用熔盐法合成铌酸钾钠(Na_(0.52)K_(0.48)NbO_3,N_(52)K_(48)N)陶瓷粉体,用传统固相烧结工艺制备N_(52)K_(48)N陶瓷。研究了熔盐含量和烧结温度对N_(52)K_(48)N陶瓷粉体及其所制备陶瓷的相结构、微观形貌及电学性能的影响。结果发现,熔盐法在750℃就合成了单一钙钛矿结构的N_(52)K_(48)N陶瓷粉体;随熔盐含量增加,N_(52)K_(48)N陶瓷粉体粒径增大,粉体团聚现象明显减弱。当熔盐与反应物质量之比为1∶5,烧结温度T=1050℃时,所制备的N_(52)K_(48)N陶瓷具有优异的电学性能:压电常数d33=137 p C/N,机电耦合系数kp=32.6%,居里温度Tc=410℃,表明熔盐法是一种很有前途的铌酸钾钠陶瓷制备方法。
Au nanoparticles dispersed NiO composite films were prepared by a chemical solution method.The phase structure,microstructure,surface chemical state,and optical absorption properties of the films were characterized by X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,and Uv-vis spectrometer.The results indicate that Au particles with the average diameters of 35-42 nm are approximately spherical and disperse in the NiO matrix.The optical absorption peaks due to the surface plasmon resonance of Au particles shift to the shorter wavelength and intensify with the increase of Au content.The bandwidth narrows when the Au content increases from 8.4wt% to 45.2wt%,but widens by further increasing the Au content from 45.2wt% to 60.5wt%.The band gap Eg increases with the increase of Au contents from 8.4wt% to 45.2wt%,but decreases by further increasing the Au content.
Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.
