• Intergranular degradation often results in decreased lifetime, reliability and economical efficiency of polycrystalline materials. In spite of persistent efforts to prevent such degradation, its complete suppression has not yet been achieved. Grain boundary studies have revealed that coincidence-site-lattice (CSL) boundaries have stronger resistance to intergranular degradations than random boundaries. The concept of ‘grain boundary design and control' has been refined as grain boundary engineering (GBE). GBEed materials which are characterized by high frequencies of CSL boundaries are resistant to intergranular degradations. Our group has achieved very high frequencies of CSL boundaries in commercial stainless steels by GBE. GBEed stainless steels showed significantly stronger resistance to intergranular corrosion (see Figs. 1 and 2), weld-decay, knife-line attack, stress corrosion cracking, liquid-metal embrittlement, radiation damage, etc. and much longer creep life (see Fig. 3) than the unGBEed ones.

By using this GBE processing, we expect to conduct effective collaborative research in related fields.

• The high-temperature strength in Co-based alloys is inferior to that in Ni-based superalloys due to no available ’ phase for strengthening Co-based alloys. We have found a new intermetallic compound Co3(Al,W) ’ phase, and /’ Co-Al-W-based wrought and cast alloys show excellent high-temperature strength. The /’ Ir-Al-W-based alloys are also available for high-temperature uses at over 1100 °C. The Co-based alloys also have good wear resistance. For example, friction stir welding (FSW) of high-softening-temperature materials such as steels and titanium alloys is possible using a Co-based alloy tool. We hope to conduct collaborative research with willing company for a practical application of the Co- or Ir-based alloys for high-temperature uses including FSW applications.

• Monoatomic layered materials of Graphene, Transition metal sulfide nanosheet, nanocrystalline active materials, nanoparticles and nanoporous materials are investigated for realizing high capacity, high power, high safety and low cost energy storage devices as a post- Lithium ion battery. Advanced chemistry of functional materials and device processes for All solid state battery, Magnesium battery, fuel cells, supercapacitor and wearable batteries are investigated.

Academia – Industry collaboration with manufacturing companies of functional materials, batteries, and also smart grid, renewable energy, electrical power companies are encouraged for developments of advanced energy materials and post-Lithium ion battery.

• The main research subjects in this group are the experimental investigations of the organic molecular conductors. The characteristic properties of the organic materials are multiple flexibilities owing to the assemble structure of nanometer-size molecules. This flexbility comes up recently for developing the organic electronic devices. We explore the fundamental electronic properties of the organic molecular materials which have wide range of the ground states from superconductivity to insulating states resulting from the strongly correlated electrons in the molecular pi-orbital. Such features are closely connected to flexible and multiple degrees of freedom in charge, spin, molecular latticeand molecules themselves. We are actively studying on the interesting and important issues in the condensed matter physics from the viewpoints of the characteristic flexbility of the organic molecular materials. We are prepared to provide academic consultations to companies interested in our research.

• In contrast to other scattering techniques, such as x-ray and electron diffractions, neutron scattering has the following advantages: 1) light atoms, such as H and Li, can be detected; 2) electron spins can be detected; 3) low energy excitations can be investigated. Using the neutron scattering technique, we search for macroscopic quantum phenomena in many-body electron systems, such as macroscopic singlet ground states in the quantum frustrated magnets and spin-fluctuation-mediated unconventional superconductors.

As noted above, neutron scattering can be used for investigating magnetic structure, spin dynamics, light atom positions in crystalline materials and their dynamics. Hence, this technique is very useful when those pieces of information are to be known.

• Our research group investigates creation of functional oxides and their functionalities. We synthesize thin films by pulsed laser deposition and sputtering methods and bulk specimens, and develop their novel synthetic routes. Recently, we are studying electrically conducting rare earth oxides, transparent room temperature ferromagnetic semiconductors, and layered superconductors with monatomic Bi layer. We will develop our materials design by extending materials range and performing oxide heteroepitaxy.

