The dispersion of self-assembled β-Si₃N₄ (SN) agglomerates in stainless steel (SUS316L) was decided with the multifractal analysis to investigate characters of the aggregated morphology of the average secondary particle area of SN particles. The thermal conductivity (λ_e) of SN/SUS316L with the average particle diameter of SUS316L powder of 3 μm was higher than that expected from Kanenari model because SN agglomerations were formed. On the other hand, λ_e of SN/SUS316L with the average particle diameter of SUS316L powder of 8 μm was lower than that expected from Kanenari model. On the multifractal analysis, the results showed that the capacity dimension (D₀) was not changed with adding SN particles. It suggested that the SN agglomerations were formed with similarity. λ_e was increased with increasing the average secondary particle area of SN particles. D₀ was not increased with increasing λ_e. It indicated that the forming the network of the thermal conductive particles played an important role in improving λ_e.

In this paper, the microstructure formation process of WC cemented carbide manufactured by Laser Powder Bed Fusion (LPBF) was investigated with WC/25 wt%Co agglomerated and sintered powder. The internal structure of the as-built cemented carbide specimen was categorized into two regions. The first region included many pores and a unique microstructure which was not observed from the samples fabricated with conventional manufacturing methods. In this region, W₂C and W₃Co₃C were formed due to a WC decomposition and an evaporation of graphite and Co during laser irradiation. On the other hand, the second region showed the similar microstructure to the conventional method. The microstructure of the first region revealed that the powder was completely melted during a laser scanning process. The precipitation process of W₂C, W₃Co₃C, and Graphite phase was considered with calculated liquidus projection of a C-Co-W ternary phase diagram.

In this paper, reaction control of metal alkoxides has been tried to obtain oxide nano-particles with controlled properties. As a result, the principle to design the molecular structure of the precursors consisted of metal-oxygen-metal bonds was proposed based on the Zachariasen and Warren’s network theory or single bond strength proposed by K. H. Sun. Some examples of the molecular design were presented and discussed, such as the stoichiometric mullite nano-particles, non-silicates of zirconia and VO₂/SiO₂ nanocomposite particles. In the case of mullite nano-particles, importance of the aggregation control was discussed for the control of the nanostructure of the resulting nanoparticles. Zirconium alkoxide was the model case of the reaction control for the metal alkoxides with lower electronegativity using controlled chemical modification (CCM) method for the partial hydrolysis and following polycondensation to obtain the bulk gel. Nanocoating on the nanoparticles was also realized by CCM method. A few nanometers thick of VO₂ nanolayer was successfully deposited on a monodispersed silica particles of 50 nm, and their thermochromic property was confirmed at around room temperatures. All these results exhibits that the molecular design using metal alkoxides is the powerful tool to obtain the high performance oxide nano-particles.

Powders of metals, oxides, and sulfides have been widely investigated as electrochemical catalysts to enhance the performance of energy devices such as fuel cells and metal-air batteries, and to establish efficient electrolysis processes. The author has been studying electrochemical catalysts with high activities and stabilities for oxygen electrochemical reactions utilized in metal-air batteries, water splitting, and electrowinning of zinc in cooperation with domestic researchers. Here, a method to modify electrodes with catalyst powders is explained in detail in addition to evaluation methods and compensations for reliable comparison.

Tetragonal ZrO₂ was coated on the SiO₂ nanoparticles by liquid phase deposition. In this study, the liquid phase deposition was carried out using the boric acid as the fluoride ion scavengers. The amount of the nano-coated ZrO₂ was controlled by the amount of the fluoride ion scavengers. As a result, the highest yield of the ZrO₂ nanocoating process was attained at [HBO₃]/[Zr] = 20.0 condition. After the annealing at 900°C for 1 hour, the tetragonal ZrO₂ was confirmed by XRD and Raman analysis. Namely, the SiO₂-ZrO₂ core-shell hybrid particles was obtained by controlled liquid phase deposition process.

As a method of combining ceramics and metal, a molten metal stirring method, a pressure impregnation method, have been reported. However, since these methods use a molten metal, high-temperature conditions are indispensable, being production methods with high environmental loads. Our laboratory has developed a “non-firing sintering process” that can produce high-density solids by drying at ultra-low temperatures below 100°C (373 K). In this study, by using this process, a low-melting-point alloy with a melting point of 83°C (356 K) is combined with silica powder in a solid state, so that the low-temperature exhaust heat below 100°C (373 K), which is currently discarded, can be stored. In addition, an attempt was made to produce a solidified material having high strength and low-temperature heat storage ability with low environmental load by using silica particles as reinforcing particles. The obtained solidified body has excellent low-temperature heat storage capacity, and succeeded in suppressing the leakage of the low-melting alloy during the phase transition.

It is considered that there is a causal relation between the increase in CO₂ concentrations due to energy consumption and climate change/temperature increase in each region. On the other hand, applying investment cover-able energy-saving devices and/or systems to manufacturing process consider to be effective in reducing manufacturing costs and at the same time contribute to reducing CO₂ emissions. In this paper, we consider a low environmental load type ceramics manufacturing process that combines energy-saving technologies, while confirming that the amount of energy required for heating operation in the ceramics manufacturing process is large, the majority of the waste heat is discharged, and it is more efficient to directly use the waste heat as heat than to convert it to work.