脉冲激光真空弧薄膜制备技术

本文首先介绍了脉冲激光蒸发沉积以及真空弧沉积技术，在此基础上对激光真空弧技术的原理、特点、研究现状及应用进行了文献综述。可以预测，激光真空弧技术在薄膜材料科学与技术以及工业生产中必将具有广阔应用前景。     

等离子喷涂沉积过程与残余应力分析

介绍了等离子喷涂的沉积过程。由于基体与涂层的热膨胀系数的不匹配，在它们共同冷动的过程中，产生了不同的热变形。采用有限元瞬态热分析方法对等离子喷涂过程的温度场进行了分析。在此基础上，进一步计算了常用的Al2O3涂层与16Mn基体组成的喷涂系统的残余应力分布，并对计算结果进行了讨论。     

微型机械材料的残余应力测量

硅类薄膜材料是微机电系统使用的主要结构材料它的力学特性直接关系到微机电系统的可靠性和使用寿命,而残余应力是微型机械设计的一个十分重要的力学特性。概述了国内外微型机械薄膜材料残余应力的测量原理、方法和特点,可供微机电系统的设计和制造者参考。     

用热评价方法测量残余应力

物体的比热是随应力而变化的。如果能够精确的控制注入构件表面能量,并准确测量由此而产生的温升,就可以得到一条与构件残余应力相关的温升曲线。我们利用激光器和红外热成像仪对焊接试板的残余应力进行了测量,结果表明,构件由于残余应力引起的温升变化是可测的,残余应力的热评价方法是一种很有前途的新方法。     

用X射线应力仪测量凸轮轴表面激光淬火相变层的残余应力

利用CO2激光对凸轮轴所用材料QT600-3表面进行了淬火处理试验,并用X-350A型X射线应力仪测定其残余应力分布,分析了残余应力的形成机理.结果表明:经CO2激光淬火后QT600-3的显微组织为隐晶马氏体 石墨,残余应力均为压应力,其值在120 MPa以上,且随着功率的增大而增加;相变层深度随着扫描速率和光斑直径的增加而减小,且随着功率的增大而增加;激光淬火后的材料组织结构比较均匀,有利于提高凸轮轴的使用寿命.     

损伤轴面激光熔覆修复残余应力测量及分析

残余应力直接影响激光熔覆修复机械零件的结构强度和安全性能,为了掌握损伤轴面激光熔覆修复后的残余应力分布情况,以40Cr钢零件轴为基材,Ni60自熔合金粉末为熔覆材料,采用脉冲激光熔覆工艺制备零件轴表面修复试件,利用盲孔法对零件轴修复试件进行残余应力分布特性分析。结果表明,在轴面激光熔覆的镍基合金修复层中产生了不可忽略的残余拉应力,高应力区位于熔覆层始末两道上;轴线方向检测点上X方向残余应力呈"M"形分布,Y方向残余应力呈"Λ"形分布,σx值较高,接近基材屈服强度的45. 9%,而圆周方向检测点的X方向和Y方向残余应力相对稳定,最大拉应力约为200 MPa;激光扫描路径对轴面熔覆层的残余应力值的影响大、分布形状的影响小,螺旋路径熔覆产生的残余应力值较低,更适合圆周面修复,但熔覆层始末两道边沿处的残余应力比中间部位高,有必要采取适当措施进行消应力处理,以获得优良的修复效果。     

脉冲激光溅射沉积技术的发展及其应用研究

薄膜材料已经在半导体材料、超导材料、生物材料等方面得到广泛应用.为了得到高质量的薄膜材料,脉冲激光溅射沉积(PLD)技术受到了广泛的关注.文中介绍了脉冲激光溅射沉积薄膜的基本原理及特点,分析了脉冲激光溅射沉积技术在制备高温超导膜、铁电薄膜、生物陶瓷薄膜等功能薄膜方面的应用研究.大量研究表明,脉冲激光溅射沉积是目前最好的...     

