Portable nano probe for micro/nano mechanical scratching and measuring

A nano probe system which can measure precise micro parts or optical parts in nanometer range resolution and scratch contact force in mN scale was demonstrated. The nano probe was originally designed for on-machine measuring applications and one kind of contact type measuring probes was designed for miniaturized or microfactory system. It ideally should be of small size and able to measure surface topography in nanometer scale. A commercial capacitive displacement sensor was proposed. It was a new concept in nano probe systems which can measure the displacement of shaft driven by the variation of surface topography. The nano probe mainly consisted of three parts: a capacitive displacement sensor, a porous type air slide and a contact probe part with various tip radiuses. The porous type air slide assured the shaft slided smoothly with controllable normal force in mN scale and had high positioning accuracy. The probe part which was directly in contact with target surface, can be applied to micro/nanoscale scratching as well as the measurement of sample topography by a simple tip change.     

Development of a 45° tilted on-machine measuring system for small optical parts

A new contact type of on-machine measuring system is developed in order to measure aspherical optical parts with steep surface angle for large numerical aperture (NA). A ceramic air slider made of SIALON is adopted for the measurement probe because of its low thermal expansion coefficient, high rigidity and light weight. A high accuracy glass scale is employed to reduce the thermal drift of the displacement gauge. The air slider or the measuring probe is tilted for 45° against the aspherical workpiece axis, and the probe is scanned over the workpiece surface, so as to keep the contact angle between the probe axis and the contact surface constant in order to reduce the change in the probe friction force.     

A new method of noncontact measurement for 3D micro pattern in semiconductor wafer: implementing a new optical probe

In this paper, a new type of noncontact/nondestructive measuring method has been developed, comprising a new optical probe, precision stages, and controllers. The new optical probe has been designed using the reflected slit beam through the optical window. The optical measurement system has been implemented around light illumination, optical lenses, optical window, and beam splitter. Efficient analysis algorithm has been developed in order to analyse the 3D micro pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, giving nanometer vertical resolution.     

气膜孔五轴视觉测量系统的设计与搭建

为解决空心涡轮叶片上气膜孔的孔径和分布位置的测量难题,在机器视觉测量与多轴运动控制的基础上,设计并搭建一套非接触式的气膜孔五轴视觉测量系统。该系统由三坐标测量机、双轴位置转台、工业视觉测头和叶片专用夹具等组成,具有3个直线自由度和2个转动自由度。在测量过程中,利用双轴位置转台实现被测叶片的转位,并通过三坐标测量机的运动实现工业视觉测头的移动,使工业视觉测头对焦于气膜孔的出口表面并采集其清晰图像。通过图像处理等步骤,获取被测气膜孔的几何尺寸和空间位置参数。为验证该系统的实用性和有效性,分别测量被测空心涡轮叶片上某一列气膜孔的孔径和孔中心坐标。实验结果表明:该测量系统能够完成气膜孔的孔径和孔中心坐标的检测任务,并且重复性精度指标满足使用要求。     

Friction from nano to macroforce scales analyzed by single and multiple-asperity contact approaches

Understanding friction and wear at different force and length scales is an interesting aspect in tribology. The variety of processes that make friction such a complex phenomenon includes mechanical, chemical and atomic interactions, each operating at their own time, length, and force scale.Extending local tribological information obtained from a single-asperity contact study (e.g. by lateral force microscopy LFM experiments) to contacts with multiple-asperity interactions is a challenging task. In this work, we analyze the localized friction recorded during a single-asperity LFM experiment, and compare it with that of multiple-asperity sliding contacts. Such a detailed study is relevant for miniature contacts which prevail in microelectromechanical systems of devices. In this work, the friction loops (i.e., tangential force versus displacement curves) obtained from nano to macroforce and different length scales were used to understand the scale effects of friction. Experiments were performed in reciprocating sliding conditions with a ball-on-flat configuration on diamond-like carbon and titanium nitride coatings.With decreasing contact size and stiffness of the measuring equipment, the effect of roughness is strikingly evident. The effect of surface roughness is clearly visible on the recorded friction loops as fluctuations, which were later attributed to geometrical and adhesive components. Based on our observations, a simple contact model was proposed to describe the nature of localized friction in single and multiple-asperity configurations during a sliding pass. The existing friction model for smooth and chemically interacting surfaces was extended to rough surfaces and it was found that most of the existing experimental claims could be explained as special cases of the proposed model.     

