共查询到20条相似文献,搜索用时 15 毫秒
1.
L.K. Randeniya A. Bendavid P.J. Martin M.S. Amin R. Rohanizadeh F. Tang J.M. Cairney 《Diamond and Related Materials》2010,19(4):329-335
Thin films of a novel, nanocomposite material consisting of diamond-like carbon and polycrystalline/amorphous TiOx (DLC-TiOx, x ≤ 2) were prepared using pulsed direct-current plasma enhanced chemical vapour deposition (PECVD). Results from Raman spectroscopy indicate that the DLC and TiOx deposit primarily as segregated phases. Amorphous TiO2 is found to be present on the surface region of the film and there is evidence for the presence of crystalline TiO in the bulk of the film. The hydrophilicity of the DLC-TiOx films increased with increasing titanium content. Culture studies with human osteoblasts revealed that the differences in three-day cell adhesion properties (count, morphology and area) between DLC and DLC-TiOx films containing up to 13 at.% Ti were not statistically significant. However, the cell count was significantly greater for the films containing 3 at.% of Ti in comparison to those containing 13 at.% of Ti. A post-plasma treatment with Ar/O2 was used to reduce the water contact angle, θ, by nearly 40° on the DLC-TiOx films containing 3 at.% of Ti. A cell culture study found that the osteoblast count and morphology after three days on these more hydrophilic films did not differ significantly from those of the original DLC-TiOx films. We compare these results with those for SiOx-incorporated DLC films and evaluate the long-term osteoblast-like cell viability and proliferation on modified DLC surfaces with water contact angles ranging from 22° to 95°. 相似文献
2.
Gold oxide nanoparticles were incorporated into diamond-like carbon (DLC) films in order to improve protection of AISI-1020 from electrochemical corrosion. The AuOx:DLC films were prepared by plasma enhanced chemical vapor deposition and were subsequently characterized by scanning electron microscopy, Raman spectroscopy and electrochemistry measurements. The electrochemical corrosion performance of the AuOx:DLC coating was contrasted to AISI-1020 and DLC without AuOx coating. The electrochemical techniques that were utilized for this investigation were potentiodynamic and electrochemistry impedance spectroscopy. The electrochemical analysis indicated that AuOx:DLC films presented superior corrosion resistance as compared to DLC. This resulted in 99.8% and 96.8% protection efficiency respectively, when compared to AuOx:DLC and DLC coatings. 相似文献
3.
This paper reports the pump and probe experiment for in situ reflectivity measurements in the femtosecond laser ablation that brings about nanoscale modification of diamond-like carbon (DLC) film. The characteristic reflectivity changes observed demonstrate that the formation of periodic nanostructure is preceded by a change in bonding structure of DLC in the ablation at low fluences. We have observed a coherent nonlinear wave-mixing signal that can resolve the ultrafast interaction processes for the nanoscale modification on the film surface. Based on the results obtained, a model of the interaction process is proposed. 相似文献
4.
Two metal dopants were simultaneously added into a diamond-like carbon (DLC) matrix using a KrF pulsed laser system at room temperature with no post-processing. The nanometer thin films were fabricated from carbon source targets containing the two metals of interest, Ti and Ni, in atomic percentages 2.5%, 5%, 7.5% and 10% each. Films from carbon targets containing only 5% Ni or 5% Ti were also deposited for comparison against the dual-metal containing films. Microstructure analysis shows that each individual metal reacted independently and uniquely with carbon as confirmed by XPS and surface analysis shows the presence of TiC bonds and Ni0. Therefore, there was no reaction between Ti and Ni as metals confirmed by XPS. Through this independent interaction, a superposition of microstructural properties was obtained as if the metals were doped separately into DLC. The separate interactions of the two metals with carbon were important as they were able to play separate and different roles in enhancing the properties of DLC. In addition, TEM analysis confirmed a unique self-assembly state where the nickel ions converge into nanosized clusters of ~ 5 nm in diameter and predominantly oriented in a (200) direction. The resultant films were also extremely smooth with RMS roughness of about 0.1 nm, thus retaining the inherent smoothness of DLC films. The combined Ti/Ni films could be used as substrates to grow carbon nanotubes with controlled density which could be used as cold electron emitters. Thus, it is interesting to study the growth mechanism and microstructure of the composite films. 相似文献
5.
