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Li2FeSiO4 is a promising cathode active material for lithium-ion batteries due to its high theoretical capacity. Spray-freezing/freeze-drying, a practical process reported for the synthesis of various ceramic powders, is applied to the synthesis of Li2FeSiO4/C composite powders and high-performance Li2FeSiO4/C composite powders are successfully synthesized by using starting solutions containing both Indian ink and glucose as carbon sources followed by heating. The synthesized composite powders have a unique structure, composed of Li2FeSiO4 nanoparticles coated with a thin carbon layer formed by the carbonization of glucose and carbon nanoparticles from Indian ink. The carbon layer enhances the electrochemical reactivity of the Li2FeSiO4, and the carbon nanoparticles play a role in the formation of electron-conducting paths in the cathode. The composite powders deliver an initial discharge capacity of 195 and 137 mAh g−1 at 0.1 C and 1 C, respectively, without further addition of conductive additive. The discharge capacity at 1 C is 72 mAh g−1 after the 100th cycle, corresponding to approximately 75% of the capacity at the 2nd cycle.

The present study describes the tribological properties of a bronze alloy used as a sliding interface for operation under dry conditions. Many industrial slide bearings are made from bronze alloy. To achieve easy running-in and enhanced anti-seizure, solid lubricants are added to the alloys. However, it is difficult to simultaneously achieve easy running-in and anti-seizure with one solid lubricant. Thus, the combined effects of a solid lubricant and a dispersed sulfide layer on reducing and stabilizing the friction coefficient were also examined. The tribological properties of the resulting alloy were evaluated with a 3-ball on disc type testing apparatus under dry conditions and in air atmosphere. The surface state of the solid lubricant and dispersed sulfide layer was evaluated by observation of the morphology and phase states via atomic force microscopy. Distinctive features of a phase comprising mixed stiff and soft regular regions on the micrometer scale were observed. These two regular regions are considered to be formed from graphite and sulfide by burnishing. The effect of the dual phase state leads to achievement of both easy running-in and anti-seizure.

Fe nanoparticles were generated by DC arc plasma method under atmospheric He-H2 mixture gas with different H2 concentration. The arc plasma was well constricted due to thermal pinching when H2 was mixed. The generation rate of the Fe nanoparticles significantly enhanced as H2 concentration increased to 40 %, and it was about 0.16 g/min for He-40 % H2 arc plasma. The vaporization rate of Fe did not significantly increase any more as H2 concentration exceeds 40 %. Numerical simulation based on magnetohydrodynamics (MHD) was performed and indicated that the Fe anode can be efficiently heated due to the H2 induced thermal pinching. The maximum anode temperature was calculated close to boiling point of Fe when heated by He-40 % H2 arc plasma. The specific surface area of Fe nanoparticles produced from He-40 % H2 arc plasma was about 11.7 m2/g and its corresponding diameter was 65 nm.

Dispersion behavior of nanoparticles in organic solvent depends on surface molecular structure, even if the material and size of particles are same. In order to discuss the effect of surface conditions of nanoparticles on dispersion behavior in organic solvent and surface modification behavior, single phase SiO2 and TiO2 nanoparticles and SiO2-TiO2 composite particles were prepared by using flash creation method (FC method) with different thermal source, DC plasma or burner. By the observation of TiO2-SiO2 composite particles by TEM-EDS system, the microstructure of composite particles was estimated that SiO2 layer coated on core TiO2 nanoparticles. Surface OH group structure, dispersion behavior in N-methyl-2-pyrrolidone (NMP) of each TiO2 nanoparticles was depended on the thermal source of FC method. When thermal source used was burner, the high OH group density and well dispersion behavior was observed. However, after surface modification by silane coupling agent, the aggregate size of TiO2 nanoparticles prepared by DC plasma in NMP was decreased.

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.

