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Zirconium (Zr), a potential candidate for preventing Fuel-Cladding Chemical Interaction, shows stable interdiffusion behavior between cladding and fuel materials. However, a 25 μm-thick Zr foil allows local inter-diffusion, due to defects generated during manufacturing. In this study, we investigate the use of a Zr thin film deposited on Zr foil for preventing local inter-diffusion. The diffusion behavior of the Zr thin film on Zr foil was investigated using misch metal (Ce: 75% and La: 25%) as fuel fission product, in order to effectively simulate nuclear fuel. While without the Zr barrier substantial inter-diffusion occurred at the interface between the ferritic/martensitic HT9 cladding material and misch metal, the Zr thin film on Zr foil exhibited excellent resistance to interdiffusion. The enhancement of the barrier ability of the Zr thin film on Zr foil was attributed to a lower amount of defects induced by the Zr thin film layer. [ABSTRACT FROM AUTHOR]

The distillation of an industrial Fe-Mn alloy at a high temperature and under a low pressure was suggested as an efficient method for manufacturing high purity manganese in our study. This study examined the evaporation behavior of a low carbon ferromanganese alloy melt at reduced pressure. The melt temperature, pressure, initial specific surface area of the melt and reaction time were considered as experimental variables. The evaporation ratio of manganese increased sharply in the initial reaction and remained relatively constant under various experimental conditions. The evaporation rate of manganese increased with an increasing temperature and the initial specific surface area of the melt and decreasing pressure. The activation energy of the manganese evaporation reaction decreased with a decreasing pressure. The initial specific surface area of the melt had a lesser effect than pressure. An empirical equation was derived for the rate of manganese evaporation from a low carbon ferromanganese alloy melt. [ABSTRACT FROM AUTHOR]

One of the most important issues in future Cu-based interconnects is to suppress the resistivity increase in the Cu interconnect line while decreasing the line width below 30 nm. For the purpose of mitigating the resistivity increase in the nanoscale Cu line, alloying Cu with traces of other elements is investigated. The formation of a Cu alloy layer using chemical vapor deposition or electroplating has been rarely studied because of the difficulty in forming Cu alloys with elements such as Al. In this work, Cu-Al alloy films were successfully formed after thermal annealing of Cu/Al multilayers deposited by cyclic metal-organic chemical vapor deposition (C-MOCVD). After the C-MOCVD of Cu/Al multilayers without gas phase reaction between the Cu and Al precursors in the reactor, thermal annealing was used to form Cu-Al alloy films with a small Al content fraction. The resistivity of the alloy films was dependent on the Al precursor delivery time and was lower than that of the aluminum-free Cu film. No presence of intermetallic compounds were detected in the alloy films by X-ray diffraction measurements and transmission electron spectroscopy. [ABSTRACT FROM AUTHOR]

Noise absorbing properties of two kinds of magnetic thin films (one is electrically conductive Co-Zr-O granular thin film and the other is Ni-Zn ferrite thin film with high electrical resistivity) are analyzed by the finite element method (FEM) with various film thicknesses. For the Ni-Zn ferrite film with high electrical resistivity (∼2 × 10 Ωm), a low reflection parameter (S) value is predicted, and the value does not significantly change with increased film thickness up to 10 μm. However, the transmission parameter (S) is reduced with increased film thickness due to increased power absorption by magnetic loss. For the Co-Zr-O thin films with low electrical resistivity (∼1.6 × 10 Ωm), however, reflection signal is increased with increased film thickness due to diminished sheet resistance of the thin film. Transmission loss is not very sensitive to the thickness of the conductive film. Large power absorption is, therefore, predicted for conductive film of smaller thickness. It is concluded that film thickness is an important control parameter for the achievement of a highly absorptive thin film with increased electrical conductivity. [ABSTRACT FROM AUTHOR]

Ti(N,C,O) thin films were deposited by means of metal-organic chemical vapor deposition using a glow discharge with the aim of enhancing the corrosion resistance and electrical contact conductivity of austenitic stainless steel as a candidate materials for the bipolar plates used in polymer electrolyte membrane fuel cells. The corrosion properties were found to be dependent on the composition, i.e., the precursor source, and on the thickness of the thin films. Tetrakis(diethylamino) titanium used as a liquid metal organic source for the deposition of thin Ti(N,C,O) layers onto austenitic stainless steel provided a significant improvement of the corrosion resistance, which resulted in superior interfacial electrical conductivity after corrosion tests. [ABSTRACT FROM AUTHOR]