Y.T. Pei X.L. BuiJ.P. van der Pal D. Martinez-MartinezJ.Th.M. De Hosson 《Progress in Organic Coatings》2013
Dynamic rubber seals are major sources of friction of lubrication systems and bearings, which may take up to 70% of the total friction. The solution we present is to coat rubbers with diamond-like carbon (DLC) thin films by which the coefficient of friction is reduced to less than one tenth. Coating rubber is very challenging because the film must be flexible and strongly adhered to the surface of rubber substrate. Our novel approach is depositing flexible DLC films on rubbers via self-segmentation. By making use of the substantial thermal mismatch between DLC film and rubber substrates a dense crack network forms in DLC films and contributes to flexibility. The size of film micro-segments can be tuned by varying the bias voltage of pulsed-DC plasma CVD, which governs the amplitude of the substrate temperature variation during deposition. The formation mechanism of crack network and its effect on the flexibility and friction of DLC film coated rubbers are scrutinized. This paper provides generic design rules for the deposition of flexible and ultra-low friction DLC films on rubber seals. 相似文献
6.
《Diamond and Related Materials》2007,16(8):1682-1687
In this paper the surface properties of silicon-doped diamond-like carbon films with various Si contents on 316 stainless steel substrate by a magnetron sputtering technique were investigated. X-ray photoelectron spectroscopy was applied to determine the surface chemical composition of the films. Atomic force microscopy was used for the determination of surface roughness and topography. The sp2 contents in the films were determined with Auger electron spectroscopy, which were 67.1%, 34.2% and 25.0% for silicon contents 1%, 2% and 3.8%. The sp3/sp2 ratio increases with increasing the silicon contents in the films. Contact angles of three test liquids on the films were obtained with a Dataphysics OCA-20 contact angle analyzer. Surface free energies of the films and their dispersive and polar components were calculated using van Oss acid–base approach. Staphylococcus aureus was used for bacterial adhesion test. The experimental results showed that bacterial adhesion decreased with increasing the silicon content or with increasing sp3/sp2 ratio in the films. 相似文献
7.
Single wall carbon nanohorns (SWCNHs) were coated with anatase titanium oxide thin films by metal-organic chemical vapour deposition with titanium tetraisopropoxide Ti(OiPr)4 as the precursor. The pristine SWCNHs and the new hybrid material SWCNHs/TiO2 were characterized by transmission electron microscopy, Raman spectroscopy, X-ray diffraction, thermogravimetric thermal analysis and inductively coupled plasma-mass spectrometry, showing that the deposition process does not alter the typical structures of the SWCNHs. Finally, it is shown how the hydrophilic properties of the titanium oxide coating allowed a stable dispersion of SWCNHs/TiO2 in water, opening new perspectives for water based nanofluids, biological sensing or drug delivery systems. 相似文献
8.
《Ceramics International》2022,48(11):15862-15867
Sol-gel method was employed for the preparation of strontium-doped mesoporous bioactive glass nanoparticles (Sr-MBG NPs). These NPs have the size of 50 ± 5 nm, a pore size of 8.2 nm, and a surface area of 379 m2/g. Biocompatibility was confirmed by MTT and tissue histopathology in Balb/c mice. 5-Fluorouracil (5-Fu) was loaded to obtain Fu-Sr-MBG NPs which posed substantial inhibitory effects on the viability of the cancer cells (AGS). The amount of released drug was controlled by changing the pH of release medium. Formation of hydroxycarbonate apatite (HCA) was evaluated in simulated body fluid (SBF) and confirmed by XRD and FTIR. Thus a multipurpose nano-biomaterial was prepared and screened. 相似文献
9.
《Ceramics International》2016,42(14):15502-15510
In this paper, coatings of hydroxyapatite partially substituted with zinc (ZnHA) were produced on titanium substrates by a two-step hydrothermal process using a precursor solution rich in calcium, phosphate and zinc. Activation of titanium surfaces was performed by oxidation with an acidic HF/HNO3 solution. The coated substrates were then converted into HA by immersion in an alkali 0.1 M NaOH solution. The ZnHA samples were characterized by several techniques and their in vitro behavior was studied in comparison to hydroxyapatite (HA) and titanium (Ti-control) samples. A uniform and homogeneous calcium-deficient carbonate apatite coating was obtained for all samples, both doped and undoped with zinc. The percentage of zinc incorporated in the coatings is 7 at%, and the Ca/P ratio is 1.61(±0.01) for both types of samples, suggesting that Zn is incorporated substitutionally, replacing Ca atoms into the HA structure. The incorporation of Zn in the HA structure changed the crystals morphology, reduced crystals sizes and decreased the deposition rate showing that zinc is an inhibitor of the growth of HA crystal. X-ray diffraction showed that HA is the single crystalline phase present after alkali treatment. The coating adhesion strength was evaluated in terms of the critical load (Lc) obtained from scratch tests and no significant difference was found between the two tested groups, indicating the good adhesion of ZnHA to Ti substrates. The in vitro response of human osteoblasts (HOB) exposed to the surfaces of HA and ZnHA coatings was evaluated. The results of Live/Dead tests showed cell viability for all samples surfaces, but the adhesion and proliferation tests showed that ZnHA samples presented better adhered and spread cells compared with HA. ZnHA coatings presented cells with elongated or polygonal shapes and clearly more spread than HA. Quantitative analysis showed that there was a significantly higher number of cells adhered to ZnHA coatings compared to HA, indicating the zinc incorporation stimulates osteoblast proliferation. 相似文献
10.
