类金刚石碳膜的结构特性与耐磨性能

采用双离子束增强沉积（IBED）和离子束直接沉积（IBD）技术，在CHn 能量为200~550eV和3～25keV范围内沉积的类金刚石薄膜具有光滑平坦的表面和非晶结构。X光电子谱和Raman光谱分析、以及显微硬度测量的结果表明，随着轰击离子能量的降低，薄膜的金刚石特性增强；在200～550eV能量范围内制备的DLC膜具有明显的sp3键特征和很高的显微硬度。沉积在GCr15钢上的DLC膜与GCr15钢的摩擦学对比实验表明，DLC膜具有很低的摩擦系数、比磨损率和高的抗磨损指数，这证明采用上述两种方法制备的DLC膜具有优良的抗摩擦磨损性能。     

Characterization of ion-beam-deposited diamond-like carbon films

Diamond-like carbon (DLC) films are excellent prospects for a wide range of high-technology applications but their precise structure and properties are not well understood. The purpose of the present work was to use several complementary techniques to characterize the nature, structure and microstructure of DLC films. Thin DLC films were deposited on various substrates in the presence of a Si interlayer (500 Å thick) using CH₄ ion-beam deposition at an acceleration energy of 750 eV and a current density of about 2.5 mA cm⁻². The Si interlayer was deposited by either e-beam evaporation or Si evaporation enhanced by Ar⁺ beam bombardment (1 keV). The produced DLC films were featureless, very smooth and of high hardness (2900–3300 kg mm⁻²). Auger electron spectroscopy and electron diffraction showed that the films were mainly amorphous. Their microstracture was characterized by a three-dimensional network structure with a medium-range order of about 25 nm. Fourier transform infrared and Raman spectroscopies showed that the films were mainly composed of sp³ and sp² carbon-bonded hydrogen. The sp³/sp² ratio varied from 3.2 to 4.1 and was found to depend on the nature of the Si bond layer. The results showed that the nucleation of the diamondlike structure was promoted on the Si interlayer that was deposited under Ar⁺ beam bombardment. This effect can be explained by the higher surface roughness produced in this interlayer as suggested by the reflectivity measurements. Spectroscopic ellipsometry revealed that the films had an optical band gap between 1.56–1.64 eV. The present results are consistent with previous proposals suggesting that the DLC structure is composed of small graphitelike clusters (involving fused six-fold rings) that are interconnected by sp³-bonded carbon.     

Preparation of diamond-like carbon films by cathodic micro-arc discharge in aqueous solutions

Diamond-like carbon films (DLC) and silicon doped diamond-like carbon films were deposited on Ni substrate by cathodic micro-arc discharge at room temperature in aqueous solutions. The deposit potential was 130 V. The structure of the films was characterized by a scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Raman spectra and XPS analysis demonstrated that the films were diamond-like carbon clearly. SEM observation showed that the DLC films were uniform and the thickness was about 200 nm. Potentiodynamic polarization curve indicated the corrosion resistance of the Ni substrate was markedly improved by DLC films.     

CVD of hard DLC films in a radio frequency inductively coupled plasma source

Chemical vapor deposition (CVD) of hard diamond-like carbon (DLC) films on silicon (100) substrates from methane was successfully carried out using a radio frequency (r.f.) inductively coupled plasma source (ICPS). Different deposition parameters such as bias voltage, r.f. power, gas flow and pressure were involved. The structures of the films were characterized by Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The hardness of the DLC films was measured by a Knoop microhardness tester. The surface morphology of the films was characterized by atomic force microscope (AFM) and the surface roughness (R_a) was derived from the AFM data. The films are smooth with roughness less than 1.007 nm. Raman spectra shows that the films have typical diamond-like characteristics with a D line peak at 1331 cm⁻¹ and a G line peak at 1544 cm⁻¹, and the low intensity ratio of I_D/I_G indicate that the DLC films have a high ratio of sp³ to sp² bonding, which is also in accordance with the results of FTIR spectra. The films hardness can reach approximately 42 GPa at a comparatively low substrate bias voltage, which is much greater than that of DLC films deposited in a conventional r.f. capacitively coupled parallel-plate system. It is suggested that the high plasma density and the suitable deposition environment (such as the amount and ratio of hydrocarbon radicals to atomic or ionic hydrogen) obtained in the ICPS are important for depositing hard and high quality DLC films.     