多晶硅薄膜残余应力显微拉曼谱实验分析

利用显微拉曼谱对桥式多晶硅薄膜梁的残余应力进行测量,该多晶硅薄膜采用典型的MEMS(micro-electro-mechanical systems)工艺制造.实验结果表明, 多晶硅薄膜梁的中部存在很大的拉伸残余应力(约1 GPa),且多晶硅薄膜的残余应力沿梁长方向大致呈对称分布,这种内应力分布与制造过程中的ICP(inductively-coupled plasma)工艺密切相关.多晶硅薄膜梁在残余应力作用下的变形情况可以通过WYKO白光形貌仪准确地表征,经过ANSYS计算,薄膜残余应力分布状况与显微拉曼谱法的测量结果吻合.因而,显微拉曼谱法是测量多晶硅薄膜残余应力的一种准确而可靠的方法.     

曲率测量技术在微机电系统薄膜残余应力测量中的应用

在比较曲率测量技术常用的Stoney公式及其修正式的基础上,利用有限元分析方法,建立薄膜/基底结构的有限元模型,给出一种薄膜残余应力的等效施加方法,从两个方面详细分析并对比这两个公式在微机电系统(Micro electromechanical systems,MEMS)薄膜残余应力测量中的检测精度.仿真及分析结果表明,修正后的Stoney 公式在很大程度上提高薄膜残余应力的测量精度,使曲率测量技术的适用范围得到较大扩展.但是当薄膜厚度接近于基底厚度或结构处于大变形状态下,修正式的计算精度也将受到较大影响,此时可以采用有限元分析方法来获得临界状态值,以提高残余应力的检测精度.同时,通过有限元分析,证实曲率测量技术应用中存在的另一个问题,即曲率的空间分布不均匀性现象.     

Structural analyses of Nd-doped CeO2 thin films deposited by pulsed laser deposition

CeO₂ thin films doped with neodymium oxides for application to gas sensors have been elaborated by the pulsed laser deposition technique. The films were deposited on orientated Si (100) substrates with variable deposition times (t = 90, 180 and 360 s) and molar fractions of Nd₂O₃ (0, 6.5, 15, 21.5 and 27 at.%). The resulting Nd–CeO₂ thin films were characterized by means of X‐ray diffraction analysis, scanning electron microscopy and transmission electron microscopy equipped with EDS (Energy Dispersive Spectrometer) microanalysis. From X‐ray diffraction analyses, it is clearly established that the texture is modified by Nd additions. The preferred (111) orientations of the CeO₂ crystals change into the (200) orientation. The morphology of the CeO₂ grains changes from triangles, for pure CeO₂ thin films, to spherical grains for Nd‐doped films. In addition, cell parameter analyses from X‐ray diffraction data show that a partial chemical substitution of Ce by Nd should occur in the face‐centred cubic lattice of ceria: this should give rise to Ce_1‐xNd_xO_2?z phases with oxygen non‐stoichiometry.     

Structure characterization of pulsed laser deposited MoS x –WSe y composite films of tribological interests

Pulsed laser deposition (PLD) was employed to grow MoS _x –WSe _y composite films, where x = 1.18, y = 0.78. Scanning electron micrographs show that the films have a dense granular morphology. Crystallization, d-spacing and hexagonal sheet curvature within the film were studied with X-ray diffraction, electron diffraction and transmission electron microscopy. A predominant hexagonal MoS _x phase was formed but contained W and Se, which were most likely present as substituents for Mo and S. There was no evidence for two separate crystalline phases. MoS _x –WSe _y composite films exhibited a larger expansion along the c-axis (d-spacing between basal planes) than PLD MoS₂ and WSe₂ films grown by laser ablation of pure targets. The lattice spacing along the a-axis was expanded in comparison to the MoS₂ film, and compressed in comparison to the WSe₂ film. X-ray photoelectron spectroscopy showed a significant sulfur deficiency, and verified both of S and Se bonding in the film. High-resolution electron microscope images exhibited significant curvatures of the (002) basal planes in the films. The bending behavior of basal planes was explained by S vacancies and Se substitution on the atomic site of S layers. The tribological properties of the composite films were measured in dry and wet conditions using a ball-on-disc tribometer. The reduced friction was correlated with the increased crystallinity and increased separation of basal planes in the composite films.     

二氧化钒薄膜制备工艺及其在开关器件的应用研究进展

二氧化钒薄膜由于其相变特性在多个不同领域中被广泛研究.针对其在开关器件方面的应用,介绍了近年来国内外常见的二氧化钒薄膜制备工艺研究进展并比较其优缺点,同时从不同二氧化钒相变的外部激励机制对国内外基于二氧化钒研发的开关器件进行了介绍,以期为今后的二氧化钒相变开关的研究提供参考.     