Bilayered Y2O3-stabilized ZrO2 (YSZ)/Sm2O3-doped CeO2 (SDC) electrolyte films were successfully fabricated on porous NiO–YSZ composite substrates by electrophoretic deposition (EPD) based on electrophoretic filtration followed by co-firing with the substrates. In EPD, positively charged YSZ and SDC powders were deposited directly on the substrates, layer by layer from ethanol-based suspensions. Delamination between YSZ and SDC films was avoided by reducing the SDC films’ thickness to ca. 1 μm. A single cell was constructed on the bilayered electrolyte films composed of ca. 4 μm-thick YSZ and ca. 1 μm-thick SDC films. As a cathode in the cell, La0.6Sr0.4Co0.2Fe0.8O3−x (LSCF) was used. Maximum output power densities greater than 0.6 W cm−2 were obtained at 700 °C for the bilayered YSZ/SDC electrolyte cells thus constructed.

Although several gas phase synthesis methods for nanoparticles have been developed, only few are adapted for mass-production of varoius types of nanoparticles. In this study, we developed a new method to synthesize oxide nanoparticles by gas phase reaction assisted with DC plasma. We chose ZrO2 and CeO2 as a model powder. TEM observation and specific surface area measurement showed that as-synthesized nanoparticles were in the size range of 5-100nm and they were not hollow but solid particles. From XRD results, as-synthesized nanoparticles had a high crystallinity without sintering. The present experiments suggested that the particle size is controlled by the oxygen gas feed rate of a carrier gas through a two fluid nozzle, i. e., an increase in oxygen feed rate leads to smaller nanopraticles at a constant precursor feed rate.

The infrared reflectivities of crystalline forsterite (Mg 2 SiO 4 ) were measured for the temperature range 295-50 K for each crystal axis, between wavenumber 5000 and 100 cm -1 . The reflection spectra show clear dependence of temperature; most of the bands become more intense, sharper and their peak positions shift to higher wavenumber with decreasing temperature. Reflection spectra were fitted with dispersion formula of damped oscillator model of the dielectric constants and the oscillator parameters in the model were derived. The absorption spectra of forsterite particle are calculated with the derived dielectric constants to show that the forsterite features are good thermal indicator for cold temperature range below 295 K.

We report a cost-effective processing method for fabricating intermediate temperature solid oxide fuel cells (SOFCs) with Ni-samaria doped ceria (SDC) anode. First, SDC and NiO powders were mechanically treated to make their composite powder. Then, the composite powder was applied into a ceramic tape casting method to form a thick layer for the anode supporting. Finally, an anode supported single cell with a configuration of Ni-SDC/SDC/La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 − δ (LSCF) was prepared. Because of the usage of the composite powder, homogenous distribution and connection of each Ni and SDC were achieved. Peak power densities of 460, 750 and 910 mW cm −2 were obtained on the single cell at 550, 600 and 650 °C, respectively.

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.

A La0.6Sr0.4Co0.2Fe0.8O3−a (LSCF) powder was prepared through a citric synthesis route and subsequent media agitating milling. The milling for 1.5 and 3 h reached the average particle sizes of 0.66 and 0.53 μm, respectively. Then, the LSFC cathodes were formed using the two powders in a conventional manner. It was shown that the cathode performance was strongly influenced by the starting particle size as well as sintering temperature. The smallest cathode polarization for both 700 and 800 °C operations was obtained when using the finer powder (0.53 μm) and sintering at 850 °C, suggesting an excellent cathode morphology. An anode-supported single cell with this cathode structure was fabricated and demonstrated a good generation performance under intermediate temperature operation.

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.

The effect of annealing on the electrical conductivity of the Y 2 O 3 –ZrO 2 system (8.0–10.0 mol% Y 2 O 3 ) was investigated by the direct current four-probe technique at several temperatures for 1000 h. The difference of the crystal structure before and after annealing was investigated by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The decrease of the conductivity for the specimens with composition of 8.0–9.0 mol% Y 2 O 3 was caused by the formation of a fine tetragonal phase. On the other hand, the sample of 9.5 mol% Y 2 O 3 after annealing for 1000 h supported a single phase with cubic structure. Therefore, the optimum composition as electrolyte for solid oxide fuel cell in the Y 2 O 3 –ZrO 2 system was considered to be 9.5 mol% Y 2 O 3 from the viewpoint of long-term stability with the relatively high conductivity.

