Effect of metallic interfacial layers on the properties of diamond-like carbon thin films

Diamond like carbon (DLC) thin films with metallic interfacial layers of aluminum and nickel-chromium (Al and Ni-Cr) were grown using a low cost hybrid technique involving a resistive heating thermal evaporator and radio frequency plasma enhanced chemical vapor deposition techniques. Stress, hardness, elastic modulus, bonding, phase, and electrical conductivity of these films were investigated. Introduction of interfacial Al and Ni-Cr layers in DLC led to drastic improvement of its conductivity along with a significant reduction in residual stress but with some reduction of hardness and the elastic modulus. The structural and surface properties of thin films were studied using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques.     

Effect of applied dc bias voltage on composition, chemical bonding and mechanical properties of carbon nitride films prepared by PECVD

Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and chemical bonding of the resulting films were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and elastic modulus of the films were evaluated using nano-indentation. As the results, the Raman spectra, showing the G and D bands, indicate the amorphous structure of the films. XPS and FTIR measurements demonstrate the existence of various carbon-nitride bonds in the films and the hydrogenation of carbon nitride phase. The composition ratio of N to C, the nano-hardness and the elastic modulus of the carbon nitride films increase with increasing dc bias voltage and reach the maximums at a dc bias voltage of 300 V, then they decrease with further increase of the dc bias voltage. Moreover, the XRD analyses indicate that the carbon nitride film contains some polycrystalline C3N4 phase embedded in the amorphous matrix at optimized deposition condition of dc bias voltage of 300 V.     

类富勒烯薄膜的载荷依赖摩擦滞后行为研究

目的研究类富勒烯薄膜(FL-C:H)的载荷相关性摩擦滞后行为。方法采用直流等离子体化学气相沉积技术(DC-PECVD)在硅基底上制备了FL-C:H薄膜,通过场发射扫描电镜(FE-SEM)、X射线光电子能谱(XPS)、高分辨透射电镜(HRTEM)和拉曼光谱仪分别表征了薄膜的厚度、元素结合能状态以及微观结构,利用纳米压痕仪测定了薄膜的硬度及弹性恢复,借助往复摩擦磨损试验机考察了不同频率时变载荷条件下的摩擦滞后行为。结果以CH4和H2为前躯体制备的FL-C:H薄膜具有良好的机械性能,硬度和弹性模量分别为23.42 GPa和162.27 GPa,弹性恢复高达~82%。所制备薄膜与GCr15球配偶摩擦时,表现出良好的摩擦学性能,在循环载荷条件下表现出摩擦滞后行为。结论 FL-C:H薄膜在循环载荷条件下的摩擦滞后现象与所对应的频率有关。主要是由于大气环境下,摩擦界面处H2O、O2吸附造成氧化反应和磨损的共同作用。     

A combinatorial thin film sputtering approach for synthesizing and characterizing ternary ZrCuAl metallic glasses

We report a combinatorial sputtering approach for synthesizing ternary metallic glass alloys on both silicon and sapphire substrates. ZrCuAl metallic-glass thin films were co-deposited using a multi-source radio-frequency magnetron-sputtering process. The combinatorial synthesis process yields a wide range of compositions via a single co-sputter deposition process. The compositions of the films were characterized by the energy-dispersive X-ray spectroscopy (EDS), and the structure of the ZrCuAl alloy thin films was investigated by the X-ray diffraction (XRD). Thorough phase analyses indicated the phases present in the films at different compositions were in good agreement with the binary Zr–Cu phase diagram. Nanoindentation results showed that mechanical properties of the bulk-metallic glasses (BMGs) thin film, such as elastic modulus and hardness, are functions of the Zr (or Cu) concentration. The composition with a moderate Zr content (45 atomic percent (at.%)) resulted in a high film modulus and hardness. The post anneal treatment increased the film elastic modulus and hardness. Small additions of aluminum slightly enhanced the film mechanical properties. Using this combinatorial technique could facilitate the development of the new multi-element metallic-glass alloy, particularly for systems with many elements. The first attempt of casting the optimum resultant ternary BMGs rod was successful.     

