Liquid Phase Electrodeposition Research Articles

Effect of rGO concentration on the microstructure and friction behavior of co-doped diamond-like carbon (Ni/N/rGO-DLC) films

A kind of wear-resistant and lubricated Ni/N/rGO-DLC films are deposited on the surface of Ti-6Al-4V(TC4) alloy substrate by an integrative method involving pulsed electrodeposition and liquid-phase electrodeposition with various rGO (reduced graphene oxide) concentration. The growth mechanism of the film and the formation of protrusions and gully structures on the surface of the film are investigated. Furthermore, the mechanism of the effect of rGO concentration on the dispersion stability of the electrolytic system is explored. The results reveal that the Ni/N/rGO-DLC films at 0.07 g·L−1 rGO exhibit a uniform and dense structure. rGO particles are uniformly incorporated into the carbon-based films and tend to deposit perpendicular on the substrate. Simultaneously, the highest micro-indentation hardness, the lowest coefficient of friction and wear loss are obtained as 591.88 HV, 0.072 and 1.20 × 10−4 kg·m−1 of film with 0.07 g·L−1 rGO, which are principally attributed to the synergistic effect of rGO particles and amorphous carbon matrix in improving the mechanical properties of Ni/N/rGO-DLC films.

Doped Amorphous Carbon Films Prepared by Liquid Phase Electrodeposition

It has theoretical significance and practical value to synthetize and modify amorphous carbon films by liquid electro-deposition technique due to its low cost, simple equipment, and better operability in uniform deposition of the films with large-area and complex shape work pieces. This article introduces the research situation of the carbon films prepared by liquid phase electrochemical deposition according to the applied voltage, discusses the influence of experimental parameters on the film properties, and describes possible reaction mechanisms. It summarizes the research progress of amorphous carbon films doped with metal and nonmetals. Finally, existing problems have been demonstrated and suggestions on research hotspots in the future are given.

Electro-Deposition of Carbon Structures at Mid Voltage and Room Temperature Using Ethanol/Aqueous Solutions

Direct syntheses of carbon structures including nanodiamond, microdiamond and diamond-like carbon (DLC) on silicon wafers by liquid phase electro-deposition are presented. The solution (ethanol/water) was employed as electrolyte at different concentration levels. Assays were carried out maintaining constant the electric potential between the silicon electrodes in the range of (80−300 V) at current density of approximately 2.0 mA/cm2. Scanning electron microscopy showed that non-uniform, smooth and heterogeneous structures were produced. The structural composition was evaluated by micro-Raman spectroscopy. A mechanism for the formation of sp3 and sp2 hybridizations is proposed.

Electrical Double Layer Model and Thermodynamic Coupling for Electrochemically Deposited Hydrogenated Amorphous Carbon Films

In this study, the growth mechanism for electrodeposition of hydrogenated amorphous carbon (a-C:H) films was discussed from two novel perspectives. First an electrical double layer is considered to form in the vicinity of the electrodes. The double layer is believed to govern the variation tendency of the external current density. Then by introducing a concept called thermodynamic coupling we have explained the growth mechanism of a-C:H films from liquid phase electrodeposition and pointed out that hydrogen atoms play a crucial role in lowering applied voltage. Related experiments are conducted to corroborate our opinion.

Gas Phase Electrodeposition: A Programmable Localized Deposition Method for Rapid Combinatorial Investigation of Nanostuctured Devices and 3D Bulk Heterojunction Photovoltaic Cells

ABSTRACTThis article applies a recently discovered gas phase nanocluster electrodeposition process to the formation and combinatorial improvement of 3D bulk heterojunction photovoltaic cells. The gas phase deposition process used here is a single reactor system that forms charged nanoclusters (gold, silver, tungsten, and platinum) at atmospheric pressure. The clusters deposit onto selected surface areas with sub 100 nm lateral resolution using a programmable concept similar to liquid phase electrodeposition such that biased electrodes turn ON or OFF deposition in selected areas. Continued deposition of the nanoparticles results in a tower array with different lengths and density on a single substrate which is used as contacts to the active organic layer of 3D bulk heterojunction photovoltaic cells. Applying a combinatorial approach identifies in a massively parallel way electrode designs and topologies that improve light scattering, absorption, and minority carrier extraction. We report photovoltaic cells with higher and denser nanocluster tower arrays that improve the power conversion efficiency of bulk heterojunction photovoltaic cells by approximately 47.7%.