Multiple Charged Nitrogen Ion Beam Irradiation of Fullerene Thin Films

In this work, the results of structural modification of fullerene thin films bombarded by multiple charged nitrogen ions have been reported. The properties of as-deposited and irraditated fullerene thin films have been investigated by Raman and FTIR spectroscopy and AFM analysis. After irradiation by multiple charged nitrogen ions (N²⁺, N⁵⁺) new bondings in fullerene films have been formed and the amorphicity has been enhanced at higher doses. Raman and FTIR spectra showed structural changes of deposited films depending on the energy and implantation dose. AFM analysis showed that the ion beam had destroyed the surface ordering. At lower doses the surface order has been characterized by carbon clusters of 500 nm. At higher doses significantly smaller clusters have been formed (200 nm).     

端部霍尔等离子体源沉积类金刚石膜的研究

本文通过对端部霍尔离子源特性的研究 ,采用自行研制的用于离子束辅助沉积的端部霍尔离子源成功镀制了类金刚石膜 ,并对采用该离子源制备类金刚石膜的工艺进行了研究和分析。实验结果表明 ,采用端部霍尔离子源镀制类金刚石膜不仅操作简单、可实现大面积沉积 ,而且类金刚石膜的沉积速率较大 ,最大可达 0 .8nm s,其折射率依不同工艺在 1.8～ 2 .2之间可调。并对不同工艺条件下制备的类金刚石膜的硬度进行了测试和分析。     

氮掺杂碳纤维包覆石墨烯纳米片的构建及电容特性

以石墨烯纳米片为骨架,聚吡咯为碳源,设计构建氮掺杂碳纤维包覆石墨烯纳米片（NFGNs）复合材料。采用SEM,XRD,Raman,FTIR,XPS和BET对材料进行表征,结果表明：相互连通的氮掺杂碳纳米纤维均匀地包覆生长在石墨烯纳米片层表面;NFGNs-800复合材料的氮原子分数为11.53%,比表面积为477.65 m²·g^-1。电容特性测试结果表明：NFGNs-800电极材料的比电容为323.3 F·g^-1（1.0 A·g^-1）,且具有良好的倍率特性;NFGNs-800超级电容器在功率密度为10500 W·kg^-1时,能量密度为87.1 Wh·kg^-1;经过10000次恒流充放电循环后,比电容保持率95.9%,库仑效率保持在99%以上。     

Structural characteristics of phosphorus-doped C60 thin film prepared by radio frequency-plasma assisted thermal evaporation technique

Phosphorus doped C60 (P:C60) thin films were prepared by a radio frequency plasma assisted thermal evaporation technique using C60 powder as a carbon source and a mixture of argon and phosphine (PH3) gas as a dopant precursor. The effects of the plasma power on the structural characteristics of the as-prepared films were then studied using Raman spectroscopy, Auger electron spectroscopy (AES) and X-ray photo-electrons spectroscopy (XPS). XPS and Auger analysis indicated that the films were mainly composed of C and P and that the concentration of P was proportional to the plasma power. The Raman results implied that the doped films contained a more disordered carbon structure than the un-doped samples. The P:C60 films were then used as a coating layer for the Si anodes of lithium ion secondary batteries. The cyclic voltammetry (CV) analysis of the P:C60 coated Si electrodes demonstrated that the P:C60 coating layer might be used to improve the transport of Li-ions at the electrode/electrolyte interface.     