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...     

溅射方法和基体材料对氧化钛薄膜微观结构的影响

目的研究不同溅射方法和基体材料对沉积氧化钛薄膜的晶体结构、化学价态、表面形貌的影响。方法采用高功率脉冲磁控溅射(HPPMS)和直流磁控溅射(DCMS)在316L不锈钢和硅片表面制备了氧化钛薄膜。采用等离子光发射谱检测了沉积薄膜时的等离子体特征。采用X射线衍射仪(XRD)、X射线光电子能谱(XPS)、原子力显微镜(AFM)和扫描电子显微镜(SEM),分别评价氧化钛薄膜的晶体结构、化学价态、晶粒尺寸和表面粗糙度。结果等离子体特征显示,沉积氧化钛薄膜时,HPPMS比DCMS具有更高的离化率和等离子体密度。XRD结果显示,在相同的平均溅射功率下,采用HPPMS和DCMS方法,均在不锈钢表面制备出纯金红石结构的氧化钛薄膜,而在硅片表面得到的氧化钛薄膜为金红石、锐钛矿混合结构,且采用HPPMS比DCMS技术制备的氧化钛薄膜含有更高的金红石含量。XPS结果显示,两种方法在所有基体表面均制备出了含有氧缺位的氧化钛薄膜。采用HPPMS和DCMS制备氧化钛薄膜时,不锈钢基体沉积的薄膜中,Ti3+/Ti4+比值均高于Si基体上的薄膜。SEM和硬度测试结果显示,HPPMS制备的氧化钛薄膜为等轴晶,晶粒较小,硬度较高。DCMS制备的氧化钛薄膜具有柱状晶的结构,晶粒较大。AFM的结果显示,采用不同溅射方法制备的氧化钛薄膜表面粗糙度没有明显差别。结论不同溅射方法和基体材料导致了薄膜沉积时样品表面离子轰击能量的差异,因此影响了氧化钛薄膜的晶体结构、化学价态和晶粒尺寸。     

高功率脉冲磁控溅射制备的TiN薄膜 应力释放及其结合稳定性研究

目的 探究高功率脉冲磁控溅射（HPPMS）制备的氮化钛（TiN）薄膜在自然时效过程中,应力、薄膜/基体结合性能随时间的变化规律。方法 采用高功率脉冲磁控溅射（HPPMS）技术,通过调控基体偏压（-50、-150 V）,制备出具有不同残余压应力（3.18、7.46 GPa）的TiN薄膜,并采用基片曲率法、X射线衍射法、划痕法和超显微硬度计评价了薄膜的应力、薄膜/基体结合性能、硬度随时间的变化规律。结果 在沉积完成后1 h内,-50 V和-150 V基体偏压下制备的TiN薄膜压应力分别在3.12~3.39 GPa和7.40~7.55 GPa范围内波动,薄膜压应力没有发生明显变化;沉积完成后1~7天,平均每天分别下降28.57 MPa和35.71 MPa;7~30天,平均每天分别下降2.08 MPa和2.50 MPa;30~60天内,平均每天分别下降1.67 MPa和7.00 MPa。其压应力连续下降,且均表现出前期下降速率快,后期下降逐渐放缓的趋势。自然放置60天后,应力基本释放完毕,薄膜性质基本保持稳定。同时,薄膜/基体结合性能随时间逐渐变差,薄膜硬度下降。结论 HPPMS制备的TiN薄膜在自然时效过程中,其残余应力会随时间增加,连续下降,进而影响薄膜的力学性能。     

