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Dispersion of carbon black (CB) powder in CB/polymer composites considerably influences their mechanical properties, electrical conductivity, and thermal conductance. In this study, with the aim to improve the dispersion of CB powder in the CB/polymer composites, CB was treated with oxygen and nitrogen plasma generated by radio frequency-plasma enhanced chemical vapor deposition (RF-PECVD), and then, dispersed in a poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) solution. The solution was then subjected to electrospinning, leading to the formation of a nanofiber mat. The dispersion states of plasma treated CBs have been characterized using scanning electron microscopy and Fourier-transform infrared spectroscopy. A stress–strain curve was used to investigate the influence of dispersion on the mechanical properties of CB/polymer composites.

Piezoelectric material has widely used in various applications with its high liable performance and quite smart electro-mechanical characteristics. However, solutions for number of troubles in strength and behavior of fracture have not sufficiently clarified yet. Among these associated solutions, the double torsion (DT) technique is the particular and effective method to measure toughness of fracture and growth behavior of slow crack in ceramic material. From the results of this work, it obtained the practical feasibility of the DT technique for finding growth behavior of crack initiated by kinds of cyclic electric fatigue on piezoelectric ceramics, and found that the initiated crack is able to propagate by using a relatively lower cyclical voltage than before cases under a constant mechanical load if the DT technique is used. In this study, it is also established the experimental method of the crack propagation by cyclic electric fatigue for the piezoelectric ceramics using DT technique, and found the possibility of the power law based on the classical Paris’ equation for analyzing the result of electric fatigue crack test.

Nanocrystalline diamond (NCD) is exceptionally useful for a variety of applications and is of significant interest to researchers in technological and scientific fields due to its excellent mechanical and chemical properties, such as its hardness and high thermal conductivity. We have modified a microwave plasma chemical vapor deposition (MPCVD; Astex Inc.) system with a slot antenna designed for surface wave plasma (SWP) and successfully fabricated high quality thin NCD film. This SWP-CVD process fabricates high quality diamond film at 300 °C, while a normal MPCVD process requires the temperature of the substrate to be above 800 °C. We studied the fabricated NCD samples in detail, measuring their surface morphology by field emission scanning electron microscopy (FESEM); their structural-chemical properties by Raman spectroscopy; and their surface roughness by atomic force microscopy (AFM).

Because of its stable crystal structure, a boron-doped diamond (BDD) has been attracting great attention as a promising material for a next-generation electrode. For instance, the BDD is a wellknown candidate to be exploited as an electrode for the ozone generation with its longer life-time. In this study, we have evaluated ozone-generating characteristics of the BDD electrodes related to the doping concentration of boron. In the experiment, morphology of surface was observing by scanning electron microscopy (SEM) and structural-chemical properties of the synthesized diamond layers were characterized by Raman spectroscopy. Conductivity, carrier concentration, and Hall mobility were determined by a Sheet resistance measurement and Hall effect measurement performed based on the van der Pauw method. The ozone concentration in the water was measured using an ozone colorimeter with DPD reagent.

For high-speed and large-area active-matrix displays, metal-oxide thin-film transistors (TFTs) with high field-effect mobility, stability, and good uniformity are essential. Moreover, reducing the RC delay is also important to achieve high-speed operation, which is induced by the parasitic capacitance formed between the source/drain (S/D) and the gate electrodes. From this perspective, self-aligned top-gate oxide TFTs can provide advantages such as a low parasitic capacitance for high-speed displays due to minimized overlap between the S/D and the gate electrodes. Here, we demonstrate self-aligned top-gate oxide TFTs using a solution-processed indium-gallium-zinc-oxide (IGZO) channel and crosslinked poly(4-vinylphenol) (PVP) gate dielectric layers. By applying a selective Ar plasma treatment on the IGZO channel, low-resistance IGZO regions could be formed, having a sheet resistance value of ~20.6 k&Omega, /sq., which can act as the homojunction S/D contacts in the top-gate IGZO TFTs. The fabricated self-aligned top-gate IGZO TFTs exhibited a field-effect mobility of 3.93 cm2/Vs and on/off ratio of ~106, which are comparable to those fabricated using a bottom-gate structure. Furthermore, we also demonstrated self-aligned top-gate TFTs using electrospun indium-gallium-oxide (IGO) nanowires (NWs) as a channel layer. The IGO NW TFTs exhibited a field-effect mobility of 0.03 cm2/Vs and an on/off ratio of &gt, 105. The results demonstrate that the Ar plasma treatment for S/D contact formation and the solution-processed PVP gate dielectric can be implemented in realizing self-aligned top-gate oxide TFTs.

