含硅类金刚石膜硬度压痕测试的有限元模拟

使用Abaqus有限元软件通过加载荷与加载位移两种方法对含硅类金刚石膜进行了压痕测试模拟,得到了不同硅含量类金刚石膜的硬度曲线。结果表明:两种方法的模拟结果较吻合,其中加载位移的方法较稳定,速度较快,含硅类金刚石膜的硬度随着硅含量的增加而减小;模拟结果得到了相关试验的验证。     

金刚石薄膜的性质及其应用

本文是金刚石膜膜生长技术，生长机理和结构特性检测的最后一篇，在该文中读者看到这种超硬新材料的众多的优异特性及其广泛的应用前景。     

类金刚石薄膜纳米摩擦性能的试验研究

利用摩擦力显微镜(FFM),对由等离子体增强化学气相法沉积的类金刚石(DLC)薄膜的纳米摩擦性能进行了试验研究。用原子力显微镜(AFM)观察了DLC薄膜样品的表面形貌,同时测定了其粘附力值。从外加载荷、扫描速度和湿度的角度分析了薄膜的摩擦特性。     

单晶铜薄膜纳米压痕过程的分子动力学模拟

使用三维分子动力学方法模拟了单晶铜薄膜的纳米压痕过程,研究了压头半径对纳米压痕过程的影响;采用Morse势函数计算试样原子与压头原子之间、试样原子之间的相互作用关系.结果表明:单晶铜薄膜纳米压痕的力学机理是非晶态产生的变形;纳米压痕过程具有尺寸效应,压头大小对单晶铜薄膜纳米压痕的分子动力学模拟结果有显著的影响.     

类金刚石薄膜厚度的测量

采用真空等离子休沉积法沉积了类金刚石膜,采用椭圆偏振光测量法测定了薄膜的厚度,在测量薄膜厚度的同时也可知道所沉积膜的均匀性情况。     

单晶硅纳米力学性能的测试

对材料纳米力学性能测试手段进行了研究,着重分析了纳米压痕技术的原理和方法.结合纳米压痕技术,采用尖端四面体Vickers型单晶金刚石压头对单晶硅(100)晶面进行了纳米压痕实验测试.实验发现,在载荷为1 000 mN时,晶体硅出现了明显的裂纹和脆性断裂;而在载荷低于80 mN的情况下,晶体硅则表现出延性特性.此外,在不同载荷条件下对晶体硅的硬度进行了实验测试,测试结果发现,不同载荷条件下晶体硅的硬度测量值存在较大的差异,认为导致这种差异的原因在于压痕区域晶体硅所受压力不同,使得晶体硅内部结构发生了改变,较为准确的单晶硅的硬度测量值为15.7 GPa.     

纳米金刚石薄膜的制备与应用

采用偏压辅助增强热丝化学气相沉积法(Chemical vapor deposition,CVD),以WC-Co硬质合金为衬底,采用控制沉积参数和添加惰性气体Ar等CVD新工艺,制备性能优良的纳米金刚石薄膜.进一步采用扫描电镜(Scanning electron microscopy,SEM)、原子力显微镜(Atomic force microscopy,AFM)、拉曼光谱(Raman spectroscopy)、X射线衍射(X-ray diffraction,XRD)和高分辨率透射电镜(High-resolution transmission electron microscopy,HR-TEM)分析了薄膜的纳米效应.研究结果表明:纳米涂层仍然是以金刚石结构为主的多晶体,它晶体颗粒较小(20～80 nm),含有较多的晶界和sp2结构,涂层表面粗糙度Ra≤50 nm,表面平整光滑,有利于研磨抛光.在此基础上,提出纳米金刚石复合涂层制备新技术,开发研制出各种涂层拉拔模具,在实际生产线上进行了应用,取得了显著的效果.     

磁控溅射制备Al-Cu合金薄膜的纳米压痕力学性能与强化机制

采用磁控溅射方法在不锈钢表面制备了铜原子分数在0～11.8%的Al-Cu合金薄膜,研究了铜含量对薄膜微观结构、纳米压痕力学性能和强化机制的影响。结果表明：纯铝薄膜呈现面心立方结构,铜原子分数在2.2%～6.5%时Al-Cu合金薄膜均形成过饱和固溶体相,当铜原子分数超过6.5%后,薄膜中生成了AlCu化合物。随铜含量的增加,薄膜的晶粒尺寸减小,硬度和弹性模量增加,当铜原子分数增至11.8%时,晶粒尺寸为34.7 nm,硬度和弹性模量分别比纯铝薄膜提高了212.5%,2.2%;当铜原子分数在0～6.5%时薄膜的强化主要来自于细晶强化和固溶强化,当铜原子分数超过6.5%后,薄膜的强化是细晶强化、固溶强化和第二相强化共同作用的结果。     

射频磁控溅射法制备类金刚石薄膜的研究

采用射频磁控溅射法,纯Ar溅射石墨靶,制备出了类金刚石薄膜,并对薄膜沉积速率随各工艺参数的变化规律、薄膜结构以及光学性能进行了系统的研究。结果表明,沉积速率随射频功率、CH4流量和溅射气压的增大而增大;随温度的增大呈现先增大后小的趋势。结构分析发现,所制备的DLC薄膜是由sp2键镶嵌在sp3键基体中构成的。在3μm~5μm波段对Si衬底有明显的增透效果。     

基于MEMS的胃肠道药物释放药丸的研制

介绍用于胃肠道药物定点释放的微型药丸的研制工作,该微型药丸以压力气体致动式工作原理为物理模型,由体外定点控制实现药物定点释放功能.实验表明,研制的微型药丸生物相容性好,释放动作比较可靠,可满足胃肠道定点药物释放的实验研究需要.     

