Plasma-based Ion Implantation And Deposition Research Articles

Sliding wear performance of TiAl-based nitride coatings deposited on ADI by cathodic arc deposition and plasma based ion implantation and deposition

ABSTRACT This work studied the sliding wear performance of TiAl-based nitride coatings synthesized on austempered ductile iron (ADI) by cathodic arc deposition (CAD) and plasma-based ion implantation and deposition (PBIID). Monolayer CAD TiAlN films and bilayer CAD and PBIID TiAl/TiAlN films deposited on an experimental device were analyzed and benchmarked against a commercial bilayer CAD film. Sliding wear was evaluated in a pin–on–disc tribometer. Two test conditions were employed, one intended to prevent damage (low load, short distance) and another intended to promote damage (higher load, longer distance). Regarding low load tests, all coated samples showed friction coefficients of 0.40–0.45 and negligible wear. Regarding high load tests, all coated variants exhibited lower or equal disc and pin wear rates with respect to uncoated ADI. In addition, coated samples displayed steady-state friction coefficients between 0.2 and 0.6 while uncoated ADI steady-state coefficients between 0.6 and 0.85.

Frictional and Mechanical Properties of Surface Modified Nickel-Titanium Orthodontic Archwires

The purpose of this study was to investigate the surface hardness, frictional force and load-deflection characteristic of three types of nickel-titanium archwires; DLC-coated, CH4-PBII and CF4-PBII NiTi orthodontic archwires. The NiTi wires were deposited with DLC films and were implanted with CH4 and CF4 using Plasma-Based Ion Implantation and Deposition (PBIID) method. These archwires and upper canine brackets with slot dimension of 0.022-inch were used in this study. Surface hardness of three types of surface modified NiTi orthodontic archwires was measured using atomic force microscopy (AFM). Frictional resistance was determined using a Universal Testing Machine with a load cell of 50 N. The custom-fabricated friction-testing device was designed and bonded each bracket in an accurate position. Load-deflection characteristic was evaluated by conducting the three-point bending test with universal testing machine. The results showed that DLC-coated NiTi wires had the lowest mean of frictional force followed by CH4-PBII, CF4-PBII and conventional NiTi wires. DLC-coated NiTi wires had the highest mean of surface hardness and there was no significant difference in the unloading force at 0.5, 1.0, 2.0 and 3.0 mm of the load-deflection graphs between different types of NiTi orthodontic archwires. The results can be concluded that the surfaces of nickel-titanium orthodontic archwires can be successfully modified by the PBIID method to increase surface hardness and reduce frictional force between stainless steel brackets and NiTi archwires. The load-deflection characteristics of three types of surface modified archwires remain unchanged.

Effects of consecutive processing between cleaning and deposition on adhesion of diamond-like carbon prepared by plasma-based ion implantation and deposition

The effects of pretreatment on adhesion, which is the most important challenge of diamond-like carbon (DLC) films, were investigated. DLC films were prepared by changing pretreatment conditions on austenitic stainless steel (SUS304) substrates by hybrid process of plasma-based ion implantation and deposition (PBIID) using superimposed RF and negative high-voltage pulses. Although an oxide layer on a substrate surface was removed by Ar-plasma sputter cleaning, the substrate surface was immediately reoxidized when plasma was stopped for a moment between sputter cleaning and deposition. The DLC film on the oxide layer was poor adhesion strength less than approximately 50 MPa. Even if the oxide layer existed on the substrate surface, carbon ion implantation as an interface treatment in the PBIID process broke the oxide layer. As a result, the adhesion strength of DLC films was enhanced above the strength of epoxy resin (about 70 MPa). Furthermore, it was found that continuous generation of plasma after sputter cleaning was able to suppress reoxidation of the substrate surface. Consequently, the adhesion strength of DLC films prepared with no interface treatment was increased above 70 MPa, suggesting simplification of coating process and reduction in processing time for cost reduction.

