Influence of nitrogen gas on structure and properties of DLC films prepared by XeCl pulsed laser deposition

Diamond-like carbon （DLC） films were prepared by PLD process using 308 nm（XeCl） laser beam with high power （500 W） and high fi＇equency（300 Hz）. The effects of nitrogen pressure on the structure and properties of the DLC films under such extremely high power and repetition rate were studied. The results indicate that the microstructures of the films are varied fi＇om amorphous carbon to graphitized carbon in long-order with the increase of N2 pressure, and the optical properties of the films are deteriorated as compared to that of DLC films without nitrogen.     

Cr-doped DLC films in three mid-frequency dual-magnetron power modes

A series of Cr-doped diamond-like carbon (DLC) films were deposited using a mid-frequency dual-magnetron sputtering system, whose sputtering sources had three optional power modes of continuous DC, pulsed DC and AC (40 kHz). Morphology, microhardness, adhesion, and friction properties of the films were investigated using scanning electron microscopy, nano-indentation, scratch adhesion testing, ball-on-disc testing, etc. The results exhibited that the driving voltage waveforms played an important role in the properties of the films, and the properties of the films in pulsed DC mode were superior to those in AC mode and continuous DC mode.     

Characterization and analysis of DLC films with different thickness deposited by RF magnetron PECVD

Diamond-like carbon (DLC) films have excellent mechanical and chemical properties similar to those of crystalline diamond giving them wide applications as protective coatings. So far, a variety of methods are employed to deposit DLC films. In this study, DLC films with different thicknesses were deposited on Si and glass substrates using RF magnetron PECVD method with C4H10 as carbon source. The bonding microstructure, surface morphology and tribological properties at different growing stages of the DLC films were tested. Raman spectra were deconvoluted into D peak at about 1370 cm-1 and G peak around 1590 cm-1, indicating typical features of the DLC films. A linear relationship between the film thickness and the deposition time was found, revealing that the required film thickness may be obtained by the appropriate tune of the deposition time. The concentration of sp3 and sp2 carbon atoms in the DLC films was measured by XPS spectra. As the films grew, the sp3 carbon atoms decreased while sp2 atoms increased. Surface morphology of the DLC films clearly showed that the films were composed of spherical carbon clusters, which tended to congregate as the deposition time increased. The friction coefficient of the films was very low and an increase was also found with the increase of film thickness corresponding to the results of XPS spectra. The scratch test proved that there was good bonding between the DLC films and the substrates.     

Properties of Zr-ZrC-ZrC/DLC gradient films on TiNi alloy by the PIIID technique combined with PECVD

The Zr-ZrC-ZrC/DLC gradient composite films were prepared on TiNi alloy by the techniques combined plasma immersion ion implantation and deposition (PIIID) and plasma enhanced chemical vapor deposition (PECVD). With this method, the Zr-ZrC intermixed layers can be obtained by the ion implantation and deposition before the deposition of the ZrC/DLC composite film. In our study, an optimal gradient composite film has been deposited on the NiTi alloys by optimizing the process parameters for implantation and deposition. The surface topography was observed through AFM and the influence of the deposition voltage on the surface topography of the film was investigated. XPS results indicate that on the outmost layer, the Zr ions are mixed with the DLC film and form ZrC phase, the binding energy of C 1s and the composition concentration of ZrC depend heavily on the bias voltage. With the increase of bias voltage, the content of ZrC and the ratio of sp³/sp² firstly increases, reaching a maximum value at 200 V, and then decreases. The nano-indentation and friction experiments indicate that the gradient composite film at 200 V has a higher hardness and lower friction coefficient compared with that of the bare NiTi alloy. The microscratch curve tests indicate that gradient composite films have an excellent bonding property comparing to undoped DLC film. Based on the electrochemical measurement and ion releasing tests, we have found that the gradient composite films exhibit better corrosion resistance property and higher depression ability for the Ni ion releasing from the NiTi substrate in the Hank's solution at 37°C.     