In this study, we developed a nanoscale emitter having a multi-layer thin-film nanostructure in an effort to maximize the field-emission effect with a low voltage difference. The emitter was a sapphire board on which tungsten–DLC multi-player thin film was deposited using PVD and CVD processes. This multi-layer thin-film emitter was examined in a high-vacuum X-ray tube system. Its field-emission efficiency according to the applied voltage was then analyzed.

In this study, a DLC pattern was fabricated through a photolithography process that constitutes a part of the semiconductor process, to investigate the frictional wear characteristics. The photolithography was used to produce negative patterns with a pattern width of 10 [Formula: see text]m or 20 [Formula: see text]m and a pattern depth of 500 nm on the DLC surface. The change in the coefficient of friction of the surface was investigated through a ball-on-disk tribology test on the fabricated micro/nano-sized DLC pattern. The DLC pattern fabricated by the photolithography process showed a superior coefficient of friction to that of the general DLC sample. These results show that the decrease in the surface friction coefficient of the patterned DLC thin film is due to the reduction in the surface contact area owing to the modification of the micro/nano-texture of the surface as well as the low friction characteristics of the DLC.

In general, MgF2, which is a low-reflective coating material, has a refractive index of 1.38. The refractive index of a single layer of MgF2 is not sufficient for industrial applications. In this study, an anti-reflection MgF2 coating film with low reflectivity and high wear resistance was synthesized to be used as a single layer with a TEOS binder. The prepared anti-reflection coating film was coated in the form of nanoparticles on a curvature lens having an aspherical surface coefficient by spin coating, and the correlation with optical properties was confirmed through particle size measurement. The MgF2 nanoparticle AR coating film was characterized by LDPSA, UV-Vis, SEM and ellipsometry. Mechanical and optical properties were confirmed with a minimum reflectance of 0.1% or less and a low refractive index of 1.24–1.25.

This study grew nitrogen doped ultrananocrystalline diamond (N-UNCD) conductive layer on InGaN-based light emitting diodes (LEDs) using the concave nanopattern (CNP) enhanced nucleation. The low nucleation density of the N-UNCD on bare LEDs (Br-LED) resulted in an island morphology. The nucleation density of the N-UNCD increased significantly from 1.8 × 108 cm−2 for Br-LED to 3.6 × 109 cm−2 for LEDs with a CNP density of 6.1 × 109 cm−2 (CNP-LED). The N-UNCD preferred to nucleate inside the CNP during the initial growth stage. The N-UNCD islands then merged and grew laterally to form a continuous thin film within a thickness of 300 nm. The N-UNCD/CNP-LED exhibited a stable electroluminescence peak wavelength of ~447.1 nm in the injection current range of 10–100 mA. The decrease in the compressive stress due to removing the p-GaN layer (i.e. the CNP structure) resulted in a quantum confined Stark effect (QCSE) mitigation in the multi-quantum wells (MQWs). In addition, the lower turn on voltage caused a lower electric field in the MQWs and diminished the screen of the QCSE. The N-UNCD prepared by the proposed nucleation technique demonstrated a promising conductive layer for InGaN-based LEDs.

