Nano ZnO synthesized with and without surfactant adopting Solid State Reaction (SSR) method, the later at four different temperatures and by Aqueous Chemical Method (ACM) is reported. CdO synthesized by ACM is also presented. The ZnO nanorods by SSR with surfactant are of hexagonal shape with diameter between 20–30 nm and lengths of about 350–500 nm, while that without surfactant does not exhibit rod like morphology. The particle size increases from 35 to 59 nm with temperature in the range 500 to 800°C. ACM resulted in a particle size of 15–35 nm whose SEM shows the nanoparticles forming flakes. Optical properties are studied. A blue shift is observed where the band gap increases from 3.37 (bulk) to 3.62 eV. The increase in band gap is due to quantum confinement effect. CdO synthesized by ACM was of size 30–70 nm. The XRD pattern of CdO reveals NaCl structure.

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Undoped zinc oxide (ZnO) and cobalt doped ZnO nanostructures without any surfactant were grown by hydrothermal method by varying the process parameters such as molarity of precursors and time of growth. X-ray diffraction spectra of the sample show wurtzite ZnO without any secondary Co phases. SEM image confirms the formation of hexagonal shaped rods and these rods assembled like a flower. Inductively coupled plasma atomic emission spectroscopic (ICP AES) studies confirm the incorporation of cobalt in the ZnO nanostructures. The electronic structure as well as the optical properties of ZnO:Co²⁺ have been characterized. In the energy range below the band gap, the optical absorption spectra show the internal d–d transitions related to Co²⁺ incorporated on the Zn site in ZnO lattice. The g-values of ZnO:Co samples obtained from electron paramagnetic resonance confirms the incorporation of Co²⁺ in ZnO. Photoluminescence (PL) studies shows that these nanostructures exhibit a blue luminescence on excitation with wavelength 350 nm due to the Zn interstitial related defects.

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ZnCo₂O₄ ceramics with a spinel-like structure are versatile functional materials which depending on the synthesis conditions may exhibit magnetic, electric, optical and/or catalytic characteristics. However under air atmosphere, cobalt ions experiment different red-ox processes with temperature, so contrary to many other spinel oxides, a low thermal stability can be expected for this cobaltite spinels. In addition, the final outcome of these transformations will be as well defined by the solid state chemistry of the ZnO–Co_xO_y couple, i.e. by the partial solubility of cobalt in zinc oxide and zinc in the different cobalt oxides. At first the similarity in charge and ionic size suggests the possibility of substitutional solid solution for both the Co^II into the ZnO wurtzite structure and the Zn^II into the CoO rock-salt structure. However it has been observed that once the spinel structure collapses, all the zinc diffuses into the rock salt phase.

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Low crystalline B-type carbonate apatite (CO₃Ap) block was fabricated by compositional transformation based on dissolution–precipitation reaction using microporous low crystalline calcite block as a precursor. In other words, microporous low crystalline calcite block prepared by carbonation of Ca(OH)₂ compact was phosphoridated by exposing to 1 mol·dm⁻³ Na₂HPO₄ solutions at 60°C for 14 days. XRD, FT-IR and SEM analysis showed that calcite block completely transformed into B-type CO₃Ap keeping its macroscopic morphology. Diametral tensile strength of the low-crystalline B-type CO₃Ap block was approximately 5.4 MPa, and this value was much higher when compared with the low-crystalline calcite block, 0.73 MPa. Low crystalline B-type CO₃Ap block fabricated in this method could be an ideal bone replacement due to its close similarity in its inorganic chemical composition and crystallinity to bone.

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The precursors of SiC powders were fabricated from various silica and phenolic resin sources of Si and C. The silica particles were 3.7 µm to 34 nm in size, and much finer silica was obtained from a liquid tetraethoxysilane oligomer. Silica and phenolic resin mixtures were cured and carbonized to form SiC precursors, and fine SiC powders were synthesized by carbothermic reaction of the precursors at 1600–2000°C. Powders with a grain size of 10–30 nm were synthesized at 1600°C from liquid silica and C. Dispersed SiC powder in water had primary grain size of 10–30 nm. SiC yield was higher from precursors having higher C/Si ratios. The carbon dispersion on fine-grain SiO₂ was important in fabricating the SiC nano-powders.

