DLC膜在磨损、表面改性及力电耦合作用下损伤特性

为评价超薄类金刚石（DLC）膜在使用过程中的安全状况，利用原子力显微镜（AFM）的多模式功能，从磨损、表面改性、力电失效3个方面对DLC膜进行了试验研究．研究结果表明：相同法向力作用在不同厚度薄膜的磨损深度不同；对DLC膜的形貌和电学特性进行比较发现，磨损区域导电性比未磨损区域强；在厚度为64．09nm薄膜施加正向25V电场作用下，当针尖作用在表面的压力超过一定临界压力（375nN）之后，薄膜发生击穿，形成凹坑。     

钛离子注入类金刚石碳膜的结构与性能的研究

使用金属离子注入的方法制备了 Ti掺杂的DLC膜。采用原子力显微镜观察了薄膜的表面形貌,Ti掺杂后 DLC 膜的表面粗糙度明显减小,表面光洁度增加,颗粒细化。拉曼光谱分析表明实验获得的薄膜是典型的DLC膜,掺杂Ti后的 DLC膜的拉曼光谱存在明显的肩峰,DLC膜化学结构中的sp2 组分增加,sp3 组分减少。透射电子显微镜分析表明Ti注入后有TiC纳米晶形成。掺入Ti的 DLC膜的硬度从 14GPa增加到 20GPa。Ti 掺杂后的 DLC 膜的摩擦系数(0.15)明显低于未掺杂的DLC膜的摩擦系数(0.21),Ti离子注入有助于提高薄膜的抗磨损性。     

用侧向力显微镜表征纳米级DLC膜摩擦性能

本文用侧向力显微镜(Lateral Force Microscope,LFM)研究不同厚度类金刚石(Diamond-Like Carbon,DLC)膜的摩擦性能.对厚度为153.4 nm,64.9 nm,12.07nm DLC膜摩擦力和法向力的关系进行研究,实验表明施加较低载荷,摩擦力和法向力成线性关系,符合Amontons's定律;而膜厚为4.48nm、2.78 nm样品由于粗糙度、峰态和偏态的差异导致摩擦力和载荷关系不明显,研究指出针尖和薄膜的表面接触可以简化为Tomlinson模型,借助原子晶格振动的无损摩擦机理解释了这一现象.     

工况参数对类金刚石膜摩擦学性能的影响

采用非平衡磁控溅射技术在高速钢基体上以C2H2为反应气源制备了含氢类金刚石(DLC)膜.使用激光拉曼光谱仪、X射线光电子能谱仪和原子力显微镜分析和观察了DLC膜的微观结构及表面形貌,结果表明:DLC膜表面由纳米级别的圆形颗粒堆积而成,其结构呈现出DLC的典型Raman光谱特征,薄膜中的碳元素主要以sp2C键、sp3C键和C-O键的形式存在.以G Cr15钢球为摩擦配副,在球盘式摩擦磨损试验机上考察了DLC膜在大气干摩擦条件下的摩擦学性能.实验结果发现:在摩擦初始阶段,DLC膜的摩擦系数从实验开始到达峰值的时间随着载荷和速度的增大都是减少的;而在摩擦稳定阶段,DLC膜的平均摩擦系数随着载荷和速度的增大先减小后增大;速度对DLC膜摩擦系数的影响比载荷更加显著.用扫描电子显微镜观察了磨痕形貌并分析了磨损机理:DLC膜的磨损特征主要为以犁沟现象为主的粘着磨损.随着速度的增加,磨痕表面犁沟现象变弱;而随着载荷的增加,磨损表面的犁沟现象变明显.     

用扫描隧道显微镜对材料进行表面修饰的研究

扫描隧道显微镜(STM)是对材料表面进行表面修饰(surface modification)和表面原子操纵(atomcraft)的重要工具。为了了解其机理,选择了场蒸发阈值从大到小有代表性的钨、铂、金、铜做针尖,扫描过程中在针尖与石墨表面之间施加针尖为正的脉冲电压,获得了一些新现象,并对实验结果作了比较,从而在一定程度上确定了脉冲制STM表面修饰实验中针尖与样品之间电场的重要作用。     

用STM的纳米导电图形加工技术的研究

用STM针尖对有机络合物电双稳薄膜材料施加强电场作用 ,可在材料表面产生纳米线度的导电几何图形。实验证明 :对针尖本身的几何构形、施加在针尖上的脉冲幅度、周期和占空比都必须进行细致的选择。用Ag TCNQ络合物进行实验 ,在适合的针尖 样品距离下 ,发现所加脉冲偏压的极性为负时 ,容易进行加工     