类富勒烯/非晶多层碳膜的制备及性能

针对碳基薄膜存在的高应力问题,利用单极脉冲等离子体增强化学气相沉积技术在单晶硅衬底上制备了含氢类富勒烯/非晶层交替构成的类金刚石多层膜。采用高分辨透射电子显微镜和激光拉曼光谱仪分析了多层膜的结构特征;用X射线光电子能谱分析了薄膜的化学键状态;用纳米压痕仪测定了薄膜的硬度和弹性模量;在CSM往复式摩擦磨损试验机上考察了薄膜在大气下的摩擦学性能,同时比较了多层膜与非晶、类富勒烯薄膜的力学性能和摩擦磨损性能。结果表明:多层膜的硬度高于非晶和类富勒烯单层薄膜,达到28.78GPa;在大气环境下与Si3N4球对摩时平均摩擦因数略低于类富勒烯单层膜,耐磨性明显优于单层非晶和类富勒烯薄膜。     

铝合金表面沉积类金刚石薄膜的研究进展

类金刚石(Diamond-like Carbon,DLC)薄膜因其高硬度、良好的化学惰性以及优异的摩擦性能等优势,有望成为一种理想的铝合金表面防护涂层。对比了物理气相沉积(Physical vapor deposition,PVD)技术制备DLC改性材料与传统铝合金表面改性技术的优劣,概述了DLC薄膜在提升铝合金表面力学性能、减摩抗磨方面取得的最新成果,以及在复杂服役工况下面临的抗塑性变形差、易发生结合失效等瓶颈性问题。通过分析铝合金基体上生长高性能DLC薄膜的不利因素,指出界面化学结合强度低、薄膜残余应力大以及软基体/硬质薄膜的结构体系限制是导致上述问题产生的主要原因。在此基础上,重点综述了国内外研究学者为提高铝合金表面沉积DLC薄膜的膜基结合力所采取的有效措施及结果,包括:通过基体前处理增强基体力学性能与改善宏观表面缺陷;采用PVD或其他表面处理方法制备一层或多层的中间过渡层,缓解DLC薄膜与铝合金基体结构、性能之间的差异;调控DLC薄膜组分与结构以降低残余应力。最后展望了在铝合金基体表面制备DLC防护薄膜的发展趋势。     

PECVD OF HARD AND ELASTIC BCN COATINGS

Compounds of the B-C-N system are very promising to produce superhard coatings with good tribological, chemical and thermal properties. Consequently, BCN films were prepared by plasma enhanced chemical vapor deposition (PECVD). The films were deposited from gaseous mixtures of BCl3-C2H4-N2-H2-Ar in different unipolar and bipolar pulsed glow discharges at 550℃ and analyzed with respect to composition, electronic structure and mechanical properties. The micro structure and composition of the BCN films were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and reflection electron energy loss spectroscopy (REELS). Mechanical properties were characterized using both the traditional Vickers method and nanoindentation. The films, that were deposited using a bipolar pulsed generator, were weak and had a sponge-like structure, whereas the films prepared using an unipolar generator were well adherent, had a hardness of more than 11GPa and very high e     

钽掺杂对多层Ta-DLC薄膜摩擦及腐蚀行为的影响

目的 解决316L不锈钢在苛刻海洋环境中易磨损、易腐蚀的问题。方法 采用中频磁控溅射技术在316L不锈钢上沉积了Ta/TaN/TaCN/Ta-DLC薄膜。通过扫描电子显微镜、拉曼光谱、X射线光电子能谱、X射线衍射、纳米压痕、往复摩擦磨损试验和电化学测试等手段,重点研究了DLC膜层中Ta元素掺杂含量对薄膜结构、组成成分、力学性能、摩擦学性能和耐腐蚀性能的影响规律。结果 随着Ta元素含量(原子数分数)从2.04%增到4.16%,薄膜中的sp³键含量呈现先升高后降低的趋势,当Ta原子数分数为3.60%时,薄膜中sp³键含量最高,且薄膜的硬度及弹性模量达到最大,分别为7.01 GPa和157.87 GPa。随着Ta元素含量的增加,薄膜的平均摩擦因数逐渐减小,在4.16%(原子数分数)时达到最小0.21。Ta元素含量对薄膜的结合力影响较小,且所有薄膜结合力总体在10 N左右。当Ta原子数分数为3.60%时,薄膜的腐蚀电流密度及钝化电流密度最小,分别为0.006 μA/cm²和0.63 μA/cm²,比其他薄膜的低1~2个数量级,并且薄膜电阻及电荷转移电阻最大,展现出最为优异的耐腐蚀性能。结论 Ta元素的掺杂提高了薄膜的耐摩擦性能,且适当的Ta元素掺杂能够提高Ta/TaN/TaCN/Ta-DLC薄膜的耐磨耐蚀性能。     