The electrical conductivity change with annealing at 1000 °C in the Y2O3–ZrO2 (YSZ) system was examined. Among the sintered samples doped with 8.0 mol% Y2O3 (8.0YSZ), 8.5 mol% Y2O3 (8.5YSZ), 9.0 mol% Y2O3 (9.0YSZ), 9.5 mol% Y2O3 (9.5YSZ) and 10.0 mol% Y2O3 (10.0YSZ), 9.5- and 10.0YSZ showed no conductivity decrease even for the annealing period of 1000 h, while 8.0- and 8.5YSZ showed significant decrease with time although the initial conductivities were higher than those of 9.5- and 10.0YSZ. The 9.0YSZ showed only slight conductivity decrease. The measurement of Raman spectra demonstrated that the deterioration in conductivity related to the gradual formation of fine tetragonal phase in the cubic phase. Consequently, 9.5YSZ was seemed to be optimum as the electrolyte material of solid oxide fuel cells from the point of stability in high conductivity.

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 (

The processing of advanced materials with luminescent properties (phosphors) emphasizes the importance of ultrafine powder synthesis. Aerosol synthesis is applied for the preparation of Eu-activated gadolinium oxide matrices, commonly used as red phosphors in cathodoluminescence. The process involves aerosol formation ultrasonically (1.7 MHz) from the precursor salt solutions and control over the aerosol decomposition in a high-temperature (1173 K) tubular flow reactor. During decomposition, the aerosol droplets undergo evaporation/drying, precipitation and thermolysis in a single-step process. Consequently, spherical, solid, agglomerate-free, submicronic particles with the mean particle size below 1000 nm are obtained. In order to control the particles crystal structure and establish the conditions for the stabilization of the low-temperature gadolinia cubic phase, the process parameters like temperature distribution, gas flow rate and annealing temperatures were adopted. The particle morphology, phase and chemical structure are revealed in accordance to various analysis methods (XRD, DSC, SEM-EMAX, particle stereology and size distribution) and discussed in terms of precursor chemistry and process parameters. The mechanisms of ultrafine phosphor particles generation are focused and correlated with the luminescence properties.

The change in conductivity of 8 mol% and 10 mol% yttria stabilized zirconia (8YSZ and 10YSZ, respectively) were measured during continuous current loading at 1000°C. The conductivity of 8YSZ gradually degraded with holding time in the test and it decreased to about 65% of the initial value after annealing for 1500h. However, the conductivity of 10YSZ is constant under the same condition. The crystal structure of the samples before and after annealing was investigated by X-ray diffraction techniques, Transmission electron microscopy, and Raman spectroscopy. It was concluded that the deterioration in conductivity of 8YSZ related to the phase transformation, such as gradual formation of fine tetragonal phase which had lower conductivity than cubic phase had.

This paper represents the results of the design of functional nanocrystalline powders and nanocomposites using chemical reactions in aerosols. The process involves ultrasonic aerosol formation (mist generators with the resonant frequencies of 800 kHz, 1.7 and 2.5 MHz) from precursor salt solutions and control over the aerosol decomposition in a high-temperature tubular flow reactor. During decomposition, the aerosol droplets undergo evaporation/drying, precipitation and thermolysis in a single-step process. Consequently, spherical, solid, agglomerate-free submicronic particles are obtained. The particle morphology, revealed as a composite structure consisting of primary crystallites smaller than 20 nm was analysed by several methods (XRD, DSC/DTA, SEM, TEM) and discussed in terms of precursor chemistry and process parameters. Following the initial attempts, a more detailed aspect of nanocrystalline particle synthesis was demonstrated for the case of nanocomposites based on ZnO-MeO (MeO=Bi Cr+), suitable for electronic applications, as well as an yttrium-aluminum base complex system, suitable for phosphorus applications. The results imply that parts of the material structure responsible for different functional behaviour appear through in situ aerosol synthesis by processes of intraparticle agglomeration, reaction and sintering in the last synthesis stage.

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.

