Micro/Nanotribological and Mechanical Studies of TiN Thin-Film for MEMS Applications

Micro/nanotribological and mechanical characterization of TiN film and single-crystal silicon was investigated. Hardness, friction, and wear properties of both materials were measured by a nanoindenter system. The results demonstrate the similarities and differences between both materials and show that TiN film has more preferable properties in hardness and wear resistance than those of single-crystal silicon. It is more likely that a methodology based on this study can be used for evaluating the quality of micro/nanofilms, and TiN film possesses desirable micro/nanotribological and mechanical characterization for MEMS applications.     

PAH/PAA(TiO2)分子沉积膜及其纳米摩擦学行为的研究

用分子沉积技术制备了PAH／PAA(TiO2)多层聚合物复合纳米粒子薄膜，为了增大薄膜自身的结合强度，采用加热的方式使其成膜动力发生转变。用紫外光谱及原子力显微镜(AFM)研究了薄膜的微观结构及其纳米摩擦学性能。结果表明，加热后薄膜中纳米粒子的长大导致薄膜表面粗糙度降低，同时提高了表面硬度，降低了薄膜表面摩擦力。     

小型化热丝CVD金刚石膜沉积设备的研究与开发

对传统HFCVD金刚石膜沉积设备进行小型化改进,分析了传统沉积设备在真空系统和衬底机构结构上的不足之处;介绍了小型化CVD金刚石膜沉积设备的系统构成;详细描述了该小型化设备的真空系统和衬底摆动机构。该系统具有均匀的表面温度场和很高的运行稳定性,可以用于纳米金刚石薄膜和金刚石厚膜的沉积,制备的纳米金刚石薄膜晶粒大小基本上都在200 nm以下,纳米硬度为(450~700)GPa;沉积的金刚石厚膜直径达93 mm,晶粒完整均匀。     

小型化、高密度微波组件微组装技术及其应用

徽组装技术是实现电子整机小塑化、轻量化、高性能和高可靠的关键工艺技术.本文详细介绍了微波多芯片组件技术、三维立体组装技术和系统级组装技术及其研究进展.概述了徽波组件微组装技术在新一代雷达和通讯系统中的主要应用.     

工业风机通流表面的涂护技术

工业风机包括机壳、叶轮、叶片等在内的金属通流部件表面的涂层防护是绿色再制造技术的简便技术措施之一.为进一步扩大工业风机通流部件表面的涂护技术的应用,需要提高工业风机通流部件表面的涂层材料的性能,简化涂装工艺,降低涂护成本.     

The YASHMA-2 Plasma Facility for the Deposition of Coatings on Solid Surfaces

A laboratory facility for the deposition of coatings on solid surfaces using a magnetron-discharge plasma and ion beams is described. Its main performance characteristics and functional capabilities are presented.     

Novel Characterization Techniques for Agricultural and Environmental Applications

ABSTRACT

Using the recently proposed open-photoacoustic-cell (OPC) detection technique the thermal diffusivity of potato skin has been found. Skin samples were taken from potatoes that were grown on different soils. The measurements were carried out with samples that, after being removed from the potatoes, were left in the air for different periods of time. Apparently, the process of the dehydration/oxidation resulted not only in the expected shrinkage of skin layers but also entailed chemical and/or structural changes that have produced a noticeable decrease of the thermal diffusivity coefficient.     

薄膜涂层弹性模量的表征与评价研究

因薄膜有其极小的厚度和特殊的微结构等特征,它与相同成分的块体材料相比,二者的弹性模量在数值大小、测试设备、表征方法和技术上都有一定的差异。给出了超声波测速法、弯曲法、鼓膜法和纳米压入法等六种适合于表征薄膜弹性模量的方法,研究了它们的原理和理论模型,分析和讨论了它们的特点和适用性,解释了用不同表征方法得出的弹性模量在数值上存在差异的原因。在实际测量中,应结合各表征方法和薄膜自身的特点加以灵活选用。     

超声诱导银纳米粒子的电化学制备及其表征

在络合剂EDTA、保护剂PVP存在的条件下,通过超声电沉积方法在硝酸银溶液中制备出形状不同的零维、一维银纳米材料。研究结果表明：当硝酸银浓度为0．0118mol／L、硝酸银与EDTA数量比为1：1时,银纳米粒子为类球形,直径约30nm。当加入2g／L的PVP时,可获得直径约30nm,长度不等的银纳米线。选区电子衍射和紫外可见吸收光谱表明,银纳米颗粒具有面心立方结构,其形貌和粒径影响微粒的光吸收特性。     

超声辅助电火花粉末沉积WC-Ni金属陶瓷涂层的微观结构及摩擦学性能

针对传统电火花沉积工艺中工具电极预制成本高、工艺复杂、材料选择范围受限等问题,提出了一种超声辅助电火花粉末沉积(Ultrasonic-assisted electro-spark powder deposition,UEPD)的新方法.利用UEPD工艺成功地在316L不锈钢基材上制备了 WC-Ni金属陶瓷涂层.所制备的...     