霍尔离子源制备类金刚石薄膜研究

采用霍尔离子源沉积类金刚石薄膜是近年来新出现的一种方法 ,本文研究了自行研制的霍尔离子源的性能以及采用此离子源制备类金刚石薄膜及工艺参数的影响。结果表明 ,霍尔离子源在较低的电压即可起辉 ,可提供稳定的能量较低的离子束流。采用霍尔离子源沉积类金刚石薄膜的沉积速率约为 0 5nm/s。随着霍尔离子源灯丝电流的升高 ,离子源放电电压下降 ,制备的类金刚石薄膜的硬度下降。放电电流的变化对类金刚石薄膜的硬度影响不大。     

沉积时间对聚醚醚酮表面类金刚石薄膜的结构和性能的影响

采用直流磁控溅射技术在聚醚醚酮(PEEK)表面制备不同厚度的类金刚石(DLC)薄膜,研究了沉积时间对其表/界面结构、组分、疏水、力学和光透过性能的影响。结果表明,在平均沉积速率为5.71 nm/min的条件下,随着沉积时间的延长DLC薄膜的厚度线性增大、碳原子的致密性提高、界面互锁结构增强,而界面结合强度逐渐降低。沉积时间≤15 min时,基体结构的影响使拟合计算出的I_D/I_G值为0.23~0.25和sp²/sp³比值较小(0.58~0.74);沉积时间>15 min时基体的影响较小,I_D/I_G值突增大至0.81,sp²/sp³值也比较大(0.96~1.12)。沉积时间的延长使PEEK基体的温度逐渐升高,使膜内的sp²/sp³值逐渐增大。薄膜表面的氧含量先降低然后趋于平缓,部分C=O转化为C-O。随着沉积时间的延长,PEEK/DLC复合薄膜的硬度、弹性模量及防紫外线和阻隔红外线性能都逐渐提高,其表面粗糙度和疏水性的变化趋势是先提高后降低。沉积时间为32 min的薄膜,其表面粗糙度和水接触角达到最大值,分别为495 nm和108.29°。     

Investigation of the microstructure, mechanical properties and tribological behaviors of Ti-containing diamond-like carbon films fabricated by a hybrid ion beam method

Diamond-like carbon (DLC) films with various titanium contents were investigated using a hybrid ion beam system comprising an anode-layer linear ion beam source and a DC magnetron sputtering unit. The film composition and microstructure were characterized carefully by X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy, revealing that the doped Ti atoms had high solubility in the DLC films. The maximum solubility was found to lie between about 7 and 13 at.%. When the Ti content was lower than this solubility, the doped Ti atoms dissolved in the DLC matrix and the films exhibited the typical features of the amorphous DLC structure and displayed low compressive stresses, friction coefficients and wear rates. However, as the doped content exceeded the solubility, Ti atoms bonded with C atoms, resulting in the formation of carbide nano-particles embedded in the DLC matrix. Although the emergence of the carbide nano-particles promoted graphitizing due to a catalysis effect, the film hardness was enhanced to a great extent. On the other hand, the hard carbides particles caused abrasive wear behavior, inducing a high friction coefficient and wear rate.     

Thermal stability of Cr-doped diamond-like carbon films synthesized by cathodic arc evaporation

Cr-doped diamond-like carbon (DLC) films were synthesized using a cathodic arc evaporation (CAE) process. The thermal oxidation behavior of Cr-doped DLC films was investigated using thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The phase identification and microstructural examinations were conducted by X-ray diffraction, scanning electron spectroscopy (SEM), transmission electron spectroscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) in order to understand the characteristics of Cr-doped DLC films. The as-deposited Cr-doped DLC film exhibits a lamellar structure observed by TEM. A significant weight loss of film results from the thermal oxidation of carbon occurred at 290 to 342 °C. At the temperature higher than 342 °C, slight weight gain of specimen was observed due to the thermal oxidation of the underlying CrC_xN_y and CrN interlayer. By heat-treated specimens from 200 to 400 °C, Raman spectra reveal the increase of I_D/I_G value conforming to the graphitiation process of the Cr-doped DLC films. Finally, surface reactions of the annealed films using XPS analysis were discussed.     

