Japanese ceramic industry has developed as an industry that provides parts and materials with outstanding characteristics to a number of other industries such as semiconductors and electronic equipment etc. The importance of ceramic products is expected to increase in the future, as we have seen advanced ceramics inducing new leading-edge products. “High Performance of Ceramics and Manufacturing Process” is one of the programs of A-STEP Stage I Industrial needs response type which provide a fund in fundamental research and development of technologies to bolster Japanese industrial competitiveness by contributing to the solution of technical issues common in industry. I hope that 11 projects in the program which started in 2016 will reach outcomes adopted by the industry in the near future. The outcomes will support not only industrial competitiveness and new industries but also solution of huge issues such as global warming which threatens human survival. I hope that cooperation of the members concerned will lead to the development of high performance ceramics and innovation in manufacturing processes of ceramics and contribute importantly to the accomplishment of the Sustainable Development Goals.

Sintering of most ceramic and composite materials are only possible at temperatures over 1000°C due to their high melting point. Sintering is acknowledged as an expensive process, which takes several hours to several days. In addition, high temperature sintering affects the final product by causing undesired grain coarsening or changing the initial chemical stoichiometry. Our research group has proposed a “non-firing sintering”, where no firing process is required for achieving high densities. The underlying idea of this method involves the chemical activation of powder surface via ball milling, where the surface of particles is rubbed against balls. In this review, we will introduce the mechanism of the method as well as some process know-how, with some examples of preparing solidified bodies of silicon carbide, composite of carbon nanotube (CNT) and silica, and organic/inorganic composite materials.

Attention is being paid to the control of nanostructures for enhancement of ceramics performance. In particular, attention is focused on nanoparticles having anisotropic shapes such as nanosheets and nanoneedles. Further expectation is raised for oriented structures of nanoblocks which are oriented and integrated. In this review, I would like to introduce various nanostructures formed through control of crystal growth in aqueous solutions. SnO₂ nanosheet assembled films were developed in an aqueous solution. The nanosheets stood perpendicular to the substrate to form oriented structure. Additionally, the SnO₂ nanosheet assembled films had gradient structure. Morphology control was realized with precise control of crystal growth.

Biodegradable core-shell particles were successfully obtained through a novel surfactant-free emulsification method. The particles were formed by interfacial interaction between poly (lactic acid) core and hydroxyapatite shell. The precipitated calcium phosphate played a role as stabilizer for microsphere fabrication. The method can be modified to produce various morphological particles, such as porous, hollow and nano-sized particles. The developed biodegradable particles would be expected to be used for a wide range fields as biocompatible and environmentally friendly particles.

Dielectric single-crystalline nanocube 3D-assembly has a lot of unique properties such as packing perfection, high orientation and interfacial nano-architecture of the supracrystal, and it attracts attention to utilize in the next generation electronic devices. This review reports about fabrication and enhanced dielectric properties of BaTiO₃ nanocube 3D assembly. BaTiO₃-based nanocubes were synthesized by hydrothermal method with aqueous metal compounds and surfactants. 15 nm sized single-crystalline nanocubes were assembled by capillary-force-assisted self-assembly method through the dip-coating process. The orderd nanostructure of BaTiO₃ nanocubes has an enhanced dielelctric constant above 4000 with low loss. The origin of this enhanced property was considered to be distortion induced by the interfaces between the nanocubes with a small tilted angle. It is revealed that the size and shape distribution is the most important factor to fabricate the nanocube 3D nano-architecture with high ordering.

Modulated rotating magnetic field (MRF) enables bi-axial grain alignment of substances with tri-axial magnetic anisotropy. This is a candidate of material production process which can be applicable at room temperature. However, rotation of magnetic flux is inappropriate for continuous production process with linear motion. The author introduce two topics in this review article. One is requirements for alignment of the hard magnetization axis by a rotating magnetic field. The other is development of an equipment that can generate a linear-drive type MRF. In the former topic, the author describes that magnetic energy for orientation and rotation speed of magnetic flux should be taken into account for achieving the alignment of the hard axis with high orientation degrees. In the latter topic, the author describes the details of the equipment including a design of arrayed permanent magnet unit. Moreover, the bi-axial magnetic alignment of practical rare-earth-based cuprate superconductors, DyBa₂Cu₃O_y, with twin microstructures was attempted using the equipment as a proof-of-principle experiment.

