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Cubic boron nitride (c-BN) films on tool substrates are tendency to delaminate. Therefore, many research groups have studied improvement of c-BN synthesis method and deposition processes due to many potential applications. In this paper, we show that the adhesion property of c-BN layer system can be improved by deposing multi c-BN layers. The multi c-BN layers were deposited by r.f (13.56 MHz) diode sputtering apparatus on cemented carbide tool substrates with a TiAlN adhesion layer. For industrial applications, we performed turning and milling experiments under dry and high speed cutting conditions. In this multi c-BN layer system, the lifetime of the tool is affected by the physical properties of the substrate and coated layers such as substrate grain size, thickness of the TiAlN and first c-BN layer and the total number of c-BN layers in this system. Mostly, fine grain size substrates showed longer lifetimes of over 4 times than raw one. In the turning performance, mono TiAlN layer systems were about two times lower lifetime than mono and multi c-BN layer system, moreover, we could be improved adhesion property for milling performance on tool substrates with binary multi c-BN layer systems under dry and high speed cutting conditions. The new application results of the multi c-BN layer system confirm that the high potential of c-BN coatings on cutting tools.

In this work, aluminum doped zinc oxide (AZO) thin films were synthesized at room temperature on PET substrates by using two different types of magnetron sputtering sources at the same time; deposited from two facing ZnO targets in a confined magnetic field, and co-doped from an Al target located outside of this region. The purpose of this system was not only to retain the advantages of the FTS system but also to propose a new type of doping concept. With this configuration, it was expected to get more flexibility for the tuning of Al concentration by controlling the external doping source. For the first, the gas mixture effect on the film properties was studied. In order to get a high quality crystallographic structure for acquiring high mobility, we controlled Ar working pressure, O 2 partial pressure, and H 2 partial pressure in sequence. After deposition, structural, electrical, optical, and surface morphological characteristics were examined. As a result, we could optimize the gas mixture condition including 2.5 mTorr of Ar, 1.2 sccm of O 2 partial pressure, and 3 sccm of H 2 partial pressure. Secondly, Al doping concentration was controlled by changing the external Al target power density. Moderate carrier concentration could be secured by tuning the Al doping. Also, it was deduced that doping reaction might be increased by the Al particles which had moderate energy. As a result, we could deduce the optimized Al power density as 15 W/cm 2 . Under our optimized condition, AZO films could have good electrical and optical properties with a minimum resistivity of 5.344 × 10 − 4 Ωcm and a maximum transmittance of 90.2%. At the end, TCO performance was derived (13.4 mΩ − 1 ) and this value was found to be valuable compared to other authors' latest works and commercial ITO.

Titanium oxide thin films containing silver (Ag) nanoparticles were synthesized on commercially pure titanium (cp-Ti) substrates using a reactive magnetron co-sputtering method. The goal was to maximize bactericidal activity along with sustained biocompatibility. Furthermore, this study examined the correlation between Ag nanoparticle dispersion in the films and the antibacterial efficacy of the Ag ions released from the films. The results showed that there might be two factors affecting the inhibition of bacterial attachment to the surface of the specimens: surface morphology and Ag ion release. MTT assay results demonstrated that there was no cytotoxicity on fibroblast cells in any group. Overall, the magnetron sputtered Ag nanoparticle-containing titanium oxide coatings in this study can be used as an efficient antibacterial layer with sustained biocompatibility.

We deposited MoSiN multilayer films using a MoSi2 target via pulsed-DC and radio-frequency (RF) magnetron sputtering methods. For the fabrication of the Ti-covered Si(100) substrate, we also grew Ti layers via the RF magnetron sputtering method. To improve the mechanical properties of the as-grown MoSiN thin films, argon and nitrogen plasmas ignited by RF and pulse DC under vacuum conditions were also used with a total pressure of 0.7 Pa, a substrate bias of −100 V, and a substrate ion current density of 1.5 mA/cm2. The as-grown MoSiN films were investigated for hardness (Gpa) and macro-stress(s) properties, and the relationship between film composition and micro-structures was analyzed using x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The maximum hardness and stress values of the MoSiN films were 32 GPa and −2.5 GPa, respectively, depending on variations of substrates and reactive gas.

The density of ground state and metastable Ti atoms were measured in a magnetron sputtering reactor with a 10 cm diameter Ti target by using resonant optical absorption spectroscopy. Experiments were conducted under various discharge parameters, namely the discharge current (0.2 A to 1.2 A) and the distance from the target (2 cm to 12 cm) under two working pressures (0.5 Pa and 4 Pa). The results were compared with previous results for a smaller magnetron source with a 5 cm diameter target. The Ti densities were as follows: [Ti]≈1011 cm−3, [Tim]=1010 to 1011 cm−3 for 0.5 Pa and [Ti]≈[Ti∞]=1010 to 1012 cm−3 for 4 Pa. The portion of Ti metastables in the discharge increases by a factor of approximately 2 as the working pressure increases.

