Formation Of Diamond-like Carbon Films Research Articles

Deposition processes of superhard diamond-like carbon films co-adjusted by ion energy and ion flux in arc discharges

As a kind of protective material, Diamond-Like Carbon (DLC) film can effectively improve the mechanical and tribological properties of the substrate surface. In DLC family, tetrahedral amorphous carbon (ta-C) with ultra-high hardness and excellent protective properties has been widely concerned in the field of hard protective materials. It is well known that the structure and properties of ta-C are strongly dependent on carbon plasma characteristics in the plasma environment. Therefore, it is extremely crucial to obtain the optimal process window of ta-C described by plasma micro-parameters with general significance. This paper proposed the Langmuir probe was used to diagnose the carbon plasma of the afterglow generated by arc evaporation, aiming to investigate the characteristics of carbon plasma and sheath. The effect of ion energy and ion flux adjusted by the pulse bias voltage and arc current on the sp3 hybrid bonds and hardness of DLC films was studied, aiming to find out which conditions satisfied the formation of ta-C. The results showed the microstructure and properties of DLC films were co-adjusted by ion energy and ion flux. When the carbon ions met the appropriate ion energy range (50–300 eV) and low ion flux (<8.99 × 1010 cm−2 s−1), the films tended to form ta-C structures with high sp3 bonds. However, under the condition of high ion energy and high ion flux, the structure of the films changed from sp3 bonds to sp2 bonds, resulting in the graphitization and formation of DLC films with high sp2 bonds. This work will provide new solutions to guide the design and acquisition of high-performance DLC films.

Formation of Diamond-Like Carbon Film on Organic Substrate by High Power Impulse Magnetron Sputtering

Formation of Diamond-Like Carbon Film on Organic Substrate by High Power Impulse Magnetron Sputtering

Formation of diamond-like carbon film using high-power impulse magnetron sputtering

In this study, a diamond-like carbon (DLC) films were formed using high-power impulse magnetron sputtering (HiPIMS), after which the ion energy distribution function (IEDF) for the argon ions (Ar+) and carbon ions (C+) was measured using energy-resolved mass spectrometry in order to clarify the role of the HiPIMS operating parameters and gas species on the film quality and the resulting tribological performance. We found that the IEDF for Ar+ contained both low-energy and high-energy components, whereas the IEDF for C+ contained primarily high-energy components. For DLC films formed at a substrate bias voltage of zero under the same gas-phase analysis conditions, we found that the deposition rate increased linearly as the applied voltage was increased, and that the carbon structure showed little change when analyzed by Raman spectroscopy. In addition, both the friction coefficient and the wear resistance were improved. These results indicate that both Ar+ and C+ have the potential to play important roles in determining the deposition mechanism and quality of DLC films.

Influence of diamond-like antifrictional coatings on the reliability of dry milling

The influence of an antifrictional coating obtained by the formation of diamond-like carbon films on the life of hard-alloy end mills is investigated. The capabilities of an automated diagnostic complex are analyzed. Mills with a diamond-like coating are characterized by wear resistance and low adhesion. They are more effective for machine tools with an adaptive control system on account of the slowing of processes prior to tool failure.

Raman spectroscopy of thin DLC film deposited by plasma electrolysis process

A thin diamond-like carbon film was deposited on Ni substrate by plasma electrolytic deposition in ethanol-water solution. The thickness of the deposited carbon film was measured about 40–60 nm by using glow discharge optical emission spectroscopy and optical profilometer. The characterization of film structure by Raman spectroscopy showed the superposition of Raman features on a photoluminescence background because of low thickness of the deposited film. The surface enhanced Raman scattering technique by coating the carbon film with Au nanoparticles and high power laser in Raman spectroscopy was used as Raman intensity enhancer. Amplified Raman signals by using both techniques showed formation of diamond-like carbon film and various sp2 and sp3-bonded compositions on grain boundaries of nanostructure carbon coating. The Raman spectrum of the Au coated carbon film revealed an additional band at 2150 cm− 1, which is related to the carbyne structure whereas carbyne band could not be detected using high power laser. Comparison of Raman spectra at two wavelengths of 632.8 and 785 nm showed changes in the intensity and position of Raman bands. Likewise, the 785 nm laser wavelength excitation has sufficient energy to enhance the scattering from the grain boundary structures.