Deposition of WO 3 doped amorphous hydrogenated carbon film by using liquid phase electrodeposition technique and its mechanical properties

Tungsten trioxide nanoparticles doped amorphous hydrogenated carbon (WO 3/a-C:H) films were successfully fabricated on silicon substrates by electrochemical deposition technique under atmospheric pressure. The as-deposited films were characterized by X-ray photoelectron spectroscopy, Transmission electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy, respectively. Results showed that nanocrystalline tungsten trioxide particles with a grain size in the range of 8–12 nm were homogeneously embedded in the amorphous carbon matrix, and the sp 3-hybridized carbon content in the a-C:H films increased. Compared with pure amorphous carbon film, the hardness and elastic recovery were significantly improved due to the doping of WO 3. At the end, an understandable model was proposed to interpret the growth mechanism of the WO 3/a-C:H composite films.

One-step electrodeposition of amorphous carbon films containing WO3 with high conductivity and good wettability

Tungsten trioxide-incorporated hydrogenated amorphous carbon (WO3/a-C:H) films have been fabricated on a single-crystal silicon wafer by liquid phase electrodeposition using methanol as carbon source and tungsten carbonyl as incorporated reagent. The morphology, composition and structure of the films have been investigated by SEM, XPS, Raman scattering spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscope (TEM), respectively. The effects of WO3 incorporation on the electrical and wetting properties were studied in detail. The characterization results showed that tungsten trioxide nanocrystalline particles with diameters in the range of 10–20 nm were homogenously embedded in the amorphous carbon films. Also, the electrical conductivity and wetting ability of the films were strongly improved due to the contribution of the tungsten trioxide. Copyright © 2010 John Wiley & Sons, Ltd.

Characterization of carbonaceous films deposited on metal substrates by liquid-phase electrodeposition in methanol

In this study, we report the characterization of carbonaceous films deposited on metal substrates by liquid-phase electrodeposition in methanol. The characterization of carbonaceous films by electrodeposition was examined by means of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), secondary ion mass spectrometry (SIMS), atom probe (AP) and high resolution-elastic recoil detection analysis (HR-ERDA). From these results, it was found that the films deposited on the metal substrates were composed of the sp 2 and sp 3 carbon contents, of which the ratio was about 7:3. Furthermore, the films by electrodeposition contained much hydrogen. The hydrogen contents in the surface were about 60 at.% and those in the subsurface were a few 10 at.%.

Synthesis of hollow carbon nitride microspheres by an electrodeposition method

Abstract Hollow carbon nitride microspheres have been synthesized using a novel liquid phase electrodeposition technique. The microspheres are composed of numerous nanoparticles with size of about 5–30 nm. The diameters of the spheres range from 800 nm to 1.1 μm, and shell thickness is about 80–250 nm. This is the first attempt to synthesize carbon nitride with specific nanostructure by the electrodeposition method, which is proved to be facile and effective, and can be performed in an atmospheric environment and at a rather low temperature. The hollow carbon nitride may have potential applications as lubrication, catalysis, biomolecule adsorption, drug delivery, electronic materials, etc. in the future.

Atom Probe Analysis of Diamond-like Carbon Deposited on Metal Substrates by Liquid-phase Electrodeposition in Methanol

Diamond-like Carbon (DLC) films were deposited on nickel sheets and tungsten tips by liquid-phase electrodeposition, and were investigated by using field emission scanning electron microscopy (FE-SEM), Raman spectroscopy and atom probe (AP). The surface morphology of the deposited films was observed by FE-SEM. It can be seen that the films were composed of small grains. Raman spectra of the films exhibited two broad peaks around 1200-1450 cm-1 called D-peak and 1500-1700 cm-1 called G-peak. By AP analysis, some hydrocarbon ions were detected. It indicates that the films were composed by not only carbon but also hydrogen.

Electrodeposition of diamond-like carbon (DLC) films on Ti

Diamond-like carbon films (DLC) were deposited on titanium substrates in acetonitrile and N,N-dimethyl formamide (DMF) liquids by the liquid-phase electrodeposition technique at ambient pressure and temperature. The applied voltage between the electrodes was high (1200 V) due to the use of resistive organic liquids. The surface morphology was examined by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Corrosion performance of the coatings was investigated by potentiodynamic polararization tests in phosphate buffer saline solution. Raman spectroscopy analysis of the films revealed two broad bands at approximately 1360 cm −1 and 1580 cm −1, related to D and G-band of DLC, respectively. The coated Ti was tested in a ball-on-plate type wear test machine with Al 2O 3 balls. The films presented a low friction coefficient (about 0.1), and the films deposited from DMF presented the best wear resistance.