Hot-pressed electrospun PAN nano fibers: An idea for flexible carbon mat

Fibers on the nano scale are characterized by its high surface area per unit mass which is associated with high surface free energy. It seems to be an interesting idea to take advantage of this high free surface energy in electrospun in-plane randomly oriented (quasi-isotropic) multi-layered PAN fibrous mat by stabilizing the as electrospun structure at 220 °C under suitable pressure in oxygen environment; such treatment not only activates its high surface energy but also allows the contribution of larger number of molecules on the nano fiber surfaces as well as enhances the bonding between fibers. Mechanical examination of the hot pressed electrospun PAN Nano fibers mat showed higher flexibility than commercial carbon fiber as well as 2-D structure that can be advantageous in applications where the forces are equal in all directions and no specific orientation are required. Stress–strain curves of the hot pressed electro-spun PAN mats showed ductile behavior. The absolute values for tensile strength ranged from 55 to 63 MPa similar to some ductile pure metals such as aluminum, with much larger strain (6.5–8.25%). The modulus value for the fabric was found to be a measure for the enhanced surface free energy (nano size bond) and not the measure for single nano fiber properties, which was proved by preliminary examination for the fracture pattern of the fabric mat. This revealed de-lamination between the mat's layers breaking the bond in between within a value approximately equal or slightly larger than the modulus for bulk PAN polymer (2.80–3.04 GPa) with measured Poisson's ratio of 0.33. Raman analysis for the hot pressed samples showed a formation of disordered carbon structure at 1360 cm^?1 and ordered carbon structure at 1580 cm^?1.     

基于视觉技术的三维曲面非接触无损检测方法

不规则自由曲面在机械工程中有着广泛的应用,对其进行三维无损检测是近年来国内外研究的热点问题之一,传统的接触式测量方法由于采用接触式测头,所以极易损坏待测表面,且难以测量弹性实体,测量效量差。提出了一种基于主动双目视觉传感技术的三维曲面非接触无损检测方法,通过向待测曲面投影特定结构光并接收反馈信息实现曲面三维坐标的快速高效检测。这种方法无须接触式测头,仪器小巧,测量仪器与被测件间无测量力,因而易于实现现场无损检测。分析了基于该方法的数学模型,并给出了计算机仿真实验结果。仿真实验证明,该方法能够实现三维曲面的高精度现场检测。     

微纳米覆盖层材料的力学性能表征探讨

使用Agilent公司G200微/纳米压痕仪对多种微纳米覆盖层材料的力学性能进行了测量。结果表明,通过连续刚度法测量微纳米涂层材料,可以获得涂层硬度和弹性模量,并能得到涂层硬度或弹性模量随厚度的变化规律;通过试验也可以看到,纳米压痕法测量膜材的力学性能存在明显的表面效应;基材对膜材的力学性能没有影响;膜材厚度越大,同一深度测得的膜材的弹性模量越高。     

微/纳米尺度硬度测量技术及研究

硬度综合反映了材料的弹性、塑性等一系列物理性能,是材料力学性能的一个重要参数。传统硬度测试技术在微纳米尺度已不再适用。本文介绍了微纳米尺度硬度的静态和动态测试机理,分析了纳米硬度计的测试特点,并对测量误差产生的可能原因做了说明。最后简要分析了微纳米硬度测试技术的发展趋势。     

Thermal decomposition behavior of nano/micro bimodal feedstock with different solids loading