Graphene, a two-dimensional engineered nanomaterial, is now being used in many applications, such as electronics, biological engineering, filtration, lightweight and strong nanocomposite materials, and energy storage. However, there is a lack of information on the potential health effects of graphene in humans based on inhalation, the primary engineered nanomaterial exposure pathway in workplaces. Thus, an inhalation toxicology study of graphene was conducted using a nose-only inhalation system for 28 days (6 h/day and 5 days/week) with male Sprague-Dawley rats that were then allowed to recover for 1-, 28-, and 90-day post-exposure period. Animals were separated into 4 groups (control, low, moderate, and high) with 15 male rats (5 rats per time point) in each group. The measured mass concentrations for the low, moderate, and high exposure groups were 0.12, 0.47, and 1.88 mg/m3, respectively, very close to target concentrations of 0.125, 0.5, and 2 mg/m3. Airborne graphene exposure was monitored using several real-time instrumentation over 10 nm to 20 μm for size distribution and number concentration. The total and respirable elemental carbon concentrations were also measured using filter sampling. Graphene in the air and biological media was traced using transmission electron microscopy. In addition to mortality and clinical observations, the body weights and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for blood biochemical tests, and the organ weights were measured. No dose-dependent effects were recorded for the body weights, organ weights, bronchoalveolar lavage fluid inflammatory markers, and blood biochemical parameters at 1-day post-exposure and 28-day post-exposure. The inhaled graphenes were mostly ingested by macrophages. No distinct lung pathology was observed at the 1-, 28- and 90-day post-exposure. The inhaled graphene was translocated to lung lymph nodes. The results of this 28-day graphene inhalation study suggest low toxicity and a NOAEL of no less than 1.88 mg/m3.

In this research, catalyst-free vertically aligned boron doped carbon nanowalls films were fabricated on silicon (100) substrates by MPECVD using feeding gases CH4, H2 and B2H6 (diluted with H2 to 5% vol) as precursors. The substrates were pre-seeded with nanodiamond colloid. The fabricated CNWs films were characterized by Scanning Electron Microscopy (SEM) and Raman Spectroscopy. The data obtained from SEM confirms that the CNWs films have different density and wall thickness. From Raman spectrum, a G peak around 1588 cm(-1) and a D band peak at 1362 cm(-1) were observed, which indicates a successful fabrication of CNWs films. The EDX spectrum of boron doped CNWs film shows the existence of boron and carbon. Furthermore, field emission properties of boron doped carbon nanowalls films were measured and field enhancement factor was calculated using Fowler-Nordheim plot. The result indicates that boron doped CNWs films could be potential electron emitting materials.

Multi wall carbon nanotubes (MWCNTs) and diamond are renowned as superlative material due to their relatively high thermal conductivity and hardness while comparing with any bulk materials. In this research, polyacrylonitrile (PAN) solution incorporated with MWCNTs at an alteration of mass fractions (0 wt%, 0.6 wt%, 1 wt%, 2 wt%) were fabricated via electrospinning under optimized parameters. Dried composite nanofibers were stabilized and carbonized, after which water base polytrafluorethylene (PTFE) mixed with nano diamond powder solution was spin coated on them. Scanning electron microscopy, Raman spectroscopy, X-ray scattering and Laserflash thermal conductivity were used to characterize the composite nanofiber sheets. The result shows that the thermal conductivity increased to 4.825 W/m K from 2.061 W/mK. The improvement of thermal conductivities is suggesting the incorporation of MWCNTs.

We used hot filament chemical vapor deposition to synthesize conductive diamond layers. Scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD) were employed to explore how boron affected diamond formation in terms of structural chemistry, surface appearance, and growth rate. As the boron/carbon (B/C) ratio increased, thin boron-doped diamonds (BDDs) exhibited increased levels of amorphous carbon. We used a high-temperature furnace to explore the heat resistance of BDDs.

High strength low alloy steel has excellent heat resistance and high strength. As it is commonly used as gun barrel material, a long service life and superior wear resistance are necessary for steel components. Here we investigated the wear characteristics of high strength low alloy steel surfaces under various environmental conditions, using a pin-on-disk wear test. Oxidation and wear debris effects on the coefficient of friction (COF) of the alloy steel were examined under air and argon (Ar) gas flow at atmospheric conditions.

High chrome steel (12 Cr-steel) is the material found in engine blade which required high durability and long service life at high temperatures. Therefore, it is important to produce durable and high strength 12 Cr-steel. In this study, effect of different tempering temperature on microstructure of 12 Cr-steel specimens were investigated. First, the specimens were heat treated to 1070[Formula: see text]C and quenched in an acidic solution. Then they were tempered at different temperature at 470[Formula: see text]C and 690[Formula: see text]C. Analyses on mechanical properties such as hardness, yield strength, tensile stress were performed. It is found that specimen at lower temperature (470[Formula: see text]C) has improved mechanical properties.

