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Tribological properties of copper based porous alloy with penetrated micro size graphite layer were evaluated using a ring on disc testing apparatus in dry condition. A shot peening treatment was applied to ensure the dimple for the graphite penetration. Specimens with various area fraction of the graphite layer were prepared. It was found that the friction coefficient and the wear loss decreased with the increase in the area fraction. However, the decrease of the friction and the wear loss became smaller at excess graphite area fraction.

The highly porous LSC/GDC composites were fabricated and characterized as a potential air side current collecting material for micro-tubular SOFCs. The results revealed that the properties of the composites were strongly affected by the composition, particle size ratio of starting powders, microstructure and porosity. The composite specimen with 35 vol. % GDC and an open porosity of 73% gave an electrical conductivity of 174 S/cm at 600 ºC, which is 1.8 times as large as that of the LSCF with a porosity of 61%, and a thermal expansion coefficient of 12.6×10-6 K-1 in the temperature range from room temperature to 600 ºC, which is very close to the value of the LSCF cathode. The superior combined property suggests the possibility that they serve as air side current collectors in the micro-tubular SOFCs.

The electrophoretic deposition (EPD) technique was employed to fabricate Ketjen black/polyvinylidene fluorid (KB/PVdF) composite films on stainless steel substrates. The preparing procedure of stable suspensions for EPD and its effects on the quality and properties of the composite films were studied. The results revealed that the synthesis of composite particles with a proper KB/PVdF ratio and their homogeneous distribution in the suspensions was a prerequisite to obtain uniform green coatings. The stainless steel substrates coated with KB/PVdF composites exhibited both high electrical conductivity and good corrosion resistance, suggesting the possibility that they serve as the bipolar plates in PEM fuel cells.

Ni–Y2O3-stabilized ZrO2 (Ni–YSZ) cermet anode was fabricated for solid oxide fuel cells (SOFCs) by conventional ceramic processing using NiO–YSZ composite particles. Microstructures of the anode were carefully characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Ni–YSZ cermet anode was consisting of fine YSZ connections, as the conducting pass of oxygen ions, on the surface of Ni network, as that of electrons, with continuous pore structure and as that of gaseous species. No amorphous phases were present at the interface between Ni and YSZ, and there was an orientation relationship between Ni and YSZ grains, (111)Ni//(111)YSZ. The cermet anode showed a high electrical performance at 800 °C. These results indicated that the electrochemical activity of the Ni–YSZ cermet anode was enhanced with the present microstructure.

Direct observation of the powder structure in aqueous alumina slurry was investigated using optical microscopy in the transmission mode. In this technique, the slurry was sandwiched by two glass plates kept a 100 μm apart and the structure of powder agglomerates in the slurry was projected under optical transmission mode. It was revealed that the technique is powerful for examining large-scale heterogeneity in aqueous ceramic slurry of which the solid concentration is up to 10 vol.%.

We report high-quality and high-density B1 3.25 La 0.75 Ti 3 O 12 ceramics prepared by sintering at a low temperature of 900°C from the nanosized powder with a diameter around 100 nm synthesized by the flash creation method. The densification at 900°C, which was 300°C lower sintering temperature compared with conventional solid-state reaction, enables us to obtain the ceramics showing a remanent polarization of 14.5 μC/cm 2 , a coercive field of 50 kV/cm and a leakage current of ∼10 -9 A/cm 2 . The superior properties are indicated to originate from lower defect concentration achieved by the low temperature sintering.

NiO/Y2O3-stabilized ZrO2 (YSZ) composite particles for solid oxide fuel cell (SOFC) anode was fabricated by an advanced mechanical method using an attrition type particle composing machine in dry ambient. In this study, two sets of composite particles with different mixing time were prepared. Structure of the composite particles was markedly influenced by the mixing time since the morphology of the resultant Ni/YSZ cermet anode changed with the mixing time. Then, the relationship between the structure of composite particles and the properties of the Ni/YSZ cermet anode were examined. When the composite particles processed with mixing time of 5min were used, the cermet anode showed lower electrical performance at both 800°C and 1000°C. On the other hand, the longer processed composite particles (30min) resulted in higher electrical performance. The difference of anode performances was explained by the change in cermet morphology associated with the mechanical processing time. These results suggested that the mechanical processing for NiO/YSZ composite particles significantly influenced SOFC anode performance.

