Alumite sludge is a precipitation that is generated by anodizing of aluminum sash products. The crystal structure of alumite sludge is changed to α-alumina (α-alumina sludge) by heat treatment. For effective utilization of alumite sludge, we attempted to improve the sintered body mechanical strength by applying milled α-alumina sludge to spark plasma sintering. The raw (no milling) material has a cuboid particle shape. By milling the raw material, the particle shape is changed from cuboid to cube, and the particle size is decreased. The changing particle shapes improved flexural strength to a maximum of 403 MPa at low firing temperatures. Observation of the fracture surface using SEM revealed that the fracture originated from a rectangular pore remaining in the sintered body. The shape factor of the rectangular pore (area, pore ratio, inclination angle) decreased with the change in particle shape. In order to ascertain the experimental result, the effect of rectangular pore shape on crack occurrence was investigated by using finite element method. The principal stress value around the rectangular pore decreased with the change in particle shape. Thus, crack occurrence at the fracture origin is inhibited by the change in particle shape.

FeSi₂ thermoelectric conversion materials are known for their high resistance to corrosion and heat; deposits of these materials are also plentiful and they have a low environmental impact. For this reason, extensive research has been carried out on FeSi₂ thermoelectric conversion materials for power generation. In order to extend its application range, the authors tested the use of a sensor made of FeSi₂. It is possible to use FeSi₂ in fire sensors because it can be used to detect the voltage produced due to a change in the temperature. The present study examined the thermo-electromotive force of FeSi₂ and its thermo-responsiveness in order to assess whether it has functional properties for use in fire sensors. The influence of module dimensions on thermo-electromotive force and thermal responsiveness was also examined.

In the mixed powders composed of BaTi₂O₅(BT2), BaTiO₃(BT) and Ba₆Ti₁₇O₄₀(B6T17), the quantitativity of a semi-quantitative concentration index α for actual BT2 concentration was verified. The powders of BT2, BT and B6T17 were synthesized through solid state reactions respectively. These calcined powders were mixed at various molar ratios. These mixed powders with known values of BT2 concentration were analyzed with X-ray powder diffraction. α was derived from the heights of the two particular diffraction peaks due to BT2 and BT. The quantitativity was clarified by comparing measured α values with actual BT2 concentrations.

To fine-tune the properties of ceramics, they can now be processed into uniform-size nanocrystals with spherical, cube, sheet, rod, wire shapes. Another trend in research aims at arranging individual nanocrystals into superlattices and investigating their unique properties. Despite these recent advances, controlling the shape, crystal structure, and surface characteristics of ceramic nanocrystals is still a difficult task. Here, we report an approach to tailor-made ceramic nanocrystals by means of organic ligand-assisted hydrothermal method. We succeeded in the synthesis of the ceramic nanocrystals such as ceria (CeO₂) nanocubes and titania (TiO₂) nanosheets. Also importantly, the use of water, instead of an organic solvent, provides an environmentally benign “green” chemistry route to nano building blocks for advanced materials and devices.

Element blocks, which are composed of various elements, have been widely studied due to their potential application in electric, optical, magnetic and biological fields. Element blocks can be used as functional materials without any further modifications, but it is also possible to polymerize them to prepare element block polymer materials, which are expected to be a series of new functional materials. Magnetite is one of the well-known magnetic oxides, and magnetite nanoparticles are known to exhibit superparamagnetism. In this review, we focus on surface-modified magnetite nanoparticles which can be considered as element blocks. Surface modification of magnetite nanoparticles has been achieved by using silane coupling agents, phosphorus coupling agents, carboxylic acids or alkyl amines based on according to purpose and application to improve their dispersibility and biocompatibility. And magnetite nanoparticles with grafted polymers are potentially useful to the fabrication of magnetite-based medical and biomedical materials. These element blocks prepared from magnetite nanoparticles via surface modification can be applicable to various applications including drug delivery system, hyperthermia and separation of biological matters or heavy metal ions. Examples are demonstrated for typical applications.

Pressure-sensitive adhesive (PSA) powder consists of millimeter-sized particles with a soft sticky polymer core and a hard solid nanoparticle shell morphology (adhesive liquid marbles), and shows no adhesion in its original form and flows like a powder through a funnel. Only after application of external mechanical stress, it acts as an adhesive. Adhesion can be induced by rupture of the nanoparticle coating of the liquid marble and outflow of the inner soft polymer. This article gives an exposition of fabrication and characterization of surface structure/chemistry, morphology and adhesive properties of PSA powder and adhesive liquid marble.

Construction of nanoarchitectures using cage siloxane oligomers as element blocks is of much interest because of its excellent potential for creating novel porous materials. In this review, our recent work on the fabrication of siloxane-based nanostructures from cage siloxanes is presented. The arrangement of cage siloxanes units is controlled by various methods, including amphiphilic self-assembly and hydrogen bonding of silanol groups, toward the preparation of well-defined porous siloxane-based materials.

Titanium tetraisopropoxide and phenylphosphonic acid were mixed in tetrahydrofuran and subjected to hydrolysis to provide a white crystal of titanium phosphonate with a formula of [Ti₄(μ₃-O)(OⁱPr)₅(μ-OⁱPr)₃(PhPO₃)₃]·thf. The titanium phosphonate was mixed with poly(methyl methacrylate) (PMMA) to form a hybrid film. The content of the titanium phosphonate in the resulting mixture was less than 30 wt% and yellow. The degradation temperature increased about 30°C by the hybridization of a titanium phosphonate cluster with PMMA. On the other hand, titanium phosphonate was mixed with poly(vinyl alcohol) (PVA) to form a hybrid film. The content of titanium phosphonate in the mixture was less than 50 wt% and colorless. Isopropyl alcohol was formed in this reaction, which suggests the formation of hybrid by the reaction of PVA with an isopropoxy group in titanium phosphonate.