W-Cu纳米晶粉体的制备及表征

采用机械舍金化技术制备了W-20％Cu和W-50％Cu纳米晶粉体，通过XRD、SEM、TEM等手段对机械舍佥化过程中W-Cu纳米晶复合粉的组成、晶格常数、晶粒尺寸和形貌结构进行了表征与分析。结果表明，W-20％Cu混合粉经过高能球磨，Cu元素完全固溶进w晶格中，形成W（Cu）固溶体；W-50％Cu复合粉经过高能球磨，形成W（Cu）和Cu（W）两种固溶体。W、Cu的合金化主要是依靠高能球磨过程中产生的大量纳米晶界和高密度的缺陷（位错、层错等）促使W、Cu之间的固溶。W-Cu复合粉的晶格常数和晶粒尺寸随着球磨时间的延长而减小，球磨一定时间后，都趋于稳定。球磨20h后，W-20％Cu和W-50％Cu复合粉中W（Cu）的晶粒尺寸分别为6．6和8．0nm。     

机械合金化与热处理制备Al3Ti金属间化合物

以高纯Al粉和Ti粉为原料,通过高能球磨机械合金化和空气中热处理制备了Al3Ti金属间化合物粉末.使用XRD和SEM测试分析了球磨过程中粉末的物相结构和形貌的变化过程,对热处理后的粉末进行了XRD晶体结构测试.结果表明,高能球磨60h后,原料粉末转变为非晶态粉末.将非晶态粉未在500℃以上热处理后,转变为Al3 Ti金属间化合物.     

机械合金化制备FeSiAl合金粉末的研究

采用机械合金化的方法制备了FeSiAl合金粉末样品。以硅钢粉和铝粉为原料,按摩尔分数Fe3Si0.4Al0.6配比,研究其机械合金化过程,并对机械合金化的机制进行探讨。用激光粒度仪、X射线衍射(XRD)和扫描电子显微镜分析材料的粒度、形貌和结构。研究表明,Fe3Si0.4Al0.6混合粉末球磨30h后,粉末粒径可达18μm;Fe3Si0.4Al0.6混合粉末经高能球磨20h后,形成具有bcc结构的α固溶体;球磨继续进行,合金化的粉末和晶粒不断细化。     

机械化学合成Ni2Al3/Al2O3去合金化制备Raney-Ni/Al2O3复合粉体

以NiO粉和Al粉为原料,采用机械球磨诱发化学反应制备了Ni_2Al_3/Al_2O_3复合粉体。利用X射线衍射仪(XRD)和附带能量色散谱仪(EDS)的扫描电子显微镜(SEM)对复合粉体球磨过程中的固态反应过程、表面形貌进行表征。将Ni_2Al_3/Al_2O_3复合粉体用浓度为20%的NaOH溶液腐蚀2h,可得到纳米晶结构的Ni/Al_2O_3复合粉体。利用XRD和TEM对其物相和结构进行了表征。结果表明,球磨1h后混合粉末仍为NiO粉和Al粉,球磨3h后NiO粉和Al粉在机械力的作用下反应形成Ni_2Al_3和Al_2O_3粉体,机械力诱发的NiO和Al之间的反应属于突发型反应,继续球磨10h后形成Ni_2Al_3/Al_2O_3复合粉体。Ni_2Al_3/Al_2O_3复合粉体在70℃、质量比为20%NaOH溶液中刻蚀2h,可获得Ni/Al_2O_3复合粉体。     

机械合金化法制备Cr掺杂Fe-Si合金

采用高能行星式球磨机制备了Cr掺杂Fe-Si混合粉,用X射线衍射（XRD）测试研究Cr掺杂Fe-Si合金的机械合金化过程,实验结果表明,随着球磨强度的增加,Fe、Cr、Si粉末通过原子扩散实现机械合金化,最佳的球磨工艺参数为：球磨时间35h、球磨机转速360r/min、球料比40：1。     

