纳米金刚石TiV色心的实验制备与性能研究

目的 利用磁控溅射辅助微波等离子体化学气相沉积技术制备钛掺杂纳米金刚石薄膜.方法 预先通过磁控溅射在石英玻璃基底上沉积纳米钛颗粒,然后使用微波等离子体化学气相沉积(MPCVD)设备在其表面沉积金刚石薄膜,通过活性氢原子将钛带入含碳生长基团中,从而将钛掺入纳米金刚石薄膜内.使用X射线光电子能谱(XPS)、拉曼光谱(Ram...     

大面积纳米金刚石薄膜的制备及场发射性能

以CH4和H2为反应气,采用微波等离子体增强化学气相沉积方法在直径为10 cm的硅原片上制备纳米金刚石薄膜。用X射线衍射仪、拉曼光谱、扫描电镜和原子力显微镜对薄膜的组成结构及性能进行表征。结果表明:薄膜的平均晶粒尺寸约为13.8 nm,厚度可达10.8μm,表面粗糙度约为11.8 nm;其拉曼光谱是典型的纳米金刚石薄膜的特征峰峰形,同时在高真空条件下对所制备的薄膜样品进行场发射性能测试。     

纳米金刚石薄膜涂覆钛合金的摩擦学性能

医用钛合金(Ti6Al4V)具有低密度、高强度、耐腐蚀等优点而应用广泛,但是其耐磨性差.采用微波等离子体化学气相沉积法在医用钛合金上沉积金刚石薄膜,经喇曼光谱检测为纳米金刚石结构,原子力显微镜测试其晶粒尺寸为40 nm左右,表面粗糙度Ra=39 nm(视场10×10μm).在SiC球为摩擦副的干摩擦实验中,在2 N载荷下,摩擦因数在0.25左右,并且没有出现任何薄膜破裂或剥落现象.实验结果表明,钛合金表面沉积纳米金刚石薄膜后明显提高了耐磨性,薄膜的表面粗糙度和形貌是影响其摩擦学性能的关键因素.     

硅纳米线的X射线吸收谱与X射线激发发光谱研究

采用X射线吸收精细结构谱（XAFS）和X射线激发发光谱（XEOL），在Si的K边和L3.2边研究了硅纳米线的光电特性。在XAFS中虽然没有观察到跃迁边的明显蓝移，但可观察到跃迁边平缓上升和特征峰逐渐变得模糊，这意味着长程有序被破坏并产生了显著的量子尺寸效应，XAFS测量的是各种小尺寸的硅纳米线分布的平均特性。XEOL的结果表明硅纳米线的发光来自于包裹的二氧化硅和镶嵌在氧化物层中的纳米硅晶体颗粒以及硅与二氧化硅之间的界面。     

纳米金刚石薄膜研究进展

本文对纳米金刚石薄膜的研究现状和发展趋势进行了综合评述，从纳米金刚石薄膜的沉积原理和工艺以及纳米效应表征等方面分析了国内外最新研究成果，比较了常规和纳米金刚石薄膜不同沉积工艺和形核生长机理，对纳米金刚石薄膜的硬度、内应力、摩擦特性等机械性能也作了概述，在此基础上，提出在常规金刚石薄膜基础上沉积纳米金刚石薄膜组成复合涂层的新方法。     

不同高浓度气体对金刚石薄膜制备的影响

采用微波等离子体化学气相沉积(MPCVD)法,分别制备了CH4/H2体系、CH4/H2/N2体系以及CH4/H2/Ar体系金刚石薄膜。主要采用了扫描电子显微镜(SEM)、激光拉曼光谱(Raman)和X射线衍射光谱(XRD)等方法对不同体系中制备的金刚石薄膜的晶粒尺寸及其品质进行了分析,研究了不同高浓度气体对金刚石薄膜的影响。结果显示:利用高浓度的甲烷可以在很大程度上细化晶粒,制备出纳米晶金刚石薄膜,但是薄膜的非晶相较多,品质下降;加入70%N2,薄膜中的金刚石晶粒生长速度较慢,但可制备出均匀的纳米晶金刚石薄膜;70%的Ar气氛中,金刚石晶粒生长较快,制得的薄膜中的金刚石晶粒是微米级别的。     