Collaborative research in fields of oxide electronics with novel electric conducting oxides and oxide spintronics with ferromagnetic semiconductors and novel ferromagnetic oxides.

• We are developing a new continuous flow type process for supercritical reactions. Under the supercritical state, the organic molecules and metal salt aqueous solutions are miscible and water molecule works as an acid/base catalyst which leads to rapid reactions. In order to apply such new reaction fields to an industrial process, it is necessary to establish the process design basis by understanding phenomena in the reaction fields, on the basis of phase equilibrium, flux and reaction kinetics theory. So while developing a process, we are doing research for the establishment of the process design basis.

Examples are a process for the synthesis of organic modified nanoparticles (MPs), a process for the pretreatment and solubilization of biomass in the supercritical/subcritical water and a process for the refinery of heavy oil in the supercritical water.

• Our research group has succeeded in synthesizing various metal oxide nanoparticles with controlled size and exposure crystal planes by using organic modifiers under supercritical water conditions. The oxygen storage/release capacity of those materials in the low-temperature region is very high, and the reforming reaction of oxidative hydrocarbon proceeds at a significant rate. Besides, by combining the supercritical CO2 drying method, we have succeeded in forming a complex in which oxide nanoparticles are dispersed at a high concentration on the surface of the porous material, realizing both high oxygen storage/release capability and stability.

Low-temperature reforming reaction of biomass wastes, heavy oils, and methane. In the future, it is expected to be a technology that will lead to the construction of a low-carbon society, including CO2-free complete recycling of waste plastics.

• We invented supercritical hydrothermal synthesis method for the synthesis of organic modified nanoparticles (NPs). Under the supercritical state, the organic molecules and metal salt aqueous solutions are miscible and water molecule works as an acid/base catalyst for the reactions. Organic-inorganic conjugate NPs can be synthesized under this condition. This hybrid NPs show high affinity with the organic solvent or the polymer matrix, which leads to fabricate the organic inorganic hybrid nanomaterials with the trade-off function (super hybird nanomaterials). These hybrid materials of polymer and ceramics fabricated with NPs achieve both high thermal conductivity and easy thin film flexible fabrication, namely trade-off function.

For example, by the surface modification of BN particles by supercritical method, affinity of BN and polymers could be improved, so that high BN content of hybrid materials, thus high thermal conductivity materials, could be synthesized. Also by dispersing high refractive index NPs like TiO2 or ZrO2 into polymers transparently, we can tune the refractive index of the polymers. CeO2 nanoparticles are expected to be used for high performance catalysts. To transfer those supercritical fluid nano technologies, a consortium was launched with more than 70 companies.

• General metallic biomaterials, such as stainless steels and conventional CoCr alloys, show a high Young's modulus ten times higher than that of human bones. This is an unfavored feature because it causes the so-called "stress shielding effect" when they are used as implants. β-type Ti alloys have a relatively lower Young's modulus, but they come with a compromise of low wear resistance. The current novel CoCr-based alloys are a breakthrough; they exhibit both a low Young's modulus similar to human bones and a high wear and corrosion resistance. Moreover, they exhibit superelasticity with a huge recoverable strain over 17%, also showing promise as shape memory alloys.

It is the first time that a low Young's modulus, a high corrosion and wear resistance, and a superior superelastic behavior are simultaneously obtained in a single material. The current novel CoCr-based alloys are promising for biomedical applications such as total hip or knee joint replacements, bone plates, spinal fixation devices, and vascular stents.

• Recently, we have developed a novel Cu-Al-Mn based shape memory alloy with high SM properties and with a ductility twice higher than that in Nitinol . Furthermore, this novel SM alloy needs no die for the shape setting and is fabricated with relatively low cost. Very recently, we have successfully developed a device to cure ingrown toenail by using this SM alloy.

Very recently, we established a fabrication process for the Cu-Al-Mn sheet, wire and bar with 0.1 - 20mm in thickness or diameter. We hope to conduct collaborative research with a willing company for a practical application with this new SM alloy.