In recent decades, the rapid development of nanoscience and nanotechnology has accelerated materials with high thermal conductivity, such as composite carbon nanomaterials, since heat removal has become a crucial issue. In this work polyacrilonitrile (PAN) incorporated with alteration of mass fraction (0.3 wt%, 0.62 wt%, 0.92 wt%, 2.74 wt%) of the multi-walled carbon nanotubes (MWCNTs) were used to fabricate composite fibers via electrospinning. The stabilizing and carbonization reactions of composite nanofibers are conducted in tube furnace at 280 °C and 1000 °C. The structural features of flexible composite carbon nanofiber papers were characterized under scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Raman spectroscopy. Special attention of composite carbon nanofiber papers is given to cross-plane thermal conductivity and in-plane thermal conductivity and were measured via Flash Line Analyzer. The results proved that flexible composite carbon nanofiber papers are promising heat sink radiator for a variety of applications including flexible optical and electronic devices.

This paper describes modification of catalyst surface from interaction between catalysts and dielectric barrier discharge (DBD) plasma. Ru/γ–Al₂O₃ catalyst was exposed to DBD plasma for CO₂ methanation and CH₄ direct conversion reactions. Parameters related to the modification of catalyst surface were investigated by SEM and EDS analysis.

The linear contribution of total energy release rate for fracture of ferroelectric materials was studied based on the linear theoretic framework of piezoelectricity using the double-torsion technique. It was found that three linear contributions of the total energy release rate for piezoelectric material are definitely associated with pure mechanical compliance, electromechanical compliance, and pure electrical capacitance. To confirm the entity of contributions, mechanical and electromechanical compliances were analyzed obtained from result of load vs. displacement measured on each electric field, and electrical capacitance was obtained from property and geometry of samples.

Color glasses are fabricated with Titanium target by RF magnetron sputtering. The physical properties of the Ti thin films are investigated according to preparation conditions, such as argon and oxygen gas flow ratio, RF power and Working pressure. The results indicate that it is possible to deposits various Ti thin film’s of different colors on glass substrate, such as yellow, orange, brown, purple. The thickness according to the color was analyzed using Veeco's Stylus profiler (model: dektak 6M).

To accomplish long-term use of specific parts of steel, welding technology is widely applied. In this study, to compare the efficiency in improving mechanical properties, rolled steel (SS400) was welded with stainless steel (STS304) by both CO2 welding method and MIG (metal inert gas) welding method, respectively. Multi-tests were conducted on the welded specimen, such as X-ray irradiation, Vickers’ Hardness, tensile test, fatigue test and fatigue crack growth test. Based on the fatigue crack growth test performed by two different methods, the relationship of da/dN was analyzed. Although the hardness by the two methods was similar, tensile test and fatigue properties of MIG welded specimen are superior to CO2 welded one.

Indium tin oxide (ITO) films with various oxygen partial pressure from 0 to 6 × 10 Pa were prepared onto polyethylene terephthalate (PET) using RF magnetron sputtering at room temperature. The structural, electrical and optical properties of the grown ITO films were investigated as a function of the oxygen partial pressure. The amorphous nature of the ITO films was dominant at the partial pressure below 1 × 10 Pa and the degree of crystallinity increased as the oxygen concentration increased further. This structural change comes with the increased carrier concentration and reduction of the electrical resistivity down to 9.8 × 10 Ω · cm. The average transmittance (at 400~800 nm) of the ITO deposited on the PET substrates increased as the oxygen partial pressure increased and transmittance above 80 % was achieved with the partial pressure of 4 × 10 Pa. The results show that the choice of optimal oxygen partial pressure can present improved film crystallinity, the increased carrier concentration, and the enhancement in the electrical conductivity.

High density plasma etching of ultrananocrystalline diamond (UNCD) films wasperformed in O2 and O2/Ar inductively coupled plasma (ICP) discharges. The O2/Ar ICP discharges produced higher etch rates due to enhanced physical component of the etching, and a maximum etch rate of -280 nm/min was obtained in 10 sccm O2/5 sccm Ar discharges. Very high etch selectivities up to -140:1 were obtained for the UNCD over Al mask layer. Anisotropic pattern transfer with a vertical sidewall profile was achieved in the 10 sccm O2/5 sccm Ar discharges at a relatively low source power (300 W) and a moderate rf chuck power (200 W).