Brasses are the most widely used copper-based alloys because of the good corrosion resistance, formability, high strength and excellent hot-working properties. However, dezincification occurs when one or more components of an alloy are more susceptible to corrosion than the rest and, as a result, are preferentially dissolved. In order to enhance the corrosion resistance, the brasses were exposed to pulsed DC oxygen plasma with various frequencies. The corrosion behavior of plasma oxidized brasses (POBs) with various pulse frequencies was investigated by electrochemical methods (potentiodynamic polarization test, electrochemical impedance spectroscopy) and surface analyses (X-ray diffraction, scanning electron microscopy). Particular attention was paid to the effects of pulse frequency on the corrosion properties of POBs. From the results of electrochemical test, it was found that the oxidized brass under the condition of 1.5 Torr oxygen pressure and 20 kHz frequency was effective in improving corrosion resistance. This was attributed to the protective oxidized layer (ZnO).

The synthesis of W–Ti–C multi phase film and the relationship between microstructure and composition were studied. W–Ti–C multi phase films, containing the W2C, TiC and WTiC, were successfully synthesized by hybrid system which was composed of arc ion plating (WC) and reactive magnetron sputtering (TiC). Chemical composition of each film was analyzed by Auger Electron Spectroscopy (AES). Also, microstructure of the W–Ti–C film was characterized by using X-ray diffraction (XRD) and Raman spectrometer. With increasing titanium composition, film phase transferred from W2C to WTiC and film hardness was decreased. In case of increasing carbon composition, TiC based multi phase film was formed at low carbon content and amorphous carbon or DLC (Me-C:H) film was formed at high carbon content. The film hardness was increased when the ratio of ‘(W + Ti) / C = 1’ and DLC was formed. Base on these results, we could present simple ternary diagram of W–Ti–C film as WTiC based, TiC based and amorphous carbon based multi phase films formation region.

The formation and properties of CrSiN thin films deposited on Si using closed field unbalanced magnetron sputtering system are studied. In this paper, the effect of Si concentration in the CrN films is investigated. Film hardening is generated by the two cases that result from formation of solid solution and formation of nc-CrN/a-Si3N4. Microstructure of the films due to the Si concentration is measured by XRD and TEM. Chemical composition of the films is investigated using GDOES. Also, XPS is analyzed for the examination of the bonding structure of the films. During the AFM, growth mode change from columnar to amorphous is confirmed. Hardness of the film is estimated by nano-indentation test. Maximum hardness value according to the various Si concentration is obtained at 32GPa.

In the downstream region of an unbalanced magnetron argon discharge, the influences of substrate bias (i.e., the condition of plasma boundary) on electron energy distribution function and plasma characteristics were investigated through the experiments using a single Langmuir probe. In a steady state with the grounded substrate, it could be found that the electron current flowing to the substrate compensates for the ion current flowing to the cathode due to the axial magnetic field such that the substrate plays the role of the actual anode. The potential of the anode sheath could be controlled by applying a dc voltage to the substrate, and the nonlinear behavior of the plasma potential with respect to the dc substrate voltage caused the distinctive evolution of the potential of the anode sheath. It was found that a transition of the electron energy distribution function from a bi-Maxwellian distribution at small dc voltages to a Maxwellian distribution at highly negative dc voltages occurs with decreasing...

We have treated the surfaces of Al, SUS and Cu metals using an atmospheric-pressure plasma jet generated by nitrogen and oxygen gases under the atmospheric pressure at room temperature. The plasma ignition occurred by flowing mixed gases between two coaxial metal electrodes, and the voltage was applied with impulse type and 16–20 kHz frequencies. The treated surfaces were basically characterized by means of a contact angle analyzer for the activation property on their surfaces. From the results of XPS, FE-SEM, OES and AFM, we could confirm that the main phenomena such as the reactive etching and oxidation were observed on their surfaces as well as even the aggregation of particles by the activated atoms, radicals and metastable species in the plasma space. However, all treated surfaces contained only oxygen and carbon without nitrogen, even though the excited nitrogen species were generated in the plasma due to its higher reactivity than oxygen ones observed in the OES data. The aging effect on the duration time of the surface energy, moreover, was also studied because of the production cost on the industrial applications in addition.