SiC衬底金刚石薄膜的制备与性能表征

用热丝CVD法,以丙酮和氢气为碳源,在SiC衬底上沉积金刚石薄膜,提出了分步变参数沉积法制备超细晶粒金刚石复合薄膜的新工艺.结果表明,合理控制工艺条件的新工艺,对金刚石薄膜质量、形貌和粗糙度、薄膜与衬底间的附着力以及薄膜的摩擦系数有显著影响,金刚石薄膜的平均晶粒尺寸从3 μm减小到0.3 μm,拉曼特征峰显示超细晶粒金刚石薄膜特征,涂层附着力好,超细晶粒金刚石薄膜的表面粗糙度和摩擦系数值显著下降,对获取实用化的SiC在基体上沉积高附着强度、低粗糙度金刚石薄膜的新技术具有重要的意义.     

纳米金属颗粒分散氧化物Ag/NiO薄膜的制备与光吸收特性

利用溶胶-凝胶法制备了纳米金属颗粒分散氧化物Ag/NiO复合薄膜,用X射线荧光光谱、X射线衍射分析、透射电子显微镜、紫外可见分光光度计表征了薄膜的成分、相结构、微结构以及光吸收特性.X射线衍射分析结果表明存在NiO相和单质Ag相.光吸收谱研究表明,Ag/NiO薄膜在410 nm波长附近有明显的表面等离子共振吸收峰,随着Ag含量的增加,吸收峰变窄,蓝移,强度增加.当Ag含量接近41%(质量分数)时,Ag/NiO薄膜在414 nm波长附近表现的吸收峰呈现最大的吸收强度;当Ag分散颗粒的含量超过41%(质量分数)后,吸收峰的强度开始下降.随着保温时间的延长,薄膜的光学吸收峰的强度增强,并且吸收峰峰位向波长短的方向移动.     

掺杂硅纳米线的光电特性

采用激光烧蚀法制备了磷掺杂硅纳米线和硼掺杂硅纳米链,并运用透射电子显微镜(TEM)、近边X射线吸收精细结构光谱(NEXAFS)、X射线光电子能谱(XPS)及场发射(FE)测量等对其进行了研究.结果表明:硅纳米线包覆在二氧化硅层中及其核心由磷掺杂的晶体硅构成,磷不仅存在于硅纳米线的核心内,也存在于二氧化硅与硅核心的相界面上;硼掺杂硅纳米链的外部直径约为15 nm,由直径11nm的晶核和2 nm的无定形氧化物外层构成的晶格所组成,其粒间距为4 nm,硅纳米粒子链的阀值场强为6 V/μm,优于未掺杂的硅纳米线的阀值场强(9 V/μm).X射线光吸收谱可以补充提供常规电流-电压测量得不到的信息,并提示掺杂分布的细节.     

掺Ag含量对金刚石薄膜场发射性能的影响

采用电泳沉积的方法在钛基体上沉积了不同含量Ag纳米颗粒掺杂的金刚石复合薄膜,利用扫描电子显微镜、X射线衍射光谱和拉曼光谱对样品的结构和形貌进行表征,最后进行场发射特性的测试。SEM试验结果表明,制备得到的薄膜连续、致密且纳米颗粒均匀的分布在其中。场发射测试结果显示样品的场发射性能随着复合膜中Ag含量的增加呈现先增强后降低的趋势,在Ag纳米颗粒的掺杂含量为7.5 mg （0.18 g/L）时,复合膜的场发射性能最优。此时,开启电场（E₀）低至1.55 V/μm,在1.96 V/μm的电场强度下可以得到22.69 μA/cm²的场发射电流密度,这表明适量的Ag纳米颗粒掺杂可以显著提升样品场发射性能。同时,文中结合F-N理论进一步讨论了Ag纳米颗粒掺杂含量的变化对金刚石场膜发射性能影响的作用机理。     

