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The K0.5N0.5NbO3-based powders was synthesized by surfactant-assisted solvothermal method. The influence of cosurfactant, surfactant and cosurfactant assistant surfactant on phase and morphology of K0.5Na0.5NbO3 powders was studied. The results show that when adding different content of isopropanol (IPA), the K0.5Na0.5NbO3 powders showed different structure and morphology. Surfactant made the morphology of powders regular, when isopropanol content was certain. With the increase of surfactant concentration (SBDS, PEG400), the morphology of powders made more regular and isopropanol could make the powder refine. Compared with SBDS, the PEG400 made the morphology of powders more regular. When the content of isopropanol (PEG400) was certain, the regular morphology powders with smaller particle size could be obtained by choosing appropriate isopropanol content. Namely, PEG400=1 g/L, y(IPA)/y(H2 O) = 2/3 or 3/2 and the cubic particles with a particle size of about 300 nm could be obtained. [ABSTRACT FROM AUTHOR]

The K0.5Na0.5NbO3 powders was prepared through ethylene glycol solvothermal method, the influence of V(EG)/V(H2O), reaction temperature and precursor concentration on phasemorphology and practical size of K0.5 Na0.5 NbO3 powders were studied. The results show that : the reaction condition of pure K0.5 Na0.5 NbO3 powders is achieved that the temperature is 230 °C, reaction time is 7 h and W(EG)/V(H2O) ≼ 3 : 2. the crystallization of powders is poor with the increase of temperature; The powders show Spherical and Cube morphology when the concentration is 6 mol/L; the powders all show cube morphology and the particle size decreased with increasing of reactant concentration, when reactant concentration is 10 mol/L and V(EG)/V(H2O) = 1 : 4, the particle size is the smallest. [ABSTRACT FROM AUTHOR]

Abstract: This work investigates the structural, electronic, mechanical, and optical properties of nanolaminated M2PbC (M=Ti, Zr and Hf) compounds using the first-principles method based on the density functional theory. Geometrical optimization of the unit cell is in good agreement with the available experimental data. These three compounds are mechanically stable estimated by the individual elastic constants. The calculated shear-modulus of Zr2PbC is 67GPa, which is the minimum value among all MAX phases so far and is attributed to the weak Zr–Pb bond. The band structure shows that all three materials are electrically conductive. The electronic structure discloses that the density of state at the Fermi level (Ef ) mainly originates from M d states and there are M d-C p and M d-Pb p hybridizations below Ef . The hybridization peak of M d-C p lies in lower energy range and the M d-C p bond is stronger than M d-Pb p bond. The charge density distribution shows that the M and C atoms form a strong M–C–M covalently bonded chain. Finally, the optical properties are discussed. [Copyright &y& Elsevier]