Characterization of diamond-like carbon films prepared using various source gases by plasma-based ion implantation and deposition

Diamond-like carbon (DLC) films are prepared by bipolar-type plasma-based ion implantation and deposition (PBIID) using the combination of toluene (C7H8), tetramethylsilane (TMS: Si(CH3)4) and nitrogen (N2) as a source gas. The characteristics and mechanical properties of the films are examined by Raman spectroscopy and nanoindentation measurement, respectively. The film composition is evaluated by X-ray photoelectron spectroscopy (XPS). Raman analysis reveals that polymer-like structure is formed and increases with increasing Si content. The hardness and Young's modulus decrease with increasing Si content. The ratio of Si to C (Si:C) in the films is almost equal to that in the source gases. The addition of N2 together with TMS causes a slight increase of sp2 ring clusters and improvement of the mechanical properties probably due to the formation of SiN bonds. Moreover, the Si:C ratio in the films is enhanced by the N2 addition.

Residual stress measurement in DLC films deposited by PBIID method using Raman microprobe spectroscopy

Abstract Diamond-like carbon (DLC) films were prepared and their residual stresses were measured nondestructively using Raman microprobe spectroscopy. The plasma-based ion implantation and deposition (PBIID) method was used to coat the DLC films on thin glass substrates using acetylene, a mixture of acetylene and toluene, or only toluene gas at 1.0 Pa. Peaks in the Raman spectra of the DLC films were assigned as the D′(disordered) or C–C bonding peaks at 1150 cm − 1 . The phonon deformation potentials ( a ′) of the films were estimated from data for the phonon deformation potentials for pure graphite and diamond and calculated using the sp 3 /sp 2 bonding ratio and the hydrogen content of the films. Thus, a relation was observed between the Raman shift of the G peak ( ω G ) and the residual stress ( σ c ) in each film. The Raman shifts ( ω 0 ) of the G peak for the films with no deformation were 1554, 1556, and 1562 cm − 1 for the films deposited using acetylene, a mixture gas and toluene gas. Moreover, only toluene had stress constants of − 0.378, − 0.384, and − 0.391 GPa/cm − 1 . The residual stresses constant in each film using (8.2 × 10 − 4 · a ′) − 1 ω 0 − 1 were estimated as − 0.379, − 0.384, and − 0.391 GPa/cm − 1 . The Raman shift of the D peak remained stationary as the compressive σ c in the films increased but changed when the deposition gas was varied. The distance the D peak moved from 1420 cm − 1 corresponded to that of the G peak from 1560 cm − 1 in the Raman spectra of the films in the stress-free state. In addition, the compressive residual stress in the DLC film had a major impact on the hardness.

High-Temperature Cycling Performance of Cathode with DLC Protective Film

One of the most important issues is related to the long cycling performance in the secondary batteries, considering their application to hybrid electric vehicle, electric vehicle and stationary storage system. Especially, the improvement of high-temperature cycling performance is the most challenging target. Under such an inhospitable condition, several reasons may be taken for the battery degradation. Among them, the side reaction at the electrode/electrolyte interface is taken place, irrespective to the kind of the electrode material. It can yield high-resistive interfacial layer, giving the kinetic limitation, and dissolution of transition metals, leading to the reductive precipitation on the anode surface. We have tried to suppress the side reaction with help of a diamond-like carbon (DLC) protective film and presented our experimental results. The sub-nm DLC films were deposited by a hybrid process of plasma-based ion implantation and deposition (PBIID), which enables us to obtain uniform and thin coating at low processing temperature. This process is applicable to the cathode films as well as the electrode particles. In this study, the LiCo1/3Ni1/3Mn1/3O2 cathode film was treated as a typical electrode. An aspect of the DLC protective layer was observed by a cross-sectional TEM. It was found that the sub-nm DLC film was uniformly coated along the form of cathode surface without the damage to the cathode. The electrochemical cycling of the cathode film was evaluated with Li coin cell at the range from 2.5 to 4.5 V under the CC mode at 55°C. The DLC film coating had no influence on the initial charge-discharge properties but a significant positive effect on the cycling stability. For the cathode with DLC protective film, the discharge capacity hardly decreased even after 100th cycles. The cycling stability was also studied with the AC impedance spectra; it was found that the interfacial impedance growth during the cycling was suppressed by the presence of the DLC film. At the conference, the results about the surface analysis of the high-temperature cycled cathode will be presented and discussed. This work was financially supported by Advanced and Seamless Technology Transfer Program through target-driven R&D, JST.