过共析Ti-Cr合金的机械合金化

以钛，铬元素粉为原料，在行星式球磨机上采用φ20mm的淬火钢球，以200r/min的球磨速度和15：1的球料比，研究了Ti-20%Cr(ω(B)和Ti-30%Cr(ω(B)两种合金的机械合金化（MA）规律，研究结果表明；在球磨初期的2h内钛的（011）主衍射峰强度迅速降低，（010）第二衍射峰强度提高并成为最强峰，同时铬的衍射峰强度提高；随着球磨时间的增加，钛和铬的X射线衍射峰均发生宽化，强度下降和衍射角左移并减小；当球磨时间为30-40h时，钛逐步非晶化，但在本试验条件下铬没有发生非晶化；MA的前10h是粉末晶粒细化，晶格应变和合金化进行的最迅速的时期，经该阶段球磨后铬的晶粒尺寸可以达到20nm，进一步示磨有利于获得过饱和固溶的合金粉末；两种合金在超过100h的MA过程中均未发现在固相合成Laves相TiCr2；确定30-40h为制备纳米晶或非晶过饱固溶Ti-Cr合金粉末的合理球磨时间。     

球磨对高温熔盐合成的NiTi粉体的相变影响

采用球磨工艺使高温熔盐合成的NiTi粉末的相变行为发生改变，进而研究了球磨过程中球磨转速、球磨时间、摘要过程控制剂和时效处理对NiTi相变的影响。利用差示扫描量热法（DSC）、X射线衍射（XRD）和扫描电子显微镜（SEM）等现代检测手段对NiTi粉末的成分、组织形貌以及NiTi的相变行为进行了相应的分析研究。     

溶胶-球磨超细W-Cu复合粉末烧结性能研究

采用溶胶-球磨法制备W-10Cu、W-20Cu复合粉末,研究了球磨工艺对粉末粒度、形貌和烧结性能的影响。研究结果表明,球磨粉末呈现双峰粒度分布,球磨20h的W-10Cu、W-20Cu粉末的粒度分别为1.03和1.15μm。球磨过程中,粉末比表面积变换式ln[(Sm-S0)/(Sm-S)]与球磨时间t符合线性关系。W-10Cu、W-20Cu复合粉末球磨20h,可以在1380℃一步液相烧结达到近全致密,显微组织细小且均匀。     

反应球磨钛与尿素制备氮化钛的反应机理研究

将Ti粉与尿素在室温下进行反应球磨制备了TiN粉末,对球磨不同时间后的粉末进行XRD分析,采用TG-FTIR技术分析了尿素的分解温度与产物,利用TEM及EELS观察和分析了球磨70h粉末的微观形貌、结构及成分. 结果发现,球磨70h合成了纳米TiN粉末,晶粒度为6~7nm,Ti/N原子比约为1.0∶0.6. 经800℃,5h真空退火处理后粉末的XRD谱图表明粉末组成为单相TiN. 在反应球磨过程中,Ti与尿素的分解产物NH₃与HNCO发生反应形成TiN,随球磨时间延长,Ti的缺陷能增大、活性增加,N在Ti中的扩散激活能减小,在球磨作用下N的扩散距离变短,TiN的含量逐渐增加形成晶核并逐渐长大形成纳米晶.     

球磨时间对碳热还原AlON粉体相组成的影响

以纳米γ-Al2O3和活性炭为原料,采用碳热还原法合成AlON粉体,研究原料粉末在行星式球磨机上的球磨时间对合成粉体物相组成的影响规律。结果表明,在2~24 h内混合原料粉末时,延长原料粉末的球磨时间可有效细化活性炭,提高混合粉末的比表面积,提高Al2O3和活性炭混合的均匀性,有利于纯相AlON粉体的合成,而对于球磨时间较短的原料粉末,可以通过提高烧结温度或延长保温时间促进AlON相形成。经24 h球磨的原料粉末在1 750℃碳热还原60min获得的纯相AlON粉体,在1 880℃无压烧结制备了最大红外透过率为81%的AlON透明陶瓷(3 mm厚样品)。     

Refining of copper powder by a novel micro-abrasive milling method conducted in the air

The pure copper powder was milled by conventional high-energy ball milling (CM) and micro-abrasive milling (MAM) methods in the air or vacuum. The refining behavior of copper powder milled using these different methods has been studied, and the morphologies, microstructures, compositions, and properties of the milled powders have been thoroughly investigated. The results show that, as compared to CM, the MAMed copper powder had a better refinement behavior and contained a smaller number of agglomerates. After milling in the air for 30 h by MAM, whole copper powder was converted into Cu₂₊₁O. In addition, under the synergistic effects of micro-abrasion and exposure to oxygen, the Cu₂₊₁O powder was soft-agglomerated and had a specific surface area of 15.1031 m²/g and an average size of 375.4 nm. During the dispersion process, Cu₂₊₁O was partly converted into CuO and the microstructural evolution characteristics were disclosed. The dispersed powder had an average particle size of 179.5 nm. The refining mechanism of the copper powder prepared by the micro-abrasive milling method was also discussed.     

