In order to clarify thermal conductivity mechanism of ceramics and composites, their local thermal information is very significant. Present work reviewed thermal characterization of non-oxide ceramics at the micrometer scale, and concentrated especially the conductivity of individual grain by a thermal microscope, using thermoreflectance technique and periodic heating. Strong thermal anisotropy was found into very large β-Si₃N₄ grain for developed ceramic. Furthermore, non-homogenous distribution of the conductivity of AlN and SiC ceramics was quantitatively demonstrated in term of thermal conductivity map. Based on the results, the author also discussed high conductivity of AlN and SiC ceramics fabricated with high-purity powders and effective sintering aids, and Si₃N₄ ceramic involving elongated grains with highly orientation.

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Low-temperature solution growth of Si crystals using Na was demonstrated based on the Na–Si binary phase diagram. Single crystals, films, porous bulk samples, and helical microtubes of Si crystals were prepared from a Na–Si solution by Na evaporation. Dissolution and crystallization of Si in a Na melt reduced the impurity content in the Si crystals. Low-temperature synthesis and morphology control of porous SiC ceramics using Na were also performed and a new ternary compound, Na₈B_74.5Si_17.5, was synthesized.

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Lithium manganese oxide (LiMn₂O₄) powders with particle sizes in the range of 100–600 nm have been synthesized through glucose-assisted combustion synthesis. The presence of glucose increases the stability of the precursor solution, purity of the heat-treated powders, and decreasing on size of the synthesized particle. The formation of complex metal salts-glucose in the precursor solution and effect of the methods for preparing solid precursors on the final product were investigated.

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The effects of the bond coat structure on the microstructure evolution and lifetime performance of thermal barrier coatings (TBCs) were investigated through the cyclic thermal fatigue (CTE) and thermal-shock (TS) tests. The single layer and the first layer in the layered bond coat were prepared by high velocity oxy-fuel (HVOF) spray process using nickel-based feedstock. The second layer in the layered bond coat and the top coat were formed by air plasma spray (APS) process using nickel-based metallic feedstock and 8 wt % yttria-stabilized zirconia, respectively. The CTF tests were performed till 872 cycles with a dwell time of 60 min at a surface temperature of 1100°C and a bottom temperature of 950°C. Also, the TS tests were conducted until 300 cycles with a dwell time of 60 min at 1100°C. After the CTF and TS tests, the TBC system with the layered bond coat showed a better thermal durability than that with the single layer. The hardness value of the bond coat by HOVF process was dramatically decreased after the both tests, without much change in the bond coat by APS process. The diffusion trends of elements were similar with each other, less dependent on the bond coat structure, increasing amounts of cobalt and aluminum and decreasing those of nickel and tungsten. The microstructure evolution of the top coat, the growth behavior of thermally grown oxide layer, and the thermal durability were strongly affected by the thermal exposure condition and the bond coat structure.

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It is known that Cu valence of cuprate superconductors govern transition temperature (T_c). For La_2−xSr_xCuO_y, when x = 0.15, that is, v is 2.15, the highest T_c around 40 K is achieved. The v value is determined both by strontium and oxygen content. So far, coulometry and iodometry have been used for determining oxygen content. However, chemical analysis usually requires much experience. The purpose of this research is to develop a novel measuring method of oxygen content in cuprate superconductors with a newly developed dissolved oxygen (DO) sensor and to discuss correction method. Signal received from the DO sensor is sent to PC automatically without any external power supply. Oxygen content obtained with DO sensor was compared with iodometry. It was found that this method is reliable enough to determine oxygen content in La_2−xSr_xCuO_y, and is called dissolved oxygen (DO) method.

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The excessive intake of fluoride ion (F⁻) from drinking water causes dental and skeletal disorders and thus methods for the removal of F⁻ from water are desired. A method for removing organic contaminants from water is also desired. Bone char is a composite material composed of char and hydroxyapatite (HA). Bone char can remove F⁻ because of the HA in the bone char. It is expected that bone char containing small grain size HA will remove F⁻ effectively because of its high surface area. Additionally, the char in bone char can remove organic matter from contaminated water, and controlling the amount of char in bone char is also important. Bone char is fabricated by heating porcine bone at 200–600°C for 1 h under a limited oxygen supply. The grain size of HA in these samples increases with an increase in heating temperature. The amount of organic matter and char in these samples decreases with an increase in heating temperature. Bone char with a controlled HA grain size and the amount of char was fabricated by changing the heating temperature. Their ability to remove F⁻ and methylene blue (MB), as a model organic contaminant, was evaluated by immersing the samples in F⁻-containing and MB-containing solutions. The sample prepared at 400°C was able to remove most of the F⁻ and less than 1.5 mg·dm⁻³ F⁻ remained, which is within the World Health Organization recommended level for drinking water. Additionally, the sample prepared at 400°C was also able to remove most of the MB. Bone char can thus be used to remove F⁻ and organic contaminants.