In this study, we report the synthesis and characterization of novel hybrid nanocoating based on carbon nanotubes (CNTs) on anodized aluminum surfaces (AAO). The hybrid nanocoating was deposited by number of methods which include spray coating, spin coating and dip coating. The bonding of nanocoating with metal surface is an important parameter for successful modification of the metal surfaces. The improved adhesion of nanocoating on metal surfaces could be attributed to chemical bonding of sol-gel nanocoating with anodized surfaces. The nanocoated anodized aluminum surfaces showed superior adhesion and excellent anticorrosive properties. The nanocoated panels showed enhanced galvanic protection comparable to 80% of titanium metal as determined by galvanic corrosion measurements. It also showed higher thermal conductivities than stainless steel and bare anodized surfaces.

A significant improvement in surface morphology of ultrananocrystalline diamond (UNCD) film was achieved with hydrogen heat treatment of nanodiamond (ND) seed particles. By hydrogen heat treatment, the average size of ND aggregates was greatly reduced from ∼2 µm to ∼55 nm as the ND surfaces were modified to hydrogen-containing functionalities. Si surfaces seeded with the hydrogen heat-treated ND seeds showed very high seeds densities up to ∼1011 cm−2. The grown UNCD film with ND seeds treated at 600 °C provided a very smooth surface morphology consisted of small and uniformly distributed grains compared to the film grown with untreated ND seeds. AFM scan image of the grown UNCD films seeded with untreated and hydrogen heat-treated ND particles.

Diamond-like carbon (DLC) coatings of 300, 500 and 650 nm thickness were deposited on stainless steel substrates using a filtered cathodic vacuum arc hybrid with magnetron sputtering system. A 100 nm thick chromium interlayer was deposited before the deposition of the DLC coatings. The films morphology was characterised by field emission scanning electron microscopy and structure was identified by Raman spectroscopy. Tribology was evaluated by ball disc wear test and wear tracks were observed by scanning electron microscopy. The interface adhesion was studied by scratch tester. The results of all characterisations were concluded and 500 nm DLC coating has suggested as optimum thickness that would be applicable for industrial applications.

Poly vinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) membrane were prepared by the electrospinning technique. We had applied a DLC coating process and then the surface of the membrane and the contact angle change was investigated. Electrospun fibrous PVdF-HFP membrane surface became to wrinkled shape by Ar plasma treatment and treatment conditions. The wrinkled surface of PVdF-HFP membrane became super-hydrophilic. However, after DLC coating process, it became super-hydrophobic. The resulting surfaces were characterized by water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM). Resultantly it was recognized that the wettability characteristics of the membrane surfaces depended on the chemical composition and surface morphology.

Diamond-like carbon (DLC) coatings are getting new trends for cutting tool applications. In this research work, the DLC coatings were deposited on 15 × 15 × 5-mm tungsten carbide cobalt substrates with variation of bias voltage from 0 to 500 V. The DLC films of 400 nm were deposited using filter cathode vacuum arc system, and 100-nm chromium interlayer was deposited by sputtering. The optimized conditions for plasma pretreatment at different argon flow rates and deposition rates with bias variation were found. The effect of bias voltage on microstructure, tribology, adhesion, and mechanical properties were evaluated. The characterization techniques employed were field emission electron microscopy, Raman spectroscopy, wear test, SEM, scratch test, and nano-indentation. The effect of substrate pretreatment on film adhesion was also evaluated. It was observed that etching rate increased with the increase in Ar flow rate while DLC deposition and sputtering rates decreased with increase in the bias voltage. The characterization suggests the DLC coatings deposited at 0 V bias as optimum condition because of showing the best results among all other conditions. Copyright © 2014 John Wiley & Sons, Ltd.

The purpose of this study is to examine the low-cycle fatigue (LCF) characteristics of high-chrome heat-resistant steel, which is used in a high-temperature environment, at both ambient and high temperature. High-chrome heat-resistant steel, which is used for the turbine blades of a nuclear power plant, can be subject to plastic deformation due to overloading conditions at startup and shutdown. It is therefore very important to evaluate the damage caused by LCF, which is considered as fatigue damage due to plastic deformation. To examine the mechanical properties of high-chrome heat-resistant steel, the tensile strength was tested under different heat treatment conditions. In addition, the LCF characteristics were tested at ambient temperature and [Formula: see text].