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Complex inorganic green pigments having a high near infrared solar reflectance have been synthesized. Cr₂O₃ is the host component and mixtures of TiO₂, Al₂O₃, and V₂O₅ were used as the guest components. TiO₂, Al₂O₃ and V₂O₅ were mixed into 39 different compositions. It was found that a sample, denoted by S9, with a composition of Cr₂O₃, TiO₂, Al₂O₃ and V₂O₅ of 80, 4, 14 and 2 wt% respectively, gives a maximum near infrared solar reflectance of 82.8%. The S9 pigment powder was then prepared as a reflective coating material with different amounts of pigment powder from 4–8 g in 100 g of ceramic glaze. The prepared materials were sprayed on the clay tiles for reflectance measurements. It was found that 6 g of S9 pigment powder mixed with 100 g of ceramic glaze gives the highest near-infrared reflectance value of 74.5%. The newly synthesized pigment is a suitable ceramic roof coating for its high reflectance performance and the durability performing once the ceramic roof installed on house.

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Conducting Ag–glass composite powders with spherical particles and a submicron size were directly prepared by spray pyrolysis from a colloidal solution containing nanosized glass powders. The mean size of the composite powders was 0.7 µm. The composite powders had good sintering characteristics at low temperatures because of the high degree of mixing between the Ag and glass components. Sintering of the composite powders occurred even at a low temperature of 400°C. Therefore, a conducting layer fired at a temperature of 400°C had low specific resistance because of its dense structure and low pore volume. The specific resistances of conducting layers formed from the composite powders were observed to increase from 2.4 to 4.7 µΩ cm when the firing temperature was decreased from 550 to 400°C.

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The ceramic coating was prepared on the NiTi alloy by Micro-arc oxidation (MAO) in a sodium aluminate (NaAlO₂) solution at constant current density. The surface of the coating displays a rough, porous structure. The elements of the coatings mainly contain Al, Ti, O, and Ni. The concentration of Ni in the surface is 1.63 at%, which is greatly lower than that of Ni in the NiTi substrate. XPS analysis revealed that Al exist as Al–O bond of Al₂O₃, Ti existed as Ti⁴⁺(TiO₂), Ti³⁺(Ti₂O₃), Ti²⁺(TiO), and Ti⁰(metallic Ti), and Ni exist as Ni₂O₃, NiO and metallic Ni in the coating surface. Thin-film X-ray diffraction shows that the only Al₂O₃ phase can be confirmed in the coating. Potentiodynamic polarization curves indicate that the corrosion resistance of the Al₂O₃ coating is better than that of uncoated NiTi. The amount of Ni leached from coated NiTi sample is 20.97% of that from the uncoated NiTi sample after immersion 40 d. The Tribological behavior of uncoated and coated NiTi alloy was evaluated using a computer-controlled ball-on-disk WTM-1E tribometer.

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ZnO samples added with MgO of 1.4–11.7 mol % were used for studying oxygen diffusion by the vapor–solid exchange method. The analyses of oxygen diffusion profiles and impurities were performed by secondary-ion mass spectrometry (SIMS). The results indicate that the increase of MgO concentration enhances oxygen diffusion. The difference between the bulk-diffusion coefficients of oxygen for ZnO samples added with MgO of 1.4 and 11.7 mol % was about two orders of magnitude. It was found that the grain boundary diffusion coefficients of oxygen in ZnO with 11.7 mol % of MgO were larger than those in other samples, by a factor of about 10. Above results indicate that MgO addition into ZnO increases the concentration of effective defects for that promote oxygen diffusion. As the effective defects, the possibilities of vacancy and interstitial of oxygen are discussed.

