射频功率对类金刚石薄膜性能的影响

在不同射频功率条件下,实验研究了射频等离子体化学气相沉积类金刚石薄膜的金刚石相分数、光学常数和硬度。利用Raman光谱仪、椭圆偏振仪、数字式显微硬度计分别测试了不同条件下单层类金刚石薄膜的金刚石相分数、光学常数和硬度。实验表明,随着功率的增加,金刚石相的相对分数减少,薄膜的折射率先减小再增加然后减小,射频功率大于910 W时,沉积速率急剧增大。而薄膜的硬度先增加后减小,在射频功率为860 W处获得最大值。     

射频功率对类金刚石薄膜结构和性能的影响

利用直流-射频-等离子体增强化学气相沉积技术在单晶硅表面制备了类金刚石薄膜，采用原子力显微镜、Raman光谱、x射线光电子能谱、红外光谱和纳米压痕仪考察了射频功率对类金刚石薄膜表面形貌、微观结构、硬度和弹性模量的影响.结果表明，制备的薄膜具有典型的含H类金刚石结构特征，薄膜致密均匀，表面粗糙度很小.随着射频功率的升高，薄膜中成键H的含量逐渐降低，而薄膜的sp3³含量、硬度以及弹性模量先升高， 后降低，并在射频功率为100W时达到最大. 关键词： 等离子增强化学气相沉积 类金刚石薄膜 射频功率 结构和性     

掺硅类金刚石膜的制备与力学性能研究

用脉冲电弧离子镀技术,通过调整掺硅石墨靶和纯石墨靶的数量,制备了一系列不同硅含量的类金刚石薄膜样品.研究发现：当硅含量达6.7at.%时,类金刚石薄膜的应力从4.5GPa降低到3.1GPa,薄膜的硬度还保持在3600Hv,和没有掺杂的类金刚石薄膜的硬度相比,基本保持不变;当硅含量小于6.7at.％时薄膜的摩擦系数相对于未掺杂的类金刚石薄膜也保持不变,为0.15.当薄膜中硅含量继续增加时,薄膜中C—Si键的含量增多,导致薄膜硬度和应力都有较大幅度地减小、摩擦系数增大、磨损性能也变差了. 关键词： 类金刚石膜 掺硅 应力 硬度     

类金刚石薄膜力学特性的分子动力学模拟

基于Brenner的REBO势函数,利用分子动力学方法模拟了含氢量不同的类金刚石薄膜的纳米压痕过程,依据得到的加载卸载曲线,计算了薄膜的刚度、硬度以及弹性模量.结果表明:类金刚石薄膜的硬度由氢含量和sp³键含量两个因素共同决定;当薄膜中氢含量小于39% 时,薄膜硬度主要取决于sp³键含量,sp³键越多,硬度越高;当薄膜中氢含量达到52%,薄膜硬度则显著下降,此时氢的作用占据主导地位. 关键词： 类金刚石薄膜 分子动力学模拟 纳米压痕 硬度     

微波化学气相沉积中气压对金刚石薄膜生长速率和质量的影响

研究了微波化学气相沉积中沉积气压对金刚石薄膜生长速率和质量的影响.研究表明，金刚石薄膜的生长速率随沉积气压的提高而增大，生长速率与沉积气压为线性关系.在高沉积气压下生长的金刚石薄膜晶形完整，拉曼谱测量可得到锐利的金刚石相的峰，但电压-电流测量表明，随着制备时沉积气压的提高，金刚石薄膜的暗电流增大，膜的电学质量下降. 关键词： 金刚石薄膜 生长速率 沉积气压     

晶态碳氮膜

晶态碳氮膜美国西北大学的科学家宣布说：“他们已经获得了一种新的超硬材料，其硬度仅次于金刚石．这种新材料完全是晶态的化合物薄膜，含有仅纳米级厚度的碳氮层．理论表明，碳氮晶体可能具有相当于或者超过金刚石的硬度，而金刚石是人类至今所知的最硬的材料．自理论预...     

物理学与新型(功能)材料专题系列介绍(Ⅰ) 金刚石薄膜能成为新一代半导体材料吗?