V. Barranco F. Pico J. Ibaez M.A. Lillo-Rodenas A. Linares-Solano M. Kimura A. Oya R.M. Rojas J.M. Amarilla J.M. Rojo 《Electrochimica acta》2009,54(28):7452-7457
Composites consisting of ruthenium oxide particles deposited on amorphous carbon nanofibres are prepared by a repetitive impregnation procedure. The choice of amorphous carbon nanofibres as support of amorphous ruthenium oxide leads to composites in which the deposited oxide consists of aggregates of extremely small primary particles (1–1.5 nm-size) and showing high porosity (specific surface area of 450 m2 g−1). This special deposition of the oxide seems to favour: (i) high oxide capacitance (1000 Fg−1) at high oxide loadings (up to 20 wt%) and (ii) high capacitance retention (ca. 80% from the initial oxide capacitance) at high current densities (200 mA cm−2). Amorphous carbon nanofibres are suitable supports for amorphous ruthenium oxide and perhaps for other amorphous oxides acting as active electrode materials. 相似文献
11.
12.
《Carbon》2015
Electrochemically active diamond-like carbon (DLC) electrodes featuring high specific surface area have been prepared by plasma-enhanced chemical vapour deposition (CVD) onto densely packed forests of vertically aligned multiwall carbon nanotubes (VACNTs). The DLC:VACNT composite film exhibits a complex topography with web like features and ridges generated by partial coalescence of the DLC over the CNT arrays. DLC:VACNT electrodes exhibit low background responses over a large potential window, low uncompensated resistance, as well as low charge-transfer impedance in the presence of ferrocyanide as a redox probe. The interfacial capacitance associated with the DLC:VACNT electrode is in the range of 0.6 mF cm−2, a value two orders of magnitude larger than in conventional flat carbon electrodes. DLC films grown onto single-crystal Si(1 0 0) under identical conditions resulted in essentially insulating layers. Conducting-atomic force microscopy studies reveal that the film electro-activity does not arise from specific topographic features in the highly corrugated film. The ensemble of experimental results suggests that the enhanced electrochemical responses are not connected to areas in which the CNT support is exposed to the electrolyte solution. This is remarkable behaviour considering that no dopants have been included during the DLC film growth. 相似文献
13.
M. Rubio-Roy C. Corbella E. Bertran S. Portal M.C. Polo E. Pascual J.L. Andújar 《Diamond and Related Materials》2009,18(5-8):923-926
The effects of environmental conditions and fluorine content on friction of diamond-like carbon (DLC) films are determined and discussed. Relative humidity (RH) has a considerable effect on friction values, modifying them up to a factor 2. Two regions of RH are found, depending on its effect over friction. From 20% to 60% of RH, friction decreases probably due to a better substitution of superficial atoms by hydrogen. From 60% to 80% friction remains stable and equal for almost all samples. A possible explanation would be the formation of a physisorbed layer of water on the surface, which would mask the relatively small chemical and structural variations of the films. Moreover, the different components of surface free energy (SFE) are determined using Van Oss–Chaudury–Good model. The results clearly indicate the importance of Lifshitz–Van der Waals component on SFE and the small correction that supposes acid-base interactions. According to this model, the studied DLC is a monopolar basic material. The basic component is reduced when F content is increased. 相似文献
14.
Veli-Matti Tiainen Antti Soininen Esa Alakoski Yrjö T. Konttinen 《Diamond and Related Materials》2008,17(12):2071-2074
With filtered pulsed arc discharge (FPAD) method it is possible to achieve very high adhesion of high quality diamond-like carbon (DLC). Here we explain this high adhesion with the oxide reduction and consequent carbide formation and ion mixing of the substrate when exposed to high temperature carbon plasma ions. The use of intensive high energy (> 2 keV) carbon plasma is the only practical method to achieve ultimate adhesion of DLC. With this unique method presented, the adhesion properties and the substrate interface electron spectroscopy for chemical analysis (ESCA) spectra of DLC coatings are independent of the pre-treatment of silicon substrates. High adhesion and proper selection of substrate enables to deposit thick DLC coatings (> 10 μm). We also show how the DLC deposition system can be improved and simplified. 相似文献
15.