Friction and wear of diamond-like carbon film deposited on CoCrMo alloy under different lubrication

Abstract CoCrMo alloys are widely used as artificial joint implants due to their excellent mechanical properties, good wear resistance and outstanding corrosion resistance. However, the risks of release of cobalt and chromium ions urge researchers to improve the wear resistance of implants further by using surface modification technology. Diamond-like carbon film with 3.0 μm thickness was deposited on the surface of CoCrMo alloy using ion-source-assisted magnetron sputtering. The friction coefficients of the CoCrMo alloy decreased remarkably under different conditions after the formation of diamond-like carbon film. After the deposition of diamond-like carbon film the wear rates of the CoCrMo alloy decreased by 52.4 %, 47.1 % and 49.4 %, under dry friction, physiological saline, and bovine serum lubrication, respectively.

Synthesis and characterization of diamond-like carbon film on silicon by electrodeposition from solution of ethanol and methanol

Diamond-like carbon (DLC) films were prepared by electrodeposition technique on single crystalline n-type Si (100) substrates. Electrolysis of ethanol and methanol solution with different volume ratios at 60°C under constant voltage of 1200V is presented. The DLC films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), Raman spectroscopy, and atomic force microscopy (AFM). The deposited DLC films composed of small and compact grains and seem to be uniform, smooth and homogeneous with a structure influenced by the amount of methanol. The EDX spectra of the prepared films indicated that carbon and oxygen are their main composition. The root mean square (RMS) roughness of the DLC films, synthesized from electrolytes containing 20 by volume of methanol, was 1.17nm. Raman spectra of films showed the presence of a peak located at 1450cm−1 in addition to G and D peaks which confirmed the formation of DLC film. These spectra confirmed the amorphous nature of all deposited DLC films.

Double Side Coating of DLC on Silicon by RF-PECVD for AR Application

Diamond like Carbon (DLC) films were deposited on mono crystalline, double side polished silicon (100) substrates by a capacitively coupled 13.56MHz RF plasma enhanced chemical vapour deposition (RF-PECVD) system, using acetylene (C2H2) as process gas. DLC films were deposited at a constant power of 200W with 100sccm flow of C2H2 and at deposition temperatures of 25°C (RT), 150°C and 300°C. DLC films were characterized by Fourier- transform Infrared Spectroscopy (FTIR), Ellipsometry and Raman Spectroscopy. Characterization of DLC films for anti-reflective (AR) property by FTIR on double side coated silicon at room temperature showed enhancement in maximum transmission of about 89% in 3- 5μm wavelength. Raman and Ellipsometry analysis confirmed the formation of DLC films with Ad/Ag ratio of 0.53- 0.82 and refractive index (n) of 2.3.

Formation of Diamond-Like Carbon Films by Photoemission-Assisted Plasma-Enhanced Chemical Vapor Deposition

Diamond-like carbon (DLC) films, which are an amorphous carbonaceous allotrope composed of sp2 carbon, sp3 carbon, and hydrogen, were prepared by photoemission-assisted plasma-enhanced chemical vapor deposition (PA-PECVD). The electrical behavior during film growth monotonically depended on the methane source gas concentration. Raman analysis of the films suggests that a DLC film grown at a high methane concentration condition contains a small number of graphitic domains, decreasing amorphicity of the film. In contrast, at a low concentration, the methane molecules were transformed into sufficiently fragmented radicals, forming a lot of graphitic nuclei and increasing the amorphicity. However, the variations of the relative dielectric constant, breakdown strength, and optical bandgap exhibited extreme values at an intermediate methane concentration. Thus, the two growth modes give different DLC films with varying combinations of electrical and optical characteristics.

The Formation of Diamond-Like Carbon Film at Atmospheric Pressure by the Pulsed Laser/Plasma Hybrid Deposition Method

A pulsed laser/plasma hybrid deposition method has been developed to produce the diamond-like carbon (DLC) film at atmospheric pressure in this work. A plasma torch was used to heat up the carbon particles which were simultaneously ablated by a pulsed laser, thus the kinetic energy of the carbon particle can be increased to form the carbon atoms with amorphous bonding structure of the DLC film. The influences of the plasma flow have been examined at various inlet pressures. According to the experimental results of the carbon film inspected by the Raman spectroscopy, it reveals that the intensity ratio of the D-band to G-band of the carbon film can be reduced to 0.5 by the implementation of plasma flow. Therefore the DLC film was solidly formed. The adhesive strength of the DLC film was also characterized by the scratch test, it can be found that the critical loading of the film on the iron substrate is up to 19 N.