A La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 (LSGM) thin film was fabricated by the usual tape casting method using a doctor blade to reduce the operating temperature in solid oxide fuel cells (SOFCs). The resultant LSGM film was 130 ± 3 μm in thickness and its relative density was over 99%. Also, the thin LSGM film showed a single phase, and its conductivity was 0.113 S/cm at 800 °C and 0.054 S/cm at 700 C, respectively. Therefore, it seemed that the thin LSGM film was suitable as an electrolyte for intermediate temperature operating SOFCs. Ni-SDC and La(Sr)CoO 3 synthesized by spray pyrolysis were used as an anode and a cathode, respectively, and a single cell was fabricated with the thin LSGM film as an electrolyte. This single cell with the thin LSGM electrolyte exhibited excellent electrical performance, of which power density was over 0.7 W/cm 2 at 800 C and 0.4 W/cm 2 at 700 C. These results suggested that the LSGM-based SOFCs with the thin LSGM film in this study would exhibit adequate performance at a temperature lower than 700 °C.

The sintering behavior of Ln-doped ceria (Ln=Y, Gd, Sm, Nd, La) containing gallia (Ga 2 O 3 ) was investigated. Ln-doped ceria samples containing gallia were well sintered at 1500 °C by a common solid-state reaction method. On the other hand, Ln-doped ceria samples without gallia did not become well sintered until the sintering temperature was raised to 1600 °C. We investigated the crystal structures, microstructures, density, and electrical conductivity of Ln-doped ceria sintered with gallia. The grain sizes of Ln-doped ceria sintered with gallia were much larger than those of Ln-doped ceria sintered without gallia. All samples except Y-doped ceria showed improvement in conductivity by the addition of gallia. The variation in acceleration of grain growth with Ln 3+ radius was consistent with the tendency of the melting points of solid solutions of Ln 2 O 3 and gallia, indicating that the acceleration of sintering was due to the effect of the liquid phase partly formed from Ln 2 O 3 and gallia during sintering.

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.

Herein a novel mechanochemical approach to synthesize fine ilmenite FeTiO 3 nanoparticles using high-speed ball-milling with steel balls and TiO 2 nanoparticles is reported. The pure FeTiO 3 nanoparticles with a typical particle size of 15 nm were synthesized via a reaction between the TiO 2 nanoparticles, oxygen gas, and Fe atoms around the surface of the steel balls under local high temperatures induced by the collision energy in the ball-milling process.

The short circuit of cells due to the dissolution and the deposition of NiO in a molten carbonate is a big problem that has to be resolved if we want to use Molten Carbonate Fuel Cells (MCFCs) for long-term operation. To resolve this problem, we have proposed a new cathode structure in which NiO grains have been coated with LiCoO 2 grains by usual tape casting method, because LiCoO 2 is more stable in a carbonate melt than NiO. CoO/NiO composites with 5 to 20 mass% Co could be formed by using the CoO/Ni composite particles. As confirmed by SEM, these composites consisted of NiO cores covered with the outer layer of Li(Co, Ni) oxide. The stability of the lithiated CoO/NiO composite with 5 mass% CoO was significantly improved in comparison with that of conventional NiO for MCFCs. The lithiated CoO/NiO composite was also successfully formed by in-situ oxidation and lithiation process. We thought that this composite cathode material consisting of NiO core covered with Li(Co, Ni) oxide will be adopted as the new cathode for MCFCs.

The reduced temperature solid oxide fuel cell (SOFC) with 0.5 mm thick La0.9Sr0.1Ga0.8Mg0.2O3−α (LSGM) electrolyte, La0.6Sr0.4CoO3−δ (LSCo) cathode, and Ni-(CeO2)0.8(SmO1.5)0.2 (SDC) cermet anode showed an excellent initial performance, and high maximum power density, 0.47 W/cm2, at 800°C. The results were comparable to those for the conventional SOFC with yttria-stabilized zirconia (YSZ) electrolyte, La(Sr)MnO3-YSZ cathode and Ni–YSZ cermet anode at 1000°C. Using an LSCo powder prepared by spray pyrolysis, and selecting appropriate sintering temperatures, the lowest cathodic polarization of about 25 mV at 300 mA/cm2 was measured for a cathode prepared by sintering at 1000°C. Life time cell test results, however, showed that the polarization of the LSCo cathode increased with operating time. From EPMA results, this behavior was considered to be related to the interdiffusion of the elements at the cathode/electrolyte interface. Calcination of LSCo powder could be a possible way to suppress this interdiffusion at the interface.

