The total UV energy at 254 nm was used as an index of the etching effects of both deep ultraviolet (DUV; 254 nm) and deep ultraviolet/vacuum ultraviolet irradiation （DUV/VUV; 254 nm/185 nm） on multiwalled carbon nanotubes (MWCNTs). The differing etching effects from 185 nm and 254 nm UV radiation were distinguished. As the total UV energy increased under VUV/DUV irradiation, the MWCNTs morphology changed, and both the activation energy and the MWCNTs crystallinity decreased. When the total UV energy was increased under DUV irradiation, the activation energy decreased, but the morphology and the crystallinity of MWCNTs remained the same. Therefore, it was shown that exposure to an ozone lamp, which is a type of DUV/VUV light source, was required to incite morphology changes in the MWCNTs. Furthermore, a comparison of the MWCNTs irradiated with DUV or DUV/VUV radiation suggested that an etching effect could occur if the MWCNTs were irradiated with an optical source with a wavelength of less than 242 nm. This irradiation also caused the formation of highly reactive O3 and O (1D) molecules.
The effect of adding sodium ascorbate into the plating bath used for Fe-Ni-W alloy has been investigated for its wear properties. Fe-Ni-W alloy film containing up to 31.1 at% tungsten can be prepared with the moderate addition of sodium ascorbate into the bath. Fe-Ni-W alloy film prepared under such conditions tends to include certain contents of hydrogen, which induce film embrittlement. However, results also suggest that moderate heat treatment of the embrittled film can improve its hardness and wear properties.
The influences of external and internal Si oxides on the galvannealing reaction of 0-1.8%Si-added steel were investigated. Internal and external Si oxides formed by recrystallization annealing at the dew points of 223-263 K. The distribution of Si oxides in the subsurface region of the substrate steel was analyzed using glow discharge optical emission spectroscopy, reflection electron microscopy, and transmission electron microscopy. External Si oxides suppressed the galvannealing reaction. Then the ζ phase formed locally at the interface between the substrate steel and the zinc coating after galvanizing, which suggests that the external Si oxides at the steel surface acted as a barrier to the Fe-Zn reaction. When Si oxidized internally, a depleted zone of solute Si was observed in the subsurface region of the substrate steel. In this case, the galvannealing reaction was accelerated in comparison with that when Si did not oxidize. Furthermore, decrease of the solute Si content led to acceleration of the galvannealing reaction, nucleation of the ζ phase, and growth of the Γ phase. From these results, it was concluded that depletion of solute Si attributable to internal oxidation of Si accelerated the galvannealing reaction.
In recent years, a hydrogen permeation film using a proton-electron mixed conductor has drawn much attention as a hydrogen-production process. In this work, we focus on (Ce,Sr)PO4 with the monazite-type structure as the mixed conducting ceramics, and aim to synthesize the plate-like powder by means of the hydrothermal method. As a result, it is found that micaceous powders with the single phase can be obtained successfully. From crystal-structure analyses using synchrotron X-ray diffractions, it is suggested that Sr replaces Ce in the crystal and thus (Ce,Sr)PO4 can be synthesized. This result is also supported by the electrical-conductivity measurements. In order to tailor an oriented film of the orthophosphate, we perform the electrophoretic deposition using the plate-like powders. As a result, it is demonstrated that the deposited film can be obtained by adding I2 into an acetone deposition bath and the deposition amount can be controlled by the deposition voltage and time. It is also found that the prepared film tends to be oriented by applying lower deposition voltage.