Adhesion and composite micro-hardness of DLC and Si-DLC films deposited on nitrile rubber

Thin films of hydrogenated diamond-like carbon (DLC) and silicon (Si) doped diamond-like carbon (Si-DLC) have been deposited on acrylonitrile butadiene rubber (NBR) using a closed field unbalanced magnetron sputtering ion plating system. A sputter cleaning process was integrated into the deposition process so as to reduce the likelihood of re-contamination between the cleaning and deposition stages. The deposited coatings showed excellent adherence with an adhesion rating of 4 A for films with a Si-C interlayer. The composite micro-hardness was highest for DLC films at 15.5 GPa for indentation load of 147.1 mN using a Vickers micro-hardness tester. Tribological tests undertaken under normal load of 5 N using a pin-on-disc tribometer for all of the samples of DLC and Si-DLC films, with and without Si-C interlayer, show a friction increase between 0.25 and 0.4 to between 0.45 and 0.6. This friction increase has been related to the micro-hardness of the films.     

偏压类型对磁过滤等离子体制备优质类金刚石膜的影响

采用自行研制的磁过滤等离子体装置在单晶Si基底上制备了优质类金刚石(DLC)薄膜.运用红外光谱(IR)、扫描电镜(SEM),原子力显微镜(AFM)和纳米压痕仪对样品进行了表征和分析,着重研究了衬底偏压类型对制备薄膜的影响.结果表明:在无偏压或周期性负偏压下制备的DLC薄膜的sp3含量比连续负偏压下制备的薄膜的sp3含量要高;同时在周期性偏压下制备的薄膜表面较光滑,其表面粗糙度仅为0.1 nm,sp3含量达到66.8%,相应的纳米硬度也较高(达到80GPa).同时对相应的成膜机理进行了讨论.     

Cr/WC/DLC薄膜的多环境摩擦学性能

采用磁控溅射法,在304不锈钢上制备Cr/WC/DLC多层梯度过渡类金刚石薄膜,利用场发射扫描电子显微镜(SEM)、拉曼光谱仪(Raman)、纳米压痕仪、划痕测试仪等分析薄膜的微观结构和力学性能,利用UMT-3多功能摩擦磨损试验机考察其在大气、去离子水、发动机油3种环境下的摩擦学性能。结果表明:该薄膜的多层梯度设计使其膜基间结合力得到了有效改善,且硬度高达32.6GPa,在3种环境下均具有优异的摩擦学性能。在大气环境下,薄膜具有较低的平均摩擦因数,为0.094;但具有3种环境下最大的磨损率,为7.86×10-8 mm3(N·m)-1;在去离子水环境下,薄膜的平均摩擦因数较高,为0.124;而其磨损率较低,为5.26×10-8 mm3(N·m)-1;在发动机油环境下,固-油复合润滑效应使薄膜具有更加优异的摩擦学性能,其平均摩擦因数和磨损率均为3种环境下的最小值,分别为0.065和4.44×10-8 mm3(N·m)-1。     

AZ31表面混合碳源制备DLC薄膜的结构和性能

为了提高镁合金的耐蚀性和耐磨性,扩大镁合金的应用,节能减排,保护环境,采用绿色环保的磁控溅射技术在AZ31表面制备了强保护性的DLC薄膜。采用X射线小角掠入射研究薄膜的物相结构,借助扫描电镜观察薄膜表面形貌、横截面形貌和腐蚀形貌,采用纳米压痕仪测试薄膜的力学性能,分别采用电化学工作站和摩擦磨损试验机研究薄膜的耐蚀性和耐磨性,膜基的结合性能采用划痕试验评估。结果表明,薄膜为无定形碳结构,随着活性气体流量的增加,薄膜结构由非晶向纳米晶转变。薄膜与基体结合良好,结合力19~25 N。薄膜表面具有弥散分布的不规则颗粒,且表面粗糙度受活性气体流量影响明显。薄膜厚度1.15~1.18μm,活性气体流量对薄膜厚度影响很小。随着活性气体流量的增加,DLC薄膜的硬度和杨氏模量增大,其最大值分别为17.35 GPa和94 GPa;摩擦系数和磨损率降低,其最小值分别为0.103和6.45×10^-10mm³/(N·m)。活性乙炔流量5 mL/min时,薄膜的耐蚀性能最好,活性乙炔流量10 mL/min时,薄膜的耐磨性能最好。     