自从８０年代金刚石薄膜的低压化学汽相淀积获得成功以来，人们对用金刚石薄膜制作高温、高速和大功率器件产生了浓厚的兴趣，因为金刚石的禁带宽，载流子迁移率高，同时具有优异的热学、光学和力学性质．本文对金刚石的电子学特征和金刚石器件的研制现伏作了评述，对发展金刚石器件的若干问题特别是金刚石薄膜的ｎ型掺杂、金刚石膜的异质外延和降低缺陷浓度等作了分析和讨论．金刚石薄膜是一种潜在的新型半导体材料，但要实现器件应用尚需作大量的材料研究．     

直流电弧等离子体射流CVD制备多种碳膜

本文报道了在同一直流电弧等离子体射流ＣＶＤ装置上，采用不同的沉积条件高速合成金刚石，类金刚石，高取向热解石墨以及无定形碳等四种碳膜。经Ｘ射线衍射（ＸＲＤ），拉曼散射谱（Ｒａｍａｎ），扫描电镜（ＳＥＭ）形貌分析以及显微硬度测试表明，该方法制得的金刚石膜和高取向热解石墨膜具有很高的纯度和良好的晶性，类金刚石具有独特的形貌和Ｒａｍａｎ散射特征以及可与金刚石膜比拟的硬度。     

类金刚石薄膜及其进展

为了使研究者能更详细地了解类金刚石（DLC）薄膜的研究现状,综述了类金刚石薄膜的特性及应用,分析对比了目前常用的一些类金刚石薄膜的制备方法,包括物理气相沉积法（PVD）和化学气相沉积法（CVD）,并对类金刚石薄膜的抗强激光损伤特性以及提高其激光损伤阈值的方法进行了论述。结果发现,利用PVD法制备的DLC膜的硬度可以达到40 GPa~80 GPa,且薄膜的残余应力可以达到0.9 GPa~2.2 GPa之间,而CVD法则由于反应气体的充入导致类DLC薄膜的沉积速率大大降低,故使用率不高。同时,优化膜系的电场强度设计,采用合理的制备工艺,进行激光辐照后处理,施加外界电场干预均可有效地提高DLC薄膜的抗激光损伤能力, 且目前的DLC薄膜的激光损伤阈值可达到2.4 J/cm2。     

乙炔气体流量对纳米TiC类金刚石复合膜的化学结构及力学性能影响

采用离子注入与反应磁控溅射相结合的方法在钛合金及硅片基体表面上制备了纳米TiC类金刚石(DLC)复合膜.通过纳米压痕技术检测了薄膜的纳米硬度，显微划痕试验评估了薄膜的结合力.通过X射线光电子能谱及X射线衍射表征了薄膜的化学结构.结果表明，通过改变C₂H₂气体流量，可以达到控制薄膜中钛原子含量的目的，合适的C₂H₂气体流量可以在DLC膜中形成较多的纳米TiC晶粒，形成DLC包覆TiC晶粒的复合结构，使DLC膜力学性能得到明显提高.另外，划痕试验表明掺钛、先注入后沉积工艺都使薄膜的结合力得到了较大提高. 关键词： 纳米TiC类金刚石复合膜 类金刚石膜 力学性能     

Pulsed laser deposition of multiwalled carbon nanotubes thin films

The physical/chemical properties of multiwalled carbon nanotubes have attracted much interest for applications in different fields, from micro-electronic to coating technology due, in particular, to their peculiar conductivity properties, to their hardness and high resistance to thermal stress. The technology to produce carbon nanotubes thin films with the desired properties, however, is still under development. In this work, we report on multiwalled carbon nanotubes thin films deposited by pulsed laser deposition techniques ablating commercially polystyrene-nanotubes pellets on alumina substrates. MicroRaman spectroscopy and high resolution Transmission Electron Microscopy provide the experimental confirmation that carbon nanotubes-like structures are present on the alumina surface with both minimal morphological damage of the tubes and structural changes induced by laser beam.     

