基于AFM的纳米级表面加工中切屑形成的影响因素

以原子力显微镜（AFM）为加工工具进行了纳米级加工实验,对不同加工条件下的材料去除过程和切屑形态进行了研究．切屑形态通过扫描电子显微镜（SEM）进行观察,分析了不同垂直载荷、循环次数和针尖加工方向下铝铜被加工表面的切屑形成过程．实验结果表明：低栽下切屑呈细小断屑,散布在加工区域周围;随着垂直载荷的增加,切屑逐渐变成连续的带状切屑．不同循环次数、针尖加工面时切屑形成都有很大影响．在此基础上,对比分析了相同实验条件下,不同力学性能材料的切屑形成过程．最后,通过检测被加工表面得出被加工表面质量与切屑的数量和形态之间的关系,提出了改善被加工表面质量的方法,以帮助人们更好地理解基于AFM的纳米级加工技术．     

基于SPM技术的纳米信息存储薄膜的研究进展

扫描探针显微技术SPM可以在原子或分子尺度上对表面进行表征和修饰，应用SPM技术可以在薄膜表面形成纳米级的信息点阵，特别适合发展超高密度的信息存储，是一种非常有希望代替传统磁存储，光存储的纳米级存储技术，本文介绍了纳米信息存储薄膜的研究进展，并对其制备技术和读写机制进行了初步的探讨。     

Ni针尖/Au基体纳米压痕的分子动力学模拟

采用原子镶嵌势函数（EAM）模拟Ni针尖（约1．5mm）／Au基体纳米压痕过程．研究结果表明,当Ni针尖与Au基体间距离达到一定值时（约0．23 mm）,机械的不稳定性使得针尖与基体间发生跳跃接触,产生纳米压痕和黏附现象（Au原子包裹在Ni针尖周围）．当压头离开基体表面,Ni针尖被拔起,随后在针尖与基体间形成连续的由Au组成的细颈．同时计算得到整个系统在针尖接近基体、跳跃接触、压痕、黏附、形成缩颈和一系列分离过程中的势能变化．     

纳米计量与传递标准

纳米计量不仅提供测量和表征纳米材料及器件基础,同时在纳米生产工艺控制和质量管理领域也扮演重要角色。纳米技术就某种意殳上讲就是实现原子或分子操作的超精细加工技术。纳米科技的各个领域都涉厦对纳米尺度物质的形态、成分、结构及其物理／化学性能(功能)的测量、表征。纳米测量在纳米科技中起着信息采集和分析的不可替代的重要作用。纳米测量技术包括：纳米级精度的尺寸和位移的测量,纳米级表面形貌的测量以及纳米级物理与化学特性测量。目前迫切需要解决的问题有微电子、超精密加工中线竞、台阶、膜厚等测量问题、纳米材料中的粒子特征测量问题和作为纳米科技主要测量和操作工具的扫描探针显微镜(SPM)、扫描电子显微镜(SEM)等的特性表征和测量准确度评定,文章重点评述了国际上为建立可溯源于国际基本单位制(SI)的纳米计量体系努力。包括：纳米尺度测量(台阶、节距)的国际比对,传递标准在纳米计量体系中的特殊作用,用于校准扫描探针显徽镜(SPM)、扫描电子显微镜(SEM)等的传递标准研制概况。     

SPM抑振系数的理论与实验研究

为分析外界振动对扫描探针显微镜（SPM）针尖一样品副的影响,提出“抑振系数”的概念．围绕SPM针尖一样品副的动态力学模型,对抑振系数的物理含义、影响因素等进行了理论分析．搭建了SPM激振、测振的实验系统,对不同的SPM扫描器、探针、样品、针尖预应力以及针尖一样品副开／闭环对SPM抑振系数的影响进行了实验研究．在理论分析上和实验研究中,都证实SPM抑振系数与悬臂梁的有效质量、弹性系数、空气阻尼系数、针尖与样品的接触弹性系数和接触阻尼系数等相关,反映在实际SPM部件参数上,则较短的扫描器、较长的悬臂探针、较软的样品表面、较大的探针预应力、闭环控制的针尖一样品副等都是提高SPM抑振性的途经．     

纳米磨削过程中加工表面形成与材料去除机理的分子动力学仿真

目前，以线性断裂力学为基础的加工理论对解释微切削加工机理还存在不足．分子动力学分析的方法在研究纳米尺度或原子尺度下的固体变形方面具有独特的优势；辅以压痕挤压机理分析，解释纳米磨真削过程中加工表面形成和材料去除机理．研究表明：静水压力对非结晶变形程度影响很大；晶格重构原子与一部分非晶层原子堆积在磨粒的前上方。由于磨粒不断前移，最终形成磨屑而实现材料去除，处在磨粒前下方的非晶层原子在压应力的作用下与已加工表层断裂的原子键结合重构形成已加工表面变质层；变质层由内外两层组成，外层是非晶层，内层是晶格变形层。     

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.     