DLC基纳米多层膜摩擦学性能的研究进展与展望

类金刚石（DLC）薄膜是一种良好的固体润滑剂,能够有效延长机械零件、工具的使用寿命。DLC基纳米多层薄膜的设计是耐磨薄膜领域的一项研究热点,薄膜中不同组分层具备不同的物理化学性能组合,能从多个角度（如高温、硬度、润滑）进行设计来提升薄膜力学性能、摩擦学性能以及耐腐蚀性能等。综述了DLC多层薄膜的设计目的与研究进展,以金属/DLC基纳米多层膜、金属氮化物/DLC基纳米多层膜、金属硫化物/DLC基纳米多层膜以及其他DLC基纳米多层膜为主,对早期研究成果及现在的研究方向进行了概述。介绍了以上几种DLC基纳米多层膜的现有设计思路（形成纳米晶/非晶复合结构、软/硬交替沉积,诱导转移膜形成,实现非公度接触）。随后对摩擦机理进行了分析总结：1）层与层间形成特殊过渡层,提高了结合力;2）软/硬的多层交替设计,可以抵抗应力松弛和裂纹偏转;3）高接触应力和催化作用下诱导DLC中的sp3向sp2转化,形成高度有序的转移膜,从而实现非公度接触。最后对DLC基纳米多层膜的未来发展进行了展望。     

基材、添加元素及中间层对DLC膜结构与性能的影响

扼要地介绍了基体材料、在ＤＬＣ膜中添加元素及各种中间层对ＤＬＣ膜结构与性能影响的研究现状。     

类金刚石薄膜的摩擦学特性研究进展

类金刚石薄膜(DLC)具有优良的摩擦磨损性能,但是DLC薄膜的摩擦学特性强烈依赖于制备技术、摩擦接触点的表面化学状态和物理状态,因此进一步提高类金刚石薄膜的摩擦学特性是目前的热门研究方向之一.在综合分析了近年来该领域研究的基础上,总结了影响DLC薄膜摩擦学性能的因素,并分析了各个因素的影响机理,以期找出一些规律为适应类...     

Zr-Al-N及Zr-Al-Si-N复合膜的微结构及力学性能

采用多靶反应磁控溅射技术制备不同Al含量的Zr-Al-N复合膜及不同Si含量的Zr-Al-Si-N复合膜。采用能谱仪、X射线衍射仪和显微硬度计对薄膜进行测试,研究Al含量对Zr-Al-N复合膜微结构和力学性能的影响以及Si含量对Zr-Al-Si-N复合膜微结构和力学性能的影响。结果表明,当Al含量为13.97at%时,Zr-Al-N复合膜的硬度达到最大,最大值为27.16 GPa,随着Al含量的继续增加,薄膜由B1(NaCl型面心立方结构)型结构向B1-B4(ZnS型纤锌矿结构)型双相结构转变,硬度急剧降低;当Si含量为18.79at%时,Zr-Al-Si-N复合膜的硬度达到最大,最大值为34.43 GPa,进一步增加Si含量薄膜向非晶态转化,薄膜硬度降低。     