Sulzer-type engines are widely used in ships given their excellent fuel-saving, low-noise, and low-vibration properties. Here, we evaluated the low-cycle fatigue (LCF) properties of SNCM 420H steel after heat-tempering. LCF was studied at both [Formula: see text] and [Formula: see text], at strains of 0.8, 0.9, 1.2 and 1.5%. We used a triangular waveform for LCF testing to find fracture. The fatigue life of SNCM 420H at [Formula: see text] was about 60% less than that at [Formula: see text].

Design and implementation of a low-loss K-band duplexer consisting of two narrow bandpass filters with low-impedance open-loop resonators (OLRs) is presented. Narrow bandpass filters of 4%-7% bandwidth were often implemented with OLRs, but previous designs used OLRs mostly with 50 Ω linewidth. The design process was complicated due to multiple coupling mechanisms and multiple spurious response frequencies, often resulting in excessive insertion loss, especially at higher center frequencies. With the proposed design procedure for OLR filters, the values of the low-impedance line (less than 50 Ω) and proper coupling spacing are determined in the process of optimizing the filter performance, resulting in low insertion loss up to above K-band frequencies. The size of the proposed filter is also reduced to 64% of the conventional OLR filters. As an example of the proposed design method, a duplexer consisting of 4% narrow bandpass filters centered at 18.7 GHz and 22.5 GHz was implemented and measured, and the maximum insertion loss in each passband was 1.2 dB, which is much less than those of the previous design approaches.

The diamond like carbon coatings (DLC) of 400 nm thickness was deposited by filtered cathodic vacuum arc system. The argon plasma etched and non-etched tungsten carbidecobalt (WC-Co) and stainless steel (SUS) were used as substrates. The chromium was deposited as an interlayer for diamond like carbon coatings on the etched and non-etched WC-Co and SUS substrates. The present research is to evaluate the effect of argon plasma etching of the substrates on microstructure, tribology and adhesion strength of DLC coatings. The films were characterized by field emission scanning electron microscopy, Raman spectroscopy, tribology and scratch tests. The Raman studies showed the broad peak ∼1550 cm −1 indicates the formation of amorphous carbon or diamond-like carbon. It was found that the DLC coatings on the plasma etched substrates of WC-Co and SUS have shown the low friction coefficient of ∼0.12–0.14. The DLC coatings on plasma etched substrates of WC-Co have better adhesion strength. The results showed that the argon plasma etching of substrate reduces the surface roughness to ∼2.5 nm, resulting in smooth morphology, good adhesion and wear resistance as compared to DLC coating on non-etched substrates. The scanning electron microscopic studies showed that the DLC coated specimens with plasma etched substrates have minimum damage as compared to the DLC coated non etched substrates.

Aluminum oxide (Al 2 O 3 ) thin films were deposited on silicon (100) and quartz substrates by pulsed laser deposition (PLD) at an optimized oxygen partial pressure of 3.0×10 −3 mbar in the substrate temperatures range 300–973 K. The films were characterized by X-ray diffraction, transmission electron microscopy, atomic force microscopy, spectroscopic ellipsometry, UV–visible spectroscopy and nanoindentation. The X-ray diffraction studies showed that the films deposited at low substrate temperatures (300–673 K) were amorphous Al 2 O 3 , whereas those deposited at higher temperatures (≥773 K) were polycrystalline cubic γ -Al 2 O 3 . The transmission electron microscopy studies of the film prepared at 673 K, showed diffuse ring pattern indicating the amorphous nature of Al 2 O 3 . The surface morphology of the films was examined by atomic force microscopy showing dense and uniform nanostructures with increased surface roughness from 0.3 to 2.3 nm with increasing substrate temperature. The optical studies were carried out by ellipsometry in the energy range 1.5–5.5 eV and revealed that the refractive index increased from 1.69 to 1.75 ( λ =632.8 nm) with increasing substrate temperature. The UV–visible spectroscopy analysis indicated higher transmittance (>80%) for all the films. Nanoindentation studies revealed the hardness values of 20.8 and 24.7 GPa for the films prepared at 300 K and 973 K respectively.