Jin Woo Yi Se Jun Park Myoung-Woon Moon Kwang-Ryeol Lee Seock-Sam Kim 《Diamond and Related Materials》2008,17(6):967-971
Humidity dependency of friction behavior of nano-undulated diamond-like carbon (DLC) films was investigated by a home-made ball-on-disk type tribometer under controlled relative humidity of 0, 50, and 90%. Nano-undulated DLC films with surface roughness ranging from 0.2 to 13.4 nm were prepared by deposition of DLC film on the Si substrate with Ni nanodots. Friction coefficient of the flat DLC surface increased with the relative humidity, while that of the nano-undulated surfaces revealed smaller dependence on the relative humidity. When the surface roughness increased to 13.4 nm, friction behavior was observed to be independent of the relative humidity. The analysis of chemical composition and atomic bond structure of the debris and the transfer layer revealed that the humidity dependence on the nano-undulated surface was minimized by suppressing the graphitization of the transfer layer even with high concentration of Fe in the debris. 相似文献
16.
《Diamond and Related Materials》2000,9(8):1430-1434
Diamond-like carbon (DLC) films have been reliably deposited on YZ LiNbO3, and surface acoustic wave (SAW) velocity change has been observed. These relatively thin films increase the SAW velocity sufficiently, and they can be used for SAW devices. The cut-off behavior was observed at approximately 538 MHz in a 2-μm-thick DLC film on the LiNbO3 substrate. 相似文献
17.
《Diamond and Related Materials》2005,14(8):1361-1367
In this paper, DLC multilayer films consisting of alternating layers of soft and hard carbon films were deposited on Si wafer by a plasma CVD deposition system. Different DLC multilayer films were prepared by varying the sub-layer thickness (from 1000 to 25 nm) and the ratio of hard to soft sub-layer (H/S) thickness (from 1:1 to 4:1). By using a ball-on-disk tribo-tester, the friction and wear properties of the DLC multilayer films were measured in vacuum, O2 and dry-air environments respectively. By comparing with single-layer DLC film, the change of the multilayer structure has little influence on friction coefficient of the multilayer films. However, the wear rate of the DLC multilayer films is restricted effectively by constructed the multilayer structure in the film. The wear rate of the multilayer films is lower than that of the single film in reactive (O2 and dry-air) environments. An DLC multilayer film with excellent wear resistance, approximately in the level of 10−8 mm3/Nm in different environments (dry-air, O2 and vacuum), is obtained as the DLC multilayer film at a certain sub-layer thickness and ratio. 相似文献
18.
Walter Navarrini Claudia L. Bianchi Luca Magagnin Luca Nobili Gabriella Carignano Pierangelo Metrangolo Giuseppe Resnati Maurizio Sansotera 《Diamond and Related Materials》2010,19(4):336-341
In the present work, a chemical treatment with perfluorinated peroxides is proposed to obtain protective layers covalently linked to a diamond-like carbon (DLC) surface. The lubricant properties of perfluorinated compounds and the stability of the chemical modification of DLC surface simultaneously cooperate in this technical approach. Each fluorinated layer is deposed on an bare DLC surface by a dip coating application technique and the covalent linkage of the fluorinated layers is obtained by the thermal decomposition of the peroxidic moieties of the perfluorinated peroxides. Reactive perfluorinated radicals are generated close to the sp2 sites of the DLC surface, allowing the formation of covalent bonds. The fluorinated peroxides used in this work belong to the class of the PFPE peroxides and to the class of the perfluorodiacyl (PFDA) peroxides. The effect of the fluorinated coatings on the DLC surface is studied using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), with contact angle (CA) measurements and, in particular, the friction forces are evaluated by means of lateral force microscopy (LFM). 相似文献
19.
20.
Ivan Ohlídal Miloslav Ohlídal Daniel Franta Vladimír udek Vilma Buríkov Petr Klapetek Kateina Pleníkov 《Diamond and Related Materials》2005,14(11-12):1835
In this paper the influences of the technological conditions, i.e. the influences of the hydrogen flow rate and deposition time, on the values of the intrinsic mechanical stresses inside the diamond-like carbon (DLC) thin films prepared by plasma enhanced chemical vapor deposition onto silicon substrates are studied. These stresses are measured by two-beam interferometry and optical profilometry based on chromatic aberration through the measurements of deformations of the silicon substrates originating in consequence of the film stresses. It is shown that the influence of the deposition time (i.e. film thickness) on the film stress is relatively slight in contrast to the influence of the hydrogen flow rate on this quantity. It is namely shown that the film stresses are influenced by the hydrogen flow rate values in a pronounced way within the interval of interest, i.e. within the interval 1–7 sccm. Moreover, it is shown that the method of optical profilometry used can be competitive to the method of two-beam interferometry from the practical point of view. 相似文献