We have previously developed hydroxyapatite (HAp) cement based on the chelate-setting mechanism of sodium inositol hexaphosphate (IP6-Na). In the present study, the effect of the IP6-Na concentration on material properties, such as compressive strength, setting time, consistency, and anti-washout capability, of the chelate-setting hydroxyapatite cement was investigated with the aim to develop paste-like artificial bone with anti-washout capability. Starting powders for cement fabrication (IP6-HAp powder) were prepared by simultaneous grinding and surface-modification of the HAp powder in various concentrations (0–20000 ppm) of IP6-Na solution. The amount of IP6 adsorbed on the surface of the HAp powders increased with the IP6-Na concentration and resulted in a negative charge on the powder surface. Dispersion of the IP6-HAp powder was improved with increasing IP6-Na concentration. A workable cement paste was prepared from the negatively charged IP6-HAp powder (<−20 mV) at a higher powder/liquid ratio, regardless of the low water content. The compressive strength of the resulting cement specimens increased from 1.4 to 8.3 MPa with an increase of the relative density. HAp powders surface-modified with 5000 to 10000 ppm IP6-Na are effective for fabrication of IP6-HAp cements with enhanced material properties. In particular, surface-modification with 5000 and 10000 ppm IP6-Na improved the handling feasibility of the cement paste. IP6-HAp cement fabricated by controlling the IP6-Na concentration is promising as an injectable artificial bone for minimally-invasive treatment.

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The highly (100) oriented (Pb,La)(Zr,Ti)O₃ (PLZT) films were successfully grown on (110) Al-doped ZnO (AZO) coated on (100) SrTiO₃ (ST) substrates using an RF magnetron sputter. The ferroelectric, dielectric, and optical properties of the transparent AZO/PLZT/AZO/ST structure were investigated to suggest the feasibility of AZO as an alternative transparent conductive oxide (TCO) electrode for optical devices requiring the longitudinal electro-optic (EO) effect. Recorded P-E loops showed slim hysteresis, and the remanent polarization and coercive field were 6.5 µC/cm² and 37 kV/cm. The relative permittivity and loss tangent were 745 and 0.044 at 10 kHz, respectively. The optical transmittance of the structure was over 90% in the near-infrared (NIR) region. Finally, the AZO/PLZT/AZO films grown on the ST substrate exhibited a strong quadratic EO effect and the longitudinal EO coefficient was 180 nm²/V² at λ = 1550 nm.

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Rectangular thick plates of layered hydroxide zinc acetate (LHZA) are synthesized by crystal growth in ethanolic-aqueous zinc acetate solution. The secondary nucleation and crystal growth of LHZA with two phases results in rectangular thick plates, which have clear facets with terraces. The control of Zn concentration and water/ethanol ratio would create the stable LHZA system because of the suppression of the dehydration and condensation reactions from the zinc hydroxide to the zinc oxide. Moreover, the LHZA is converted into a framework-like ZnO by a pyrolysis reaction. The unique morphology of LHZA and ZnO is reported.

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The electrochemical properties and crystal structure of LiNi_0.60Co_0.22Mn_0.18O₂ treated by supersonic-waves in a Zn-containing solution were investigated by performing charge–discharge tests, X-ray diffraction (XRD), an inductively coupled plasma (ICP) analysis, scanning electron microscopy (SEM), transmission electron microscopy, energy dispersive X-ray spectroscopy (TEM-EDX) and synchrotron powder XRD. Furthermore, the supersonic-wave bath solution was characterized by pH measurements. The electrochemical properties and crystal structure of LiNi_0.60Co_0.22Mn_0.18O₂ treated with supersonic-waves in a Zn-containing C₂H₅OH solution did not change from pristine. On the other hand, Zn²⁺ was partially substituted in the LiNi_0.60Co_0.22Mn_0.18O₂ treated with supersonic-waves in a Zn-containing aqueous solution. As a result of the ICP analysis of the supersonic-wave-treated samples and pH measurement of the supersonic-wave bath, the Li was dissolved in the supersonic-wave bath which contained H₂O from the LiNi_0.60Co_0.22Mn_0.18O₂. This suggests that Li defects are the initial points of Zn substitution by the supersonic-wave treatment.

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The thickness of the specific oxide phase scale formed on single crystal silicon carbide was measured to determine the activation energy on both the Si-face and the C-face. The oxide scales were thermally formed on both the Si- and the C-face of 6H-SiC at 1273–1473 K in a pure oxygen environment. Microstructures of the oxide scales were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Crystalline oxide scales were found to be randomly distributed on the surfaces of both the Si-face and the C-face of the oxidized samples. The focused ion beam (FIB) micro-sampling technique was employed to prepare the specific site specimens for thickness measurement of the oxide scales in the regions where the oxide scales were composed of only uniform amorphous silica. The thickness of the oxide scales was measured directly to high accuracy using SEM and TEM, and fitted to the Deal–Grove model. The oxidation activation energy for the parabolic rate constant was found to be 358 kJ/mol for the Si-face and 85 kJ/mol for the C-face. The low activation energy for the C-face that is close to that for oxygen diffusion in silica strongly suggested that the rate controlling process of the C-face oxidation is the diffusion of oxygen in the oxide layer.