BF的光学薄膜

叙述了近年在北京电影机械研究所 ( BF)研发的光学薄膜元器件 ,讨论了其中的技术要点。同时对所采用的离子辅助技术及膜层厚度监控技术进行了讨论     

Structural studies of pulsed-laser deposited nanocomposite metal-oxide films

Pulsed laser deposition in vacuum has been used to develop metal-oxide nanocomposite films with well controlled structural quality. Results for the copper–aluminium oxide (Cu:Al₂O₃) system are used to illustrate the main morphological and structural features of these films. High resolution transmission electron microscopy (TEM) analysis shows that the films consist of Cu nanocrystals with average dimensions that can be controlled between 2 nm and 10 nm embedded in an amorphous Al₂O₃ matrix. It is observed that the in-plane shape of the nanocrystals evolves from circular to elongated, and the number of nanocrystals per unit area decreases as their size increases. This evolution is explained in terms of nucleation at the substrate surface and coalescence during the later stages of growth. The thermal stability of the films has been studied by in situ TEM annealing and no transformation could be observed up to about 800 °C when partial crystallization of the Al₂O₃ starts.     

基于激光多普勒技术的PZT薄膜压电性能测试研究

应用基于激光多普勒技术的微小形变分析方法,并引入数字锁相技术,成功实现了PZT(Pb(Zr,Ti)O₃)铁电薄膜的压电性能测试。对商用压电陶瓷在小信号激励下的压电性能测试表明,数字锁相技术的引入能有效抑制系统噪声,并提高激光多普勒系统的位移检测分辨率,使其达到皮米量级。此外,研究了用溶胶-凝胶技术和溶胶-电雾化技术制备得到的PZT薄膜的电压-位移曲线和压电位移"蝴蝶线",实验结果表明:在5 V直流偏置下测得两种方法制备得到的PZT薄膜的d₃₃压电系数分别为218.7 pC/N和215.8 pC/N,相应的标准偏差分别为12.7和28.6。     

激光器使用的光学薄膜

介绍了近年来研制的激光器用光学薄膜元器件,内容涉及二极管泵浦激光器使用的光学薄膜、光参量振荡激光器使用的光学薄膜以及激光美容仪使用的光学薄膜。     

Microstructure and lubrication mechanism of multilayered MoS2/Sb2O3 thin films

Multilayered MoS₂/Sb₂O₃ thin films were prepared by pulsed laser deposition on steel substrates. A rotary multi-target holder was used to switch the laser targets for alternative growth of MoS₂ and Sb₂O₃ layers providing nanometers thickness. The tribological properties of the films were measured in dry and wet environments and the wear scars were observed using a scanning electron microscope. The multilayer films showed a much longer wear life than pure MoS₂ films in wet air tribotests. Focused ion beam and transmission electron microscopies were used to investigate the cross-sectional microstructures of wear scars. Lubricious MoS₂/Sb₂O₃ tribofilms were built up on wear scar surfaces, and produced low friction. Micro-cracks occurred along the interface between the tribofilm and the neighboring/topmost Sb₂O₃ underlayer, where the Sb₂O₃ layer effectively inhibited the crack propagation perpendicular to the interface. The orientation of MoS₂ crystals in as-deposited films was mostly random and friction-induced stress oriented the MoS₂ basal planes parallel to the surface. The reorientation was confined to the topmost MoS₂ layer and was not observed below the first intact Sb₂O₃ layer.     

退火对真空蒸发Ti3O5制备光学薄膜性能的影响

采用真空蒸发法,以T i3O5为膜料分别在基片温度为200℃、250℃、300℃的条件下制备氧化钛光学薄膜,XRD结果显示,沉积态薄膜为无定形态,400℃退火后,均由无定形态向锐钛矿结构转变;不同基片温度下制备的氧化钛薄膜退火后,折射率均随基片温度的升高而增大;随着退火温度的升高,(101)晶相择优取向十分明显,结晶度增大;经过400℃、500℃、600℃退火后,薄膜折射率逐渐上升。