Structure and tribological properties of modified layer on 2024 aluminum alloy by plasma-based ion implantation with nitrogen/titanium/carbon

1　INTRODUCTIONGoodmachinability ,lowdensityandhighspecif icstrengthmakealuminumanditsalloysextensivelybeusedinmanyindustries ,especiallyinaviationandspaceflightindustry .Howeverlowsurfacehardnessandlowwearresistanceoftenlimittheirengineeringapplications .Nitrogenionimplantationintoalu minumanditsalloysoffersthepossibilityofapplica tionswherebothhighwearresistanceandlowdensityarerequired[15] .Moreover ,ourpreviousinvestiga tion[6 ,7] presentedthatwhenaluminumalloywasim plantedwithnitrogen…     

Study of growth processes and mechanical properties of nanoscale multilayered C/C films

The growth processes of carbon films deposited using two techniques (sputtering and RF plasma assisted chemical vapor deposition, PACVD), and the effects of stacking these films in a multilayered structure on their mechanical and adhesion properties were studied. The films deposited by the two techniques differed in composition, structure and hardness. They are termed “hard C” and “soft C” according to their synthesis process, sputtering and PACVD respectively. By means of stress measurements and angle-resolved X-ray photoelectron spectroscopy, the growth mechanism of the films was characterized when they were deposited on a silicon substrate and when one kind of carbon film was deposited onto the other kind, in order to simulate a multi-layer film formation. This study evidenced the effect of converting the individual layer surfaces into interfaces when building a multilayer film. On one hand, this conversion appeared to increase the compressive stress of the multilayer films for the lowest periodicity (14 nm and 7 nm of half-period). On the other hand, a strong correlation between the stress resulting from multilayering and the film elasto-plastic properties was found. A hardening effect, put in evidence by applying a nano-indentation “plasticity index”, was obtained for the most layered films (i.e. with the lowest modulation period) and this effect is discussed in relation with the existing models for multi-layer strengthening. The film adhesion to polyethylene terephtalate (PET) substrates was investigated. A beneficial effect of multi-layering on film adhesion was significant only when the half-width period went down to 14 nm and 7 nm. The adhesion improvement cannot be related to a reduced internal stress, since the most stressed films were also the most adherent. Instead the compressive stress found in the films with the lowest periodicity is thought to induce a stronger bonding of the soft C layer (polymer-like) to the PET substrate and to the hard C layers, through chain entanglement across the interface.     

A study of TiN-coated metal-on-polymer bearing materials for hip prosthesis

The TiN-coated metal-on-polymer hip prosthetic pair has the potential to reduce wear debris of UHMWPE (ultra-high molecular weight polyethylene) and to prevent metallic-ion-induced cytotoxicity. However, high quality and adherent film is a key to the clinical success of hip prostheses. In this study, titanium nitride (TiN) films were deposited on stainless steel using plasma immersion ion implantation & deposition (PIII&D) technique to create high-quality film and an adherent interface. The chemical state and composition were analyzed by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and energy dispersive spectroscopy (EDS). The mechanical properties of the films were characterized using a micro-hardness tester and a pin-on-disk wear tester, and an x-ray diffractometer (XRD) was used for a crystallographic analysis. The PIII&D-treated TiN films showed a stoichiometric and (200) preferred orientation and micro-hardness up to 150 % higher than untreated film. A TiN-coated specimen using the PIII&D process also showed less UHMWPE wear compared to untreated specimens. The volumetric wear rate of UHMWPE could be reduced by as much as 42 % compared to when Co-Cr alloy was used. The results of this study show that advanced TiN-coating via the PIII&D process is a viable means of reducing UHMWPE wear in the metal-on-polymer bearing couple.     

