类金刚石膜的结构与性能研究

用激光Ｒａｍａｎ谱和ＸＲＤ谱对用直流－射频等离子体化学气相沉积法制备的类金刚石膜的结构进行了分析，并研究了工艺参数对膜的沉积速率，内应力和直流电阻率的影响，结果表明，类金刚石膜是由ｓｐ＾２和ｓｐ＾３键组成的非晶态碳膜，当负偏压高于３００Ｖ时，膜中ｓｐ＾３／ｓｐ＾２键的比值随负偏压的升高而降低，类金刚膜的沉积速率与负偏压Ｖｂ的成正比，膜内存在１～４．７ＧＰａ的压应力，随负偏压的升高而降低，膜的电阻率     

影响金刚石膜刀具涂层形貌的因素分析

采用高分辨金相显微镜对硬质合金刀生上沉各的ＣＶＤ金刚石薄膜进行了表面形貌和膜／基横截面组织形貌的观察;并利用该显微镜配备的功能测量了金刚石颗粒大小,膜厚;利用显微镜正焦／过焦观察判断了金刚石薄膜的成膜状况。初步观察结果表明：甲烷浓度和基体钴含量对金刚石薄膜的表面形貌和膜／基横截面组织形貌有显著的影响。     

微波等离子体化学气相沉积工艺对透明金刚石膜质量的影响

在自制的２４５０ＭＨｚ／５ｋＷ不锈钢谐振空型微波等离子体学气相沉积装置中研究了基片预处理和工艺参数对微波等离子体化学气相沉积金刚石膜质量的影响,研究了提高成核密度和沉积速率的方法,用ＳＥＭ,ＸＲＤ,ＦＴＩＲ,Ｒａｍａｎ和ＡＦＭ分析了金刚石膜的质量,结果表明：用纳米金刚石粉研磨单晶基片,在沉积气压６．０ｋＰａ,ＣＨ４／Ｈ２的体积流量比为０．７５％时,可 出红外透光率达６８％,表面粗糙度为１１４．１０     

CVD纳米金刚石涂层工具研究进展

概述了CVD纳米金刚石涂层工具的研究开发现状、存在的主要问题,重点介绍了硬质合金基体表面预处理方法及纳米金刚石生长工艺参数对CVD纳米金刚石涂层工具结构和性能的影响,其中,介绍了硬质合金基体表面预处理方法主要有酸液浸蚀去钴、施加中间过渡层、机械或等离子体处理、负偏压等;蚋米金刚石生长工艺参数则主要从碳源浓度、基体温度、...     

单晶金刚石膜与多晶金刚石膜的制备工艺及性能

本文主要介绍了用微波等离子体化学气相沉积法(以下简称MP CVD法)以甲醇-氢气混合气和丙酮-氢气混合气为源气体,分别以单晶硅的(111)面和人造金刚石的(100)面为衬底材料,制备出了面积为20mm×20mm厚为10μm的多晶金刚石膜和面积为1.0mm×1.0mm厚为5μm的单晶金刚石膜。通过试验发现,源气体配比和衬底温度对薄膜质量起决定性作用。另外,衬底在反应腔中的位置对薄膜的生成也有很大影响。单晶金刚石膜制备过程中衬底金刚石的晶体取向与金刚石薄膜的生长及质量有密切的关系。在金刚石的(100),(110)和(111)面上分别获得了单晶金刚石膜和金刚石多晶粒子。选用扫描电镜、显微激光拉曼、反射电子衍射对多晶金刚石膜及单晶金刚石膜的性能进行了测试。     

形核密度对CVD金刚石涂层附着性能的影响

采用热丝化学气相沉积法(HFCVD)在硬质合金基体上进行金刚石的形核生长,使用扫描电镜(SEM)对金刚石涂层形核情况进行分析,研究了不同形核密度对CVD金刚石涂层附着力的影响。结果表明:当碳源浓度达到3%时,表面形核密度最高,约为107/cm2;浓度增大为4%时,形核密度降低。通过压痕实验对比分析得出形核工艺中碳源浓度为3%时沉积的金刚石涂层压痕最浅,压痕直径最小,金刚石涂层具有良好的附着性能。     