A variety of spray pyrolysis (SP) techniques have been developed to directly produce ceramic powders from solutions. Examples that are discussed include the following powders: (La0.8Sr0.2)0.9MnO3-YSZ (La(Sr)MnO3-YSZ), La0.6Sr0.4CoO3 (La(Sr)CoO3), (CeO2)0.8(SmO1.5)0.2-NiO (SDC-NiO) and La0.9Sr0.1Ga0.8Mg0.2O3-NiO (LSGM-NiO). For all these powders, spherical, non-agglomerated, submicrometer particles were obtained from aqueous solution of metal salts into a furnace using an ultrasonic atomizer at 1.7 MHz. After SP some of the particles exhibit a hollow-shell morphology. Subsequent calcination at 1000°C yielded crystalline particles. The electrical performance of Ni-SDC/LSGM/La(Sr)CoO3 fuel cells operating at 800°C, prepared from the powders obtained by SP, is reported.

The polarization properties and microstructure of Ni-SDC (samaria-doped ceria) cermet anodes prepared from spray pyrolysis (SP) composite powder, and element interface diffusion between the anode and a La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolyte are investigated as a function of anode sintering temperature. The anode sintered at 1250°C displays minimum anode polarization (with anode ohmic loss), while the anode prepared at 1300°C has the best electrochemical overpotential, viz., 27 mV at 300 mA cm−2 operating at 800°C. The anode ohmic loss gradually increases with increase in the sintering temperature at levels below 1300°C, and sharply increases at 1350°C. Electron micrographs show a clear grain growth at sintering temperatures higher than 1300°C. The anode microstructure appears to be optimized at 1300°C, in which nickel particles form a network with well-connected SDC particles finely distributed over the surfaces of the nickel particles. The anode sintered at 1350°C has severe grain growth and an apparent interface diffusion of nickel from the anode to the electrolyte. The nickel interface diffusion is assumed to be the main reason for the increment in ohmic loss, and the resulting loss in anode performance. The findings suggest that sintering Ni-SDC composite powder near 1250°C is the best method to prepare the anode on a LSGM electrolyte.

The solubility and deposition of LiCoO 2 in carbonate melts have been studied under the cathode condition (1-7 atm, CO 2 -air or CO 2 -O 2 -N 2 working atmosphere). The solubility of LiCoO 2 in the (Li 0.62 K0. 38 ) 2 CO 3 melt for the applied pressure of I atm was found to be directly proportional to P CO2 1.5 and P O2 -0.25 ), while in the case when applied pressure was 7 atm it was proportional to P CO2 1.7 and P O2 -0.3 . Although the dependence of P CO2 and P O2 on the solubility at 7 atm was a little different from the result at I atm, it was thought that the dissolution of LiCoO 2 at the elevated pressure would be regarded as the acidic dissolution mechanism. The solubility of LiCoO 2 in the (Li 0.52 Na 0.48 ) 2 CO 3 melt was less than half of that in the (Li 0.62 K 0.38 ) 2 CO 3 melt and this trend was the same as that of NiO. Moreover the deposition rate of LiCoO 2 in the (Li 0.62 K 0.38 ) 2 CO 3 melt was smaller than that of NiO and was about one-thirtieth.

To develop higher protonic conductivity, we have been studying a new perovskite-type oxide and found that BaPrO 3 based perovskite oxides showed high conductivity in a moist H 2 atmosphere. Their conductivity was about 0.1 S/cm at a temperature of 500°C and remained almost constant up to 700°C, which is much higher than that of Ba(Ce 0.8 Gd 0.2 )O 3− α . Ba(Pr 1− x Gd x )O 3− α prepared by solid state reaction exhibited an orthorhombic and/or cubic perovskite structure and with a high Gd content was stable in a reducing atmosphere. When Ba(Pr 0.7 Gd 0.3 )O 3− α was used as an electrolyte, the open circuit voltage of the cell was about 1 V and this cell was able to operate at 500°C. During the testing of the cell, the formation of water on an air electrode led us to conclude that mobility of protons in the electrolyte occurred. The dominant conduction species in Ba(Pr 1− x Gd x )O 3− α electrolyte were considered as oxygen ions and/or protons.