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A porous coating process is presented for solid oxide fuel cell electrodes that reduce manufacturing costs and production time. The process used aluminum as a pore-former for creating anisotropic mille-feuille-like porosity in plasma-sprayed 3.9 mol. % yttria-stabilized zirconia (3.9YSZ) coatings. After etching, almost no aluminum phase can be detected by X-ray diffraction and the porous coating hardness decreases to below 40 HR15Y. A porosity of between 44.5 and 50.4 vol. % is obtained in the etched porous plasma-sprayed coating. Most of the monoclinic phase originally in the 3.9YSZ feedstock powder is suppressed after plasma spraying.

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The formation mechanism of LiFePO₄ crystals in lithium iron phosphate glass (33.3Li₂O–33.3Fe₂O₃–33.3P₂O₅) particles with a diameter of <63 µm was investigated by using X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) techniques. LiFePO₄ was mainly crystallized by heat treatments at 350–800°C for 30 min under 7%H₂/Ar atmosphere. At low temperature heat treatments, nano-scaled (∼40 nm) Li_xFePO₄ crystallites are formed through a homogeneous nucleation process. With increasing temperature, a contribution of the reduction of Fe³⁺ to Fe²⁺ becomes larger, and LiFePO₄ grows from the surface toward the inside of particles. Li₃Fe₂(PO₄)₃ and Fe₂O₃ crystals with Fe³⁺ are formed in the inside. In the heat treatment at 800°C, the formation of LiFePO₄ crystals is largely promoted through the reduction of Fe³⁺ and the phase transition of Li₃Fe₂(PO₄)₃ and Fe₂O₃ crystals. An existence of amorphous layer with a thickness of several nm between the crystallites is confirmed even in the well crystallized sample from HRTEM observations.

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Open-cell silicon carbide foams were fabricated from a blend of carbon-filled polysiloxane using three different plastic forming methods: compression molding, injection molding, and extrusion. Compression molding process led to more homogeneous microstructure than the other forming methods, resulting in superior compressive strength (20.6 MPa at 72.4% porosity). In contrast, extrusion molding led to higher porosity (∼84%) than the other forming methods (72–74%) as a result of a higher level of expansion of expandable microspheres. Injection molding process led to a partial segregation of expanded microspheres and resulted in moderate compressive strength (9.1 MPa at 74.1% porosity).

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Spherical aggregates of leaf-like YPO₄ particles have been prepared by the reactions of tri-n-butylphosphate [PO(OC₄H₉)₃, TBP] with the acidic Y(NO₃)₃ aqueous solution in an autoclave at 180°C. The products of the reactions for 1, 3 and 6 h consisted of an intermediate exhibiting an intense X-ray diffraction line at d ≈ 1.28 nm, while those of reactions for 12–48 h were pure YPO₄. The products of the reactions for 8 and 8.5 h were mixtures of the intermediate and YPO₄. YPO₄ formation thus seems to proceed via the formation of the intermediate. Since the intermediate seems to be Y[PO₂(OC₄H₉)₂]₃, it is likely that TBP was hydrolyzed to form PO₂(OC₄H₉)₂⁻ ions, which then reacted with Y³⁺ ions to form the solid intermediate, Y[PO₂(OC₄H₉)₂]₃. Scanning electron microscopy (SEM) revealed the corresponding morphological change from the belt-like products to spherical aggregates of leaf-like particles, indicating that the solid intermediate Y[PO₂(OC₄H₉)₂]₃ was hydrolyzed to form leaf-like YPO₄ particles.

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Low-temperature joining of boron carbide (B₄C) ceramics using an Al sheet was investigated in the temperature range of 600–1200°C for 2 h in vacuum (10⁻²–10⁻⁴ Pa). Successful joining and high bending strength close to that of the B₄C base were achieved in the samples joined at 700–1100°C. Different techniques including scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) were used to characterize the high-strength B₄C joints. SEM observations suggested the dense interlayer and the crack-free interface as well as the penetration of Al into the surface microcracks of B₄C base. Further TEM examinations revealed that B₄C and Al joined directly. EPMA analysis demonstrated the existence of several reaction products within interlayer, including AlB₂ and Al₃BC, which resulted in the development of high-strength composite interlayer.

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