抓住机遇,推动我国微型机械的快速发展

阐明微型机械新型学科的内涵和广阔的应用前景。综述美、日等发达国家从事微型机械的研究与开发状况和国内微型机械的研究现状。提出了推动我国微型机械快速发展的建议。     

Nano-wear mechanism of amorphous carbon thin films

Tribological performance of diamond-like carbon (DLC) overcoat on a magnetic hard disk was evaluated using a contact start stop wear tester. The analysis of worn surfaces suggests that wear of the carbon overcoat took place by a delamination type of wear mechanism at a nanoscale, resulting in the formation of wear particles of about 1.5 nm thick and 30–90 nm wide. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mechanical properties of thin carbon overcoats

Components used in magnetic storage systems (hard discs, tape heads and drums) are often very small and lightweight, and operate under very low loads (of the order of a few micrograms to a few milligrams). As a result, friction and wear processes occur on a nanometre scale and conventional tribological test methods and assessment tools are usually not appropriate. Furthermore, the assessment of the mechanical properties of the coatings or surface treatments used to protect these components from wear is complicated by the low thickness of the layers generally used. This paper details the problems associated with the assessment of the mechanical properties of thin diamond-like carbon coatings used to protect hard discs, tape heads and air bearings. Whereas thick coatings (>1 μm) are relatively easy to assess, even if the substrate has a low hardness and offers little support to the coating, there are many more problems when it comes to measuring the properties of the 5–10 nm layer on a hard disc. In many cases there is no plastic deformation of the coating which merely flexes and bends into the hole produced by plastic deformation of the substrate. Deformation of the coating is then limited to localised plasticity at the indenter edges, and/or fracture along the same edges and at the edge of the contact. The limits for use of Nanoindentation to assess the plasticity of the coating are discussed for such cases.     

微型机械材料的力学特性测量

概述了国内外MEMS材料力学特性的测量原理、方法和特点,主要包括弹性模量、残余应力、疲劳特性、破坏强度的测量,为微机电系统的设计和制造提供有益的参考。     

Microfrictional properties of diamond-like carbon films sliding against silicon, sapphire and steel

The low contact pressure characteristic of the microtribological regime relative to macro and nanosystems is suited for testing the microfrictional properties of different types of thin films. Motivated by macro as well as microsystem applications, this study investigates the microfrictional properties of different types of diamond-like carbon (DLC) films, prepared using low- and high-frequency plasma-assisted chemical vapor deposition (HF-PACVD) and the vacuum arc method. Testing was performed with a reciprocating precision microtribometer. Silicon, sapphire and steel balls were used as counterbodies. Friction-load curves suggest that, for applied forces in the μN to mN regime, two properties have a strong influence on the microfriction: first, the chemical composition plays a dominant role and second, the film roughness. With silicon and steel balls, the microfriction of hydrogen-free DLC films was greater than the hydrogen-containing films. With sapphire counterbodies, the results indicate that microfriction is inversely proportional to the film roughness. Also, for the films tested, microfriction was determined to be independent of the sliding velocity. For the force (pressure) regimes tested, mild wear was observed on silicon and some steel counterbodies, while no wear could be detected on any of the DLC films. These results illustrate the utility of implementing microtribological testing in comparative coating studies.     

微型机电系统的建模与仿真研究

概述了开展微型机电系统 (MEMS)建模与仿真研究的意义和必要性。提出了MEMS建模与仿真技术的特点 :( 1)多物理场耦合 ;( 2 )材料特性的变化 ;( 3 )依赖快速有效的算法 ;( 4 )原子尺度仿真。分别从器件级仿真、过程仿真和系统级仿真三个层次说明了MEMS仿真的方法。最后结合MEMS建模与仿真技术的发展现状 ,指出了该领域今后的发展趋势。     

微装配技术的发展现状

微器件的装配并不是一个新兴的领域 ,但随着微加工技术、显微技术和集成电路技术的发展 ,微装配概念发生了根本性的变化 ,产品的范围和应用领域被拓宽 ,出现了许多新的技术 ,它的发展是与微机电系统 (MEMS)、纳米技术 (Nanotechnology)密切相关的。本文对微装配技术的发展现状进行了综述 ,介绍了微装配的特点和使用的许多新技术     

复杂微机电系统多学科设计方法研究

针对复杂微机电系统设计涉及多个学科领域的特点,提出了应用多学科设计优化方法来设计复杂微机电工程产品,归纳分析了复杂微机电系统在设计过程中可能涉及的学科,探讨了多学科设计方法在复杂微机电系统设计中的应用。     

飞秒脉冲激光沉积类金刚石膜实验研究

期望用类金刚石膜作为硅的红外保护/增透膜,采用波长为800nm,脉宽50fs,重复频率1KH z的T i:Sapph ire飞秒激光器及石墨靶材在单晶S i片上沉积了约0.7μm~1μm厚的类金刚石膜(d iam ond-like carbon film s,DLC),获得了光滑致密,硬度显著提高,红外透过率有一定增加的样品。通过对薄膜拉曼光谱和X射线光电子能谱等的测试,发现单脉冲能量在0.4m J~1.6m J范围内变动时,单脉冲能量0.8m J获得的类金刚石膜综合性能最佳,其对应的焦斑功率密度计算值为1.4×1014W/cm2。