Deposition and properties of Al-containing diamond-like carbon films by a hybrid ion beam sources

Metal incorporation is one of the most effective methods for relaxing internal stress in diamond-like carbon (DLC) films. It was reported that the chemical state of the incorporated metal atoms has a significant influence on the film internal stress. The doped atoms embedding in the DLC matrix without bonding with C atoms can reduce the structure disorder of the DLC films through bond angle distortion and thus relax the internal stress of the films. In present paper, Al atoms, which are inert to carbon, were incorporated into the DLC films deposited by a hybrid ion beams system comprising an anode-layer ion source and a magnetron sputtering unit. The film composition, microstructure and atomic bond structure were characterized using X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy. The internal stress, mechanical properties and tribogoical behavior were studied as a function of Al concentration using a stress-tester, nanoindentation and ball-on-disc tribo-tester, respectively. The results indicated that the incorporated Al atoms were dissolved in the DLC matrix without bonding with C atoms and the films exhibited the feature of amorphous carbon. The structure disorder of the films tended to decrease with Al atoms incorporation. This resulted in the distinct reduction of the internal stress in the films. All Al-DLC films exhibited a lower friction coefficient compared with pure DLC film. The formation of the transfer layer and the graphitization induced by friction were expected to contribute to the excellent friction performance.     

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。     

硼掺杂对钛基金刚石薄膜附着力的影响

采用微波等离子体化学气相沉积(MPCVD)技术在钛基片上沉积了掺硼金刚石薄膜,并对掺杂前后的薄膜形貌及结构进行了检测.结果表明掺杂元素对形貌和结构有很大的影响,同时掺杂后薄膜与基底附着力有所下降.掠角衍射(GIXD)检测表明,中间层的主要成分是TiC和TiH_2.随着硼的加入,两者的含量增加.薄膜与基底的附着力下降的原因主要是受中间过渡层成分和残余应力增加的共同影响.     

不同过渡层对钢基金刚石薄膜的影响

采用超高真空热丝化学气相沉积(HFCVD)系统,以甲烷和氢气为反应气体,在高速钢W18Cr4V基体上利用3种不同的过渡层(WC、Cr、WC/Cr)制备金刚石薄膜。采用场发射扫描电子显微镜(FE–SEM)、X射线衍射仪(XRD)、显微激光拉曼光谱仪(Raman)以及洛氏硬度计对过渡层和金刚石薄膜进行检测分析,研究了不同过渡层对金刚石薄膜形貌质量和附着性能的影响。结果表明,3种过渡层均可以有效减少钢基中Fe对金刚石薄膜的负面影响,提高金刚石的形核率;其中,采用WC/Cr过渡层时膜基间残余应力最小,仅为0.25 Gpa,附着性能最好。     

Surface nitridation of titanium metal by means of a gas tunnel type plasma jet

The surface nitridation of titanium was carried out at a low pressure in nitrogen atmosphere using a gas tunnel type plasma jet. The titanium nitride (TiN) film, 10 μm thick and 2000 HV, could be formed in 10 s. The structure of the TiN film was investigated by XRD. The Vickers hardness on the surface of the film was measured. The effects of deposition conditions on the properties of TiN films (TiN thickness,Vickers hardness, etc.) were investigated, and the advantage of this deposition method was identified from those results.     

Preparation of diamond-like carbon by PBII-enhanced microwave ECR chemical vapor deposition

Diamond-like carbon (DLC) films were fabricated with methane on the surface of Si(100) wafer by combining plasma-based ion implantation and microwave ECR chemical vapor deposition. Raman scattering spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to analyze the chemical structure of the DLC films and sp³ content of the DLC films was measured by XPS. Atomic force microscope was employed to investigate the surface morphology information of DLC films synthesized by different methods. The hardness of the films was evaluated using microindentation techniques. Results showed that plasma-based ion implantation enhanced ECR chemical vapor deposition could result in the better surface morphology, the higher adhesion strength and the enhanced hardness; in addition, the hardness of the DLC films was elevated by doping with nitrogen.