Diamond-like Carbon Film from Camphor Soot

Diamond-like carbon film (DLC) has been deposited from the soot of camphor, a natural source, by a simple vacuum deposition technique, for the first time. This method of deposition is simple, convenient and much faster than the conventional gas cracking technique usually adopted for the DLC film deposition. DLC thin film is characterized by Raman, FTIR, solid state ¹³C NMR, ESR and SEM. Preliminary results (XRD and SEM analyses) suggest that the polycrystalline diamond film may also be obtained from this source. The prime novelty of this work is that from the same source, we have been able to synthesize both DLC film as well as polycrystalline diamond film by a simple vacuum deposition technique without using any external gas like the conventional chemical vapour deposition (CVD) methods.     

Effects of molybdenum dithiocarbamate and zinc dialkyl dithiophosphate additives on tribological behaviors of hydrogenated diamond-like carbon coatings

The tribological behaviors of hydrogenated diamond-like carbon (DLC) coatings under varied load conditions lubricated with polyalpha olefin (PAO), molybdenum dithiocarbamate (MoDTC) and zinc dialkyl dithiophosphate (ZDDP) additives were investigated in this paper. Hydrogenated DLC coatings were synthesized through the decomposition of acetylene by the ion source. The tribological performances were measured on a SRV tribometer. The morphologies and chemical structures of the DLC coatings were investigated by the scanning electron microscope (SEM), Raman spectrometer (Raman) and X-ray photoelectron spectroscope (XPS). It was shown that the low friction and high wear were achieved on the hydrogenated DLC coating under MoDTC lubrication, while low wear was found on the hydrogenated DLC coating lubricated by ZDDP. The primary reason was attributed to different tribofilms formed on the contact area and the formation of graphitic layer. Both factors working together leaded to quite different tribological behaviors.     

Characteristics and mechanical properties of titanium-containing diamond like carbon films deposited by cathodic arc evaporation

Depositions of titanium-containing diamond-like carbon (Ti-DLC) films were conducted by mixing C+ and Ti+ plasma streams originated from cathodic arc plasma sources in argon (Ar). The deposition was processed at Ti target current ranging from 20 Amp to 70 Amp. Film characteristics were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS). Film microstructures were evaluated using field emission scanning electron microscopy (FEGSEM), an atomic force microscope (AFM), X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HRTEM). Mechanical properties were investigated by using a nanoindentation tester and ball on disc wear test. Results shows that surface roughness (Ra) of the films ranged between 2.4 and 7.2 nm and roughness increased relative to the increase in Ti target current. The FESEM studies showed that the surface micrographs of Ti-DLC films revealed a cauliflower-like microstructure and the cross-sectional micrograph revealed a snake-skin like structure. HRTEM studies showed that the Ti-DLC films consisted of nano scale TiC particles which were comparable with low angle XRD and XPS results. XPS analysis established that the Ti2p spectrum is present when the Ti target current reaches 30 Amp or higher. Ti concentration increased as the Ti target current was increased. An extremely thin TiO2 layer exists on the top of the Ti-DLC films which was comparable with the AES results. The film thickness which could be deposited for Ti-DLC is much higher than that of conventional DLC films. Nanoindentation tests show that the nanohardness of the films ranging 15-22 GPa, with Er values ranging from 145 to 175 GPa. The wear test demonstrates the friction coefficient of the 420SS substrate, DLC and Ti-DLC films were about 0.8, 0.3 and 0.2, respectively. Obviously, the friction coefficients of the Ti-DLC films were lower than that of the DLC films.     

Structure and Mechanical Performance of Nitrogen Doped Diamond-like Carbon Films

Nitrogen doped diamond-like carbon （DLC：N） films were prepared by electron cyclotron resonance chemical vapor deposition （ECR-CVD） on polycrystalline Si chips. Film thickness is about 50 nm. Auger electron spectroscopy （AES） was used to evaluate nitrogen content, and increasing N2 flow improved N content from 0 to 7.6%. Raman and X-ray photoelectron spectroscopy （XPS） analysis results reveal CN-sp^3C and N-sp^2C structure. With increasing the N2 flow, sp^3C decreases from 73.74% down to 42.66%, and so does N-sp^3C from 68.04% down to 20.23%. The hardness decreases from 29.18 GPa down to 19.74 GPa, and the Young＇s modulus from 193.03 GPa down to 144.52 GPa.     

