铜粉的电解制备工艺研究

对电解法制取铜粉的工艺进行了研究 ,探讨了电解液的稳定性及各工艺条件如离子浓度、电流密度、温度等对铜粉性能的影响。采用电解铜和钛为阳极 ,不锈钢为阴极 ,以 1 80 g/LH2 SO4和 8g/LCu2 +为电解体系 ,阴极电流密度为 6A/dm2 的工艺条件下稳定获得平均粒径为 1 2 μm的铜粉。阴极电流效率为 72 %。产品经BTA试剂处理后可长期贮存     

电子探针法测定超细铜粉中氧含量

超细铜粉的氧化程度决定其产品性能和应用,快速、准确测定超细铜粉中O含量具有重要实际意义。实验利用自制铝质模具进行粉末压片制样,选择粒径小于10 μm的CuO、Cu₂O和Cu粉末分别代表O含量高、中、低的超细铜粉,采用电子探针(EPMA)法对超细铜粉中的O进行定量分析。在加速电压为15 kV下,考察了O和Cu元素定量分析的束流线性范围,讨论了Cu元素分析线、束流和束斑大小对O元素定量分析的影响。结果表明,Cu Kα线定量优于Lα线,束流线性范围为5~100 nA,束斑以50 μm为佳。在优化的测量条件下,对铜粉中高、中、低含量O测量的相对标准偏差(RSD,n=9)均不大于3.0%;O元素的检出限为0.042%;Cu₂O标准样品中O含量的相对误差为-4.11%;与氢损法测定值相比较,CuO和Cu粉末样品中O含量检测结果的相对误差分别为-5.95%和-7.04%。     

氨性体系下新型添加剂对电积锌的影响研究

以自制的胺类衍生物为氨性体系电积锌的添加剂,考察其用量对电流效率和阴极锌表面形貌的影响。结果表明,在添加剂用量2mL/L、Zn2+浓度40g/L、氯化铵浓度5mol/L、氨水浓度2.5mol/L、电流密度400A/m2、异极距3cm、温度40℃的条件下,电流效率达到90.43%,阴极锌板表面形貌较为致密平整。     

均匀沉淀法制备球形Co-Y_2O_3复合粉末

以钴粉、氧化钇和草酸铵为原料,采用均匀沉淀法制备Co-Y2O3的前驱体,经氢还原后得到Co-Y2O3复合粉末,研究反应溶液中CoCl2浓度、YCl3与CoCl2的物质的量比n(YCl3)/n(CoCl2)以及表面活性剂对Co-Y2O3复合粉末形貌和粒度的影响。结果表明:YCl3与CoCl2的物质的量比以及表面活性剂对Co-Y2O3复合粉的形貌都有很大影响。当n(YCl3)/n(CoCl2)的值由0增加到0.014时,复合粉形貌由棒状转变为梅花状;当n(YCl3)/n(CoCl2)进一步增大到0.040和0.078时,复合粉分别为絮状和粗棒状;向n(YCl3)/n(CoCl2)为0.014的混合溶液中加入十二烷基硫酸钠时,复合粉末形貌由梅花形转变为球形。CoCl2的浓度c(CoCl2)对复合粉末粒度和分散性有较大影响。随c(CoCl2)从0.2 mol/L增加到0.5 mol/L,复合粉末的平均粒度由7μm减小到4μm,并且粉末的分散性更好;当c(CoCl2)增加到0.8 mol/L时,粉末的平均粒度增大到10μm,粉末的分散性变差。     

分步还原法制备电子浆料用球形银粉及其形貌与粒径

采用分步还原法制备银粉,即以硝酸银为银源,硼氢化钠为还原剂制备出晶种,然后还原硝酸银制备银粉,通过扫描电镜(SEM)和X射线衍射分析,研究还原剂的种类、晶种数量、溶液体系中还原剂的浓度及硝酸银浓度对银粉形貌和粒径的影响。结果表明:采用强还原剂制备的银粉团聚严重,粒径不均匀;当体系中还原剂浓度太小(0.05 mol/L)或太大(0.25 mol/L)时,银粉粒径很小,团聚严重;当加入的晶种数量较少时(1 m L),银粉粒径不均匀,而当晶种数量较大(3 m L)时,银粉粒径很小,团聚严重;随硝酸银的浓度从0.05 mol/L增加到0.20 mol/L,银粉粒径先增大后减小。采用还原性较弱的抗坏血酸为还原剂,晶种体积为2 m L,体系中C6H8O6和Ag NO3的浓度均为0.15 mol/L时,制备出表面光滑、分散性较好、粒径均匀、粒度为1.5μm的球形银粉。     

超声辅助水溶液电解钴粉的实验研究北大核心

本实验研究了不同工艺参数对钴粉粒度和电流效率的影响,得到水溶液电解制备钴粉的最佳工艺参数。在阴极有效电解面积为6 cm^2、p H为4、超声功率为400 W,刮粉周期为5 min的条件下电解制备钴粉,结果表明:电解温度为64℃、电流强度为0.4 A,在Co^2+浓度为0.09 mol/L时电流效率最大,为80.42%;钴粉的平均粒径在Co2+浓度为0.08 mol/L时最小,为21.66μm。在此基础上,加入3%分散剂(C12H25NaO4S)、电解温度为64℃、电流强度为0.4 A时,电流效率和钴粉的平均粒径均在Co2+浓度为0.09 mol/L时最优,电流效率最大为84.52%,相对提高4.1%,钴粉的平均粒径最优为17.21μm,相对减小了20.54%。     