退火温度对DLC膜热稳定性及摩擦学性能的影响

采用非平衡磁控溅射技术分别在氮化硅陶瓷球和高速工具钢圆盘表面制备了类金刚石(DLC)膜。使用箱式电阻炉对DLC膜在大气环境中进行高温退火处理以研究环境温度对DLC膜摩擦学性能的影响;并分别采用激光拉曼光谱仪和球-盘式摩擦磨损试验机对退火处理前后DLC膜的结构和摩擦学性能进行了研究。采用金相显微镜观察了摩擦副磨损表面的形貌。研究发现,随着退火温度的升高,DLC膜中sp3杂化键向sp2杂化键的转化加快,当退火温度为600℃时,DLC膜发生严重的石墨化。而当退火温度为400℃时,DLC膜的摩擦系数及磨损率最小。拉曼测试表明400℃退火处理后DLC膜表层含有Si及SiO2,在摩擦过程中形成了含SiC的转移膜,使得DLC膜的摩擦系数明显降低,磨损减小。研究结果表明,退火处理对DLC膜的热稳定性和摩擦学性能有重要的影响。     

用STM的纳米导电图形加工技术的研究

用STM针尖对有机络合物电双稳薄膜材料施加强电场作用，可在材料表面产生纳米线度的导电几何图形。实验证明：对针尖本身的几何构形、施加在针尖上的脉冲幅度、周期和占空比都必须进行细致的选择。用Ag-TCNQ络合物进行实验，在适合的针尖-样品距离下，发现所加脉冲偏压的极性为负时，容易进行加工。     

基于GeSbTe膜的探针存储机制的研究

针对基于原子力显微镜(AFM)的探针相变存储研究中存储介质和存储方贩性的研究.比较了用直流磁控溅射部分不同工艺参数所制备的GeSb2Te4薄膜的表面性能,同时对探针诱导相变机理进行了初步探讨.试验观察的结果表明,利用AFM导电探针对相变化材料GeSb2Te4膜施加一定的直流电压,可以通过形貌和相结构的变化来获得存储的信息点,并且通过施加一定时间的反向电压可以实现信息点的消除.     

医用TiNi合金表面等离子体沉积梯度DLC膜及抗腐蚀性能

采用双放电腔MW-ECR等离子体源增强磁控溅射和沉积技术,在TiNi合金表面成功地镀制了梯度DLC膜.拉曼光谱分析表明实验获得的薄膜是典型的DLC膜,其结构受梯度层工艺影响.采用原子力显微镜(AFM)观察了薄膜的表面形貌,结果显示其表面较为平整.在Troyde's模拟体液中的电化学腐蚀实验结果说明,梯度DLC膜显著地增强了TiNi合金基体的抗腐蚀能力.从示差扫描量热仪(DSC)结果看到表面改性没有明显影响TiNi合金基体的使用性能.     

基体负偏压对类金刚石涂层结构和性能的影响

采用直流等离子体增强化学气相沉积技术(DC-PECVD),通过控制基体负偏压的变化在YG8硬质合金基体上制备一系列类金刚石涂层。选用扫描电子显微镜、原子力显微镜、拉曼光谱、X射线光电子能谱、粗糙度仪对涂层形貌和结构进行表征测试。同时,利用显微硬度计、划痕测试仪系统地分析涂层的显微硬度和界面结合性能。结果表明:随着负偏压增大,涂层表面形貌逐渐平整光滑、致密,颗粒尺寸减小及数量降低。拉曼光谱表明,涂层具有典型的类金刚石结构,涂层中sp3键含量呈先增大后减小趋势,最大值约67.9%出现在负偏压为1000V左右,负偏压过大导致sp3键含量降低。显微硬度随负偏压变化规律与sp3键基本相符,sp3键含量决定显微硬度值大小。负偏压过大对吸附离子产生反溅射作用导致涂层厚度减小。当负偏压为1100V时,涂层与基体间的界面结合性能最优。     

利用脉冲激光真空弧沉积技术制备类金刚石薄膜

介绍了一种新的脉冲激光真空弧沉积技术, 利用该技术在硅基片上制备了类金刚石薄膜. 利用激光拉曼分析技术对沉积膜进行了结构分析, 结果表明沉积膜为非晶结构, 具有明显的sp³ 结构特征. 同时利用纳米划痕压痕仪、原子力显微镜等分析设备对膜的表面形貌、微观摩擦学性能进行了分析, 结果表明Si<100>基片上沉积膜的表面形貌和微观摩擦学性能略优于 Si<111>基片上沉积的薄膜, 其摩擦系数平均值为0.036.     

X-ray reflectivity study of bias graded diamond like carbon film synthesized by ECR plasma

Diamond like carbon (DLC) coatings were deposited on silicon substrates by microwave electron cyclotron resonance (ECR) plasma CVD process using plasma of Ar and CH ₄ gases under the influence of negative d.c. self bias generated on the substrates by application of RF (13·56 MHz) power. The negative bias voltage was varied from ?60 V to ?150 V during deposition of DLC films on Si substrate. Detailed X-ray reflectivity (XRR) study was carried out to find out film properties like surface roughness, thickness and density of the films as a function of variation of negative bias voltage. The study shows that the DLC films constituted of composite layer i.e. the upper sub surface layer followed by denser bottom layer representing the bulk of the film. The upper layer is relatively thinner as compared to the bottom layer. The XRR study was an attempt to substantiate the sub-plantation model for DLC film growth.     

