磁过滤直流真空阴极弧制备含铬类金刚石膜的结构及其性能研究

采用磁过滤直流真空阴极弧沉积技术在单晶硅片、载玻片、不锈钢片基体上制备了含铬类金刚石(Cr-DLC)膜.用光学显微镜、椭偏仪、分光光度计、X射线光电子能谱(XPS)、X射线衍射能谱(XRD)、Raman光谱、纳米硬度计、摩擦磨损仪、洛氏硬度计检测了薄膜的组分结构、光学、力学等相关特性.结果表明,硅片上的薄膜厚度为47.6nm,碳含量为89%,s p~3键占碳含量的55.15%.不锈钢片上的薄膜具有典型的DLC膜Raman光谱特征,在空气中的摩擦系数约为0.1,耐磨性能优良,膜与基体的结合性能良好.     

脉冲真空弧源沉积类金刚石薄膜耐磨特性研究

本文利用脉冲真空弧源沉积技术在Cr17Ni14Cu4不锈钢和Si(100)基体上制备了类金刚石(DLC)薄膜,研究在不同基体偏压下,DLC薄膜的结构与性能.采用拉曼光谱和X射线光电子能谱(XPS)研究DLC薄膜的原子结合状态,利用CSEM销盘摩擦磨损试验机研究其耐磨性,利用HXD1000B显微硬度仪测试其显微硬度,并采用压痕法评价其结合力.研究结果表明:DLC薄膜与基体结合牢固.随着基体偏压的提高,DLC薄膜内sp3键含量增大,薄膜硬度提高.Cr17Ni14Cu4不锈钢表面沉积DLC薄膜后,耐磨性大幅度提高,本文探讨了DLC薄膜的耐磨机理.     

Effect of Substrate Bias on Microstructure and Properties of Tetrahedral Amorphous Carbon Films

The microstructure and properties of tetrahedral amorphous carbon (ta-C) films deposited by the filtered cathodic vacuum arc technology has been investigated by visible Raman spectroscopy, AFM and Nano-indentor. The Raman spectra have been fitted with a s     

增强型脉冲离子源镀制DLC薄膜拉曼光谱研究

本文利用增强型脉冲电弧离子源在硅基底上沉积类金刚石薄膜，拉曼光谱分析表明DLC薄膜中sp^3键含量比不加磁过滤装置时脉冲离子源所镀的类金刚石薄膜高，折射率更接近金刚石折射率2．4并且光学带隙也增大，证明用增强型脉冲离子源镀制的类金刚石薄膜sp^3键含量提高，性能得到了很大改善。     

H2S／CO2环境中碳钢的腐蚀电化学行为研究

采用电化学测试方法,结合SEM、EDS等分析技术,研究了在H2S／CO2环境中服役和未服役的碳钢弯管的电化学行为。结果表明：在H2S／CO2环境中服役后的弯管耐H2S／CO2腐蚀性能降低。在CO2体系中,电化学阻抗谱由高频容抗弧和低频感抗弧组成,金属表面局部覆盖疏松多孔且保护性差的FeCO3膜。当腐蚀体系中存在H2S时,低频感抗弧消失,金属表面形成均匀致密的FeS膜,可以显著降低弯管的腐蚀速率。     

Soot and other Products Formation from the Submerged Carbon Arc in Halogenated Solvents

A series of selected halomethanes were treated with the submerged carbon arc using graphite electrodes at 10A. CCl₄ and CHCl₃ produce abundant soot which is double in comparison to the soot produced by arcing CH₂Cl₂ and is one order of magnitude higher than the amount of soot produced by arcing hydrocarbons such as n-hexane or decalin and two orders of magnitudes higher in comparison to the amounts of soot produced by arcing alcohols. It was found a anticorrelation between the amount of polyynes present in the solution of the arced solvent and the amount of soot produced by arcing. In the case of CCl₄ and CHCl₃ no polyynes were detected by liquid chromatographic analysis (HPLC-DAD), while polyynes were detected in CH₂Cl₂ and are present in higher concentration in arced hydrocarbon solutions. The soot produced from halomethanes was analyzed by FT-IR spectroscopy in comparison to the soot produced by arcing hydrocarbons and alcohols. Furthermore, the soot from halomethanes was analyzed by HPLC-DAD after extraction with acetonitrile and found to contain a mixture of halogenated polycyclic aromatic hydrocarbons (PAHs). Also CHClBr and CH₂I₂ were arced between graphite electrodes. The former compound produces free bromine and soot; bromine causes halogenation of the polyynes. In the case of the latter compound, free iodine is released from the arc and the amount of soot produced is comparable to that obtained by arcing CH₂Cl₂.     

