Optical absorption and photocatalytic activity can be enhanced by surface plasmon resonance (SPR) effect, but the charge transfer (CT) mechanism between the dispersed noble metal nanoparticles (NPs) and the semiconductor matrix has been ignored. Herein, we adduce a direct and strong evidence in Ag-nanoparticle-dispersed BaTiO₃ (Ag/BTO) composite films through X-ray photoelectron and photoluminescence spectra which reveals the CT from BTO trapped by Ag NPs under UV light and from Ag...

A series of asymmetric cordierite ceramics with hierarchical porous structure were prepared and characterized. The macroporous support was obtained from natural raw materials (bauxite, silica sand, kaolinite, talc, and alumina) via ceramic technology. The prepared ceramic discs were characterized by a narrow pore size distribution. The average pore size was about 9.5?μm, and the open porosity was estimated to be 30%. Coating the discs with micro/mesoporous cordierite layer was performed using...

We prepared (1−x)CaTiO₃–xLaAlO₃ (0 ≤ x ≤ 1) microwave dielectric ceramics using a conventional two-step solid-state reaction method, and investigated microwave dielectric properties of the ceramics in terms of A/B-site ionic-parameters. Ionic-parameters such as ionic polarizability, A-site bond valence, and ionic rattling were linked to the microwave dielectric properties. As the LaAlO₃ content x in the (1ȡ...

Different from the oxidation kinetics of other nitrides, the oxide layer on AlN can easily reach tens of micrometers at a temperature above 1200?℃. In the present study, the oxidation mechanism of AlN is investigated through microstructure observation. The analysis indicates that the oxide layer is full of small pores. The formation of pores generates additional surface area to induce further reaction. The reaction thus controls the oxidation in the temperature range from 1050 to 1350?...

Monoclinic yttrium tantalate (M′-YTaO₄, M′-YTO), and two different kinds of yttrium niobium-tantalate (M′-YTa_0.85Nb_0.15O₄ (M′-YTNO) and Eu³⁺ doped M′-YTa_0.85Nb_0.15O₄ (M′-YTNO:Eu³⁺)) were produced by sol–gel method and grown on single crystalline Si (100) substrate by spin coating approach. Structural properties and thermal behaviours of the films were characterized by means of X-ray diffraction ...

The electronic structures and optical properties of the monoclinic ZrO₂ (m-ZrO₂) are investigated by means of first-principles local density approximation (LDA) + U approach. Without on-site Coulomb interactions, the band gap of m-ZrO₂ is 3.60?eV, much lower than the experimental value (5.8?eV). By introducing the Coulomb interactions of 4d orbitals on Zr atom (U^d) and of 2p orbitals on O atom (U^p), we can reproduce t...

(Ba_1−xSr_x)₄(Sm_0.4Nd_0.6)_28/3Ti₁₈O₅₄ (x = 0.02, 0.04, 0.06, 0.08, 0.1) solid solutions were prepared by the conventional solid-state reaction process. It was found that (Ba_1−xSr_x)₄(Sm_0.4Nd_0.6)_28/3 Ti₁₈O₅₄ ceramics are fully composed of BaSm₂Ti₄O_12...

Silicon carbide (SiC) fiber has recently received considerable attention as promising next-generation fiber because of its high strength at temperatures greater than 1300?℃ in air. High-quality SiC fiber is primarily made through a curing and heat treatment process. In this study, the chemical vapor curing method, instead of the thermal oxidation curing method, was used to prepare cured polycarbosilane (PCS) fiber. During the high temperature heat treatment of the cured PCS fiber, vari...

Aluminum nitride ceramic sheets were formed for the first time by a novel and simple method, namely gel-tape-casting process, where only two additives were used to prepare the slurries. PIBM (a water-soluble copolymer of isobutylene and maleic anhydride) acted as both dispersant and gelling agent, and PEG (polyethylene glycol) acted as plasticizer. Combining the advantages of gel-casting and tape-casting processes, flexible and uniform green tapes were obtained. The rheological properties of ...

A new type of polymer-infiltrated-ceramic-network composites (PICNs) was fabricated by infiltrating methacrylate-based monomers into partially sintered porous ceramics. The mechanical properties (flexural strength, flexural modulus, elastic modulus, Vickers hardness, fracture toughness) were investigated and compared with that of the natural tooth and common commercial CAD/CAM blocks. Our results indicated that sintering temperature and corresponding density of porous ceramics have an obvious...