Cu(Ⅱ)-NH3-(NH4)2SO4-H2O体系浸出-电积生产铜的工艺研究

对氨法炼铜新工艺进行了探索性的研究,得到了NH3-(NH4)2SO4-H2O体系中浸出铜锌精矿焙砂及在氨性硫酸铜溶液中电积生成铜板的最佳工艺条件.在浸出时间2 h,氨水浓度3 mol/L,液固比6:1,温度40℃的条件下,铜的浸出率为65.39%;电积最佳条件为铜离子浓度30 g/L,电解液温度40℃,电流密度200A/m2,电流效率达到85.66%.     

葡萄糖水热还原法制备铜粉

以葡萄糖为还原剂,CuO为铜源,PVP为添加剂,NaOH为中和剂,采用水热还原法制备铜粉,研究反应液中NaOH的浓度、葡萄糖的浓度、反应时间及反应温度对铜粉的形貌与物相组成以及粒度与抗氧化性能的影响。结果表明,当反应溶液中NaOH的质量浓度r(NaOH)小于120 g/L时,或葡萄糖的质量浓度小于270 g/L时,或反应时间不足6 h时,CuO不能完全被还原为金属铜,产物中存在氧化亚铜。NaOH浓度与葡萄糖的浓度以及反应温度对铜粉粒度都有显著影响。随r(NaOH)增加,铜粉粒度增大,团聚加重,而随葡萄糖浓度增加或反应温度升高,铜粉粒度减小。在r(葡萄糖)为315 g/L,r(NaOH)为120 g/L,反应温度为120℃,反应时间为6 h条件下可制得平均粒径为4.039μm的类球形铜粉,该铜粉的起始氧化温度为190℃,具有较好的抗氧化性能。     

电化学方法回收废旧电路板制备高纯超细铜粉

采用电化学方法回收废旧电路板中的铜,以十二烷基硫酸钠(SDS)和吐温-80(Tween-80)为添加剂,制备高纯超细铜粉,通过四因素(电流密度、温度、SDS质量浓度和Tw-80浓度)三水平的正交实验优化工艺条件。采用等离子发射光谱分析仪、扫描电镜、X射线衍射和傅立叶红外光谱分析等对铜粉的形貌与结构进行观察与分析,并对铜粉的抗氧化性能进行测试。结果表明,最优工艺条件为:在p H值为0.5,温度为20℃的点解液中,脉冲占空比0.8、周期10 ms,电流密度100 m A/cm~2,电解液中SDS的质量浓度为2 g/L,Tween-80的体积分数为2%。制备的铜粉纯度为99.92%、平均粒度为4.9μm,其微观形貌为紧密堆积的圆形颗粒,平均晶粒尺寸为33 nm,抗氧化性能良好,接近400℃温度下才开始氧化。     

ZnCl2/TMAC离子液体中电沉积锌的研究

本文研究了ZnCl2/TMAC离子液体体系在铜电极上的阴极沉积过程,考察了电解液的电导率、电解质浓度、温度等工艺条件对镀层的影响.结果表明,温度为85℃,电压为2.04 V,电沉积时间为30min时,镀层形貌比较致密,颗粒大小接近3 μm,电流效率达75%.     

约束弧等离子体制备铝纳米粉体的研究

利用自行研制的约束弧等离子体制备金属纳米粉试验装置,成功制备了平均粒度为44nm的铝纳米粉体。利用X射线衍射(XRD)、BET吸附法、透射电子显微镜(TEM)和相应选区电子衍射(SAED)等测试手段对所制备样品的晶体结构、形貌、粒度及其分布、比表面积进行性能表征。试验结果表明:约束弧等离子体法制备的铝纳米粉晶体结构为fcc结构的晶态,与体材料相比晶格常数发生膨胀。比表面积为41m2.g-1,粒径范围分布在20~70nm之间,平均粒径为44nm,粒度均匀,分散性好,呈规则球形链状分布。     

微波合成Pb(Zr0.52Ti0.48)O3(PZT)粉体

分别采用电热法(conventional synthesis,CS)和微波法(microwave synthesis,MS)合成Pb(Zr<,0.52>Ti<,0.48>)O<,3>(简称PZT)粉体,利用X射线衍射(XRD),扫描电镜(SEM)和激光粒度分析仪分别对粉体的相组成、形貌和粒度分布进行表征,并根据实验结果...     

Submicron LaB6 powders with high purity prepared in large scale by salt-assisted combustion synthesis

LaB₆ powders were synthesized in large scale by salt-assisted combustion synthesis (CS) with different NaCl diluent contents. The variety of phases, particle size and purity of the powders were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and transmission electron microscope (TEM). With increase of NaCl content, the adiabatic combustion temperature of the reaction system linearly declines, the average particle size of leached products decreases, the impurity phases are easier to remove, and the products purity enhances obviously. When NaCl content is 40 wt%, the purity of the superfine powders of LaB₆ is more than 98 wt%, and the average particle size is 380 nm.     