Plasma immersion ion implantation and deposition of DLC coating for modification of orthodontic magnets

This study was aimed to use the plasma immersion ion implantation and deposition (PIII-D) technique to form diamond-like carbon (DLC) thin films on orthodontic magnets to solve the corrosion problem. To search for the optimal material modification effect, PIII-D conditions including gases, processing time, and pulsing mode were varied. The formation of DLC films was confirmed and characterized with Raman spectra. The intensity of the remnant magnetic field of the magnets and the hardness, adhesion and thickness of the thin films were then measured. A corrosion test was carried out using clinic dental fluid. Improved benefits including a satisfying hardness, adhesion, remnant magnetic strength and corrosion resistance of the DLC coating could be achieved by using a higher interrupting time ratio and shorter processing time.

Synthesis of functional diamond-like carbon nanocomposite films containing titanium dioxide nanoparticles

Synthesis of diamond-like carbon (DLC) films with UV-induced-hydrophilicity function was studied by inductively-coupled plasma (ICP) chemical vapor deposition. Titanium tetraisopropoxide (TTIP) and oxygen gases were employed as the precursors to deposit diamond-like nanocomposite films containing titanium dioxide (TiO 2) nanoparticles. X-ray diffraction and high-resolution transmission electron microscopy revealed that TiO 2 nanocrystallites were formed in the DLC films when oxygen concentration was higher than TTIP concentration during deposition. The DLC nanocomposite film was hydrophobic without ultraviolet (UV) irradiation, and became highly hydrophilic under UV irradiation, exhibiting the self-cleaning effect. A very broad peak centered at 1580 cm − 1 was observed in the Raman spectra confirming the formation of DLC films. The hardness of the film was about 8 GPa with a stress of 3 GPa. ICP was essential in forming the photocatalytic TiO 2 nanoparticles in the DLC matrix.

The formation of diamond-like carbon film at atmospheric pressure by the pulsed laser/plasma hybrid deposition method

A pulsed laser/plasma hybrid deposition method has been developed to produce the diamond-like carbon (DLC) film at atmospheric pressure in this work. A plasma torch was used to heat up the carbon particles which were simultaneously ablated by a pulsed laser, thus the kinetic energy of the carbon particle can be increased to form the carbon atoms with amorphous bonding structure of the DLC film by this proposed hybrid deposition method. The influences of the plasma flow have been examined numerically and experimentally. In the numerical analysis, the temperatures of the plasma flow at various inlet pressures and electrode currents have been predicted. According to the experimental results of the carbon film inspected by the Raman spectroscopy, it reveals that the intensity ratio of the D-band to G-band of the carbon film can be reduced to 0.5 by the implementation of plasma flow. Therefore the DLC film was solidly formed. The adhesive strength of the DLC film was also characterized by the scratch test, it can be found that the critical loading of the film is up to 19 N.

Formation of diamond-like carbon by fs laser irradiation of organic liquids

The high intensities generated in femtosecond (fs) laser interactions offers the possibility of novel formation routes for diamond and diamond-like carbon materials. Coulomb explosion, a common phenomenon in intensive fs irradiation, has recently been shown to lead to a direct graphite–diamond phase transition on the surface of graphite. In this paper we report the results of fs irradiation of a variety of liquid organic compounds at intensities in the Coulomb explosion regime. The products of laser-induced chemistry under these conditions have been studied using visual/surface enhanced Raman and transmission electron microscopy (TEM). Surface enhanced Raman spectra/TEM show that an intermediate diamond phase, trans-polyacetylene chains and amorphous carbon are present after fs irradiation of liquid alkanes. We also find that the diamond component can be enhanced by irradiation in the presence of certain transition metals; however the origin of this effect is still uncertain. Diamond films deposited in this way are found to exhibit a nano-assembled structure involving individual nanodiamonds extending over an area of about 1 cm 2. This process represents a wet chemical method for room temperature formation of diamond-like carbon films

プラズマイオン注入・成膜によるＤＬＣ成膜技術とゴム，樹脂への産業応用

DLC (Diamond-Like Carbon) film formation technologies on the surface of 3-dimensional substrates by a uniform plasma-based ion implantation / deposition (PBIID) have been developed by applying pulse voltage coupled with RF voltage to the substrates, such as plastics, rubbers as well as metals with the similar deposition rate. DLC film onto rubbers, plastics is effective to wear resistance, low friction, gas barrier, corrosion resistance, anti thrombus and non-cohesiveness. These technologies are widely applicable to the automobile parts, mechanical parts, electronic parts and metal molds for rubbers and plastics.In this paper, the DLC film formation technologies by applying both RF and pulse voltage, their applications and their prospect are presented.