Influence of Nitrogen Flow Rate on the Microstructure and Properties of N and Me (Me=Cr,Zr) Co-doped Diamond-like Carbon Films

In this paper,Me (Me=Cr,Zr) and N co-doped diamond like carbon (DLC-MeN) composite films were prepared on cemented carbide substrates by pulsed bias arc ion plating.The effect of nitrogen flow rates on the microstructure and properties of the films were investigated by X-ray photoelectron spectroscopy (XPS),Raman spectra,grazing incident X-ray diffraction (GIXRD),high resolution transmission electron microscopy (HRTEM) and nano-indentation.Raman,GIXRD and HRTEM results show that the deposited films are nano...     

轮胎模具无氢DLC涂层的制备及表征

为探究轮胎模具类金刚石(DLC)涂层的应用前景,提高模具表面的硬度和疏水性,按照模具加工工艺制备35钢基体试样,利用电弧离子镀在基体上沉积无氢DLC涂层,对涂层粗糙度、三维表面形貌、断面结构、元素组成及含量、Raman光谱、纳米硬度和疏水性进行了分析.结果表明:通过改变粗糙度可以改善涂层的疏水性,涂层疏水性随粗糙度增大而显著增加,水接触角最高可达96°,且涂层硬度可达30.3 GPa.无氢DLC涂层可满足轮胎模具耐磨性和易清洁的使用要求,为制造高性能轮胎模具提供了一种可行的工艺选择.     

Alternative Synthesis Method for Carbon Nanotubes

It is demonstrated that carbon nanotubes (CNTs) can be synthetized on the surface of an example carbon background, activated carbon, using the thermal conversion of poly(furfuryl alcohol) (PFA). This newly discovered CNTs synthesis method is an alternative solution to previously known methods, e.g., chemical vapor deposition, arc discharge, and laser ablation. Scanning electron microscopy and high‐resolution transmission electron microscopy images deliver direct evidence of CNT formation through the thermal degradation of PFA in a temperature range of 500–700 °C. The discovered process consists of the free growth of CNTs from PFA without any mechanical patterning, casting, or molding. CNTs obtained in this manner resemble MWCNTs in size, though according to microscopic investigation the tubes do not possess the well‐developed layered structure of MWCNTs. Nonetheless, X‐ray photoelectron spectroscopy and Raman spectroscopy studies fully confirm that carbon (C) is the main elemental constituent of the tubes (C atomic content above 85%) and C atoms are structured in a manner typical of defected CNTs (D, G, and G' intensity ratios).     

粗丝CO_2气体保护焊熔滴过渡与潜弧机理的研究

本文详细分析了粗丝CO_2气体保护潜弧焊熔滴过渡的特点和潜弧机理。潜弧状态可以分为三种类型:半潜弧(熔滴主要以较大的颗粒形式过渡)、临界潜弧(熔滴主要以较小颗粒的射滴形式过渡)和深潜弧(熔滴以细小射滴与射流混和形式过渡)。大电流、低电压、粗焊丝、反极性和氧化性气氛是形成潜弧过程的必要条件,其中电流是最重要的条件。潜弧后弧柱气氛改变,焊丝端部的弧根由集中形态扩展为覆盖整个端部形态,使得熔滴尺寸变得细小,熔滴过渡形式发生变化。采用临界潜弧区域的焊接规范参数施焊,飞溅小,工艺过程稳定,焊缝成形优良。     

Anisotropies in Carbon Nanotube Synthesis by the Hydrogen Arc Plasma Jet Method

Single-wall carbon nanotubes were prepared under hydrogen gas atmosphere with a DC arc discharge maintained between the tip of a sharpened graphite cathode and an anode formed by a catalytic mixture of graphite, FeS, Ni, Fe and Co compressed powders. The cathode is placed with an inclination with respect to the anode, so that the plasma jet of the discharge is deviated towards the empty space of the growth chamber. Samples were classified and analyzed according to their type and growth positions relative to the direction of the plasma jet flow. Characterization of the samples was performed with mass spectrometry, Raman spectroscopy and transmission electron microscopy. A subtle variation is found in the properties of the nanotubes obtained in different locations due to the directionality of the plasma jet flow. Observed differences in sample properties may be qualitatively understood in terms of accepted mechanisms of SWNT growth.     