Debinding is one of the most critical processes for powder injection molding. The parts in debinding process are vulnerable to defect formation, and long processing time of debinding decreases production rate of whole process. In order to determine the optimal condition for debinding process, decomposition behavior of feedstock should be understood. Since nano powder affects the decomposition behavior of feedstock, nano powder effect needs to be investigated for nano/micro bimodal feedstock. In this research, nano powder effect on decomposition behavior of nano/micro bimodal feedstock has been studied. Bimodal powders were fabricated with different ratios of nano powder, and the critical solids loading of each powder was measured by torque rheometer. Three different feedstocks were fabricated for each powder depending on solids loading condition. Thermogravimetric analysis (TGA) experiment was carried out to analyze the thermal decomposition behavior of the feedstocks, and decomposition activation energy was calculated. The result indicated nano powder showed limited effect on feedstocks in lower solids loading condition than optimal range. Whereas, it highly influenced the decomposition behavior in optimal solids loading condition by causing polymer chain scission with high viscosity.     

Application of rare- earth and nano elements on diamond cup wheels

Diamond cup wheel is used widely as an important tool for machining ceramic tile. In this paper, nano rare - earth oxide and nano carbide were added in the segments of seven kinds of diamond cup wheels. The performance of diamond cup wheels were tested on a special designed test machine by grinding two kinds of ceramic tiles. The surface morphology of the segments was examined by Scanning Election Microscopy （SEM） and the micro-hardness of segments was measured. The results showed that nano rare-earth oxide and nano carbide can fine segment micro structure, make grain boundary clear and increase grasping of diamond grits. They can increase also the wear resistance of diamond cup wheels as well as the grinding ratio.     

冷轧钢表面复合纳米硅烷膜的耐蚀性能研究

采用正交试验法探讨了在冷轧钢表面制备复合纳米硅烷膜的最佳工艺条件,通过塔菲尔曲线研究了硅烷膜在3．50％NaCl溶液中的自腐蚀电流密度与自腐蚀电位。实验表明,形成复合纳米硅烷膜的最佳工艺条件为：水解温度为40℃、水解时间为8h、水解溶液的pH为10、水解溶液各组分的体积比为V（y-APS硅烷）：V（乙醇）：V（水）=7：22：75、浸涂时间20min、固化温度90℃、固化时间20min。纳米材料最佳用量为0．3g·L^-1。通过阳极极化曲线研究了存在与不存在纳米材料的硅烷膜的耐蚀性能,用扫描电子显微镜观察了在相同超电势下存在与不存在硅烷膜的冷轧钢在腐蚀前后的形貌变化。结果表明,复合纳米硅烷膜的耐蚀性能明显优于纯y-APS硅烷膜。     

纳米Fe-Al/Cr_3C_2复合涂层的制备及性能研究

目的制备纳米Fe-Al/Cr_3C_2复合涂层并对比分析结合强度、显微硬度、孔隙率,为利用热喷涂技术治理易损部件提供有效手段。方法运用自主研发的造粒系统,成功对高活性的纳米Fe-Al/Cr_3C_2复合喷涂粉体实施团聚造粒。使用高速火焰喷涂方法,在结构材料表面制备出了纳米Fe-Al/Cr_3C_2复合涂层。测试了纳米Fe-Al/Cr_3C_2复合涂层的基本性能,包括结合强度、显微硬度、孔隙率。结果纳米Fe-Al/Cr_3C_2复合喷涂材料的粒径由原始的50 nm团聚到最终的114~178μm,团聚后的纳米颗粒呈圆形或椭圆形,各成分比例保持原始比例,团聚颗粒内部仍然保持纳米粉体状态。纳米Fe-Al/Cr_3C_2表面及截面元素分布均匀、致密,纳米涂层的孔隙率、硬度和结合强度分别是微米涂层的0.25倍、1.39倍和2.43倍。结论团聚后的纳米Fe-Al/Cr_3C_2颗粒满足热喷涂材料的相关要求,纳米Fe-Al/Cr_3C_2比微米涂层具有更精细的涂层结构和更优异的基本性能。     