Al元素对Zr-Si-N复合膜的微结构与力学性能的影响

采用反应磁控溅射方法制备了一系列不同铝含量的Zr-Al-Si-N复合膜,用能谱仪、X射线衍射仪和显微硬度计对复合膜进行表征,研究了铝元素对Zr-Si-N复合膜的微结构和力学性能的影响.结果表明,当铝的原子分数N_(Al) ≤10.84%时,Zr-Al-Si-N复合膜中fcc-(ZrAlSi)N为主要相;当N_(Al) ≥14.67%时,Zr-Al-Si-N复合膜是fcc-(ZrAlSi)N和h-AlN的混合相;铝原子分数为4.80%时,Zr-Al-Si-N复合膜的显微硬度达到最大值43.92 GPa;随着铝原子含量的进一步增加,Zr-Al-Si-N复合膜的显微硬度迅速下降.对复合膜的致硬机理进行了讨论.     

DLC and UHMWPE as hard/soft composite film on Si for improved tribological performance

The main purpose of this study is to explore the advantages of using a composite thin film of ultra high molecular weight polyethylene (UHMWPE) on a hard diamond like carbon (DLC) coating deposited on Si, for high wear life and low coefficient of friction. The experiments are carried out using a ball-on-disc tribometer at a constant linear speed of 0.052 m/s. A 4 mm diameter silicon nitride ball with a normal load of 40 mN is used as the counterface. The tribological results are discussed on the basis of hardness, elastic modulus, contact area, contact pressure and optical images of surface films. As a result of higher load carrying capacity (high hardness and elastic modulus), the wear life of Si/DLC/UHMWPE coated layer is approximately five times greater than that of Si/UHMWPE. Looking at the film thickness effect, UHMWPE film shows maximum wear resistance when the film is of optimum thickness (6.2 μm-12.3 μm) on DLC. Wear mechanisms of different UHMWPE thicknesses for Si/DLC/UHMWPE film are explained using optical microscopy of worn surfaces. Further, the use of perfluoropolyether (PFPE) ultra-thin film as the top layer on the composite coatings reduces the coefficient of friction to very low values (0.06-0.07) and increases the wear life of the films by several folds.     

Thickness dependence of the structure of diamond-like carbon films by Raman spectroscopy

The thickness dependence on structure of Diamond-like carbon films of a-C:H deposited by ECR-CVD and ta-C by FCVA has been studied by visible and UV Raman spectroscopy. The results show that the evolution of structure as a function of the thickness for a-C:H films contains two stages: when thickness is less than 50 Å, the film contains less sp³ sites and not continuous; and when thickness is up to 50 Å, the film contains more sp³ sites and become continuous. However, for ta-C films, it includes three stages. In the first stage of thickness lower than 20 Å, the film is not continuous, and also contains less sp³. In the second stage of thickness between 20 Å and 50 Å, the sp³ site abruptly shifts a higher value in 20 Å and then keeps stable. In the third stage of thickness over 50 Å, the sp³ site has a little increase and then almost not changed. Thus, the fundamental limitation thickness in using DLC as an ultrathin overcoat for ta-C films is 20 Å (> 10 Å), and for a-C:H films is 50 Å. The implications of result on the mechanisms proposed for the film growth mode were also discussed.     

Electrodeposition of DLC films on carbon steel from acetic acid solutions

In this paper the electrodeposition of DLC films on carbon steel from aqueous acetic acid solutions and their structural and mechanical characterization are reported. The process is performed at room temperature at relatively low cell voltages (from ?8 to ?20 V) with entirely environmentally friendly chemicals. Qualitative and quantitative evaluation of C hybridisation type have been performed by Raman spectroscopy. Microhardness and adhesion of the supported electrodeposited films have been measured by micro-indentation and scratch-testing. Notably, ductile failure was found to correspondence to a wide range of film growth conditions. The corrosion resistance of DLC-coated steel has been assessed by electrochemical impedance spectrometry in a neutral chloride solution. Optimal electrodeposition conditions were identified for the formation of high-quality DLC films ca. 270 nm thick with a high content of diamond-coordinated carbon and an ideal combination of hardness and adhesion; films formed under these conditions also confer some degree of corrosion protection to the steel substrate.     