厚度对真空电弧制备传感器用非晶ta-C膜性能的影响

采用双弯曲磁过滤阴极真空电弧沉积方法在传感器用P型单晶硅上制备ta-C膜,并通过实验测试的手段研究厚度对其组织及性能的影响。研究结果表明:逐渐延长沉积时间后,沉积速率始终保持1.6 nm/min的稳定状态。分别运用椭偏仪和光度计测定ta-C膜的厚度结果基本一致,差值小于2 nm。随着膜厚的增加,sp³C比例发生了减小,原先的sp³结构逐渐转变为sp²结构。当膜厚增大后,ta-C膜内形成了更高比例的sp³C。当膜厚增大后,G峰发生了低位移动,此时膜内的sp³C比例发生了降低。当膜厚增大后,ta-C膜色散值和残余压应力发生了不断减小,表明膜获得了更小的拓扑无序度。不同厚度的涂层粗糙度基本接近,都在0.6 nm以内。膜表面呈现光滑的连续分布形态,粗糙度保持基本恒定。     

Carbon arc plasma as a source of nanotubes: emission spectroscopy and formation mechanism

Diagnostics of carbon arc plasma by optical emission spectroscopy during the synthesis of carbon nanotubes is reviewed. Spatial distributions of temperature and C2 radicals in different plasmas are presented. The influence of gas pressure, anode composition, and reaction environment is discussed. Mechanisms of carbon nanotube formation are reviewed, with an emphasis on surface diffusion processes and catalytic effects.     

碳纳米管工具电极的制备

纳米工具电极是进行纳米电解加工的必备条件,其特征尺寸直接影响纳米结构的最终尺寸.提出了利用电弧放电将碳纳米管束焊接在钨针尖上的纳米工具电极制备方法,并通过试验研究了钨针的针尖圆弧半径和放电电压对制备碳纳米管工具电极的影响.试验结果表明,不同尖端圆弧半径的钨针,所需有效放电电压不同,圆弧半径越小,有效放电电压越小,强电场分布越集中,越容易将碳纳米管束焊接在针尖的顶端;圆弧半径越大,强电场分布区域越大,越不容易控制碳纳米管束焊接的方向性.在针尖圆弧半径约为100 nm和300 nm的钨针上,放电电压分别为25 V和35 V时,成功制备出碳纳米管工具电极.     

Synthesis of aluminium nanoparticles by arc evaporation of an aluminium cathode surface

Aluminium nanoparticles (Al Nps) are synthesized using arc discharge method by applying direct current between aluminium electrodes in liquid environment without any use of vacuum equipment, heat exchangers, high temperatures furnaces and inert gases. After synthesis of Al Nps, in situ coating process on the nanoparticles was performed immediately. The effects of media on the yield and morphology of aluminium nanoparticles were investigated. Analysis result of the samples indicated that particle size was less than 30 nm, when 120 A/cm² arc current was used. In addition, coating agent can affect arc velocity, arc stability, morphology and composition of the nanoparticles. Resultant nanoparticles were identified using X-ray powder diffraction (XRD), also their surface morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and finally the accuracy of coating was assessed with infrared (IR) spectroscopy.     

不同技术制备DLC膜的激光损伤特性研究

随着高能量大功率激光器的发展和激光元件的广泛应用,用于红外窗口表面增透保护的类金刚石薄膜(DLC)的抗激光损伤特性成为评价薄膜质量优劣的一个重要指标。然而,不同的制备方法和技术沉积的DLC薄膜具有各异的微观结构,从而具有不同的抗激光损伤特性。本文采用脉冲真空电弧(PVAD)和非平衡磁控溅射(UBMS)技术沉积了DLC膜,对两种DLC膜抗激光损伤特性进行了研究,测试结果表明,两种技术沉积的DLC薄膜激光损伤阈值分别0.6 J/cm2和0.3 J/cm2,PVAD技术比UBMS技术沉积的DLC薄膜具有更高的抗激光损伤阈值。基于实验研究了薄膜光学常数和表面形态,分析了两种技术制备DLC膜激光损伤特性差异的主要原因。结果表明,采用UBMS技术沉积的DLC膜具有较小的折射率和较大的消光系数,薄膜表面存在较多的疵病和缺陷,这些是其激光损伤阈值较低的主要原因。     