Liquid-phase Electrodeposition of Diamond-like Carbon Films on Conducting Glass Substrates Using a Low Deposition Voltage at Room Temperature

Abstract By using formamide as the carbon source, an attempt was made to electrodeposit diamond-like carbon (DLC) films on indium tin oxide (ITO)-coated glass plate substrates at a low constant voltage and room temperature. The structures and morphologies of the films were analyzed by Raman spectroscopy and field-emission scanning electron microscopy.

Synthesis and characterization of high voltage electrodeposited phosphorus doped DLC films

Phosphorus doped diamond-like carbon (DLC) films were firstly synthesized by the electrolysis of methanol-Triphenylphosphorus (PPh 3) solution under high voltage, atmospheric pressure and low temperature. The microstructure and morphology of the as-deposited films were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The measurements results suggested that phosphorus doping enhanced the carbon films graphitization and the doped phosphorus existed mainly in C P bonds with the P/C ratio of 0.034. The P-DLC films have larger surface roughness compared to the DLC film. Moreover, the formation of P-DLC films in liquid-phase electrodeposition was via the reactions of the –CH 3 and –P groups to form CPx network.

Synthesis and tribological behaviors of diamond-like carbon films by electrodeposition from solution of acetonitrile and water

Diamond-like carbon (DLC) films were prepared on silicon substrates by liquid phase electrodeposition from a mixture of acetonitrile and deionized water. The deposition voltage was clearly reduced owing to the presence of deionized water in the electrolyte by changing the basic properties (dielectric constant and dipole moment) of the electrolyte. Raman spectra reveal that the ratio of sp 3/sp 2 in the DLC films is related to the concentration of acetonitrile. The surface roughness and grain morphology determined by atomic force microscopy are also influenced by the concentration of the acetonitrile. The UMT-2 universal micro-tribometer was used to test the friction properties of the DLC films obtained from electrolytes with different concentration. The results convey that the DLC film prepared from the electrolyte containing 10 vol.% acetonitrile has the better surface morphology and friction behavior comparing with the other. In addition the growth mechanism of the film was also discussed.

Fabrication of hydrophobic fluorinated amorphous carbon thin films by an electrochemical route

A novel electrochemical route for the preparation of hydrophobic fluorinated amorphous carbon (a-C:F) films with nanostructured surfaces on single crystal silicon substrate was reported. The films were investigated in terms of the surface morphology, chemical composition, microstructure and hydrophobic behavior. The results showed that a highly uniform and densely packed bamboo shoot-like nanostructure was obtained without any use of template. The incorporation of fluorine presented mainly in the forms of CF 2 chains and C CF x ( x = 1, 2) in the films. Sessile drop water contact angle measurements showed that the contact angle of a-C:F films deposited by electrochemical route was about 145°, which can be attributed to the lower surface energy of CF x groups and higher diffusion resistance of the special nanostructured surface to water. Moreover, the related growth mechanism of the resulting films in liquid-phase electrodeposition is discussed as well.

Structure and tribological properties of amorphous carbon films deposited by electrochemical method on GCr15 steel substrate

Amorphous carbon films were deposited on GCr15 steel substrates by electrolysis of methanol, dimethylsulfoxide (DMSO) and the methanol–DMSO intermixture electrolytes, respectively, under high voltage and low temperature conditions. The microstructure and wear morphology of the deposited films were analyzed using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM) combined with energy dispersive X-ray fluorescence spectrometer (EDX), respectively. The tribological properties of the films were evaluated using a ball-on-disk rotating friction tester under dry friction condition. The results show that the films deposited by electrodeposition technique on GCr15 steel substrates are amorphous carbon films. It is also found that the electrolytes have an obvious influence on the tribological properties of the deposited films with the electrodeposition method. The tribological properties of the films deposited with the intermixture electrolyte are better than those of the films deposited by other pure electrolytes. The related growth mechanism of the films in the liquid-phase electrodeposition is discussed as well in this study. Via the reaction of the CH 3 groups with each other to form carbon network and reaction of the CH 3 and SO 2+ groups to achieve the doping of sulfur atom in the carbon network, respectively, in other words, amorphous carbon films can be obtained on GCr15 steel substrates by electrodeposition technique.