基于复合测头的工件加工在机测量技术研究

研究一种用于数控加工机床的工件在机检测技术,用于对加工过程质量进行监测和控制,以缩短大型工件的加工制造周期,改变现有制造加工领域手工检测模式或离线抽检模式的现状。设计一种新的复合式在机测头并提出其测量系统实现方案。在机检测系统主要由数控机床、复合测头、无线信号收发器、控制计算机及其测量软件组成。数控机床作为测量运动驱动机构,其主轴带动复合测头对工件进行测量,并把测量结果通过无线信号收发器传输到控制计算机,通过模型反求和数据融合后处理,在机实时给出工件加工质量报告。通过在机修正工件加工路径,提高工件制造合格率和加工效率。     

Performance of nano/micro CBN particle coated tools in superfinish hard machining

A two-stage composite coating method has been developed for coating of nano/micro cubic boron nitride (CBN) particles on cutting tools. Since nano/micro CBN particle coated tools are more cost-effective than solid polycrystalline CBN (PCBN) tools, a comprehensive study on the coated tools is required. This paper studies the performance of these tools in superfinish hard machining. Specimens were machined by a solid PCBN tool and CBN particle coated tools with two different CBN particle size distributions: less than 0.5 and 2 μm. The specimen machined by a tool with small CBN particle coating (less than 0.5 μm) showed more compressive residual stresses and less thermal damage below the machined surface than other specimens. Furthermore, the specimen machined by a tool with small CBN particle showed less residual stress scatter than other specimens. The rolling contact fatigue life was predicted by using a rolling contact fatigue life model. The rolling contact fatigue life predictions indicate that the predicted life of the specimen machined by a tool with small CBN particle coating is longer than that of other specimens. The results thus indicate that a tool with small CBN particle coating provides better performance than other tools in superfinish hard machining.     

Fabrication of nano Rhizama Chuanxiong particles and determination of tetramethylpyrazine

Rhizama Chuanxiong is a kind of traditional medicinal herb used to promote blood circulation and eliminate wind to relieve pain. In this work, nano Rhizoma Chuanxiong particles were successfully prepared by high speed centrifugal sheering （HSCS） pulverizer. The influence of processing parameters on the size ofRhizama Chuanxiong particles and the different properties between nano Rhizoma Chuanxiong particles and original fine powder were systematically studied by ZetaPALS light scattering granulometric analyzer and optical microscope. The content of effective ingredient tetramethylpyrazine （TMP） was determined by high-performance liquid chromatography （HPLC）. The results illustrate that general Rhizama Chuanxiong powder can be ultrafinely ground to nanometer within 50 min, and the cellular tissues ofRhizoma Chuanxiong are broken into pieces and dispersed stably and homogeneously after being ultrafinely ground. In addition, the active ingredients can dissolve out directly and fully, and the extraction ratio of TMP is increased 32.2% by HSCS processing.     

地下工程环境大气腐蚀监测系统设计

根据腐蚀电化学原理,应用微机技术对地下工程环境大气的腐蚀性,温度,湿度ｐｈ值进行监测,其测试单元具有高灵敏度、自动选择量程,自动测量等功能,控制主机通过与各测试进行数据通讯,控制各测试单元进行周期及随机测量,接收,贮存,处理并显示各测试点数据,并可通过扩展串口与ＰＣ机进行数据通讯,接受其控制。     

Size dependency of melting point of crystalline nano particles and nano wires: A thermodynamic modeling

A semi-empirical thermodynamic model for size dependency of melting point of nano particles and wires has been proposed by introducing a size dependency of surface energy. The model predicts the size dependency of melting point of nano particles and wires for a wide range of elements: fcc (Au, Pt, Ni), hcp (Mg), and bcc (W), all in good agreement with experimental data and/or molecular dynamics simulations. Since the model is free from adjustable parameters, it is applicable to a wider range of materials.     

Microstructure and preparation of nano S-W-S new solid lubrication system

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