Structural evolution in nano-crystalline Cu synthesized by high energy ball milling

Nano-crystalline copper with a mean crystallite size of 27 nm was synthesized through solid state reduction of Cu₂O by graphite using high energy planetary ball mill. The structural and morphological changes during mechanical milling were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mean crystallite size and residual strain were determined by XRD peak broadening using the Williamson–Hall approximation. It was found that the reaction is completed in a manner like a nucleation and growth process. Although the crystallite size and internal strain changes in Cu₂O were regular during mechanical milling, there was an irregularity in both parameters in Cu particles. This irregularity was probably due to the progressive formation of copper during milling.     

Mechanical alloying and sintering of nanostructured tungsten carbide-reinforced copper composite and its characterization

Elemental powders of copper (Cu), tungsten (W) and graphite (C) were mechanically alloyed in a planetary ball mill with different milling durations (0–60 h), compacted and sintered in order to precipitate hard tungsten carbide particles into a copper matrix. Both powder and sintered composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and assessed for hardness and electrical conductivity to investigate the effects of milling time on formation of nanostructured Cu–WC composite and its properties. No carbide peak was detected in the powder mixtures after milling. Carbide WC and W₂C phases were precipitated only in the sintered composite. The formation of WC began with longer milling times, after W₂C formation. Prolonged milling time decreased the crystallite size as well as the internal strain of Cu. Hardness of the composite was enhanced but electrical conductivity reduced with increasing milling time.     

Enhanced photocatalytic performance of Cu2O nano-photocatalyst powder modified by ball milling and ZnO

In this paper, a ball milled Cu₂O-ZnO nano-photocatalyst with good photocatalytic performance in visible light range was prepared. Effect of ZnO presence and ball milling of Cu₂O on the structure, microstructure, optical properties and photocatalytic performance were studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), high resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) analysis and UV–Vis spectrophotometer were used as characterization techniques. FESEM results indicated that ball milling of Cu₂O changed the morphology of Cu₂O-ZnO composite. The uniform formation of ZnO particles with average size of 30 nm over the Cu₂O surface was observed. The formation of p-n heterostructure with good contact between Cu₂O and ZnO nanoparticles was found by HRTEM image. Ball milling of Cu₂O promotes visible light absorption and reduction band gap to 1.9 eV in Cu₂O-ZnO photocatalyst. Intensity of PL spectra for the ball milled Cu₂O-ZnO photocatalyst was obviously lower. Ball milled Cu₂O-ZnO photocatalyst shows the highest photocatalytic activity and degradation efficiency of 98% was obtained for 2 mg/L methylene blue (MB) solution after 240 min. The kinetics of the photodegradation was followed the Langmuir-Hinshelwood (L-H) model and degradation rates were decreased by increase of MB concentration. In the case of ball milled Cu₂O and presence of ZnO, the MB degradation kinetics was two times faster.     

Fabrication of the supersaturated solid solution of carbon in copper by mechanical alloying

Mechanical alloying of powder mixtures of copper and graphite was performed in a high energy ball mill. The as-milled powder was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. These investigations indicated that high energy ball milling could largely extend the solid solubility of carbon in copper and the 4 wt.% C was dissolved in Cu. It was ascribed to the decrease of the grain size and the increase of the lattice strain. Nanostructures, amorphous carbon and lamellar graphite were observed in the as-milled powder after milling for 24 h.     