SF6/O2 plasma surface texturing was employed to pretreat Si substrate for achieving enhanced diamond nucleation density. Surface roughness of the textured Si was found to be strongly dependent on the process pressure and normalized roughness values in the range of 2-16 were obtained. Remarkably enhanced nucleation densities of ~1010 cm-2 compared to conventional mechanical abrasion were obtained after seeding for the surface textured Si substrates. Raman spectroscopy revealed that ultrananocrystalline diamond films with grain size below 10 nm were grown on the surface textured Si.

Cerium oxide (CeO 2 ) thin films were deposited on Si (100) and glass substrates at various oxygen partial pressures (2×10 −5 mbar–3×10 −1 mbar) and a substrate temperature of 673 K, by pulsed laser deposition (PLD). The structural, morphological and optical properties of the films were characterized by X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, atomic force microscopy, photoluminescence and UV–visible spectroscopy. XRD analysis revealed the polycrystalline and cubic structure of the CeO 2 films with preferred orientation for (200) as the increase of oxygen partial pressure. The Raman studies indicated the formation of Ce–O with the systematic variation of peak intensity and FWHM with oxygen partial pressures. The high resolution transmission electron microscopy investigation confirmed the polycrystalline and cubic nature of the CeO 2 films with (200) preferred orientation. The AFM studies showed the roughness (RMS) values of the films increased from 0.8 nm to 4.6 nm with increasing oxygen partial pressure from 2×10 −5 mbar to 3×10 −1 mbar. The photoluminescence (PL) investigation indicated the bandgap values in the range 3.05–3.10 eV with increasing oxygen partial pressures. The UV–visible spectroscopy analysis demonstrated that the refractive index of the films decreased from 2.41 to 1.72 with increasing oxygen partial pressures.

It is well known that fatigue failure occur on welded structures in industrial application due to the repetitive load force. In order to decrease the fatigue failure, we analysed the mechanical properties based on their structural aspect, roll steel (SS 400) welded onto stainless steels (STS 304) by CO2 gas as well as structure roll steel welded onto itself. We compared the hardness, tensile and fatigue properties with two kinds of samples which had no defects on the welding part observed by X-ray topographic analysis. It was recognized that the tensile and fatigue strength of SS 400 welded onto itself by CO2 gas was higher than that of SS 400 welded onto STS 304.

Indium tin oxide (ITO) films with various thicknesses from 104 nm to 513 nm were prepared onto polyethylene terephthalate (PET) substrates by using r.f. magnetron sputtering without intentionally heating the substrates. The structural, optical, and electrical properties of ITO films were investigated as a function of film thickness. It was found that the amorphous nature of the ITO film was dominant below the thickness of about 200 nm but the degree of the crystallinity increased with an increasing thickness above the thickness of about 250 nm, resulting in the increase of carrier concentration and therefore reducing the electrical resistivity from 5.1 x 10(-3) to 9.4 x 10(-4) omega x cm. The average transmittance (400-800 nm) of the ITO deposited PET substrates decreased as the film thickness was increasing and was above 80% for the thickness below 315 nm. The results show that the improvement of the film crystallinity with the film thickness contributes to the increase of the carrier concentration and the enhancement of the electrical conductivity.

Very smooth ultrananocrystalline diamond (UNCD) film growth on SiC substrate was achieved by a novel pretreatment technique consisted of SiC surface texturing and deaggregation of nanodiamond (ND) seed particles. Texturing of SiC surfaces in Ar and SF6/02 plasmas was found to be able to provide normalized roughness values of 0.5-7.0 compared to the untreated surface. SiC surface plasma-textured and seeded with H2 heat-treated ND particles at 600 degrees C showed the highest nucleation density of ~44.2 x 10(11) cm(-2) and a highly uniform coverage of surface with very fine ND seeds. The UNCD film grown with this new pretreatment technique showed a very smooth surface morphology consisted of small and uniformly distributed grains.