原子力显微镜在高分子薄膜领域的应用

介绍了原子力显微镜(AFM)在高分子薄膜领域中的最新应用技术。在定位观察薄膜时,可采用碳纳米管定位法以及针尖打孔定位法对所观察的样品进行定位,该方法可实现对样品进行离位处理之后再次精确定位。在测量高分子薄膜厚度时,可采用针尖打孔法和漂膜法通过制备断面台阶利用AFM精确测量薄膜厚度。基于特殊相分离形貌的嵌段共聚物薄膜,可采用AFM针尖对其表面进行锻造纳米加工。这些技术拓展了AFM在聚合物薄膜表征以及纳米加工等领域的应用。     

AFM针尖耦合激光加工PMMA薄膜的加工重复性

利用飞秒激光与原子力显微镜的针尖部分耦合进行加工,是有望突破衍射极限,实现多隧道结加工的技术。本文在室温大气环境下,利用微焦级别脉宽为130fs、波长800nm的飞秒激光照射镀有金薄膜的原子力显微镜的探针针尖,使其耦合产生局域场加强效应在PMMA薄膜表面加工出光栅状纳米图形。通过最大残差法计算了条纹高度和宽度的重复性百分比,计算得到高度和宽度的最大残差值分别为6.3%和2.9%。结果表明在文中所提供的加工条件下,原子力显微镜针尖耦合激光是一种有潜力的激光加工方法。     

原子力显微镜探针针尖修饰的研究进展

介绍了当前几种AFM探针针尖修饰技术,以及它们在高分子材料、生物材料、微观摩擦学、粘附力、纳米级电化学、碳纳米管及纳米加工方面的研究进展。AFM探针针尖修饰的目的主要是:提高扫描图像分辨率,其分辨率可达纳米或亚纳米级别;用力曲线探究特定基团间的相互作用,定量分析端基与端基之间、分子链与分子链之间及端基与分子链之间的相互作用力,避免针尖对生物样品表面的损坏;对分子材料结构进行修饰,特别是在生物细胞、DNA分子链上及分子识别;避免Si或Si3N4针尖与表面硬度较大的样品直接接触,延长探针针尖的使用寿命。在研究天然橡胶硫化的作用机理时,可以用针尖修饰技术来模拟这个过程,探究天然橡胶分子链与单个硫原子的相互作用方式与作用力。通过电化学接枝聚合把高分子接枝在AFM针尖上,为研究单链的弹性力、引起构象转变的力、相互作用的双分子的分离力及特定的官能团的相互作用提供了许多可能性。分析了影响AFM探针针尖修饰的因素,结合材料领域方面的发展,对针尖修饰技术的发展及应用前景做了分析和预测。     

Investigation of method for measuring adhesion force of ice in nano/micro scale by using SPM

Ice adhesion to a cooling solid surface occurs in many situations, and it causes many serious problems that can lead to economic losses. Therefore, it is necessary to clarify the mechanism of ice adhesion to a cooling surface. In past studies, the adhesion force of ice was reported to be strongly governed by the surface energy of the cooling solid surface. In consideration of this surface energy, it is essential to investigate the ice adhesion force on a nano/micro scale. However, very little research has been conducted in nano/micro scale. Thus, in this paper, by using a scanning probe microscope (SPM), the methods for measuring the ice adhesion force and contact area between the cooling solid surface and formed ice are proposed, and the optimal measurement conditions of the SPM are determined. Then, the validity and effectiveness of the method are clarified.     

Micro/nano surface modification on brittle materials by tribo nanolithography using PCD tool

In this study, brittle materials were mechanically modified under precise normal force control at the mN approximately microN level using PCD tools as a nano tool. The lab-made PCD attached micro cantilevers were customized for tribo nanolithography. The machined patterns were measured under an atomic force microscope (AFM) to obtain the machining characteristics of the samples for each set of conditions. Then the samples were etched using aqueous solution to verify the etch characteristics of the machined surface. Our results showed that either protruding or depressed patterns could be generated on the scratched surface by controlling normal load, scan pitch, and etching condition. The unique mask effect of brittle material after mechanical scratching under PCD tool can be controlled by the conventional mechanical machining conditions such as chip formation, plastic flow, and material removal. We used SEM, TEM, SIMS, and AFM to investigate the etch characteristics and structural change of brittle material under nano scale mechanical machining conditions.     

A review of machining theory and tool wear with a view to developing micro and nano machining processes

This paper reviews the current state-of-the-art surrounding macro scale machining; it discusses how these factors will influence the future development of micro and nano scale machining. The paper begins by reviewing machining theory, and then discusses high speed machining, tool wear, tool coatings, micromachining, meso machine tool design and future applications and research directions. Tool wear is a factor that determines the economy of the machining process. Therefore, an extensive part of the paper is devoted to the development of materials used to coat tools; in turn, it is anticipated these coatings will used in future micro machining applications. Consideration is also given to machine structures that are required to use these cutting tools at speeds in excess of one million revolutions per minute. This review provides a timely explanation of the literature surrounding the factors required for successful micro and nano machining.     