Chemical bond analysis of amorphous carbon films

Hydrogen-free carbon films with the various sp³ bond fractions between 83% and 40% were prepared by mass-separated ion beam deposition (MSIBD). These sp³ bond fractions were obtained by electron energy loss spectroscopy (EELS). Chemical bond analysis of these carbon films was performed by x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and Raman spectroscopy, and the comparison of these methods was examined. XPS C1s spectra of carbon films show two contributions at the energies of 284.5 and 285.5 eV, which are originated from sp²-bonds and sp³ bonds, respectively. The sp³ bond fractions obtained by XPS are in good agreement with the values given by EELS. The fine structure of AES spectra at the kinetic energy region between 245 and 265 eV reflects the sp³ bond fraction. AES spectra are changed from the diamond-like feature to the graphite-like one with decreasing the sp³ bond fraction. Raman spectra show two broad peaks of G band and D band, the ratio of two peak intensities is independent on the sp³ bond fraction of films. The shift of G peak position has a correlation with the sp³ bond fraction in the sp³ bond rich region.     

Surface characterization and nanomechanical properties of diamond-like carbon films synthesized by RF plasma enhanced chemical vapor deposition

Diamond-like carbon (DLC) films were synthesized by RF plasma enhanced chemical vapor deposition using acetylene as the carbon source and the effects of acetylene/nitrogen ratio in the reaction atmosphere, deposition pressure, and plasma post-treatment using different atmospheres on the surface roughness and mechanical properties of DLC films were investigated. Although the surface roughness, characterized by AFM, decreased as the acetylene/nitrogen ratio in the reaction atmosphere decreased, the hardness of DLC films measured by nanoindentation also decreased with the decrease of the acetylene/nitrogen ratio, which is consistent with the Raman results of the I_D/I_G ratio. Rougher films with higher residual stress were obtained when using a deposition pressure higher than 40.0 Pa (0.3 torr). For the effect of plasma post-treatment using different atmospheres, surface smoothing was found for the hydrogen plasma post-treatment, whereas nitrogen and argon plasma post-treatments resulted in surface roughening. Hydrogen plasma post-treatment was found to lower the surface roughness without significantly sacrificing the hardness.     

9Cr18轴承钢表面不同等离子体浸没离子注入强化处理技术研究

采用不同的等离子体浸没离子注入(PⅢ)工艺在9Cr18轴承钢表面进行了气体、金属、金属加气体的离子注入和碳化钛(TiC)、类金刚石(DLC)薄膜的等离子体浸没离子注入与沉积(PⅢD).对处理后的试样进行了X射线光电子能谱(XPS)、X射线衍射(XRD)、俄歇电子能谱(AES)和拉曼光谱(Raman)分析;测试了处理前后试样的显微硬度、磨痕宽度和摩擦系数.结果表明:处理后试样表面均形成了不同的改性层,且改性层中化学组成和各元素的浓度-深度分布随处理工艺的不同而变化;处理后试样的显微硬度都有较大提高,最大增幅达77.7%;表面摩擦系数由0.8下降到0.16;磨痕宽度减少了23倍;与PⅢ工艺相比,相同参数下,PⅢD处理后的试样表面综合性能更加优异.     

Growth and properties of the ion beam deposited SiOx containing DLC films

In the present study SiO_x containing diamond-like carbon (DLC) films were synthesized by the closed drift ion source from hexamethyldisiloxane vapor. Kinetics of the growth of DLC films was investigated using optical emission spectroscopy (OES). Structure, chemical composition, electrical and optical properties of the synthesized films were studied. The effects of ion beam energy were investigated. The main atomic hydrogen Balmer series lines and the intense broad CH group related peak were detected in the OES spectra registered in-situ during SiO_x containing diamond-like carbon film synthesis. The intensity ratio of H-β/CH peaks increased with the increase of applied ion beam energy. It was explained by activation of the dissociation of the hexamethyldisiloxane molecules. Changes of the structure of the diamond-like carbon films were observed for the films deposited under intense dissociation conditions.