类金刚石膜结构的红外分析

采用直流－射频等离子化学气相沉积方法制备出类金刚石薄膜,用Ｆｏｕｒｉｅｒ秀昨吸收谱对类金刚石膜的结构进行了研究,类金刚石膜中大部分碳原子以ｓｐ＾３组态存在,结合在膜中的氮原子与碳原子之间可形成ｓｐ＾３Ｃ－ＣＨ２,ｓｐ＾３Ｃ－ＣＨ３和ｓｐ＾２Ｃ－ＣＨ２基,其含量以ｓｐ＾３Ｃ－ＣＨ２,增加Ａｒ气分压与提高极板负偏压对类金刚石膜结构产生的影响,是相似的,增大极板负偏压或Ａｒ气的含量将减小类金刚石膜中ｓｐ     

类金刚石薄膜在模拟体液中的电化学阻抗

利用双放电腔微波等离子体源全方位离子注入设备,分别采用等离子体增强化学气相沉积技术、等离子体源离子注入和等离子体增强化学气相沉积复合技术两种工艺对医用3161,不锈钢进行类会刚石薄膜表面改性。利用电化学阻抗谱法考察了两种工艺制备的类金刚石薄膜在模拟体液中的抗腐蚀性能。结果表明：与采用等离子体增强化学气相沉积技术制备的类金刚石薄膜相比,在72h的浸泡时间内,采用等离子体源离子注入和等离子体增强化学气相沉积复合技术制备的类金刚石薄膜防腐蚀性能明显增高,腐蚀阻抗较高,碳注入层可有效抑制溶液渗入薄膜和基体之间的界面,起到了腐蚀防护层的作用。动电位极化测试表明：采用复合技术制备的类金刚石薄膜在模拟体液中的腐蚀倾向性更低,钝态稳定性更好。     

Effect of microwave power on diamond-like carbon films deposited using electron cyclotron resonance chemical vapor deposition

Diamond-like carbon (DLC) films have been deposited using electron cyclotron resonance chemical vapor deposition (ECR-CVD) under various microwave power conditions. Langmuir probe measurement and optical emission spectroscopy (OES) were used to characterize the ECR plasma, while the films were characterized using Raman and infrared (IR) spectroscopies, hardness and optical gap measurements. It was found that the ion density and all signal peaks in the optical emission (OE) spectra increased monotonously following the increase in microwave power. Raman spectra and optical gap measurements indicate that the films become more graphitic with lower content of sp³-hybridized carbon atoms as the microwave power was increased. IR and hardness measurements indicate a reduction in hydrogen content and decrease in hardness for the film produced at relatively high microwave powers. A deposition mechanism is described which involved the ion bombardment of film surfaces and hydrogen–surface interactions. The deposition rate of DLC film is correlated to the ion density and CH₃ density.     

类金刚石薄膜在橡胶表面改性中的研究进展

介绍了类金刚石薄膜的结构、制备方法及其在橡胶表面改性中的研究进展。     

Antifungal behavior of silicon-incorporated diamond-like carbon by tuning surface hydrophobicity with plasma treatment

Silicon-incorporated diamond-like carbon (Si-DLC), an amorphous material containing Si atoms with sp³- and sp²-hybridized carbon, is a promising biomaterial for versatile biomedical applications due to its excellent mechanical properties, chemical inertness, biocompatibility, and antimicrobial capability. However, the antifungal properties of plasma-treated Si-DLC have not been systematically evaluated. In this study, Si-DLC coatings were deposited by chemical vapor deposition and further treated with either oxygen or fluorine plasma to render the surface anchored with different functional groups and hydrophobicity. Surface roughness was probed with atomic force microscopy, whereas bonding character and surface composition were assessed using Raman and X-ray photoelectron spectroscopy. Wettability and surface charge were investigated via water contact angle and zeta potential measurements. Antifungal assessment was performed using a Candida albicans multi-well plate screening technique and crystal violet biomass quantification. The results demonstrate that oxygen plasma–treated Si-DLC exhibited hydrophilic properties, lower negative zeta potential, and significant antifungal behavior. This material can potentially be applied on surfaces for the prevention of reduced nosocomial infections.     