Si添加およびTi添加DLC/DLC摺動のトライボロジー特性

Diamond-like carbon (DLC) films have been widely applied to machine components of many types. DLC has excellent tribological properties, but it must be improved to reduce friction further. Deposition with a different element-doped DLC on both sides of a sliding surface is expected to produce a superior friction coefficient. Therefore, we investigated the tribological properties of different element-doped DLC/DLC sliding to achieve sliding with lower friction. For our study, we used Plasma-Based Ion Implantation and Deposition (PBIID) to prepare three DLC films of pure-DLC, Si-DLC, and Ti-DLC. Each DLC film bond structure was analyzed using Raman spectroscopy. Hardness and roughness were measured by nano-indentation and atomic force microscopy. Regarding their tribological properties, friction coefficients were measured using ball-on-disk friction tests. Subsequently the chemical elements in wear tracks were analyzed using energy dispersive x-ray spectroscopy. Results obtained through the study revealed the following. (1) Different kinds of DLC/DLC sliding achieved a much lower friction coefficient than a single kind of DLC/DLC sliding. (2) Occurrence of mild wear particles functioned as a solid lubricant. The particles effectively reduced the friction coefficient. (3) Adhesion of wear particles was observed in wear tracks after Si-DLC/Ti-DLC sliding. (4) Friction coefficients of the Si-DLC/Ti-DLC sliding were the lowest, about 0.021, by appropriate adhesion of the wear particles.

Effect of deposition pressure on the properties of DLC coatings deposited by bipolar‐type PBII&D

AbstractIn the present study, the effect of deposition pressure on the deposition rate and various properties of diamond‐like carbon (DLC) coatings were investigated. The DLC coatings were deposited on Si substrates using a bipolar‐type plasma‐based ion implantation and deposition plasma based ion implantation and deposition (PBIID) technique. The toluene was used as a source gas and the deposition pressure ranged from 0.03 to 2.0 Pa. The deposition rate of the DLC coatings increases about 12 times as the deposition pressure is changed from 0.03 to 2.0 Pa. Also, the surface roughness increases with increasing deposition pressure due to high deposition rate. The hardness and elastic modulus decrease when the deposition pressure exceed 0.7 Pa due to the remarkable growth of graphitic islands. The corrosion protection performance of the DLC coating deposited at 2.0 Pa is superior to that of the DLC coating deposited at 0.2 Pa for the same deposition time of 1 h. The high deposition pressure for the DLC coating is effective in improvement of corrosion protection properties. Copyright © 2008 John Wiley & Sons, Ltd.

Improved Adhesion Properties of DLC Film Using Silicon-Carbide Fine Particle Bombardment

The effect of silicon-carbide fine particle bombardment (FPB) was examined as an easy way to improve the adhesion of diamond-like carbon (DLC) films to a substrate. DLC films were deposited on FPB-treated substrates by plasma-based ion implantation and deposition (PBIID) using CH4 and C2H2 as reactant gases. The adhesion force between the film and substrate was evaluated using the critical load as determined by scratch testing. The FPB treatment improved the adhesion about five times and clearly reduced the wear area of the films. Investigation of the reasons for its effectiveness showed that increased surface roughness accounted for about 67% of the improvement, that increased residual stress of the substrate accounted for about 23%, and that an increased ratio of embedded silicon accounted for about 10%.

STEM observation of nano-interface between substrate and DLC film prepared by plasma-based ion implantation and deposition

This paper discusses the nano-interface between an aluminum alloy (A5052) substrate and diamond-like carbon (DLC) film prepared by a hybrid process of plasma-based ion implantation and deposition (PBIID) using superimposed RF and negative high-voltage pulses. Adhesion strength of DLC films were enhanced by carbon ion implantation to the substrate. The nano-interface between DLC film and substrate was observed by high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) and analyzed by energy dispersive X-ray spectroscopy (EDS). It was found that an unclear crystal structure damaged by ion implantation was formed in the carbon ion-implanted layer. Besides, the amorphous mixing layer of oxide and DLC was produced on the substrate surface. The formation of the mixing layer, the layer of unclear crystal structure and the destruction of oxide led to the enhancement in adhesion strength of DLC film.

Effect of a hard supra-thick interlayer on adhesion of DLC film prepared with PBIID process

Diamond-like carbon (DLC) films were prepared on aluminum alloy (A5052) and tungsten-carbide (WC) substrates with plasma-based ion implantation and deposition (PBIID) using hydrocarbon gas. Adhesion strength of DLC film was increased by the formation of interfacial mixing layer by carbon ion implantation and the production of SiCx nanolayer on the substrate prior to DLC deposition. As DLC films on the softer substrate were broken easily because of large deformation of substrate by local loads, the hard and supra-thick interlayer of plasma-sprayed tungsten-carbide (WC) with the thickness of 100–200μm was produced to protect the softer substrate between the DLC film and the substrate. The scratch testing evaluation showed that the supra-thick WC interlayer improved remarkably the adhesion of DLC films on the aluminum alloy substrate and the thicker WC interlayer was more effective for improvement of adhesion.