Characterization of hydrogenated diamond-like carbon films electrochemically deposited on a silicon substrate

Diamond-like carbon (DLC) films were deposited on a Si substrate by electrolysis in a methanol solution at ambient pressure and low temperature. The morphology and microstructure of the resulting DLC films were analysed using atomic force microscopy, Raman spectroscopy, Fourier transformation infrared spectrometry, x-ray photoelectron spectroscopy (XPS), and x-ray excited Auger electron spectroscopy (XAES). The surface energy and mechanical properties of the DLC films were examined, and the growth mechanism of the DLC films in liquid phase electro-deposition is discussed as well. The results of the study show that the hydrogenated diamond-like carbon films are smooth and compact. The percentage of sp3 carbon in the DLC films is determined as 55–60%, based on the corresponding XPS and first-derivative XAES spectra of graphite, diamond, and the tested films. The DLC films show low surface free energy, good mechanical properties, excellent friction–reduction and wear-resistance. It is suggested that methanol dissociates to generate the active species of and C2H4 at high voltage applied to the electrode, followed by the generation of the alkyl chain [–CH2–CH2–]n whose C–C and C–H bond lengths and C–C–C and H–C–H bond angles are close to that of diamond. Subsequently, a diamond-like structure was formed by the ordered dehydrogenation of a short-chain [–CH2–CH2–]n in the electrolysis process.

Study of structure, tribological properties and growth mechanism of DLC and nitrogen-doped DLC films deposited by electrochemical technique

Diamond-like carbon (DLC) and nitrogen-doped DLC films were deposited on Si (100) substrates by electrolysis of methanol–urea solution under high voltage, at atmospheric pressure and low temperature. The microstructure and morphology of the resulting films were analyzed by means of Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectrometry (FTIR) and atomic force microscopy (AFM). The tribological properties of the films were examined using a ball-on-disk tribometer. As per the results, Raman spectrum, XPS and FTIR measurements suggested the different microstructure between DLC and nitrogen-doped DLC films. The DLC film is consisting of sp2 and sp3 carbon, with the percentage of sp3-bonding carbon to be 55%, while both single and double carbon nitride bonds exist in the nitrogen-doped DLC film, with the N/C ratio of 0.08. The nitrogen-doped DLC film has generally larger surface roughness and better tribological properties compared to the DLC film. Moreover, the related growth mechanism of the resulting films in liquid-phase electrodeposition is discussed as well. Via the reactions of the –CH3 groups with each other to form carbon network and the reactions of the –CH3 and –NH2 groups to form carbon nitride network, respectively, DLC and nitrogen-doped DLC films can be obtained on Si substrates.

Preparation and characterization of electrochemically deposited carbon nitride films on silicon substrate

Carbon nitride films (CNx films) were deposited on Si(100) substrates by the electrolysis of methanol–urea solution at high voltage, atmospheric pressure, and low temperature. The microstructure and morphology of the resulting CNx films were analysed by means of Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometry (FTIR), x-ray diffraction (XRD), and atomic force microscopy. The tribological properties of the CNx films were examined on an UMT-2MT friction and wear test rig. The Raman spectrum showed two characteristic bands: a graphite G band and a disordered D band of carbon, which suggested the presence of an amorphous carbon matrix. XPS and FTIR measurements suggested the existence of both single and double carbon-nitride bonds in the film and the hydrogenation of the carbon nitride phase. The XRD spectrum showed various peaks of different d values, which could confirm the existence of the polycrystalline carbon nitride phase. The hydrogenated CNx films were compact and uniform, with a root mean square roughness of about 18 nm. The films showed excellent friction-reduction and wear-resistance, with the friction coefficient in the stable phase being about 0.08. In addition, the growth mechanism of the CNx films in liquid phase electro-deposition was discussed as well. It was assumed that the molecules of CH3OH and CO(NH2)2 were polarized under high electric field, and the CNx film was formed on the substrate through the reaction of the –CH3 and –NH2 groups on the cathode.

Aroused problems in the deposition of diamond-like carbon films by using the liquid phase electrodeposition technique

Hydrogenated diamond-like carbon (DLC) films were prepared by using liquid phase electrodeposition technique. The effects of the applied potential and the carbon sources on the deposition process and film structures were studied. It has been found that the organic liquids with high dielectric constants, small viscosities and the methyl group bonding to the polar group are appropriate carbon sources. The increasing of potential improves the formation of sp3 carbon during the deposition process. In a high electric field, organic molecules are polarized and reacted on the surface of the electrode, turning out DLC and other products. It is believed that the reaction follows a polarization-reaction mechanism.