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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.

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.

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.

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.

A series of LSC/CeO2 composites were prepared as potential air side current collecting materials for micro-tubular SOFCs and their properties were examined and discussed in relation with the composition, microstructure and porosity. The results revealed that the composite specimen with 35 vol.% CeO2 and an open porosity of 73% gave a electrical conductivity of 130 S/cm at 600 ºC, which was 1.4 times as that of the LSCF with a porosity of 61%, and a thermal expansion coefficient of 12.2×10-6 1/ºC between room temperature and 600 {degree sign}C, which was almost the same as that of the LSCF cathode. The composite specimen also demonstrated good stability during a long-term test, suggesting the possibility that they serve as air side current collectors in the micro-tubular SOFCs.

Nickel oxide–yttira stabilized zirconia (NiO–YSZ) interdispersed composite (IC) particles were prepared by a mechanochemical processing using NiO and YSZ nanoparticles. Transmission electron microscopy (TEM) revealed that primally particles of YSZ (75 nm) and NiO (160 nm) were presented alternatively in the composite particles. Specific surface area (SSA) decreased from 8.6 to 7.1 m2/g during the mechanochemical processing. The SSA reduction suggested that the chemically bound NiO/YSZ hetero-interfaces were formed during the processing. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) visualized that the anode made from the IC particles consisted of three-dimensional textured structure of fine Ni and YSZ networks (grain size of them was approximately 500 nm) with 34 vol% of porosity. The anode demonstrated not only low polarization of 152 mV at 1 A/cm2 even under the operation at 700 °C but also long-term stability for 920 h.

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.

We report synthesis of well-grown blue phosphor powder, CaMgSi2O6:Eu2+, from new vapor phase method (Flash creation method) derived nanopowder precursor. Single phase phosphor sample was obtained by post-annealing at 1100 oC. Luminescence properties were compared with that of the sample synthesized by a conventional solid state reaction. The post-annealed sample showed intense blue emission under UV excitation.

The present research investigates the removal of particulate matter smaller than 2.5 μm (PM2.5) from high-temperature exhaust gas using a twin ceramic candle filter. Computational fluid dynamics (CFD) is used to simulate gas flow behavior since the technique could provide crucial support to experimental investigation, especially for harmful conditions, as well as yield cost savings and fast results. In this research, the dynamic behavior of gas flow in a prototype twin-candles ceramic filter was studied. One interesting phenomenon not seen in single candle filtration systems is the unforeseen cleaning effect on an adjacent candle filter due to the pulsed cleaning of another. It is useful to investigate the face velocity distribution on the candle as it illustrates how the filter cake is formed on the filter surface and hence leads to improvement in the dust cleaning. The obtained simulation results were validated with available experimental data.

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.

A Ni-GDC cermet is expected as one of the materials for lower temperature SOFC anode, which is obtained from reducing NiO-GDC powder. In this work, we report the effects of NiO-GDC powders produced by mechano-chemical technique on the fabricating processes of anode and the electrical performance of the anode. The properties of sintering and dispersion of NiO-GDC powders were studied and the morphology of Ni-GDC anode was characterized. The performance of the cell which consisted of Ni-GDC anode, GDC electrolyte and LSCF cathode was evaluated by current interruption method. The experimental results indicated that the maximum power densities were 0.93 and 0.31 W/cm2 when the cell was operated at 600{degree sign}C and 500{degree sign}C respectively.

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.

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.%.

This paper reports a study of the phase evolution induced by mechanical milling of a mixture of industrial grade La2O3, SrCO3 and Mn3O4 powders under a humid atmosphere. In this milling, no media balls were employed and the mechanical activation was applied through friction among particles in the powder mixture. Under humid atmosphere (relative humidity 70% at 25°C), X-ray diffraction peak intensities of La2O3, SrCO3 and Mn3O4 decreased, and the specific surface area of the powder mixture increased at the early stage of the milling (less than 10 min). In further milling, the perovskite strontium-doped lanthanum manganite (LSM) started to appear. Differential thermal analysis suggests that the present mechanical activation brought about the decomposition of SrCO3. Single-phase LSM was obtained by annealing of the milled powder mixture at a relatively lower temperature of 900°C and its particle size was about 100 nm. The present mechanical milling resulted in considerably lower contamination release from milling media.

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 (

Nickel Oxide-Yttria Stabilized Zirconia (YSZ) composite powders for the fabrication of the cermet anode of solid oxide fuel cell (SOFC) was produced by an advanced dry mechanical process. The morphology of the Ni-YSZ cermet anode fabricated from NiO-YSZ composite powder could be controlled by the operating conditions of the mechanical process. Highly homogeneous cermet anode with very fine Ni and YSZ grains was obtained by applying the mechanical process. As a result, the Ni-YSZ cermet anode showed exceptional performance at low operating temperatures (≤800°C) for the SOFC. It is evident that the homogeneous Ni and YSZ grain structure in the size of less than several hundred nano-meters has increased the Three Phase Boundary (TPB) length for the electrochemical reaction, which contributed to the performance improvement of the cermet anode.