溅射工艺参数对TiAIN薄膜力学性能及结构成分的影响

采用反应磁控溅射法和钛-铝镶嵌靶制备TiAIN薄膜；运用纳米压入硬度测试仪、划痕仪和能谱仪、X射线衍射仪等对薄膜进行表征；研究了制备工艺参数对薄膜力学性能、薄膜成分及组织结构的影响。结果表明：随着氮气分压增大，薄膜厚度降低，薄膜（111）取向减弱，（220）和（311）取向增强，薄膜中的氮原子含量逐渐增多，而钛、铝原子含量逐渐减少；随着基体偏压增大，薄膜纳米硬度和膜／基界面临界载荷均逐渐增大，纳米硬度最高可达48．73GPa，膜／基界面临界载荷最高可达40N。     

Ultrananocrystalline Diamond Film as a Wear-Resistant and Protective Coating for Mechanical Seal Applications

Mechanical shaft seals used in pumps are critically important to the safe operation of the paper, pulp, and chemical process industry, as well as petroleum and nuclear power plants. Specifically, these seals prevent the leakage of toxic gases and hazardous chemicals to the environment and final products from the rotating equipment used in manufacturing processes. Diamond coatings have the potential to provide negligible wear, ultralow friction, and high corrosion resistance for the sliding surfaces of mechanical seals, because diamond exhibits outstanding tribological, physical, and chemical properties. However, diamond coatings produced by conventional chemical vapor deposition (CVD) exhibit high surface roughness (R_a ≥ 1 μm), which results in high wear of the seal counterface, leading to premature seal failure. To avoid this problem, we have developed an ultrananocrystalline diamond (UNCD) film formed by a unique CH₄/Ar microwave plasma CVD method. This method yields extremely smooth diamond coatings with surface roughness R_a = 20–30 nm and an average grain size of 2–5 nm. We report the results of a systematic test program involving uncoated and UNCD-coated SiC shaft seals. Results confirmed that the UNCD-coated seals exhibited neither measurable wear nor any leakage during long-duration tests that took 21 days to complete. In addition, the UNCD coatings reduced the frictional torque for seal rotation by five to six times compared with the uncoated seals. This work promises to lead to rotating shaft seals with much improved service life, reduced maintenance cost, reduced leakage of environmentally hazardous materials, and increased energy savings. This technology may also have many other tribological applications involving rolling or sliding contacts.     

溅射工艺参数对TiAlN薄膜力学性能及结构成分的影响

采用反应磁控溅射法和钛一铝镶嵌靶制备TiAlN薄膜;运用纳米压入硬度测试仪、划痕仪和能谱仪、X射线衍射仪等对薄膜进行表征;研究了制备工艺参数对薄膜力学性能、薄膜成分及组织结构的影响.结果表明:随着氮气分压增大,薄膜厚度降低,薄膜(111)取向减弱,(220)和(311)取向增强,薄膜中的氮原子含量逐渐增多,而钛、铝原子含量逐渐减少;随着基体偏压增大,薄膜纳米硬度和膜/基界面临界载荷均逐渐增大,纳米硬度最高可迭48.73 GPa,膜/基界面临界载荷最高可达40 N.     

丙烷压力对超声速微粒沉积铝青铜涂层组织和性能的影响

采用超声速微粒沉积技术在不同丙烷压力(0.469 MPa,0.496 MPa,0.524 MPa,0.551 MPa)条件下制备4种铝青铜涂层,采用环境扫描电子显微镜、X射线衍射仪、能谱仪等试验仪器表征涂层的微观组织、相结构以及氧元素质量分数等,运用显微硬度仪、拉伸试验机和CETR摩擦磨损试验机等试验设备分析涂层的力学性能和摩擦学性能。结果表明,丙烷压力对涂层组织结构及力学性能有显著的影响,随着丙烷压力的升高,涂层孔隙率与氧元素质量分数呈负相关关系,在丙烷压力为0.524 MPa时,涂层孔隙率为0.8%,氧元素质量分数为0.97%,更接近其平衡点;丙烷压力为0.524 MPa以下时,涂层较原始粉末物相无明显变化,主要仍为α+β'+K相;涂层显微硬度、结合强度及耐磨性能随丙烷压力的升高均呈先增大后减小的趋势变化,丙烷压力为0.524 MPa时,涂层的力学性能和耐磨性能达到最优。     