Surface of a stainless steel has been modified by atmospheric-pressure plasma jet method at room temperature. The impulse voltage is applied to ignite a plasma discharge using high purity (99.999%) reactive gases: N 2 and O 2 . The treated stainless steel is characterized by the activation property of the surface using a contact angle analyzer. Surface energy for the treated stainless steel is increased remarkably when compared to the untreated surface. From the results of X-ray photoelectron spectroscopy and atomic force microscopy, we could confirm that the main functional groups, causing the change in hydrophilic surface were generated under the surface reactions caused by reactive etching and oxidation of ions and activated species in the plasma. In addition, the aging effect during the duration of the hydrophilic property is also studied to investigate the production cost for the industrial applications.

New WC–Ti(1−x)AlxN nanocomposite films were synthesized on Si wafer WC–Co substrate by cathodic arc ion plating. A rotating substrate holder operated at 6 rev./min was used to obtain a layered structure, and the arc power density of Al cathodes was controlled for the change of Al concentration (x) in the film. For the evaluation of crystal structure and compounds formation behavior, X-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM) analyses were performed. The microhardness of WC–Ti(1−x)AlxN films was measured at a normal load of 30 mN by a nano-indentation instrument. WC–Ti0.43Al0.57N nanocomposite film that revealed the highest hardness and good adhesion strength were applied to a printed circuit board (PCB) drill for the evaluation of the drill's lifetime. As a result of adapting a PCB drill coated with WC–Ti0.43Al0.57N film, the lifetime of the PCB drill was improved by more than two times than that of the ordinary one.

We have deposited Hf(C,N) thin films on Si(100) and STD11 steel substrates by pulsed d.c. plasma assisted metal–organic chemical vapor deposition (PA-MOCVD) in the temperature range of 200–300°C. Tetrakis diethylamido hafnium, Hf[N(CH 2 CH 3 ) 2 ] 4 (TDEAH), was used as the hafnium precursor. A mixture of He (90%) and H 2 (10%) in volume ratio was used as the carrier gas, and the N 2 was used as the reactive gas. During CVD, radical formation and ionization behaviors in plasma were analyzed in situ by optical emission spectroscopy (OES) at various pulsed bias voltages and N 2 flow rates. The deposition rate with the change of the flow rate ratio of N 2 reactive gas to He+H 2 carrier gas was also increased to 0.1. With increasing bias voltage, moreover, the film growth rate was continuously increased resulting in carbon-rich films. Highly oriented oxygen-free, polycrystalline Hf(C,N) thin films in the {111} direction were successfully grown on the STD11 steel substrate at 300°C. The hardness of film changed from 1000 to 2500 HK, depending on N 2 gas flow rate ratio and bias voltage. Higher hardness can be obtained for a N 2 gas flow rate ratio of 0.1 and bias voltage of 600 V. The film composition was confirmed with XPS and RBS analysis, and the N 2 reactive gas makes low carbon contents in the films. SEM revealed that surfaces of as-deposited Hf(C,N) thin films were smooth and featureless.

We have deposited Ti(C,N) thin films on Si(100) and D2 steel substrates in the temperature range of 200–300 °C using tetrakis diethylamidotitanium (TDEAT) and titanium isopropoxide (TIP) by pulsed dc plasma-enhanced metalorganic chemical vapor deposition (PEMOCVD). Radical formation and ionization behaviors in plasma are analyzed in situ by optical emission spectroscopy at various pulsed bias voltages and gas conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameters, and the effect of N2 and NH3 as reactive gas is also evaluated by the reduction of the C content of the films. Polycrystalline Ti(C,N) thin films were successfully grown on either D2 steel or Si(100) surfaces with TDEAT at temperatures as low as 200 °C. For TIP, however, only TiOCN thin films were obtained on Si(100) substrates. The best deposition process is evident for H2 and N2 gas atmospheres and bias voltage of 600 V. The higher film hardness is about 1760 Hk 0.01, but depends on gas species and bias voltage. ...

We have deposited thick SiC thin films on graphite substrates in the temperature range of 700–850 °C using single-molecular precursors by both thermal metal–organic chemical-vapor deposition (MOCVD) and plasma-enhanced MOCVD (PEMOCVD) methods for oxidation-protection wear and tribological coating. Hexamethyldisilane (HMDS), (CH3)3Si–Si(CH3)3, was used as a single-source precursor, and hydrogen and Ar were used as a bubbler and carrier gas. A highly oriented polyerystalline cubic SiC layer in the [111] direction was successfully deposited on graphite at temperatures as low as 800 °C with HMDS by PEMOCVD. For thermal MOCVD, on the other hand, only amorphous SiC layers were obtained at 850 °C. From this study, we confirmed that PEMOCVD was a highly effective process in improving the characteristics of the SiC layers compared to those grown by thermal MOCVD. The mechanical and oxidation-resistant properties have been assessed. The optimum SiC film was obtained at 850 °C and rf power of 200 W. The maximum depo...