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 influence of the mechanical milling of the corresponding powder elements on the formation of superconducting MgB 2 phase was investigated. Mg and B powders were attrition-milled, and then the milled powder mixture was annealed under atmospheric pressure of argon. MgB 2 phase clearly appeared after annealing the 60 min milled powder mixture at 500 °C. This powder mixture showed much larger diamagnetism magnitude at 4 K than that was milled for 5 min. The structural analyses revealed that the superconducting phase in this powder was formed at the Mg and B composite structure which was fabricated by the longer mechanical milling. These results indicate that the mechanical milling of the powder elements can enhance the reactivity for the formation of MgB 2 .

NiO–YSZ (YSZ: Y2O3-stabilized ZrO2) composite particles for a Ni–YSZ cermet anode in solid oxide fuel cells (SOFCs) were synthesized via spray pyrolysis (SP). The formation mechanism of the composite particles by this process was analyzed. The internal microstructure of the particles synthesized during SP processing was observed at each heating temperature of 200, 300, 400 and 1000 °C, and then the formation mechanism of the composite structure was discussed. As a result, it was found that NiO–YSZ composite particles were formed through the following steps. Firstly, during the evaporation stage up to 200 °C, a filled particle with Ni(CH3COO)2 and YSZ fine grains were formed from the atomized droplet containing Ni ion and dispersed YSZ sol by volume precipitation. Secondly, during the continuous thermolysis stage up to 400 °C, YSZ grains were formed and moved to the surface of the composite particle by the outgas and the oxidation of Ni(CH3COO)2. Finally, the NiO–YSZ composite particle that has NiO grains uniformly covered with fine YSZ grains was formed after the final sintering stage up to 1000 °C.

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.

新規な溶融炭酸塩形燃料電池（MCFC: Molten Carbonate Fuel Cell）用CoO-NiO系複合カソードの細孔構造制御と導電率改善を行った．まず，機械的手法により合成したCoO被覆Ni粒子を原料（被覆原料）とし，MgCO3を添加することにより導電率の改善を図った．その結果，10mol%の添加にて，従来カソード（NiO）材料と同等な導電特性が得られた．さらに，同じ被覆原料とMgCO3添加を用いたテープ成形法にて，複合カソードを作製した．その結果，成形条件と焼成条件を調整して気孔率約70%，平均細孔径約6µmの細孔構造を持ち，ハンドリング性の良好な複合カソードを作製することができた．また，MCFCカソードは，細孔構造と共に，細孔中への溶融炭酸塩電解質の充填量がその性能を左右する．そのため，複合カソード細孔中への溶融炭酸塩充填量の制御を行い，50%の電解質充填量にて，従来カソードとほぼ同様なカソード分極値（電流密度150mA/cm2にて約100mV）を得ることができた．以上から，このCoO-NiO系複合カソードの有効性を明らかにした．

Metal and ceramic (CoO/Ni and MgFe 2 O 4 /Ni) composite particles for molten carbonate fuel cell (MCFC) cathodes were prepared from filament shaped Ni particles by a mechanical coating technique using a new vessel type mixer named the Theta composer. The morphology of the composite particles consisted of a Ni grain coated with fine ceramic particles without changing the filament structure. Moreover, a CoO/NiO composite cathode and a MgFe 2 O 4 /NiO composite cathode were successfully fabricated from the composite particles by a doctor blade tape casting method. The composite cathode had good porous structure with high porosity. It suggests that the composite cathode can be applied as practical large area cathodes. Ni solubility of the CoO/NiO composite cathode and MgFe 2 O 4 /NiO composite cathode into a (Li 0.52 Na 0.48 ) 2 CO 3 melt at 650 °C in 10%CO 2 –7%O 2 –83%N 2 at 1.2 MPa were about half and one-quarter of that of NiO, respectively. Therefore, the composite cathode is a promising candidate for a new cathode of MCFCs because of its high stability in molten carbonate and good porous structure.

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.

The effect of the alteration of cold isostatic pressing (CIP) and dewaxing procedures on the pore structure and fracture strength of silicon nitride ceramics was examined. The difference of the fracture strength between two sintered bodies was explained by the pore size variation in ceramics observed in thinned specimens by the transparency technique. It was explained that CIP after dewaxing lowered the compressive strength of the granules in the green body and thus contributed to making the pore size of the sintered body small.

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 solid oxide fuel cell constructed from Ni–SDC anode and LSGM electrolyte was applied to the partial oxidation of methane to syngas (CO+H2) at 700–800 °C with the merits of co-generation of electricity and controllable O2 supply. It was found that the co-generated syngas at H2/CO ratio of 1.4–2.0 varied with applied current densities, CH4 flow rates and operating temperatures. The cell voltage at 100 mA cm−2 and 800 °C was 0.90 V, i.e. about 90 mW cm−2 power density could be obtained. The cell operating at 50 mA cm−2 for 24 h almost showed no degradation of the cell performance. The observed carbon deposition seemed mainly taking place by CH4 cracking reaction.

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.