Tribological Performance of UHMWPE/GNPs Nanocomposite Coatings for Solid Lubrication in Bearing Applications

Ultra-high molecular weight polyethylene (UHMWPE)/ graphene nanoplatelets (GNPs) nanocomposite coatings were developed to reduce friction and wear in the absence of liquid lubrication. UHMWPE nanocomposite powders with different loadings (0.25, 1, and 2 wt.%) of GNPs were prepared and electrostatic spraying technique was then used to deposit the nanocomposite powders on aluminum alloy to form a thin coating. Friction and wear tests were conducted on the coatings against a flat-end pin, made of hardened tool steel to determine the best loading of GNPs. That was further tested to investigate the effect of sliding speed and contact pressure on its tribological properties and to establish coating operating limits. Results showed that UHMWPE nanocomposite coating reinforced with 1 wt.% GNPs showed the best tribological performance. It reduced wear rate by about 51% as compared to the pristine UHMWPE coating. The coating sustained a maximum sliding speed of 1 m/s at a contact pressure of 4 MPa equivalent to a pressure and velocity (PV) value of 4 MPa.m/s.     

工艺参数对多弧离子镀TiAlN涂层铝含量和硬度的影响

为研究不同工艺参数对多弧离子镀制备TiAlN涂层性能的影响规律,设计了L9(3~4)正交试验表,并通过试验研究了弧电流、衬底负偏压、氮气/氩气流量比以及腔体压强对涂层Al含量和硬度的影响规律,得到了最佳工艺参数优化组合。结果表明:影响Al含量的因素按重要性排序依次是:腔体压强、氮气/氩气流量比、衬底负偏压、弧电流。影响涂层硬度的因素按重要性排序依次是:弧电流、氮气/氩气流量比、腔体压强、衬底负偏压。     

Analysis of Linear Prediction for Soil Characterization in GPR Data for Countermine Applications

Ground-penetrating radar (GPR) is a versatile technology for subsurface sensing, and has shown promise in countermine applications when a target detection algorithm is employed. Because the soil environment is naturally heterogeneous and nonstationary, many detection algorithms have taken the form of adaptive filters operating on the real-aperture radar data. In particular, linear prediction techniques have received much attention for their ability to screen for anomalous signals that differ from the background. In this work, we demonstrate that linear prediction may provide a low-dimensional feature set that is indicative of various soil properties. Experiments were performed with simulated and field-collected GPR data, and results provide greater understanding of how linear predictors might be useful in landmine detection over varying terrain.     

聚电解质原位生长CuS纳米粒子分子沉积膜的制备及表征

采用分子沉积技术制备了基础聚二烯丙基二甲基氯化铵/聚丙烯酸分子沉积(MD)膜,然后在基础MD膜中原位反应生长了CuS粒子;利用紫外一可见分光光度计、X射线光电子能谱仪及原子力显微镜对此膜进行了表征.结果表明:在膜中原位生长的CuS颗粒为纳米粒子,且纳米粒子在膜中分布均匀,无明显团聚现象;随着反应时间的增加,纳米粒子的粒径明显增大;随着循环反应次数的增加,除纳米粒子的粒径略有增大外,纳米粒子的数量也明显增多.     

沉积温度对CrN涂层干摩擦及大豆油润滑下摩擦学性能的影响

为探究沉积温度对CrN涂层摩擦学性能的影响,同时寻找适合CrN涂层润滑的绿色润滑剂,采用磁控溅射技术在不同温度下制备CrN涂层。利用X射线衍射仪、扫描电子显微镜、AFM原子力显微镜、划痕仪、纳米压痕仪和摩擦磨损试验机评价涂层的微观结构、力学性能,以及在干摩擦及大豆油润滑条件下的摩擦磨损性能。结果表明：在250 ℃下沉积的CrN涂层具有最致密的晶状结构,且力学性能最优。摩擦试验结果显示,在干摩擦和大豆油润滑下250 ℃下沉积的CrN涂层表现出最优的摩擦学特性。XPS分析表明,由于摩擦的存在,大豆油会在涂层表面发生摩擦化学反应并生成一层化学吸附膜,从而能有效减轻涂层的摩擦和磨损。250 ℃下沉积的CrN涂层具有最优的力学及摩擦学性能,且大豆油极为适合CrN涂层的润滑。