The energy storage density of (1-x) BaTiO3 – x Ba(Mg1/3Nb2/3)O3 (x = 0, 0.1, 0.2, 0.3) ceramics was investigated. The microstructure of samples was characterized by scanning electron microscopy (SEM). The energy storage density was calculated from the P-E hysteresis loops measured at room temperature. Experimental results show that the energy storage density of 0.9 BaTiO3 – 0.1 Ba(Mg1/3Nb2/3)O3 ceramics is highest among all compositions. At 15.8kV/mm electric field, the energy storage density of the sample can reach up to 1.07J/cm3, which is about 1.5 times higher than pure BaTiO3. The improvement of the energy density can be due to two factors: one is the improved breakdown strength caused by the optimized microstructure, the other is the decreased remnant polarization. This result indicates that bulk 0.9 BaTiO3 – 0.1 Ba(Mg1/3Nb2/3)O3 ceramic has advantages compared with pure BaTiO3 ceramic for energy storage applications, and with further improvements in microstructure and reduction of sintering temperature, could be a good candidate for energy storage capacitors.
Paper packaging materials like cardboards are widely used to protect archives which are a major kind of cultural relics. Unfortunately, paper is a combustible material, and thus exploring environment-friendly flame retardant for paper-based archive packaging material plays an important role. Herein, boric acid, borax and disodium octaborate are used to modify the craft paper-based packaging materials for archive conservation to improve fire safety. The modified craft paper exhibits much higher flame retardancy than the pristine one dose based on vertical burning tests, without much influence on mechanical properties such as tensile strength and elongation at break. Thermogravimetric analysis (TGA), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) reveal that porous glass structure is formed during the combustion, because thermal decomposition of boric acid, borax and disodium octaborate will produce porous glassy matter as B 2 O 3 . The porous glass covers the paper surface as an insulating layer which retards the further pyrolysis and combustion, resulting in a denser carbon layer. Our study provides a robust way to reduce the fire hazard of the archive packaging material by applying environment-friendly boron-based fire retardants.
1-x)Ba 0.67 Sr 0.33 TiO 3 (BST)+xCaBi 4 Ti 4 O 15 (CBT) (x=0, 2%, 4%, 6% and 8%) lead-free relaxor ferroelectric ceramics with submicro grain size of about 200nm were prepared by solidstate reactions. Structure and dielectric properties of BST-CBT have been investigated. X-ray diffraction patterns show a relative low degree of solubility as a result of coupled substitutions of Bi 3+ and Ca 2+ both on the A site and the specific structure of CBT. The temperature and frequency dependences of the dielectric constant indicate a crossover from a normal ferroelectric to relaxor behavior. The degrees of diffuseness and relaxor behavior are found to increase with the increasing amount of CBT. The frequency dependence of the temperature of dielectric peak Tm can be well described by Vogel-Fulcher relation. The activation energy Ea increases with x increasing, indicating the more and more energy for the polarization reversal of micropolar regions, which is associated with the enhanced interactions of polar domains.
Porous silicon (PS) was prepared with catalyst of Cu nanoparticles in HF/H2O2 solutions. The effects of the key fabrication parameters (amount of copper, etching temperature and concentration of H2O2) on the nanostructure of PS were systematically investigated and discussed. The experimental results indicated that the porosity of PS increased with the amount of copper, the reaction temperature and the concentration of H2O2, respectively. Copper can be used as catalyst to assist in etching silicon and the evolution process of copper nanoparticles was explored showing that the mass of copper experienced a drastic reduction in the first 60 seconds. A mechanism is proposed to explain the formation of PS by Cu-assisted chemical etching.
(1-x)(K0.44Na0.52Li0.04)(Nb0.84Ta0.10Sb0.06)O3-xSrTiO3 (KNNT-ST) lead free piezoelectric
ceramics have been synthesized by a solid state reaction method. The effect of SrTiO3 content on the
piezoelectric properties, sintering behavior and microstructure of (1-x) KNNT-x ST ceramics was
investigated. The experimental results showed that the addition of SrTiO3 can restrain the volatilization of
Na ions and K ions and improve relative density of the samples. A morphotropic phase boundary between
orthorhombic and tetragonal phases is found in the composition range of 0.03<x<0.05. The piezoelectric
properties can be enhanced for (1-x) KNNT-x ST ceramics near the morphotropic phase boundary.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.