表面微/纳米计量中的光学测量方法综述

微纳检测技术旨在以微/纳米级的精度测量加工表面特征,在加工过程的控制、建立表面特征与功能间的联系等方面具有重要作用。光学测量方法具有高精度、快速和无损的特点,是微纳检测技术研发的重要内容。本文介绍了表面形貌和薄膜的光学测量方法,并对各方法的特点及应用场合进行了对比总结。微纳制造技术加工的表面具有结构日益小型化、特征日益复杂化的特点,因此开发多模式测量系统是微纳检测技术的发展趋势。     

Fabrication of magnetic nanodot arrays for patterned magnetic recording media

Fabrication processes of arrayed magnetic nanodots for the use of patterned magnetic recording media were reviewed. One candidate for the patterned media is ordered assemble of magnetic nanoparticles, and the other is patterned magnetic thin films fabricated using various micro/nano scale machining processes. For the formation of patterned masks and molds, lithography processes as well as self-organized pattern formation are utilized. For the deposition processes of magnetic dots, electrochemical deposition processes were widely used. These fabrication processes are reviewed mainly from recent reports. The recording systems for the patterned media including probe-type-recording are also overviewed.     

扫描探针显微镜在粗糙度、纳米尺寸、表面形貌观测方面的应用

扫描探针显微镜是近十几年来在表面特征、表面形貌观测方面最重大的进展之一，是纳米测量学的基本工具。叙述了扫描探针显微镜的工作原理、检测模式及在观察检测纳米级的粗糙度、微小尺寸、表面形貌方面的特点和方法，比较了原子力显微镜、常规的表面轮廓仪、干涉显微镜、扫描电子显微镜在表面特性、表面形貌观测方面的性能，着重介绍了扫描探针显微镜在粗糙度、纳米尺寸、表面形貌观测方面的应用和存在的问题。     

Performance evaluation of Al2O3 nano powder mixed dielectric for electric discharge machining of Inconel 825

Electrical discharge machining (EDM) process is popular for machining conductive and difficult-to-cut materials, but low material removal rate (MRR) and poor surface quality are major limitations of the process. These limitations can be overcome by adding the suitable powder in the dielectric. The powder particles influence electric field intensity during the EDM process which in turn improve its performance. The size (micro to nano) and properties of the mixed powder also influence the machining efficiency. In this regard, the objective of the present work is to study the performance of EDM process for machining Inconel 825 alloy by mixing Al₂O₃ nanopowder in deionized water. The experimental investigation revealed that maximum MRR of 47?mg/min and minimum SR of 1.487?µm, which are 44 and 51% higher in comparison to conventional EDM process, respectively, can be achieved by setting optimal combinations of process parameters. To analyze these observed process behavior, pulse-train data of the spark gap were acquired. The discharge waveform identifies the less arcing phenomenon in the modified EDM process compared to conventional EDM. Further, surface-topography of the machined surface was critically examined by capturing field emission scanning electron microscopy and atomic force microscopy images.     

Nano surface generation of grinding process using carbon nano tubes

Nano surface finish has become an important parameter in the semiconductor, optical, electrical and mechanical industries. The materials used in these industries are classified as difficult to machine materials such as ceramics, glasses and silicon wafers. Machining of these materials up to nano accuracy is a great challenge in the manufacturing industry. Finishing of micro components such as micro-moulds, micro-lenses and micro-holes need different processing techniques. Conventional finishing methods used so far become almost impossible or cumbersome. In this paper, a nano material especially multi wall carbon nano tube is used in the machining process like grinding to improve the surface characteristics from micro to nano level.     

燃料喷嘴口微孔的几何与表面表征

燃料喷嘴口的微孔在汽车发动机的燃料效率和尾气排放中起关键作用．微孔的几何与表面质量的表征对理解其制造过程及其对喷嘴功能的影响十分重要，然而由于其尺寸小，对这类微孔质量的表征一直是一个难题．本文介绍作者最近进行的用扫描电子显微镜、扫描隧道显微镜、原子力显微镜来表征微孔质量研究的一个实例．虽然大多数计量系统并不是为测量像喷嘴口的微孔这类非平面特征设计的，只要合理选择装置和测头，微孔的高精度多尺度表征是可以实现的．     

玉米植株中的植硅石及其纳米SiO2的制备

以玉米植株为原料制备了纳米结构SiO₂. 通过常温混酸浸泡等手段在玉米植株中观察到了微米级植硅石,并以植硅石为原料,通过煅烧、硝酸煮沸等方法制备了纳米级SiO₂;运用X射线粉末衍射（XRD）、光学显微镜、透射电子显微镜（TEM）、扫描电子显微镜（SEM）、电子能谱（EDS）、红外光谱(IR)等手段对样品进行了表征. 结果表明,玉米茎表皮和叶中植硅石均为哑铃形,前者沿木质素导管方向顺向排列,后者为横向排列;经硝酸煮沸煅烧后,植硅石可以形成103nm左右的SiO₂球,并随着煅烧温度的升高,纳米球逐渐交联.