磁控溅射和退火制备ZnO/SiO2复合薄膜

采用射频磁控溅射和退火处理的方法在单晶硅衬底上制备了ZnO/SiO2复合薄膜,利用X射线衍射(XRD)、扫描电镜(SEM)、能谱分析(EDS)和接触角测量等测试手段研究溅射气压、溅射功率、氧氩比和退火温度等对复合薄膜成分组成、组织结构及润湿性能的影响。研究表明,复合薄膜中主要有ZnO、SiO2、Zn2SiO4 3种物相,且分别以六方纤锌矿结构、无定形态和硅锌矿型等形式存在。随着溅射和退火工艺的改变,复合薄膜的接触角在41°～146°间变化,组织形态由颗粒状向纳米竹叶状变化。溅射气压0.5 Pa,溅射功率120 W,氧氩比(O2∶Ar)为0∶30,退火温度为700℃的条件下获得具有六方纤锌矿结构的ZnO纳米组织,该组织呈现出竹叶状,在薄膜表面交错排列形成了无序多空隙的微观形貌,使复合薄膜具有超疏水性,接触角为146°。     

TiN(111)/DLC界面粘附功和电子结构的第一性原理研究

利用基于密度泛函理论的第一性原理,采用平面波赝势方法,研究了 TiN(111)/DLC界面的粘附功和电子结构,阐明了 TiN过渡层改善金属基体和DLC薄膜结合性能的内在机理.根据TiN(111)面不同的表面终端(Ti终端和N终端)和界面原子配位类型(顶位、中心位和孔穴位),构建和计算了 6种可能的TiN(111)/DL...     

316L不锈钢表面沉积类金刚石膜的拉曼光谱分析及润湿性研究

采用等离子体辅助化学气相沉积(PECVD)法,在316L不锈钢基体表面以不同的沉积气压和射频功率制备出类金刚石(DLC)薄膜.拉曼光谱分析结果表明:所沉积的DLC膜具有典型的类金刚石膜结构,薄膜中sp#键含量随工艺参数的不同而不同,射频功率100 W时,sp#键含量随沉积气压增高而降低.接触角测试结果表明:DLC膜沉积...     

Zr掺杂类金刚石薄膜摩擦性能及耐腐蚀性能的影响

目的改善不锈钢摩擦性能及耐腐蚀性能。方法通过线性阳极层离子源辅助非平衡磁控溅射法,制备了不同Zr含量的类金刚石(DLC)薄膜,采用扫描电子显微镜、拉曼光谱仪、纳米硬度仪、高温销盘磨损仪、电化学工作站,对薄膜的化学成分、显微结构、纳米硬度、薄膜摩擦性能及耐腐蚀性能进行测试研究。结果随着Zr靶功率的增大,Zr含量线性增加。Zr含量从4.9%增加至16.3%时,I_D/I_G增大,薄膜硬度从12.1 GPa逐渐下降至8.4 GPa;Zr含量增大至21.2%时,I_D/I_G减小,薄膜硬度增大至11.4 GPa。涂镀类金刚石薄膜的不锈钢基体比无涂层的不锈钢基体有更低的摩擦系数,更好的耐磨损性能。Zr掺杂DLC薄膜的最小摩擦系数为0.07。Zr含量从4.9%增加至16.3%,DLC薄膜的耐腐蚀性能减弱;Zr含量继续增加,DLC薄膜的耐腐蚀性能增强。当Zr含量不大于11.9%时,沉积Zr掺杂DLC膜的不锈钢基体的耐腐蚀性能比不锈钢基体的更强。结论 Zr含量不大于11.9%时,Zr掺杂类金刚石薄膜既可以有效地改善不锈钢基体的摩擦磨损性能,又可以大幅提高耐腐蚀性能。