We demonstrate the formation of precisely designed double-walled carbon nanotube (DWNT) structures via growth optimization of thermal chemical vapor deposition. Effects of various growth factors such as different catalyst film- and buffer layer-thicknesses, flow rates and growth time were investigated to produce desired DWNT structures. We used acetylene as the main feedstock and fabricated site selective DWNT vertical structures through a catalyst patterning process. The DWNT structures will be applicable to areas where mechanical stability with thin diameter is required, such as in nanotube-based composites, electron emission devices, heat release components in electric devices and nanoelectromechanical systems. [ABSTRACT FROM AUTHOR]

Various types of nanostructures were synthesized by the simple thermal evaporation of ZnO powders at 1300 °C. Three types of nanostructure were formed as the substrate temperature increased from 100 °C to 300 °C: Zn-core/ZnO-shell nanocables (120 °C to 150 °C), Zn-ZnO core-shell nanocables connected to mesoporous ZnO (200 °C to 260 °C), and ZnO nanotubes (260 °C to 300 °C). The formation process of the ZnO nanotubes, which were formed at the highest temperature (260 °C to 300 °C), involved the solidification of liquid Zn droplets, surface oxidation, and the sublimation of the Zn. This result was demonstrated experimentally as well as via microstructural analysis using XRD, field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) equipped with an energy dispersive X-ray spectrometer (EDS). [ABSTRACT FROM AUTHOR]

Recently, Diamond like carbon (DLC)-based functionally gradient coatings have been used in a variety of engineering applications as useful films with appropriate tribological properties verified in many tests. However, due to their inherent residual stresses, they have a tendency to peel off, thereby limiting their applications (involving high contact stresses) and deposition thickness. Their brittleness and low adhesion may stem from either a faulty layer design or the wrong choice of material and deposition method. Therefore, using both a suitable interleaving material and an appropriate deposition technology will create an inclusive vision to accommodate better film properties. In this study, Ti-a:C and Ti-TiC-a:C films on AISI M2 steel substrates were deposited by Closed Field Unbalanced Magnetron Sputtering (CFUBMS) method using pulsed-dc biasing, and the mechanical, the structural, and the tribological properties for both films were investigated. It was seen that the incorporation of a TiC buffer layer between the Ti interlayer and the a:C matrix played a positive role in terms of hardness, wear rate, and adhesion properties. [ABSTRACT FROM AUTHOR]

Carbon nanotubes were produced on a quartz plate and a silicon wafer by chemical vapor deposition using xylene as a carbon resource, iron and cobalt as catalysts, and ammonia as a reactive gas. A series of experiments was carried out to investigate the effects of reaction temperature, substrates, and catalysts on the synthesis of the nanotubes. The TEM analyses revealed that the nanotubes had a typical bamboo-shaped inner layer structure. Ammonia gas was found to have played a very important role in producing such bamboo-shaped CNTs by easing the formation of the graphite layers due to the catalyst activator and amorphous carbon reducer. The growth of CNTs was affected by the thickness of the silicon oxide layer. With iron catalysts, the growth of CNTs increased with an increase in the thickness of the silicon oxide layer. However, an opposite phenomenon occurred with the use of cobalt catalysts. [ABSTRACT FROM AUTHOR]

This study examines the friction and wear of ceramic matrix composites designed for use in automotive brake discs. The composites are produced by reinforcing a SiC matrix with carbon fibers using a liquid silicon infiltration method. C/C-SiC composites with two different compositions are fabricated to examine the compositional effect on the tribological properties. The tribological properties are evaluated using a scale dynamometer with a low-steel type friction material. The results show that the coefficient of friction is determined by the composition of the composite, which affects the propensity of friction film formation on the disc surface. A stable friction film on the disc surface also improves the wear resistance by diminishing the abrasive action of the disc. On the other hand, the friction film formation on the disc is affected by the applied pressure, and stable films are obtained at high pressures. This trend is prominent with discs with high Si content. However, both C/C/-SiC composites show superior performance in terms of the friction force oscillation, which is closely related to brake-induced vibration. [ABSTRACT FROM AUTHOR]

Silica-based oxide layers were deposited in-situ on turbine blades made from Inconel 713 during the operation of a 13 kgf-class gas turbine, and their effect on the ex-situ oxidation behavior of the blades at 1050 °C was examined. The two turbines were driven by burning liquid petroleum gas (LPG), one turbine at a rotation speed of 35,000 rpm for 4 h (TB04), and the other at 42,000 rpm for 8 h (TB08). For deposition, tetraethylorthosilicate (TEOS) was sprayed into the fuel line immediately ahead of the combustion chamber. The TEOS-to-LPG ratio for TB04 and TB08 was maintained at 5.4 wt. % and 2.3 wt. %, respectively. Directly after operation, the turbine blades were coated with silica layers to a thickness of ∼10 μm, independent of the operating conditions. These oxide layers on the blades provided excellent protection against oxidation during both operation and the ex-situ isothermal oxidation test. [ABSTRACT FROM AUTHOR]