Atomistic aspects of ductile responses of cubic silicon carbide during nanometric cutting

Cubic silicon carbide (SiC) is an extremely hard and brittle material having unique blend of material properties which makes it suitable candidate for microelectromechanical systems and nanoelectromechanical systems applications. Although, SiC can be machined in ductile regime at nanoscale through single-point diamond turning process, the root cause of the ductile response of SiC has not been understood yet which impedes significant exploitation of this ceramic material. In this paper, molecular dynamics simulation has been carried out to investigate the atomistic aspects of ductile response of SiC during nanometric cutting process. Simulation results show that cubic SiC undergoes sp³-sp² order-disorder transition resulting in the formation of SiC-graphene-like substance with a growth rate dependent on the cutting conditions. The disorder transition of SiC causes the ductile response during its nanometric cutting operations. It was further found out that the continuous abrasive action between the diamond tool and SiC causes simultaneous sp³-sp² order-disorder transition of diamond tool which results in graphitization of diamond and consequent tool wear.     

Phase transformation of diamond-like carbon/silver composite films by sputtering deposition

This study fabricated hydrogenated diamond-like carbon/silver bioceramic films on glass substrates using radio frequency magnetron sputtering with a single silver target in an atmosphere of Ar/CH4 mixture. The effects of applied power on the composition and microstructure of bioceramic film were evaluated. A phase transformation, amorphous diamond-like carbon → nano-silver precipitation → nano-silver growth in the amorphous diamond-like carbon matrix was observed during sputtering. The film growth rate, surface roughness, silver content and size of silver nanoclusters in the films all increased with the silver target power due to the higher flux of sputtered silver species toward the substrate.     

Effect of oxygen and fluorine plasma surface treatment of silicon-incorporated diamond-like carbon coatings on cellular responses of mouse fibroblasts

The surface chemistry of silicon-incorporated diamond-like carbon (Si-DLC) was tailored utilizing oxygen and fluorine plasma treatments. Successful anchoring of oxygen and fluorine functional groups to the surface of Si-DLC was verified using X-ray photoelectron spectroscopy. The impact of surface modification of Si-DLC on hydrophobicity was correlated with the viability of L929 mouse fibroblasts. The confocal microscopy and viability results indicated that oxygen-treated Si-DLC showed increased cell viability compared to untreated Si-DLC and fluorine-treated Si-DLC samples 5 days after seeding. The increased cell viability was correlated with the conversion of the hydrophobic surface of Si-DLC into a hydrophilic surface by oxygen plasma treatment.     

Characterization of diamond-like carbon films before and after heavy energetic ion implantations