纳米片状金刚石膜的生长过程

采用微波等离子化学气相沉积系统（MPCVD）在镀钛的单晶硅衬底上制备纳米金刚石薄膜。反应气体为CH4和H2,其流量比为1∶1,微波功率为1 800 W,反应气压为10 kPa。利用扫描电镜（SEM）和Raman光谱分析薄膜的形貌和碳结构。结果表明,纳米金刚石薄膜呈现片状的组织特征,其生长过程为：生长初期在单晶硅衬底上形成由纳米碳颗粒组成的球状碳团簇;随着沉积时间的增加,碳团簇逐渐增大,纳米碳颗粒定向排列或自组装,最终形成片状纳米金刚石膜。     

铝合金微弧氧化陶瓷膜表面复合化学镀 Ni-P-SiC 的研究

采用复合化学镀方法在铝合金微弧氧化陶瓷膜表面制备了Ni-P-SiC复合镀层,研究了镀液中SiC浓度对复合镀层物相、显微组织、沉积速率的影响,并测试了复合涂层(陶瓷膜/复合镀层)的结合力。结果表明:Ni-P-SiC复合镀层为非晶态结构,与陶瓷膜的界面清晰,完全封闭了微弧氧化陶瓷膜表面的微孔;随着镀液中SiC含量的增加,复合镀层沉积速率降低,SiC共析量则是先快速增大,当含量达到16 g/L后就基本保持不变。     

Influence of substrate bias on the composition of SiC thin films fabricated by PECVD and underlying mechanism

The influence of the substrate bias on the composition of SiC thin films synthesized by plasma-enhanced chemical vapor deposition was studied. Our results indicate that the ratio of Si to C in the thin films is almost stoichiometric at a bias of − 300 V, whereas excessive carbon is observed in the films if the bias is lower or higher. Very little oxygen can be detected in the film produced without biasing. The effects of the bias on the composition of the thin films can be attributed to the interaction between the positive ions in the plasma and the surface atoms. The underlying mechanism is also discussed.     

AFM Study on Reliability of Nanoscale DLC Films Deposited by ECR-MPCVD

IN the last twenty years,amorphous carbon film due toits particular diamond-like performance has beenattracting much attention.As the deposition process isgradually perfected,the DLC film,with highmechanical hardness,chemical inertness,opticaltransparency,and its wide band gap,is becoming thefocus of thin film area I1>21.At present,DLC film haswidespread applications for its peculiarities ofdecoration and function,such as optical windows,magnetic storage disks,biomedical coatings,micro-elec…     

NanoSIMS investigation of passive oxide films on high-Cr cast iron

The discrete depth characteristics of thin passive oxide films were investigated using high-resolution electron microprobe and nanoscale secondary ion mass spectrometry (NanoSIMS). A novel NanoSIMS method involving a Cs layer deposition before Cs⁺ sputtering was employed for the first time to determine the elemental distribution at different sub-layers of a passive film. The film was formed in air on the surface of a multi-phase microstructure of high-chromium cast iron (HCCI). It was found that the film composition and thickness varied according to the underlying microstructure phase. Based on the microprobe and NanoSIMS results, the influence of the HCCI passive film thickness and composition on the localized passivity breakdown has been proposed.     

Polymerized hexamethyldisilazane coated on equiatomic TiNi shape memory alloy using DC-pulsed plasma assisted chemical vapor deposition

SiC:H organic-like thin films are deposited on Ti₅₀Ni₅₀ shape memory alloy by asymmetric bipolar DC-pulsed plasma assisted chemical vapor deposition (PACVD) in the gas mixture of hexamethyldisilazane (HMDSN) and Ar at room temperature. The deposition rate of the plasma-polymerized HMDSN (PPHMDSN) thin film is faster than that of RF process and the PPHMDSN thin films not only enhance the corrosion resistance but make the corrosion current density decay four orders. The surface morphology of the films is very smooth and uniform and the root mean square of surface roughness is in the range between 3 and 5 nm. The organic-like thin films containing peroxides or free radicals can be grafted with polymer acrylamide (AAm) which can improve the biocompatibility of TiNi shape memory alloy.     