Synthesis and Characterization of CuNi Magnetic Nanoparticles by Mechano-Thermal Route

In the present investigation, Cu_0.5Ni_0.5 nanoparticles were synthesized using high energy ball milling of a mixture of Cu₂O, NiO, and graphite powders. The mixture of powders was milled up to 50 h. The 30 h milled sample was heat treated at various temperatures for 1 h in a vacuum tube furnace. The effects of milling time and heat treatment temperature on the powder particle characteristics were studied employing X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), differential thermal analysis (DTA), and vibrating sample magnetometer (VSM) techniques. XRD results indicated incomplete formation of Cu_0.5Ni_0.5 after 30 h of milling. Further heat treatment at 500 ^°C led to the formation of a single phase Cu_0.5Ni_0.5 powder. FESEM and TEM images of the heat treated sample showed spherical Cu_0.5Ni_0.5 nanoparticles with a mean particle size of 15 nm. Magnetic properties data measured by VSM of the above sample are correlated well with the XRD results. Coercivity and saturation magnetization have been approximately achieved at 25 Oe and 18 emu/g, respectively.     

激光蒸凝法制备氧化铜纳米粒子

以１５０Ｗ ＣＷ ＣＯ_２激光器为光源,Ｃｕ（ＡＣ）_２·Ｈ_２Ｏ为靶材,采用激光蒸凝法制备出了氧化铜纳米粒子．初步研究了反应参数对纳米粒子性能的影响,并用Ｘ射线衍射、电子衍射、透射电镜等技术对纳米粒子的性能进行了表征,同时对纳米粒子的形成机理进行了初步的探讨．实验结果表明;激光功率密度、反应压力、载气种类及流量等工艺参数对产品的粒度、晶型等性能均有影响．在惰性气氛下,产物主要是Ｃｕ和Ｃｕ_２Ｏ,粒径为１０～３０ｎｍ;在氧气气氛下,产物主要是Ｃｕ、Ｃｕ_２Ｏ和ＣｕＯ的混合物,粒径为１０～５０ｎｍ．     

Synthesis of copper and copper(I) oxide nanoparticles by thermal decomposition of a new precursor

The present investigation reports, the novel synthesis of nanoparticles Cu and Cu₂O using thermal decomposition and its physicochemical characterization. The nanoparticles copper powder have been prepared using [Bis(salicylidiminato)copper(II)], [Cu(sal)₂], as precursor. Cu nanoparticles are initially formed and subsequently oxidized to form Cu₂O. Transmission electron microscopy (TEM) analysis demonstrated nanoparticles Cu₂O with an average diameter of about 10 nm. As-prepared copper nano-particles were characterized by X-ray diffraction measurements (XRD), scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), and Fourier transform infra-red spectroscopy (FTIR). XRD analysis revealed broad pattern for fcc crystal structure of copper metal and cubic cuprite structure for Cu₂O. Optical absorption measured by UV–visible spectroscopy was used to monitor oxidation course of Cu → Cu₂O and to determine the band-gap energy about 2.4 eV for Cu₂O nanoshells.     

Mechanical alloying of Cu–Mo powder mixtures and thermodynamic study of solubility

A set of Cu-based powder mixtures containing up to 8 at.% Mo has been processed through mechanical alloying for a range of milling times up to 75 h. The milling operation was carried out using two types of milling media, stainless steel and tungsten carbide balls, keeping a constant powder to balls weight ratio of 10:1. The alloyed powders obtained were characterised by X-ray diffraction and scanning electron microscopy in order to determine the mean crystallite size and particles morphology after milling, respectively. The crystallite size produced after milling was quantitatively determined based on both, the Scherrer and Williamson–Hall methods. An estimate of the increased solubility of Mo in Cu, produced by the microstructural refinement during milling, was carried out through a thermodynamical analysis based on the influence of crystallite size reduction on chemical potentials.     

Structural and microstructural phase evolution during mechano-synthesis of nanocrystalline/amorphous CuAlMn alloy powders

The formation mechanism of Cu–11.5Al–4Mn alloys by mechanical alloying (MA) of pure elemental powders was investigated. During milling, the powder sampling was conducted at predetermined intervals from 1 h to 96 h. The quantitative phase analyses were done by X-ray diffraction and the particles size and morphology were studied by scanning electron microscopy. Furthermore, the microstructure investigation and phase identification were done by transmission electron microscopy. Concerning the results, the nanocrystalline Cu solid solution were formed at short milling times and, by milling evolution, the austenite-to-martensite (2H) phase transformation occurred. Moreover, the formation of considerable amount of amorphous phase and its partial transformation to crystalline phases during the milling process were revealed. It was also found that, by milling development, the powder morphology changes from lamellar to semi-spherical and their size initially increases, then reduces and afterward re-increases.