In this study, ceramic foams were manufactured by using granite sludge as the principal material, red mud as the additive and SiC as the foaming agent, and the effects of different granite sludge-to-red mud mass ratios, firing temperatures and foaming agent content on the bulk density, porosity, mechanical properties and thermal conductivity of the foams were systematically investigated. The addition of 5–15 wt % red mud produced foams with well-distributed pores that possessed different dimensions and thus improved their physical and mechanical properties. A close correlation was found between the firing temperature, foaming agent content, and the pore structures and properties of foams based on the degree of matching between liquid phase generation and gas emission. The optimal conditions for preparing the ceramic foams were 10 wt % red mud and 1.0 wt % SiC at 1150 °C. The corresponding foam had a low bulk density of 296 ± 38 kg/m³, a considerable compressive strength of 2.75 ± 0.41 MPa and a low thermal conductivity of 0.061 ± 0.010 W/(m·K), exhibiting good prospects for applications in the building and construction sector.

The ferromagnetic Zinc ferrite (ZnFe₂O₄: ZFO) were synthesized by the metal organic decomposition technique. The ferromagnetic ZFO is an attractive material for new magneto-optical devices because they show transparency in short wavelength region of the visible light. The possible cause of the ferromagnetism of ZFO is the inverse spinel structure. The saturation magnetization of ZFO film strongly depended on the annealing conditions. The annealing conditions showing the large magnetization lie between 420 and 600 °C and between 2 and 12 h, respectively. The Mössbauer and magnetization measurements indicate that the films show paramagnetic at room temperature and the estimated Curie temperature was approximately 190 K. The Faraday rotation at 80 K showed large values in the short wave length region of visible light.

The topology of materials is an important structural feature, which cannot be determined from crystallographic information in crystalline materials and pairwise correlations in disordered materials. We extracted the density-driven modification of the topology of tetrahedral silica (SiO₂) crystals, siliceous zeolites (MFI, SOD, and FAU), and glass on the basis of the results of ring size, homology, cavity distribution, and tetrahedral order analyses. A series of analyses confirmed a universal feature that oxygen atoms are buckled in –Si–O– rings except in some symmetrical even-numbered rings such as twelvefold (Si–O)₁₂ rings in coesite and SOD/FAU. In addition, large cavities were found in β-cristobalites and siliceous zeolites, whose cavity volume ratios are much higher than that of SiO₂ glass. A comparison between α- and β-cristobalite indicated that the arrangement of oxygen atoms governs the formation of cavities. Moreover, a topological similarity between glass and MFI was found, in which fivefold and sevenfold rings are observed in the King ring size distribution. This feature can break their symmetry because these odd-number rings are not observed in other SiO₂ polymorphs. Moreover, it was suggested that SiO₂ glass is crystallographically an analogue to β-cristobalite in terms of the position of the diffraction peak, but topologically an analogue to MFI. It is demonstrated that the topological analyses provide us with crucial information for the design of novel nonequilibrium materials at high pressures and/or high temperatures by tuning density.

Oxide-based lithium-ion conductive solid electrolytes are promising owing to their safety. Both crystalline and glass-oxide solid electrolytes have been explored to obtain materials with high ionic conductivity and ductility. Amorphous Li₂O–LiI solid electrolytes exhibit ionic conductivities of approximately 10⁻⁵ S cm⁻¹ and excellent ductility, and all-solid-state batteries can be fabricated solely by cold pressing. However, the ionic conductivity of Li₂O–LiI solid electrolytes should be further increased to enhance battery performance. Herein, glass-forming oxides (B₂O₃, SiO₂, P₂O₅, and GeO₂) and intermediate oxides (Al₂O₃ and V₂O₃) were added to Li₂O–LiI solid electrolytes using mechanochemical techniques to increase the ionic conductivity of Li₂O–LiI solid electrolytes. The structure varied depending on the additives used in the prepared Li₂O–LiI-based solid electrolytes. The ionic conductivity decreased as the amount added increased. However, the ionic conductivity was maintained after V₂O₃ was added. V₂O₃ is preferable candidates for increasing the ionic conductivity of Li₂O–LiI solid electrolytes. Our fundamental research on material synthesis will contribute to the future development of oxide-based solid-electrolyte materials.

ZnO thin films with controllable morphologies were fabricated using the simple and cost-effective mist spin spray (MSS) method at 70 °C. The MSS technique involves the reaction between an inorganic zinc salt precursor and a strong base in mist particles. The thin films obtained by the MSS method exhibited advantageous characteristics, including strong adhesion to the glass substrate, high uniformity, high crystallinity, negligible impurities, and no requirement for post-annealing treatment. The morphology of the thin films could be readily modified from nanoparticles to nanorods simply by changing the molar ratio of zinc(II) ions (Zn²⁺) to hydroxide ions (OH⁻) in the reaction solution. The preferred orientation of the thin films was along the [001] direction at a Zn²⁺/OH⁻ molar ratio of 1:4 and transitioned to the [100] direction at a Zn²⁺/OH⁻ molar ratio of 1:10. The Zn²⁺/OH⁻ molar ratio also influenced the optical absorption peak and band gap of the ZnO thin films because of changes in the grain size. The ZnO nanoparticles observed in the films fabricated with lower Zn²⁺/OH⁻ molar ratio are thought to primarily result from the nucleation process. Conversely, the nanorods consisting of both primary and secondary nanostructures observed in the films fabricated with higher Zn²⁺/OH⁻ molar ratio formed through nucleation and a subsequent crystal growth process.

