• We developed both pH and Cl- imaging plates, which can visualize the pH and Cl- concentration on metal surfaces in acidic environments. The pH range is from 3.0 to 0.5, and Cl- concentration up to 4 M can be measured. Fluorescent dyes are successively used for pH and Cl- imaging in the field of biology, but their sensitivity tends to be insufficient in acidic and/or highly concentrated chloride solutions. A glass plate with a sol-gel sensing layer, which contains a pH indicator or a Cl- sensitive florescent dye was fabricated and validated using the solutions with various pH values and Cl- concentrations. Changes in the pH and Cl- distribution on stainless surface in an acidic environment were measured quantitatively.

The newly developed imaging plates can be used to investigate the mechanism of various chemical reactions, such as corrosion, which occurs in an acidic environment. Micro-flow imaging using our sensing technique will be a promising approach to understand the catalytic chemistry of metal surfaces.
強調

• We are studying hydrogen embrittlement property of high strength steels from the aspects of both the effect of hydrogen on mechanical properties of high strength steels and hydrogen uptake behavior in corrosive environments. The topics of our study includes clarification of mechanism of hydrogen embrittlement of various steels, investigation of hydrogen entry caused by corrosion using electrochemical techniques, hydrogen visualization, proposing evaluation methods for hydrogen embrittlement property and so forth.

Collaborative research in the field of hydrogen embrittlement, for example, hydrogen embrittlement properties of high strength steels and the effects of metallographic structure and hydrogen traps, proposal of evaluation methods for hydrogen embrittlement property for some specific steel and for parts with specific shape, development of novel hydrogen visualization techniques.

• 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.

Colorful TiO2 Particle
https://www.t-technoarch.co.jp/data/anken_en/T19-849.pdf

Transition metal compounds are known to exhibit a wide variety of colors. Until now, it has been possible to color white titanium oxide by doping with transition metal ions, but it is difficult to avoid biotoxicity derived from transition metals.

• In the present invention, titanium oxide inorganic pigments that do not contain transition metals and have various colors such as white, yellow, red, gray, green, purple, black, and skin color have been realized.

New applications of titanium oxide pigments are expected in the cosmetics field, where biotoxicity is an issue.

• 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.

• We developed both pH and Cl- imaging plates, which can visualize the pH and Cl- concentration on metal surfaces in acidic environments. The pH range is from 3.0 to 0.5, and Cl- concentration up to 4 M can be measured. Fluorescent dyes are successively used for pH and Cl- imaging in the field of biology, but their sensitivity tends to be insufficient in acidic and/or highly concentrated chloride solutions. A glass plate with a sol-gel sensing layer, which contains a pH indicator or a Cl- sensitive florescent dye was fabricated and validated using the solutions with various pH values and Cl- concentrations. Changes in the pH and Cl- distribution on stainless surface in an acidic environment were measured quantitatively.

The newly developed imaging plates can be used to investigate the mechanism of various chemical reactions, such as corrosion, which occurs in an acidic environment. Micro-flow imaging using our sensing technique will be a promising approach to understand the catalytic chemistry of metal surfaces.
強調

• 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.

• This lab is concerned with the novel approach mainly for the growth from melt by studying the relationship between the interface dynamics during growth and properties of grown crystals. Special interests lie in the growth of new crystals via the imposition of an interface-electric field. Nano-scaled control of crystal growth is executed in an electric double layer of ~nm thickness that is induced by applying an external electric field on the growth interface. Some of our growth results brought by applying an electric field are;
• 1. Growth of Langasite-type crystals for the pressure sensor at high temperature by manipulating the energy relationship between crystal and melt.
• 2. Easy nucleation of protein crystals that are normally hard to crystallize.
• 3. Formation of Si crystals with desired structure by manipulating the interface instability of Si.
• Crystals developed this way will widen an opportunity to collaborate with industries in the field of the piezoelectric, magnetic, optic and other fields related to the highly-networked information society.

• The main research subject of our group is developing material purification methods, crystal growth methods and detector fabrication technologies for compound semiconductor radiation detectors. Our group intensely studies a compound semiconductor, thallium bromide (TlBr), for fabrication of gamma-ray detectors for the advanced radiation applications. The attractive physical properties of TlBr lie in its high atomic number (Tl: 81, Br: 35), high density (7.56 g/cm3) and wide bandgap (2.68 eV). Due to the high atomic number and high density, TlBr exhibits high photon stopping power. The wide bandgap of TlBr permits the device low-noise operation at and above room temperatures.

Our group focuses on development of compound semiconductor radiation detectors for advanced radiation applications including ultra-high resolution PET systems, ultra-high resolution SPECT systems, photon counting CT systems and Compton cameras. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• Fukuyama laboratory studies novel material processing based on chemical thermodynamics with high-temperature thermophysical property measurements. As examples, we are developing new crystal growth processes to bring a breakthrough in nitride-semiconductor devices, which are promising materials for next-generation optical devices applied in environmental, medical, bio and information technologies fields. Database of thermophysical properties of materials is needed for modeling heat and mass transports in materials processes.

A new thermophysical property measurement system is currently under development, which enables accurate measurements of heat capacity, thermal conductivity, emissivity, density and surface tension of high-temperature melts, utilizing electromagnetic levitation in a dc magnetic field.

The sea pineapple is the only animal that produces cellulose, and its shells, excluding the edible parts, are treated as industrial waste. By removing proteins and other components from the sea squirt shells and fibrillating them, cellulose nanofibers (CNFs) can be extracted. We have focused on the fact that CNFs derived from sea squirt shells have a higher degree of crystallinity and greater mechanical strength compared to those from wood, and we are exploring various applications of this material. Furthermore, since the material transforms into high-quality carbon upon calcination, we successfully developed "nano-blood carbon catalysts" by mixing it with dried blood powder and calcining the mixture. These catalysts are being applied in fuel cells, water electrolysis, and metal-air batteries.

CNFs derived from sea pineapple's shells have a higher degree of crystallinity compared to those from wood and provide longer fibers, resulting in high strength. When calcined, they transform into high-performance carbon.

• We are the only research laboratory that has consistently developed a process for the simple and large-scale purification of CNFs derived from sea pineapple's shells, along with the creation of film materials that leverage their unique properties (mechanical, engineering, surface science, electrical, and thermal characteristics), as well as the development of carbonized materials.

We offer materials derived from sea pineapples' shell CNFs, as well as their carbonized products and catalysts. Please feel free to consult us regarding material supply, carbonization processes, or the utilization of catalysts.