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The microwave dielectric properties and microstructures of (1 − y)(Mg_0.95Ni_0.05)₄Ta₂O₉–y(Ca_0.8Sr_0.2)TiO₃ ceramics prepared using a mixed oxide route were investigated. (Mg_0.95Ni_0.05)₄Ta₂O₉ has a dielectric constant (ε_r) of ~12.23, a high quality factor (Q×f) of ~442,092 GHz, and a temperature coefficient of resonant frequency (τ_f) of ~−55 ppm/°C. To produce a temperature-stable material, Ca_0.8Sr_0.2TiO₃, which has a large positive τ_f value of 990 ppm/°C, was added to (Mg_0.95Ni_0.05)₄Ta₂O₉. The temperature coefficient of resonant frequency increased with increasing Ca_0.8Sr_0.2TiO₃ content, going through nearly zero at y = 0.7. The microwave dielectric material 0.3(Mg_0.95Ni_0.05)₄Ta₂O₉–0.7(Ca_0.8Sr_0.2)TiO₃ has an excellent combination of microwave dielectric properties: ε_r ~ 29.8, Q×f ~ 226,000 GHz (at 9 GHz), and τ_f ~ −2.38 ppm/°C sinter at 1350°C. It is proposed as a candidate material for industrial, scientific and medical band components and Global Position System antennas.

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We have produced a trial high alite cement in a cement plant and have researched the hydration reaction of the high alite cement with blended materials. The high alite blended cement has a higher heat of reaction and produces a more hydrated product than ordinary Portland cement, as confirmed by heat liberation from a calorimeter. The amount of Ca(OH)₂ (or CH) was confirmed to be higher than that of ordinary Portland cement. In this research, we focused on measuring the properties of blended high alite cement in the early hydration period. Results were obtained for hydrated samples at up to 28 days to ascertain the possibility of using high alite cement and its potential improvement in blending.

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Siloxane-containing vaterite doped with magnesium (MgSiV) was prepared by a carbonation process for application in bone regeneration. Ca(OH)₂, aminopropyltriethoxysilane (APTES) and Mg(OH)₂ were mixed with a solvent consisting of methanol and distilled water under CO₂ gas. After the mixture was aged, the translucent precursor gel was dried, resulting in the formation of MgSiV particles containing 2.0 wt % magnesium and 2.8 wt % silicon. The MgSiV consists of distorted spherical particles with diameters of approximately 1.3 µm and a thickness of approximately 0.6 µm while the siloxane-containing vaterite without magnesium (SiV) was spherical with a diameter of approximately 1.5 µm. X-ray diffraction (XRD) analysis suggests the incorporation of magnesium into the vaterite structure. Fourier transform infrared spectroscopy (FTIR) indicated the presence of amorphous calcium carbonate (ACC) while the magnesium and the siloxane formed Si–O–Mg bonds. After heating the MgSiV at 500°C, the magnesium removed from the vaterite structure formed Si–O–Mg bonds with the siloxane. The MgSiV released Ca²⁺, Mg²⁺ and Si⁴⁺ ions into a Tris buffer solution. The amount of Ca²⁺ ion dissolved in the Tris buffer solution increased within the initial 12 h and subsequently decreased with time because of the formation of precipitates.

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Transparent ceramic composite of non-doped and Ce-doped YAG was prepared by Konoshima Chemical with the vacuum sintering technique and investigated on pulse shape discrimination capability for functional collimator. Scintillation responses such as X-ray induced radioluminescence and decay time profiles of non-doped and Ce-doped YAG were evaluated. Pulse shape discrimination capability of the composite ceramic was evaluated by ¹³⁷Cs 662 keV γ-ray irradiation. As a result, clear separation of γ-ray events at non-doped or Ce-doped YAG layers was observed in two dimensional histogram by using signal processing with two different shaping times.

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The leaching behavior of cathode ray tube (CRT) funnel and neck glasses were compared in 0.001 N HCl and 0.001 N NaOH at 70 and 90°C. We measured the weight loss and leached amount of each component and observed the surface changes by scanning electron microscopy (SEM). In acid solution funnel glass showed t^1/2-dependent leaching, whereas neck glass only demonstrated congruent dissolution after 8 weeks. In basic solutions leaching behavior was almost equivalent for both types of glass. Dissolution halted after one or two weeks as a result of the deposition of a protective layer. This layer was formed by saturation of Pb and was subsequently dissolvable by refreshing the leachant solution.

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ZrO₂/multi-wall carbon nanotube (MWCNT) composites were consolidated using a spark plasma sintering technique. Micro- and nano-scale mechanical properties of sintered composites with various MWCNT contents were investigated using X-ray diffraction and instrumented indentation techniques. Transitional behavior in the hardness and elastic modulus of the composites was observed and attributed to the contrasting effects of the MWCNT addition; i.e., beneficial effects such as inhibition of crystal growth and phase transition and detrimental effects due to the agglomerated MWCNTs.

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