Hydrogenated diamond-like carbon films were implanted by 110 keV Fe⁺ at doses ranging from 1 × 10¹³ to 5 × 10¹⁶ ions cm⁻². The film resistivities and the infra-red transmittances of the specimens were determined as functions of the implanted doses. Raman spectra and the infra-red transmittances of the film layers were used to characterize the structural changes of the implanted films. It was found that, when the implantation dose was higher than about 5 × 10¹⁴ or 1 × 10¹⁵ ions cm⁻², the film resistivity and the total infra-red transmittance of the specimens decreased significantly. However, when the dose was smaller than this value, the resistivity decreased firstly and then increased with dose and the measured values were higher than those of corresponding as-grown ones. The infra-red transmittance of the specimens was also improved to some extent under the lower dose range. By using structural characterization results, especially the infra-red transmittances of the film layers, we conclude that the electrical and optical property changes at doses higher than about 5 × 10¹⁴ or 1 × 10¹⁵ ions cm⁻² were due to the following changes, i.e., the decrease in the population of both sp² C-H and sp³ C-H bonds (compared with that of sp³ C-H bonds, the decrease in speed of sp² C-H bonds is smaller), the decrease of bond-angle disorder and the increased population of sp² C-C bonds. However, at doses between 1 × 10¹⁴ and 5 × 10¹⁴ or 1 × 10¹⁵ ions cm⁻², the implantation induced increase of C-H bonds was responsible for the observed property changes. Compared with the previous reports, the novelty of the present work is: the IR transmittance curves of the single film layers give us direct evidence for the changes of different C-H bonds with increasing ion dose and thus proved the transformation mechanism proposed previously.     

Effect of N doping on properties of diamond-like carbon thin films produced by RF capacitively coupled chemical vapor deposition from different precursors

In this paper, we report results concerning properties of diamond-like carbon (DLC) thin films obtained in different experimental conditions: various RF power values and different precursors (methane, acetone and toluene or in combination with nitrogen). The deposition rate of DLC thin films obtained from precursors with low ionizing energy and high number of carbon atoms in molecule as acetone and toluene was higher (142 nm/min for acetone and 607 nm/min for toluene as compared with 79 nm/min for methane at 400 W input power). The highest value of hardness was obtained from methane (18 GPa). In the case of acetone and toluene precursors, the hardness increased with input power to the highest values of 16.8 and 14.8 GPa. By utilizing nitrogen as doping element, the resistivity of DLC thin films obtained from methane and acetone decreased from values higher than 10⁷ Ω cm to lower values of 12.5×10³ Ω cm for 3.79% nitrogen atomic concentration in the case of films obtained from methane and 40×10³ Ω cm for 4.26% nitrogen atomic concentration in the case of films obtained from acetone.     

Structural investigation and gas barrier performance of diamond-like carbon based films on polymer substrates

In this report, tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon (a-C:H), silicon doped tetrahedral amorphous carbon (ta-C:Si:H), and silicon doped hydrogenated amorphous carbon (a-C:H:Si) films with thickness in the range 50-370 nm have been produced by PECVD (Plasma Enhanced Chemical Vapour Deposition) and FCVA ( Filtered Cathodic Vacuum Arc) techniques on Polyethylene terepthalate (PET) and polycarbonate (PC) substrates. The paper is concerned with exploring the links between the atomic structure, gas barrier performance in carbon based films deposited on polymer substrates. A range of techniques including XRR, NEXAFS, Raman, surface profilometry, nano-indentation and water vapour permeation analysis were used to analyze the microstructure and properties of the films. The intensity and area of π* peak at the C K (carbon) edge of the NEXAFS spectra was lower in the FCVA films in comparison to that of PECVD ones confirming the higher sp³ content of FCVA films. The surface of ta-C films showed a network of micro-cracks, which is detrimental for gas barrier application. However, the surfaces of both ta-C:H:Si and a-C:H:Si silicon-incorporated films were almost free of cracks. We also found that the incorporation of Si into both types of DLC films lead to a significant reduction of water vapour transmission rate.     

Structural study of β‐SiC(001) films on Si(001) by laser chemical vapor deposition

β‐SiC thin films have been epitaxially grown on Si(001) substrates by laser chemical vapor deposition. The epitaxial relationship was β‐SiC(001){111}//Si(001){111}, and multiple twins {111} planes were identified. The maximum deposition rate was 23.6 μm/h, which is 5‐200 times higher than that of conventional chemical vapor deposition methods. The density of twins increased with increasing β‐SiC thickness. The cross section of the films exhibited a columnar structure, containing twins at {111} planes that were tilted 15.8° to the surface of substrate. The growth mechanism of the films was discussed.