Electrochemical behaviors of TiO 2− x films synthesized by plasma-based ion implantation and deposition in fibrinogen containing PBS solution

TiO 2− x films were synthesized on carbon by plasma-based ion implantation and deposition (PBII-D). Electrochemical behaviors of the prepared films were investigated in phosphate buffer solution (PBS) and fibrinogen containing PBS solution (PBS(Fn)), to probe charge transfer phenomena between TiO 2− x film and fibrinogen. Electrochemical impedance spectroscopy (EIS) as well as simulated values of equivalent circuit units including reaction resistance and electric double layer has been obtained, indicating different charge transfer rate occurred across the interfaces. The shape of Mott-Schottky spectroscopy around the rest-open potential indicates that TiO 2− x films are typical n-type semiconductor. Donor density results calculated by Mott-Schottky theory show that TiO 2− x films exhibit higher donor density in PBS(Fn) than in PBS, indicating charge transfer from fibrinogen to TiO 2− x films, and the space charge layers bend lower.

Effect of ion implantation layer on adhesion of DLC film by plasma-based ion implantation and deposition

High adhesive diamond-like carbon (DLC) film on SUS304 was obtained using carbon ion implantation between DLC film and substrate material by plasma-based ion implantation and deposition (PBIID). Implantation of mixed silicon and carbon ions to the substrate resulted in much higher adhesion strength than that of the epoxy resin. Effect of ion implantation on adhesion of DLC film was studied by cross sectional STEM observation and EDS element analysis. Enhancement in adhesive strength by ion implantation of mixed carbon and silicon was ascribed to the formation of the multilayer interface consisting of mixed carbon and silicon ion implanted layer and the amorphous layer of carbon and silicon.

Effect of Ion Implantation on DLC Preparation Using PBIID Process

This paper discusses the effects of ion implantation on a diamond-like carbon (DLC) preparation using a hybrid process of plasma-based ion implantation and deposition (PBIID) using superimposed RF and negative high-voltage pulses. Adhesion strength of a DLC film on A-5052 and SUS304 was enhanced by carbon ion implantation to substrate materials. Cross section of interface between the DLC film and substrate was observed by scanning transmission electron microscopy (STEM) and analyzed by energy dispersive X-ray spectroscopy (EDS). It was found that the amorphouslike mixing layer of graded carbon component and substrate materials was produced in the ion-implanted region of substrate and the oxide layer on the substrate surface was destroyed. Besides the reduction of residual stress in the DLC film, the formation of amorphouslike mixing layer and the destruction of oxide layer led to the enhancement in adhesion strength of the DLC film. Residual stress, sp3 fraction, hardness, density, and hydrogen content of the DLC films deposited from acetylene and toluene plasma have the variation with negative pulsed voltage for ion implantation

Structure and morphology of diamond-like carbon coated on nylon 66/poly(phenylene ether) alloy

In order to investigate the structure and morphology of diamond-like carbon (DLC) film coated on a polymer alloy prepared by a particular four-steps method in the plasma-based ion implantation and deposition (PBIID) process, studies were made on the structure and properties of the DLC film with special reference to its surface morphology by scanning (SEM) and transmission (TEM) electron microscopies. It is revealed from TEM microscopy that the amorphous structure of the DLC film consists of a silicon-implanted layer on the polymer substrate, a hard acetylene-implanted layer and a flexible acetylene/toluene-deposited layer. Some properties of the DLC film can be accounted for by the morphology examined in this study.

Negative pulsed voltage discharge and DLC preparation in PBIID system

The spectrum of optical emission from the plasma of hydrocarbon gases was measured with a photomultiplier and an optical multichannel analyzer in PBIID (plasma-based ion implantation and deposition) system. When negative pulsed voltage was applied to a sample, a strong optical emission was observed. It is important to know a contribution of negative pulsed voltage discharge on DLC (diamond-like carbon) synthesis. Spectra of CH (431 nm), H α (656 nm), H β (486 nm) and H γ (434 nm) were observed. Deposition rate of DLC film using acetylene gas was almost proportional to intensity of CH spectrum.