非金属基体表面涂层质量检测方法研究

为研发新型的涂层检测方法,本文在分析和研究现阶段涂层质量检测技术的基础上,通过对输电线路绝缘子RTV涂层施涂质量的抽检实验,提出一种新型且适用于非金属基体表面涂层质量的检测方法——敲击测声法,用于基体为陶瓷、玻璃等高硬度材料,涂层为橡胶等低硬度材料的质量检测,可以保证在不损伤被测涂层的情况下检测涂层厚度、均匀度等质量指标。当基体与涂层有较明显硬度差别时,通过相同力度敲击被测涂层表面,检测返回的声强峰值(即分贝数值),判断非金属基体表面涂层质量的差异,并在检测软件Wensn Sound Link界面实时显示检测数据的变化,直观地反映检测结果。此方法对航天、电力、机械制造等多个领域的涂层检测具有良好的推广应用价值。     

Nanocrystalline soft ferromagnetic Ni-Co-P thin film on Al alloy by low temperature electroless deposition

Soft ferromagnetic ternary Ni-Co-P films were deposited onto Al 6061 alloy from low temperature Ni-Co-P electroless plating bath. The effect of deposition parameters, such as time and pH, on the plating rate of the deposit were examined. The results showed that the plating rate is a function of pH bath and the highest coating thickness can be obtained at pH value from 8 to10. The surface morphology, phase structure and the magnetic properties of the prepared films have been investigated using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and vibrating magnetometer device (VMD), respectively. The deposit obtained at optimum conditions showed compact and smooth with nodular grains structure and exhibited high magnetic moments and low coercivety. Potentiodynamic polarization corrosion tests were used to study the general corrosion behavior of Al alloys, Ni-P and Ni-Co-P coatings in 3.5% NaCl solution. It was found that Ni-Co-P coated alloy demonstrated higher corrosion resistance than Ni-P coating containing same percent of P due to the Co addition. The Ni-Co-P coating with a combination of high corrosion resistance, high hardness and excellent magnetic properties would be expected to enlarge the applications of the aluminum alloys.     

Structure,phase evolution and properties of Ta films deposited using hybrid high-power pulsed and DC magnetron co-sputtering

Crystalline phase and microstructure control are critical for obtaining desired properties of Ta films deposited by magnetron sputtering. Structure, phase evolution and properties of Ta films deposited by using hybrid high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) under different fractions of DCMS power were investigated, where Ta ion to Ta neutral ratios of the deposition flux were changed. The results revealed that the number of Ta ions arriving on the substrate/growing film plays an important role in structure and phase evolution of Ta films. It can effectively avoid the unstable arc discharge under low pressure and show a higher deposition rate by combining HiPIMS and DCMS compared with only HiPIMS. Meanwhile, the high hardness α -Ta films can be directly deposited by hybrid co-sputtering compared to those prepared by DCMS. In the co-sputtering technology, pure α -Ta phase films with extremely fine, dense and uniform crystal grains were obtained, which showed smooth surface roughness (3.22 nm), low resistivity (38.98 μΩ · cm) and abnormal high hardness (17.64 GPa).     

The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to −200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp³ carbon content and mechanical properties of the deposited DLC films. A maximum sp³ content of 33.3% was obtained at −100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.     

脉冲高能量密度等离子体材料表面改性及其应用

脉冲高能量密度等离子体（pulsed high energy density plasma, PHEDP）是一项新的材料表面改性技术.它集高电子温度、高能量密度、高定向速度于一身,在制备薄膜时具有沉积薄膜的温度低、沉积效率高、能量利用率高的优点,并兼具表面溅射、离子注入、冲击波和强淬火效应等综合效应;它可以制备纳米晶或非晶硬质薄膜,提高基底材料的表面硬度和耐磨、耐蚀性能;能够实现非金属材料表面金属化,所制备薄膜与基底之间存在很宽的混合过渡区,因此膜/基结合良好.文章主要介绍了作者近年来在该领域的部分研究成果,简要介绍了脉冲高能量密度等离子体的原理、特点及应用.分析了脉冲等离子体与材料相互作用的基本物理现象.     