超薄四面体非晶碳膜的结构和性能

使用磁过滤阴极真空电弧(FCVA)技术制备不同厚度的超薄四面体非晶碳膜(ta-C)，研究了表征和测量超薄ta-C碳膜微观结构和性能的方法以及膜厚的影响。使用X射线衍射仪验证椭圆偏振光谱仪联用分光光度计表征膜厚度的可靠性并测量了膜密度；用拉曼谱分析薄膜的内在结构，验证用椭偏联用分光光度计表征sp³ C含量的可靠性；用Stoney^，s公式计算了薄膜的残余应力。结果表明，薄膜的厚度由7.6 nm增大到33.0 nm其沉积速率变化不大，为1.7±0.1 nm/min；根据椭偏联用分光光度计的表征结果，薄膜中sp³ C的含量逐渐减少，拓扑无序度降低，与拉曼谱的表征结果一致；厚度为7.6 nm的超薄ta-C碳膜中p³ C的含量最高；随着厚度的增大薄膜中的残余压应力从14 GPa降低到5 GPa；厚度为11.0 nm的薄膜主体层密度最大，为3070 kg/m³，致密性较好；厚度对薄ta-C碳膜表面粗糙度的影响较小。用椭偏和分光光度计测量超薄ta-C碳膜的厚度和表征显微结构是可行的，X射线反射法可用于测量超薄ta-C碳膜密度和表面粗糙度，但是对薄膜的质量要求较高。     

Synthesis and photocatalytic activity of WO(3) nanoparticles prepared by the arc discharge method in deionized water

In this paper, we discuss the synthesis and characterization of tungsten trioxide nanoparticles prepared by the arc discharge method in deionized (DI) water. The size and morphology of WO(3) nanoparticles prepared using different arc currents (25, 35 and 45?A) were studied. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) results indicate that at an arc current of 25?A, the size of the particles is about 30?nm, and this increases to 64?nm by increasing the arc current. This size increase caused a decrease of optical band gap from 2.9 to 2.6?eV. X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) spectra demonstrate the formation of the WO(3) phase. Photodegradation of Rhodamine B shows that samples prepared at the lowest current have more photocatalytic activity due to having the smallest particle size and highest surface area. The results demonstrate the ability of the arc discharge method for direct formation of WO(3) nanoparticles in DI?water medium.     

不同压力下碳纳米管的电弧法合成及其表征(英文)

采用电弧放电法在氦气/乙炔混合气氛中,在不同压力下合成了碳纳米管.运用场发射扫描电镜、场发射透射电镜、X-射线衍射仪和拉曼光谱对碳纳米管的形貌进行了表征.采用可见发射光谱对碳纳米管的形成过程进行了原位诊断研究.场发射扫描电镜结果表明,在氦气/乙炔气氛中合成的碳纳米管的长度大于50微米,许多碳颗粒沉积在碳纳米管壁上.场发射透射电镜结果表明,在0.100MPa下合成的碳纳米管的壁厚明显大于0.035MPa下合成的碳纳米管的壁厚.可见发射光谱诊断结果表明,CH和C2物种可能作为碳纳米管形成的前驱体,其中,以H原子作为无定形炭的刻蚀物种.阳极消耗速率和产物在阴极的沉积速率随着反应器中压力的增加而增加.因此,可以通过加强阳极和乙炔的蒸发速率及CH和C2物种的沉积速率而增加碳纳米管的形成速率.     

氩气流量对四面体非晶碳膜结构和摩擦性能的影响

利用自主研制的45°单弯曲阴极电弧沉积系统,通过改变Ar流量(2,5以及10 ml/min),在p型(100)硅基底上制备了四面体非晶碳膜。借助表面轮廓仪测定薄膜厚度和粗糙度变化;采用X射线光电子谱获得薄膜微结构信息,利用残余应力仪和摩擦磨损试验机测定薄膜的内应力和摩擦学性能。实验结果表明:随Ar流量增加,薄膜的沉积速率降低,表面趋于光滑;薄膜中sp3含量由2 ml/min时的68%下降至10 ml/min时的55%;薄膜应力值随Ar流量的增大而减小,在10 ml/min处取得最小值;不同Ar流量条件下所制备薄膜的摩擦系数在0.024~0.045之间,且随Ar流量增加而增大。