Improvement of adhesion of DLC coating on nitinol substrate by hybrid ion beam deposition technique

Diamond-like carbon (DLC) films were prepared for a protective coating on nitinol substrate by hybrid ion beam deposition technique with an acetelene as a source of hydrocarbon ions. An amorphous silicon (a-Si) interlayer was deposited on the substrates to ensure better adhesion of the DLC films followed by Ar ion beam treatment. The film thickness increased with increase in ion gun anode voltage. The residual stresses in the DLC films decreased with increase in ion gun anode voltage and film thickness, while the stress values were independent of the radio frequency (RF) bias voltage. The adhesion of the DLC film was improved by surface treatment with argon ion beam for longer time and by increasing the thickness of a-Si interlayer.     

液相沉积法制备类金刚石膜的研究

探讨了用液相法在钛合金表面沉积制备类金刚石膜的可能性,研究了沉积膜工艺条件对膜的影响,得出了适宜的沉积条件。结果表明,通过液相法可以沉积制备得到DLC膜,但与沉积条件有着密切的关系。当电压为1600~1850V、温度为60~62℃、电极间距为8~10mm、沉积时间大于36h时,才能在钛合金表面得到完整的DLC绝缘膜。     

Interaction between sputtered beta-Ta films and diamond-like carbon with Ru intermediate layer

Interaction between beta-tantalum film and Diamond-like Carbon (DLC) film was studied with and without ruthenium intermediate barrier layer. Phase identification using X-ray Diffraction showed that the phase transformation of tantalum film from beta to alpha crystalline structure was delayed by 100 degrees C and the formation of tantalum carbide was also hindered when ruthenium interlayer is present. X-ray reflectivity measurements indicate that the surface and interfacial area of C/Ta film was maintained to achieve desired magnetic and tribological performance even after N2 annealing at 400 degrees C. In C/Ru/Ta film there is minimum intermixing between tantalum and DLC. In C/Ta film, severe reaction between tantalum and carbon took place. Raman spectroscopy analysis revealed the as-deposited carbon film possessed amorphous structure regardless of the existence of Ru interlayer. Graphitization of carbon film was observed in both structures, upon annealing, however the films with Ru layer was thermodynamically more stable thus desirable in magnetic recording.     

液相电沉积类金刚石薄膜的相关物理化学问题

利用液相电沉积技术制备了含氢类金刚石薄膜(ＤＬＣ);讨论了应用电位和沉积碳源对沉积过程和薄膜结构的影响;结果表明有高介电常数、低粘度、分子中甲基基团直接与极性基团键合的有机液体是合适的沉积碳源;通过增加沉积电位将有利于薄膜中ｓｐ^３碳的生长;最后,作者提出了液相沉积类金刚石薄膜的反应机理－极化－反应机制,在电场的作用下,有机分子被极化并在电极表面反应生成ＤＬＣ薄膜和其他产物．     

Direct analysis of oxidizing agents in aqueous solution with attenuated total reflectance mid-infrared spectroscopy and diamond-like carbon protected waveguides

A novel approach for the direct detection of oxidizing agents in aqueous solution is presented using diamond-like carbon (DLC) protected waveguides in combination with attenuated total reflectance (ATR) mid-infrared spectroscopy. Pulsed laser deposition was applied to produce high-quality DLC thin films on ZnSe ATR crystals with thicknesses of a few 100 nm. Scanning electron microscopy and X-ray photoelectron spectroscopy has been used to investigate the surface properties of the DLC films including the sp(3)/sp(2) hybridization ratio of the carbon bonds. Beside excellent adhesion of the DLC coatings to ZnSe crystals, these films show high chemical stability against strongly oxidizing agents. IR microscopy was utilized to compare differences in the chemical surface modification of bare and protected ATR waveguides when exposed to hydrogen peroxide, peracetic acid, and peroxydisulfuric acid. The feasibility of DLC protected waveguides for real-time concentration monitoring of these oxidizing agents was demonstrated by measuring calibration sets in a concentration range of 0.2-10%. Additionally, principal component regression has been applied to analyze multicomponent mixtures of hydrogen peroxide, acetic acid, and peracetic acid in aqueous solution. Due to high chemical stability and accurate monitoring capabilities, DLC protected waveguides represent a novel approach for directly detecting oxidizing agents in aqueous solution with promising potential for industrial process analysis.     

脉冲真空弧源沉积类金刚石薄膜耐磨特性研究

本文利用脉冲真空弧源沉积技术在Cr17Ni14Cu4不锈钢和Si(100)基体上制备了类金刚石(DLC)薄膜,研究在不同基体偏压下,DLC薄膜的结构与性能.采用拉曼光谱和X射线光电子能谱(XPS)研究DLC薄膜的原子结合状态,利用CSEM销盘摩擦磨损试验机研究其耐磨性,利用HXD1000B显微硬度仪测试其显微硬度,并采用压痕法评价其结合力.研究结果表明:DLC薄膜与基体结合牢固.随着基体偏压的提高,DLC薄膜内sp3键含量增大,薄膜硬度提高.Cr17Ni14Cu4不锈钢表面沉积DLC薄膜后,耐磨性大幅度提高,本文探讨了DLC薄膜的耐磨机理.