Synthesis and photocatalytic property of Ce-doped SnO₂

Pure SnO2 and Ce-doped(1%,4%,7%,10% in mass ratio) SnO2 powders were prepared by a simple sol-gel method.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and Brunauer-Emmett-Teller(BET) specific surface area analyzers.Results showed that the 7% Ce-doped sample has a particle size of 0.1-0.3 μm with a narrow particle size distribution while the pure SnO2 was consisted of large agglomerated particles with a diameter up to several micrometers.When used as the catalyst to degrade methyl orange(MO),the 7% Ce-doped sample showed best photocatalytic property.These properties can be attributed to the large surface area and small particle size of the 7% Ce-doped sample.     

溶剂热法合成CoS纳米晶及其表征

以六水合硝酸钴(Co(NO3)2·6H2O)和硫脲为原料,采用混合溶剂热法制备硫化钴(COS)纳米晶.利用X射线衍射(XRD),扫描电镜(SEM)和透射电镜(TEM)对硫化钴纳米晶的组成、粒径及表面形貌进行表征.结果表明,在180℃恒温条件下所得粉末样品为六方相CoS纳米粉末,粉末粒径在40nim左右.粉末的产率随温度...     

Synthesis and photocatalytic property of Ce-doped SnO2

Pure SnO₂ and Ce-doped (1%, 4%, 7%, 10% in mass ratio) SnO₂ powders were prepared by a simple sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) specific surface area analyzers. Results showed that the 7% Ce-doped sample has a particle size of 0.1-0.3 μm with a narrow particle size distribution while the pure SnO₂ was consisted of large agglomerated particles with a diameter up to several micrometers. When used as the catalyst to degrade methyl orange (MO), the 7% Ce-doped sample showed best photocatalytic property. These properties can be attributed to the large surface area and small particle size of the 7% Ce-doped sample.     

Analysis on Microstructure Characteristics and Precipitation Behavior of Automobile Beam Steels Produced by Compact Strip Production

 The microstructure characteristics and precipitation behavior of automobile beam steels produced by Compact Strip Production (CSP) were investigated by use of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy. The result shows that the final microstructure is mainly of polygonal ferrite and small amount of pearlite, the average ferrite grain size is about 3～6μm. Small amount addition Ti to aluminium-killed steel can help to refine the microstructure and improve the mechanical properties. A large number of fine precipitates have been observed in automobile beam steels. The mean particle size is about 10～30nm. Remarkable strengthening and grain refinement can be obtained by these nano-particles.     

Analysis of Microstructure Characteristics and Precipitation Behavior＇of Automobile Beam Steels Produced by Compact Strip Production

The microstructure characteristics and precipitation behavior of automobile beam steels produced by compact strip production (CSP) were investigated by use of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy. The result shows that the final microstructure is mainly composed of polygonal ferrite and small amount of pearlite, and the average ferrite grain size is about 3—6 μm. Small amount addition Ti to aluminium-killed steel can help to refine the microstructure and improve the mechanical properties. A large number of fine precipitates have been observed in automobile beam steels. The mean particle size is about 10—30 nm. Remarkable strengthening and grain refinement can be obtained by these nano-particles.     

Enhancing Physicochemical Properties and Indium Leachability of Indium-Bearing Zinc Ferrite Mechanically Activated Using Tumbling Mill

The synthetic indium-bearing zinc ferrite (IBZF) was activated mechanically using a tumbling mill under different rotation speeds, milling times, media fillings, and ball-to-material ratios. Subsequently, the changes in the physicochemical properties and leaching behavior of IBZF induced by mechanical activation were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), M?ssbauer spectrometry, particle size analysis, and leaching tests in sulfuric acid. The results showed that different milling conditions could form different particle size distribution, morphologies, and crystal structures, which influenced indium extraction differently. In addition, the indium extractions from various activated samples were related closely to the changes of physicochemical properties induced by mechanical activation. The strengthening effect of mechanical activation in IBZF decomposition lies mainly in the damage of crystal structure besides the decrease of the particle size because the indium-leaching efficiencies increased significantly with the increase of the damage of the crystal structure when the particle size is kept constant.     

Analysis of Microstructure Characteristics and Precipitation Behavior of Automobile Beam Steels Produced by Compact Strip Production

The microstructure characteristics and precipitation behavior of automobile beam steels produced by compact strip production (CSP) were investigated by use of scanning electron microscopy (SEM),transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy. The result shows that the final microstructure is mainly composed of polygonal ferrite and small amount of pearlite,and the average ferrite grain size is about 3-6μm. Small amount addition Ti to aluminium-killed steel can help to refine the microstructure and improve the mechanical properties. A large number of fine precipitates have been observed in automobile beam steels. The mean particle size is about 10-30nm. Remarkable strengthening and grain refinement can be obtained by these nano-particles.