Transparent diamond-like carbon (DLC) films were synthesized on glass using radio frequency plasma enhanced chemical vapor deposition method from the gas mixture of , and Ar. The pressure, the rf-power, ratio, and the deposition time were 0.1Torr, 100W, 20 : 1 : 1, and 20 min, respectively. The optical transmittances of DLC-deposited glass and uncoated glass were compared with each other in the visible light regions. The DLC-deposited glass showed transmittance of approximately 83 % and 95 % as compared to the uncoated glass for the wavelength of 380 nm and 500 nm, respectively. The hardness and roughness of DLC-coated glass have been measured by nanoindentation and AFM, respectively. The DLC-coated glass showed a little less or similar optical transmittance compared to the uncoated glass, while the hardness of DLC-coated glass was 2.5 times higher than that of the uncoated glass. The deposited DLC film had the very smooth surface and was thicker than 150 nm after deposition for 20 min.

Several R&Ds are being performed for Korean helium cooled solid breeder (HCSB) test blanket module (TBM) in the field of hydrogen isotopes permeation characteristics measurement in the helium purge line, joining technologies of structural materials, breeder pebble materials development, and the measurement of pebble bed characteristics. Electron beam welding for reduced activated ferritic–martensitic (RAFM) steel is evaluated to find optimal welding conditions. Also, a hydrogen permeation measurement apparatus is newly installed for the evaluation of the permeation barrier characteristics of stainless steel and RAFM steels. Two fabrication methods of lithium orthosilicate pebbles are investigated using slurry droplet methods. As methods of silicon carbide coating on the graphite pebble, microwave coating and chemical vapor deposition coating are evaluated. Two apparatuses are established to assess the thermo-mechanical properties of graphite and breeder pebble beds. The current status of R&D activities on these areas is introduced and the main progresses are addressed in this paper.

Numerical simulation and experimental study of the Vickers indentation testing of the Al2O3 ceramic coated by diamond-like carbon (DLC) layer were conducted. The numerical analysis was implemented by a two-dimensional finite element (FE) axis symmetry model. FE analysis results gave insight into the fracture mechanism of DLC films coated on brittle ceramic (Al2O3) substrates. The maximum principal stress field was used to locate the most expected area for crack formation and propagation during the Vickers indentation testing. The results show that the median crack initiates in the interface under indenter, before ring crack occurs as the indenter presses down. Finally, the plastic deformation appears when the indenter penetrates into the substrate. The thicker DLC coating increases the Vickers hardness and fracture toughness.

Silicon carbide film was coated by RF sputtering system onto graphite plate substrate. Surface roughness of substrate was polished by wet polishing with sand paper, number of 3000. RF power was 200 W in 0.4 Pa of argon gas. Deposition holding time was 3hours in 600 °C temperature. Specimens were heat treated by 1200, 1400 and 1500 °C for 1 hour to research the effect of heat treatment on SiC coating layer. Atomic Force Microscope (AFM) was used to characterize the surface morphology and the Sq surface roughness. AFM was used to investigate the grain size and roughness of the surface of thin coating film. X-ray diffraction (XRD) was used for detecting the coated SiC thin film by thin film mode. FE-SEM was used to characterize the microstructure of SiC coating film.

In this study, we have developed the method for obtaining a conductive DLC layer on glass substrate of 30×30mm size by adding Nitrogen or Silane gas during CVD(Chemical Vapor Deposition) growth. The growth rate and electrical conductivity were investigated under different plasma deposition condition. In addition, we measured the optical transmittance spectra of the films. From the measurements of optical transmittance in range of 300 to 1150 nm wavelength, an optical transmittance is obtained from 80% to 90% from the DLC films grown with lower gas flow rates. The characteristic of DLC films were evaluated by various techniques including alpha step surface profiler, micro Raman spectroscope, X-ray diffraction(XRD) and Nano- indentation.

High density plasma etching of SnO 2 and ZnO films was performed in chlorine- ( Cl 2/ Ar and BCl 3/ Ar ) and fluorine-based ( CF 4/ Ar and SF 6/ Ar ) inductively coupled plasmas. The etch process window for fabricating metal oxide nanowires with high aspect ratios including high and controllable etch rates, high etch selectivities to mask material and high anisotropy was established. Maximum etch rates of ~2050 Å/minute ( BCl 3/ Ar ) and ~1950 Å/minute ( SF 6/ Ar ) for ZnO , and ~1950 Å/minute ( Cl 2/ Ar ) and ~2000 Å/minute ( SF 6/ Ar ) for SnO 2 were obtained. Ni was found to provide very high etch selectivities with maximum values of ~67 to SnO 2 and ~17 to ZnO , respectively.