Plasma-based ion implantation and deposition: a review of physics, technology, and applications

After pioneering work in the 1980s, plasma-based ion implantation (PBII) and plasma-based ion implantation and deposition (PBIID) can now be considered mature technologies for surface modification and thin film deposition. This review starts by looking at the historical development and recalling the basic ideas of PBII. Advantages and disadvantages are compared to conventional ion beam implantation and physical vapor deposition for PBII and PBIID, respectively, followed by a summary of the physics of sheath dynamics, plasma and pulse specifications, plasma diagnostics, and process modeling. The review moves on to technology considerations for plasma sources and process reactors. PBII surface modification and PBIID coatings are applied in a wide range of situations. They include the by-now traditional tribological applications of reducing wear and corrosion through the formation of hard, tough, smooth, low-friction, and chemically inert phases and coatings, e.g., for engine components. PBII has become viable for the formation of shallow junctions and other applications in microelectronics. More recently, the rapidly growing field of biomaterial synthesis makes use of PBII and PBIID to alter surfaces of or produce coatings on surgical implants and other biomedical devices. With limitations, also nonconducting materials such as plastic sheets can be treated. The major interest in PBII processing originates from its flexibility in ion energy (from a few electron volts up to about 100 keV), and the capability to efficiently treat, or deposit on, large areas, and (within limits) to process nonflat, three-dimensional workpieces, including forming and modifying metastable phases and nanostructures.

Cell adhesion to nitrogen-doped DLCS fabricated by plasma-based ion implantation and deposition method

Diamond-like carbon (DLC) has excellent mechanical properties and chemical stability. Several techniques have been proposed for DLC fabrication. The plasma-based ion implantation and deposition (PBIID) method has several advantages, such as few limitations in sample shape, in comparison with conventional PVD or CVD methods. We have investigated the cell adhesion to nitrogen-doped DLCs fabricated by the PBIID method. The cell adhesion percentage for a non-doped DLC was 67% and for nitrogen-doped DLCs the adhesion increased by more than 10%. The cell adhesion percentage was 85% for a sample with a ratio of nitrogen to carbon of 0.2. We consider the possibility that the cell adhesion percentage is improved due to C–N and N–H bonds that promote the protein adsorption on the surface of the sample.

Measurement of residual stress in DLC films prepared by plasma-based ion implantation and deposition

A hybrid process of plasma-based ion implantation and deposition (PBIID) was used to achieve relaxation of compressive residual stress in diamond-like carbon (DLC) films. The residual stress in each film was determined from the curvature of quartz glass plate using Stoney's equation. The compressive residual stress in the DLC film prepared using acetylene gas was about 0.46 GPa without the negative pulsed voltage for ion implantation. The residual stress decreased considerably with the increase of the negative pulsed voltage during deposition and reduced to about 0.16 GPa at the negative pulsed voltage of −20 kV. The residual compressive stress in the DLC films prepared using toluene gas was reduced to about several MPa at the region of negative pulsed voltage of −5 to −7 kV. These reduction of stress might be due to the thermal spike effect by ion implantation. However, at the negative pulsed voltage exceeding about −10 kV, the reduction of residual stress was not observed because of generation of glow discharge by the negative pulsed voltage. In either case, the observed residual stress of the DLC film was almost two orders less than that of conventional DLC films.

DLC coating of a few microns in thickness on three-dimensional substrates

Uniform coating of the thick diamond-like carbon (DLC) on three-dimensional substrates was studied using a hybrid process of plasma-based ion implantation and deposition (PBIID). In the PBIID system, an RF pulse for plasma generation and a negative high-voltage pulse for ion implantation were supplied to a substrate through a single electrical feedthrough. Then the high-density plasma was produced along the substrate, leading to the formation of uniform coating film and the ion implantation on three-dimensional substrates. Ion implantation by PBII technique served to the reduction in compressive residual stress of DLC film and the formation of mixing layer between the DLC film and the substrate. As a result, the thick and good-adhesive DLC film with more than a few μm in thickness was almost uniformly prepared on the surface of cylindrical pipe, triangle prism, and trench structure. The deposition rate was approximately 1 μm/h using the toluene as a precursor gas. The hardness of the DLC films was found to be about 12 GPa by nano-indentation method.