In order to improve the ability of CO2 adsorption for ceramic membrane with the surface diffusion of CO2, alumina was modified by adding basic metal oxides. Due to such additions, CO2 was effectively separated from an N2-containing mixture gas at elevated temperatures. Modifiers examined were the oxides of rare earth metals (La, Ce, Nd, Pr), alkaline earth metals (Mg, Ca, Sr, Ba) and alkali metals (Na, K, Rb, Cs). IR observation of CO2 species adsorbed on the surface modified alumina revealed that the added elements reacted with the alumina to form surface aluminate layer. The ability of CO2 adsorption was evaluated by using a high temperature gas chromatograph: the column was packed with modified alumina onto which small amounts of a mixture of CO2 and N2 were injected via the helium carrier gas. It was observed that CO2 was adsorbed on the modified alumina even at elevated temperatures above 773 K, while N2 was eluted immediately. The effect on CO2 adsorption varied from one metal oxide to another. The heat of adsorption, determined from the gas chromatogram, increased from 80 to 170 kJ mol−1 with decreasing electronegativity of the cation used for modification. The increase in the heat of adsorption among the oxide groups was in the following sequence: rare-earth metal oxides

The effect of the oxides of Na, K, Mg, and Ca on CO2-reforming of CH4 over Ni/Al2O3 catalysts was studied from the viewpoint of carbon deposition. These added oxides markedly suppressed the carbon deposition during CO2-reforming, also in the absence of CO2. It was concluded that the suppression of carbon deposition resulted from the decrease in the ability of Ni catalyst for CH4 decomposition. It was also observed that the added basic metal oxides changed the reaction order from negative to positive with respect to the partial pressure of CH4 and from positive to negative with respect to the partial pressure of CO2. The observed reaction kinetics suggested that the surface of the Ni catalyst with basic metal oxides was abundant in adsorbed CO2, while the surface without them was abundant in adsorbed CH4. The abundance in adsorbed CO2 on the Ni metal surface was considered an unfavorable condition for CH4 decomposition and as a result, carbon deposition was further suppressed during CO2-reforming on Ni/Al2O3 catalysts with basic metal oxides.

Spray pyrolysis was used to fabricate TiO2-Ag composite powders for application in oxide barrier between filaments of superconducting multifilamentary tapes. The powders were prepared from an aqueous solution of TiO2 sol and AgNO3. SEM and TEM observations revealed that the average size of the synthesized powder was less than 1μm and consisted of well-dispersed fine primary particles of TiO2 and Ag. It was clearly observed that the microstructure of the particles was altered by conditions of heat treatment.

CoO/Ni composite particles were prepared by the advanced mechanical-coating method called Mechanofusion™. These composite particles were composed of nickel particles uniformly covered with fine CoO particles. A new cathode structure for molten carbonate fuel cells (MCFCs), where the NiO core was coated with an outer layer of lithiated cobalt and nickel solid-solution oxide (Li(Co,Ni) oxide), was formed by oxidation and lithiation using these CoO/Ni composite particles. The solubility of nickel in this Li(Co,Ni) oxide layer into carbonate melt decreased to two-thirds of that of NiO when used as a cathode for MCFCs.

(La0.8Sr0.2)0.9MnO3–YSZ composite particles were synthesized by spray pyrolysis. The mean particle size of the synthesized powders was about 1 pm and the particle size distribution was very narrow. The synthesized powders were composed of the perovskite (La,Sr)MnO3 and cubic phase YSZ. Each particle synthesized consisted of uniform and well-dispersed line primary particles of (La,Sr)MnO3 and YSZ (0.1 μm particle size).