Displacement deposition of gold nanoparticles and electroless deposition of nickel films on silicon-carbide (4H-SiC) wafers

Metallisation of silicon carbide (SiC) wafers is a key technology for producing efficient power devices. Conventional autocatalytic electroless deposition cannot produce adherent metal films directly on SiC substrates. The authors applied their recently developed surface-activation process for electroless metal-film deposition on silicon wafers to SiC wafers. Gold nanoparticles were produced on 4H-SiC substrates by displacement deposition after immersing the substrates in a tetrachloroauric(III) acid solution that includes hydrofluoric acid or potassium hydroxide. The size and the particle density of the deposited gold are changed with deposition parameters such as the surface condition of the substrates, the solution composition, and the UV-light illumination. The gold nanoparticles work not only as catalysts to initiate autocatalytic electroless deposition but also as binding-points between the metal film and the SiC surface. Adherent and uniform nickel-phosphorus alloy films are produced on such SiC substrates by autocatalytic electroless deposition without any further treatments.     

Ta12W合金表面离子束沉积薄膜与U-Nb合金之间的摩擦性能

采用离子束沉积方法在Ta12W合金表面制备了Sn,In软金属薄膜,Al2O3陶瓷薄膜和In/Al2O3复合薄膜.利用销盘摩擦磨损试验机并结合SEM观察分析了对偶销为U-Nb合金时,试样的摩擦学性能并讨论了摩擦磨损机理.当用SiC对偶进行评价时,Sn,In软金属薄膜降低了Ta12W合金摩擦系数.然而当对偶销改为工程状态的U-Nb合金时,由于用离子束溅射沉积法制备的Sn薄膜太薄、In薄膜与U-Nb合金发生粘着,Sn,In软金属薄膜与In/Al2O3复合薄膜均未降低Ta12W合金的的摩擦系数.当Sn薄膜增加到一定厚度时,摩擦性能得到明显改善.Al2O3陶瓷薄膜与U-Nb合金对偶销摩擦时,与Ta12W合金表面直接摩擦结果一样,由于U-Nb合金容易被磨损而使磨屑转移到试样表面,摩擦系数没有下降.     

Concepts for the design of advanced nanoscale PVD multilayer protective thin films

Technological challenges in future surface engineering applications demand continuously new material solutions offering superior properties and performance. Concepts for the design of such advanced multifunctional materials can be systematically evolved and verified by means of physical vapour deposition. The classical multilayer coating concept today is well established and widely used for the design of protective thin films for wear and tribological applications. It has proven great potential for the development of novel thin film materials with tailored properties. In the past decade, the emerging new class of nanoscale coatings has offered to the material scientists an even more powerful toolbox for the engineering thin film design through a combination of the multilayer concept with new nano-coatings. Some examples are the use and integration of low friction carbon-based nanocomposites in advanced multilayer structures or the stabilization of a specific coating in another structure in a nanolaminated multilayer composite. This paper reviews the latest developments in hard, wear-resistant thin films based on the multilayer coating concept. It describes the integration of nanocrystalline, amorphous and nanocrystalline/amorphous composite materials in multilayers and covers various phenomena such as the superlattice effect, stabilization of materials in another, foreign structure, and effects related to coherent and epitaxial growth. Innovative concepts for future, smart multilayer designs based on an extremely fine structural ordering at the nanoscale are presented as well.     

衬底与缓冲层的晶格失配对CeO_2缓冲层外延生长的影响

采用金属有机沉积(MOD)技术在La Al O3(LAO)、Y稳定的氧化锆(YSZ)和Ni-W衬底上沉积了Ce O2缓冲层薄膜,并研究了衬底与缓冲层的晶格失配对其外延生长的影响。结果表明,随着衬底和缓冲层薄膜之间晶格失配的增大,缓冲层薄膜内部的压应变增加,晶界浓度增加,晶粒生长速率减小。衬底和缓冲层薄膜之间的晶格失配越小,越有利于薄膜织构度的增大。Ce O2薄膜的表面形貌及粗糙度的演化对衬底和缓冲层薄膜之间的晶格失配并没有明确的依赖关系。