Effect of hydrogen on hardness of amorphous silicon

A comparative study of hardness of thin films of hydrogenated amorphous silicon (a-Si:H) and hydrogen-free amorphous silicon (a-Si) was carried out to reveal the role of hydrogen in the plastic properties of amorphous silicon. In addition, the effect of hydrogen on hardness was established by changing hydrogen concentration in the material using post-deposition processing of the samples. The hydrogen concentration in a-Si:H was decreased by thermal annealing. In a-Si hydrogen was introduced by plasma hydrogenation. The values of hardness of the as-prepared a-Si and a-Si:H films were determined by nanoindentation using depth profiling. Low-depth indentation was applied to evaluate the effect of post-hydrogenation. The results obtained show that the presence of hydrogen in the amorphous silicon network leads to the increase in hardness. The conducted experiments demonstrate that plasma hydrogenation can be used as an effective tool to increase the hardness of amorphous silicon. Hardness of a-Si:H of about 12.3–12.7 GPa is as high as of crystalline silicon, suggesting a-Si:H can be a substitute for crystalline silicon in some MEMS.     

Nanoscale morphology for high hydrophobicity of a hard sol-gel thin film

It is challenging to obtain a hydrophobic smooth coating with high optical and mechanical properties at the same time because the hydrophobic additives are soft in nature resulting in reduced hardness and durability. This paper reports a durable hydrophobic transparent coating on glass fabricated by sol-gel technology and a low volume medium pressure (LVMP) spray process. The sol-gel formula consists of a pre-linked hydrophobic nano-cluster from hydroxyl-terminated polydimethylsiloxane, titanium tetraisopropoxide and a silica-based sol-gel matrix with silica hard fillers. Polydimethylsiloxane (PDMS) is uniformly distributed throughout the coating layer providing durable hydrophobic property. Mechanical properties are achieved by the hard matrix and hard fillers with the nano-structures. Due to the surface nano-morphology, a high degree of hydrophobicity was maintained with only 10 vol.% PDMS, while the hardness and abrasion resistance of the coatings were not significantly compromised. Chemical analyses by FTIR confirmed the uniform distribution of the PDMS and surface morphology analyses by atomic force microscopy (AFM) displayed the nano-surface structures that enhanced the hydrophobicity. The special surface nanostructures can be quantified using surface Kurtosis and ratio between asperity peak height to distance between peaks. The LVMP process influences the spray droplet size resulting in different surface structures.     

Successful incorporation of multi-walled carbon nanotubes in nickel electrodeposited coating by electrophoresis

A homogenous and adhesive multi-walled carbon nanotube (MWCNT) coating was electrophoretically deposited on stainless steel from an aqueous solution by applying high strength electric fields. Then, nickel was electrodeposited on MWCNT films. MWCNTs content in the composite coatings was reached to 12.5 wt% which was much higher than the content of MWCNTs in conventional nickel-MWCNT electrodeposited coatings. The hardness value of composite coatings significantly increased up to 870 Vickers which it was measured by both micro and nanohardness tests.     

Effect of plasticizer on surface of free films prepared from aqueous solutions of salts of cationic polymers with different plasticizers

Acquisition of a more detailed understanding of all technological processes is currently a relevant tendency in pharmaceutical technology and hence in industry. A knowledge of film formation from dispersion of polymers is very important during the coating of solid dosage forms. This process and the structure of the film can be influenced by different additives. In the present study, taste-masking films were prepared from aqueous citric acid solutions of a cationic polymer (Eudragit^® E PO) with various hydrophilic plasticizers (glycerol, propylene glycol and different poly(ethylene glycols)). The mechanical properties, film thickness, wetting properties and surface free energy of the free films were studied. The aim was to evaluate the properties of surface of free films to predict the arrangement of macromolecules in films formed from aqueous solutions of salts of cationic polymers. A high molecular weight of the plasticizer decreased the work of deformation. The surface free energy and the polarity were highest for the film without plasticizer; the hydrophilic additives decreased these parameters. The direction of the change in polarity (a hydrophilic component caused a decrease in the polarity) was unexpected. It can be explained by the change in orientation of the macromolecules, a hydrophobic surface being formed. Examination of the mechanical properties and film thickness can furnish additional results towards a knowledge of film formation by this not frequently applied type of polymer from aqueous solution.