A NiO–Y2O3 stabilized ZrO2 (YSZ) composite particles for solid oxide fuel cell (SOFC) anode was fabricated by advanced mechanical method in dry process. The processed powder achieved better homogeneity of NiO and YSZ particles, where submicron NiO particles were covered with finer YSZ particles. A Ni–YSZ cermet anode fabricated from the NiO–YSZ composite particles showed the porous structure in which Ni and YSZ grains of less than several hundred nano-meter as well as micron-size pores were uniformly dispersed. The cermet anode achieved high electrical performance at low temperature operation (

NiO/YSZ composite particles with 20–35 mol% Y2O3 stabilized ZrO2 (YSZ) were synthesized by the spray pyrolysis (SP) method. The NiO/YSZ composite particles showed morphology of NiO grains partially or fully covered with fine YSZ grains. The composite particles also had good interface connection between nickel oxide and yttria stabilized zirconia (YSZ). The morphology of the Ni/YSZ cermet anode fabricated from composite particles is noticeably influenced by the YSZ content of the composite particles. Ni/YSZ cermet anodes with 25 mol% YSZ show the highest electrochemical activity and lowest internal resistance (IR). The electrochemical activity and IR of the anode in solid oxide fuel cells (SOFCs) highly depend on the three-phase boundary structure based on the metal (Ni) and ceramic (YSZ) interface as well as the network structure of each Ni grains. Moreover, the cell voltage of a single cell with the Ni/YSZ cermet anode kept almost constant value during 7200 h of operation. Consequently, it is concluded that the performance and stability of the Ni/YSZ cermet anode is improved by controlling the morphology of the NiO/YSZ composite particles.

Ni–YSZ cermet anodes for solid oxide fuel cells (SOFCs) were fabricated at various sintering temperatures from NiO–YSZ composite particles made by spray pyrolysis (SP) technique. NiO particles covered with fine YSZ (Y 2 O 3 stabilized ZrO 2 ) particles were used as the composite particles, and the initial ratio of Ni and YSZ was set at 75:25 (mol%). As a result, the cermet anode sintered at 1350 °C showed the morphology in which fine YSZ grains were uniformly dispersed on the surface of Ni grain network. Electrical performance such as electrochemical activity and internal resistance of a Ni–YSZ cermet anode changed with sintering temperature. The anode fabricated at 1350 °C showed the highest electrical performance. Especially, a single cell voltage with the Ni–YSZ cermet anode kept very stable for 8000 h at 1000 °C in the SOFC operation condition of H 2 —3% H 2 O and air. The cermet anode after a long-term test had its initial morphology. It indicates that the Ni–YSZ cermet anode fabricated from NiO–YSZ composite particles is a very promising material for its practical use as SOFCs.

Polycrystalline alumina developed by the Japan Fine Ceramics Center (JFCC) has been studied as a candidate thermal diffusivity reference material. It was experimentally confirmed that the alumina developed by the JFCC is homogeneous and stable enough to be used as a reference material. The thermal diffusivities of two specimens of different thicknesses (2 and 3 mm) were measured by the laser flash method with high accuracy in the temperature range from room temperature to 1000 K. From the results obtained by measurements, the reference equation of thermal diffusivity in the alumina was determined. The uncertainty of the equation consists of the uncertainties associated with material inhomogeneity of 1.61% and the measurement of 2.29%. Then the combined standard uncertainty is 2.80% (1σ) and the expanded uncertainty is derived as 5.60% with the coverage factor of `2' (2σ). Moreover, we developed a new measurement system for practical use of the laser flash method with a high accuracy technique. In the new system, the uncertainty of the measurement was evaluated by using specimens with the existing reference equation. The difference from the thermal diffusivity value measured by using the new system to the reference value is within ±2.3%, which is equal to the uncertainty of measurement obtained by using the system in the National Research Laboratory of Metrology.