In this paper, we introduce novel slurry characterization techniques, the hydrostatic pressure measurement and the osmotic pressure measurement. In the hydrostatic pressure measurement, the particles dispersion and flocculation state in the slurry containing the micron or sub-micron particles be determined from the decreasing rate of its hydrostatic pressure (the time change of the hydrostatic pressure). The hydrostatic pressures of single and multi component slurries are introduced and their particles dispersion and flocculation states are discussed.

On the other hand, the osmotic pressure measurement can evaluate the particles dispersion and flocculation state in slurries containing the nano particles. It was demonstrated that the osmotic pressure of the nano particles slurry increased as the particles in the slurry well dispersed, corresponding to the particles concentration of the sampled slurry after ultracentrifugation.

Recently, a flash sintering method, which is one of field assisted sintering technique (FAST), has been developed. In the flash sintering method, lower sintering temperature and shorter sintering time can be realized using a flash event showing a spike of specimen electric current at a critical furnace temperature. The flash sintering method has been applied to many kinds of ceramics so far, its usefulness is being clarified. Improvement of techniques and theoretical analysis for the flash sintering method will be progressed. And it can be considered that the flash sintering method will be spreading as a new sintering one, as in spark plasma sintering (SPS) method, in near future. In this paper, we summarize the outline of the flash sintering method including control parameters and the recent researches on the elementary processes related to large-scale mass transfer occurring under application of electric fields.

We are developing plasma nanoManufacturing process based on atmospheric pressure plasma process. This process consists of plasma CVM technique for shape creation and plasma-assisted polishing technique for surface finishing, and it makes it possible to create an arbitrary shape with nanometer order shape accuracy without forming subsurface damage. In this article, we introduce the outline of plasma nanoManufacturing process and some results.

Optical coherence tomography (OCT) is an observation technique utilizing optical interferometry. Images of the internal structure of opaque materials can be obtained dynamically and three-dimensionally in a few seconds. In this work, the internal structures of ceramic sintered body and slurry was observed by OCT. In the case of Al₂O₃ ceramics, an artificially induced spherical defect having smaller than 50 µm in diameter which lies 700 μm below the top surface was observed successfully. Furthermore, it was observed that the internal structure of Al₂O₃ slurry was drastically changed during drying, followed by formation of a crack in the dried green body.

Behavior of particles to be ground between two grinding balls in wet ball milling was analyzed by DEM-CFD coupling simulation. Effects of dimeter of the particles, diameter of grinding balls and colliding speed of two grinding balls on the volume of particles sandwiched between two grinding balls were investigated. The volume was assumed as an index for progress of grinding. The volume decreased with a decrease in the diameter of the particles. In case of larger particles, the volume increased with an increase in the diameter of grinding balls. On the other hand, in case of smaller particles, the volume increased with a decrease in the diameter of grinding balls. Higher collision speed between two grinding balls enhanced the volume. In order to perform fine grinding more efficiently, it is important to use smaller grinding balls and make them collide each other at high speed.

In this study, KNbO₃ films were deposited on Ni-based metal coils with different curvature by hydrothermal method. The deposition of KNbO₃ films was hardly observed directly on metal coils. However, the growth of well-adhered KNbO₃ films was promoted by using LaNiO₃-surface layers on Ni-based metal coil. Film thickness increased with increasing deposition time above 1 h and reached to 12.5 μm at 2.5 h. X-ray diffraction measurements revealed that the crystal structure did not depend on the average curvature radius. The dielectric constant and the remanent polarization were respectively 105 and 11 μC/cm², which were almost the same with flat films. This means that these are almost independent of the radius of curvature. These results indicate that the hydrothermal method is an effective way as a deposition technique for the piezoelectricc films onto metal substrates having a three-dimensional structure.