We clarified the dependence of the biaxial orientation degrees on the oscillation angle (θ) for YBa₂Cu₃O_y (Y123) and ErBa₂Cu₃O_y (Er123) powder samples, which are aligned under an oscillation (OS) type of modulated rotating magnetic field (MRF). Y123 and Er123 exhibit an opposite relationship on the magnetization axes and large difference in magnetic anisotropy. It was found that the biaxial orientation degrees depended not only on magnetic field strength of the OS type MRF but also on θ. In details, both static field (SF) and rotating field (RF) components of the magnetic alignment energy require approximately ∼10⁺⁵k_BT or higher. A respective increase and decrease in the biaxial orientation degrees were observed with the increase and decrease in the RF components. The above experimental results were found to be theoretically explainable. The findings in the present study possibly lead to the production of biaxially aligned RE123 (RE: rare earth elements) ceramics and thick films by appropriate distribution of the SF and RF components of magnetic alignment energy with taking the type of RE and viscosity of the slurry into account.

We have developed the titanium oxynitride (TiON) layer which exhibits antibacterial activity against Escherichia coli without sunlight irradiation. This TiON layer with the segmented structure was formed on a pre-oxidized Ti substrate by the electron beam physical vapor deposition method while spraying the substrate and Ti target with N₂-0.1 % O₂ gas. An XRD pattern of the surface of the segmented layer revealed that the layer has a rock salt structure, which is preferentially deposited in a [111] direction to the substrate surface. TEM observation of the TiON layer showed that the columnar segments have a feather-like structure. The width of the segments near the surface was 100–500 nm, and their outermost surfaces were covered with nanometer-sized spines of 10–50 nm width. The TiON layer contained about 20 at % nitrogen as determined by XPS, and the surface was slightly negatively charged with a zeta potential of −0.9 mV at pH 7.2. The maximum average pressure in the elastic deformation region for the layer was over 100 MPa, which was much higher than the average occlusal pressure (<10 MPa). It is concluded that the segmental structure of the film facilitates the elastic deformation without distorting of the unique surface structure in response to external stress.

We investigate oxygen evolution reaction (OER) catalytic activity for CaFe_1−xMn_xO₃. The OER activity of CaFe_1−xMn_xO₃ decreases almost monotonically with increasing Mn content x. No any compositions do not exceeded CaFeO₃ in OER activity, but we observe that the OER activity is gently decreased except for Fe-rich side (x = 0.1) in comparison with the weighted average OER activity between the endmembers of highly active CaFeO₃ (x = 0) and less active CaMnO₃ (x = 1). We discuss probable electronic effects of the Fe⁴⁺–Mn⁴⁺ couple on OER activity based on the density functional theory calculation using the special quasirandom structure models. The local electronic states of Mn ions were deactivated by Fe substitution on the Fe-rich side (x = 0.25), whereas the Fe ions are constantly activated by Mn substitution in the entire composition range. This finding proposes that local electronic states are variously changed by the kind of couples of multiple elements, which may contribute to the design of mixed transition metal oxides for OER catalysts.

The utilization of Bi₂O₃ heat-treated at 700 °C lowered the combustion temperature of 660 °C for carbon alone to 414 °C in the tight contact state. Owing its exceptional carbon combustion capacities, the carbon combustion properties of (Bi₂O₃)_1−x(RE₂O₃)_x, a solid solution of rare earth oxides in Bi₂O₃ heat treated at 700 °C, (Bi₂O₃)_1−x(Y₂O₃)_x, and (Bi₂O₃)_1−x(La₂O₃)_x, exhibited lower carbon combustion temperatures than Bi₂O₃ below x = 0.10. Lower carbon combustion temperatures were observed for Y₂O₃ solid solution at 380 °C for x = 0.01 and 0.02 and for La₂O₃ solid solution at 383 °C for x = 0.02 and 0.03. In addition, (Bi₂O₃)_0.97(RE₂O₃)_0.03 (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu, and Sc) exhibited lower carbon combustion temperature than Bi₂O₃ in solid solution. The carbon combustion temperatures of (Bi₂O₃)_0.97(RE₂O₃)_0.03 decreased with an increase in the ionic radius of RE³⁺. In the loose contact state, the carbon combustion temperature of Bi₂O₃ was 558 °C, and the carbon combustion temperature of (Bi₂O₃)_0.97(RE₂O₃)_0.03 was higher than that in the tight contact state.