Deposition of Diamond-like Carbon Films using Graphite Sputtering in Neon Dense Plasma

This paper reports the deposition of diamond-like carbon (DLC) films on Si , using a low energy (1.45 kJ) dense plasma focus assisted sputtering of graphite insert at the tip of the tapered anode. The substrates are placed in front of the anode at different axial and angular positions and are exposed to multiple focus shots. The information regarding the DLC structure is acquired by using Raman spectroscopy. The spectra are characterized by two broad bands known as “G-band” and “D-band”. The results point towards the formation of DLC films with both sp3 (diamond like) and sp2 (graphite like) domains. In X-ray diffraction (XRD) pattern, no additional peak is observed except a peak at 2θ = 69° which corresponds to the silicon (Si) substrate. The intensity of Si peak is reduced after treatment indicating the deposition of amorphous carbon. Scanning electron microscopy (SEM) results demonstrate that the smoothness of the film increases with increasing the substrate angular positions with respect to the anode axis. Energy dispersive X-ray (EDX) analysis reveals that the films deposited at lower axial and angular positions are thicker which is complemented by the cross-sectional views of the films.

Formation of DLC films by three‐dimensional ion implantation under high vacuum

AbstractUsing a modified loop antenna, RF plasmas are formed under high vacuum without collisions between neutral atoms and a test piece or a target (Si) that is mounted in the plasma. By applying a negative high voltage to the target, carbon ions are implanted into the target by the three‐dimensional ion implantation method. Films thus formed have been identified as DLC (diamond‐like carbon) by Raman spectra, X‐ray diffractometry, and Rutherford back scattering. In the case of a target of WC with 10% Co, it has been found that the sticking force of the film is 60 N and the friction coefficient 0.13. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(3): 1–11, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20444

The study of doped DLC films by Ti ion implantation

Diamond-like carbon (DLC) films were prepared by unbalanced magnetron sputtering. Ti-doped DLC films were obtained by Ti ion implanted into the achieved DLC films using metal vapor vacuum arc (MEVVA). The effects of Ti+ ion implantation on the surface morphology, structure, and tribological properties of the DLC films were investigated by means of atomic force microscopy (AFM), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and friction measurement. The smooth and uniform Ti-doped film with the surface roughness of 0.595 nm was obtained. Raman result revealed that the formation of DLC films and sp2 bonds content increase by Ti+ ion implantation. TEM showed that the nanocrystalline phases of TiC were formed in the films. Ti+ was implanted into the interface between C and substrate, detecting the sputtering depth profiles of the film by XPS; thus, the interface was widened due to reserve diffusion. Tribological test experiment indicated that friction coefficient of the films decreased to approximately 0.15 by Ti+ ion implantation.

Formation of DLC Films by the Three-dimensional Ion Implantation under High Vacuum

Using a modified loop antenna, RF plasmas are formed under high vacuum without collisions between neutral atoms and a test piece or a target (Si) is mounted in the plasma.By applying a negative high voltage to the target, carbon ions are implanted into the target by the three-dimensional ion implantation method. Films thus formed have been identified as DLC (diamond-like carbon) by Raman spectra, X-ray diffractometry and Rutherford back scattering. In the case of a target of WC with 10% Co, it has been found that the sticking force of film is 60N and the friction coefficient 0.13.

Polymer Treatment by Plasma Immersion Ion Implantation of Nitrogen for Formation of Diamond-Like Carbon Film

Nitrogen ions were implanted by plasma immersion in Kapton, Mylar and polypropylene, with the objective of forming a diamond-like carbon layer on these polymers. The Raman spectrum of the implanted polypropylene showed typical Diamond-Like Carbon (DLC) graphite (G) and disorder (D) peaks, with an sp3/sp2 hybridization ratio of approximately 0.4 to 0.6. The XPS analysis of the three implanted polymers also showed peaks of C–C and N–C bonds in the sp3 configuration, with hybridization ratios in the same range as the Raman result. The implanted polymers were exposed to oxygen plasma to test the resistance of the polymers to oxygen degradation. Mass loss rate results, however, showed that the DLC layer formed is not sufficiently robust for this application. Nevertheless, the layer formed can be suitable for other applications such as in gas barriers in beverage containers. Further study of implantation conditions may improve the quality of the DLC layer.