LSM(La(Sr)MnO3)/YSZ(Y2O3 stabilized ZrO2) composite cathode for Solid Oxide Fuel Cells (SOFCs) was fabricated by using the composite particle consisting of well-dispersed nano-size grains of LSM and YSZ. The composite cathode had a porous structure as well as uniformly dispersed fine LSM and YSZ grains. Such unique morphology of the composite cathode led high electrochemical activity at 800°C. It suggests that the intermediate temperature (less than 800°C) operation of SOFCs will be achieved by using composite particles.

We report a new sealant material for solid oxide fuel cells (SOFCs) using glass-ceramic. A glass-ceramic based on the CaO-Al2O3-SiO2 system was selected as a sealant because it can be easily molded to give a gastight seal and remains in a solid-like state under typical fuel cell operating conditions. Calcium alumina silicate glass powder is placed in the gas-sealing area before crystallization. During heating, the glass softens and bonds with the SOFC components. At higher temperatures, bulk crystallization occurs in the glass and the viscosity of the glass-ceramic sealant increases. We show that this sealing material which is able to seal at higher viscosities compared with the melt sealing method produces a good gas-tight seal and is chemically stable in contact with SOFC components, e.g., yttria-stabilized zirconia electrolytes and lanthanum chromite separators.

La0.8Sr0.3MnO3(LSM)/Y2O3 stabilized ZrO2(YSZ) composite powders were mechanically prepared. By changing the mechanical device or processing time, three composite powders with different size distributions were obtained. Then the powders were formed into cathodes of solid oxide fuel cells (SOFCs). The microstructures of the cathodes were carefully characterized by scanning electron microscope (SEM). Losses by internal resistance (IR) and by polarization between the electrolyte and cathode were measured with the current interruption technique. The cathode fabricated by using the powder with the narrowest particle size distribution showed fine grains, uniform porous structure and good contact with the electrolyte layer, thereby resulting in low IR and polarization losses. In contrast, the cathode fabricated from the powder with the broadest particle size distribution contained a large mass of coarse particles and had less uniform structure in the grains and pores, thereby resulting in relatively high IR and polarization losses.

A new mechanical milling device with glow discharge has been developed for aiming of surface modification of nanoparticles without heating. The configuration of this device is based on that of Mechanofusion system (Hosokawa Micron Corp.), which consists of a rotating chamber and an arm fixed with a certain clearance against the inside wall of the chamber. By applying an electric power into the clearance under controlled ambient and rotating the chamber, any particles can be subjected to mechanical forces such as compression and shearing, in glow discharge. Using this device, TiO 2 nanoparticles were processed under a gas pressure of 50Pa of Ar with 10% NH 3 . TEM-EELS spectrums of the particles indicated that the mechanical milling with glow discharge can promote effective solid-gas reaction without heating.

Electrophoretic deposition (EPD) was used for the fabrication of anode-supported yttria-stabilized zirconia (YSZ) electrolyte films. For the EPD, thin layers of graphite were pre-coated on the surface of a nonconducting porous NiO-YSZ composite anode substrate. Uniform YSZ green films were formed on the reverse sides, which did not have the graphite layers. The specimens were transformed into dense bodies ∼5 to 10 μm thick after being co-fired with the substrates. The cell performance of the ∼5 μm thick dense YSZ films supported on the anode substrates was tested using a La(Sr)Co(Fe)O 3 cathode. Maximum output power densities of ∼0.19, ∼0.61, and ∼1.02 W/cm 2 were attained at 600, 700, and 800°C, respectively.