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(006)-, (104)- and (012)-oriented α-Al₂O₃ films in a single phase were prepared by laser chemical vapor deposition (LCVD) using a diode laser. The effects of laser power (P_L), deposition temperature (T_dep) and total pressure (P_tot) on the crystal phase, orientation, microstructure and deposition rate (R_dep) were investigated. The orientation of α-Al₂O₃ films changed from (006) to (104) to (012) with increasing P_L. Higher oriented films were deposited at a lower P_tot. The microstructure of α-Al₂O₃ films changed from a cauliflower-like structure to a hexagonal faceted structure to a pyramid-like structure with increasing P_L. The R_dep of oriented α-Al₂O₃ films slightly increased from 30 to 40 µm·h⁻¹ with decreasing P_L, which was about 50 times greater than that of conventional thermal CVD.

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A suspension of charged silica colloids was forced to flow in a flat capillary cell using an air-pulse-drive system. Above a critical air-pulse pressure, almost the entire capillary space was filled with a single-domain crystal with high spectral quality. The obtained flow-aligned particle arrays in water were immobilized as a self-standing hydrogel film using a photo-polymerization technique, thereby preserving the high quality. These results are basically the same as those for the previously reported polystyrene colloidal crystals, and they indicate that the present method is widely applicable to various kinds of particles.

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Electrophoretic deposition (EPD) was used to deposit dielectric thin films. A fine Ba_0.9Sr_0.1TiO₃ powder slurry was suspended in acetone and iodine was added to enhance the film quality by increasing the zeta potential. The highest zeta potential was obtained by adding 0.10 g/L of I₂, which allowed a 0.54-µm-thick film to be deposited on a Ni foil in 10 s at 20 V. After annealing the film at 800°C for 30 min in a N₂ atmosphere, the capacitance density of the film was 73.9 nF/cm² and its loss tangent was 0.021, while the residual leakage current density at 10 V was as low as 0.3 µA/cm². No frequency dependence was observed in the range 1 kHz to 10 MHz.

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Porous SiC ceramics were fabricated by the carbothermal reduction of polysiloxane-derived SiOC containing hollow microspheres followed by sintering. The effect of the Al₂O₃–Y₂O₃–CaO (AYC) content on the microstructure and flexural strength of the porous SiC ceramics were investigated. The growth of large platelet α-SiC grains increased with increasing additive content due to enhanced grain growth and the β → α phase transformation of SiC. In situ toughened microstructures consisting of large platelet grains and fine equiaxed grains were obtained when 10 or 20 wt% AYC was added. The porosity generally decreased with increasing the additive content, whereas the flexural strength increased. The typical flexural strength of the porous SiC ceramics sintered with 10 wt% AYC was 61 MPa at a porosity of 44%.

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Thermal decomposition of the coordination polymer, (NH₄)La[Fe^II(CN)₆]·4.5H₂O, with a three-dimensional network structure formed by the Fe^II–CN–La^III linkages, was investigated. The decomposition began at around 323 K and proceeded via a few steps to give the anhydride complex, (NH₄)La[Fe^II(CN)₆], at around 523 K. Further heating gave rise to an abrupt collapse of cyanide groups at around 573 K, followed by the initial formation of the perovskite-type oxide, LaFeO₃, at 603 K and the completion of the decomposition to produce LaFeO₃ at around 898 K. Any formation of the component metal oxides, La₂O₃ and Fe₂O₃, was not recognized during the decomposition. From the XRD line broadening using Scherrer’s equation, the average size of the thermal decomposition product was evaluated to be 21, 22, 25 and 30 nm at 773, 823, 898 and 1073 K, respectively. The specific surface area of the LaFeO₃ particles prepared at 898, 1073 and 1273 K was 13.2, 8.6 and 2.5 m² g⁻¹, respectively.

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Homologous compounds, Fe₂O₃(ZnO)_m, with the modulated natural superlattice structure were obtained within a short period by solid state reaction of component oxides under 2.45 GHz microwave irradiation. TEM observation revealed that two types of superlattice structures were observed in different Fe concentration; one is longitudinal superlattice structure in a rod shaped precipitation at high Fe concentration, and the other is modulated structure showing zigzag shape at low Fe concentration. It is conclude that the non-equilibrium nature of microwave selective heating, as well as rapid heating and quenching effects, plays a key role to form the superstructure. The obtained products exhibit ferromagnetic behavior with the Curie temperature above 300 K.

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