for the exo- and endothermic weight losses seen in the TA profiles. The particle size is determined by transmission electron microscopy (TEM), supported by XRD-determination of the crystallite size using the Scherrer formula, and the Brunauer, Emmet, and Teller (BET) adsorption analysis used to determine the specific surface area. All the analyses give consistent results, and show nanoparticles of a fairly uniform, small size, with a cubic crystal structure, and fully of the same quality as is produced using the known organic precursors.