Narrow Results

In this review, the crystal structure and the synthesis of the sodium potassium niobate (K_0.5Na_0.5NbO₃) as a promising candidate for lead-free piezoelectrics are addressed. The sintering and the microstructure as prerequisites for obtaining ceramics with reliable and sufficiently high piezoelectric properties for selected applications are discussed.

Fe₂SiS₄ and its composite with porous carbon from carbonization of PAN porous carbon (PC) were synthesized using one-pot method, which were characterized by XRD, SEM, TEM, XPS and Raman spectrum techniques. Their electrochemical data as anode materials for lithium-ion batteries were firstly studied. The results indicate that the Fe₂SiS₄ particles dispersed on the surface or in the pores of PC has the 1st capacity of 961.9mAh/g, and around 400mAh/g capacity can be still maintained after 50 cycles at 0.2C, much enhanced electrochemical performance than those for pure Fe₂SiS₄.

Lead–free Sr${}_{1-x}$Ca_xTiO₃ ($x=0,0.4$) ceramics were synthesized via a solid state reaction technique at room temperature. The effects of ionic substitutions in A-sites between strontium and calcium on the structural and dielectric properties were investigated. XRD technique was used to identify the crystal structure and to demonstrate the phase purity. SEM observations have shown homogeneous morphologies for all samples. Dielectric measurements were investigated for a wide range of frequency (100Hz–1GHz) and temperature (25${}^{\circ }$C–250${}^{\circ }$C). Strontium substitution by calcium has not only led to a decrease in the dielectric permittivity value, but also to the loss tangent value by a considerable factor. Interesting values of the quality factor and the quite constant value ${\epsilon }^{\prime }\sim 200$ in extended frequency and temperature ranges show that SCT ceramic could be a real candidate for the development of monolithic ceramic capacitors dedicated to high-frequency lead-free components and/or to extremely high-temperature environments.

The experimental data of electrodeposition kinetics researches and structure formation of ternary CoNiFe alloys deposited onto low-carbon steel 08kp in the presence of X-rays are presented. Relations of deposit rate, current efficiencies, element and phase compositions of CoNiFe coatings formed from sulfate baths with respect to cathode current densities (0.5–3A/dm${}^2)$, electrolyte composition and irradiation were obtained. It is shown that, the CoNiFe coatings deposited by the electrochemical method involving exposure of the X-rays are characterized by more perfect morphology surfaces with less developed surface geometry than reference coatings. The effect of the X-ray irradiation on the electrodeposition of CoNiFe coatings promotes formatting of alloys with increased electropositive component and modified phase composition.

Envisaged through adding sintering additives to achieve low-temperature sintering preparation, in order to overcome the volatilization of sodium ions and potassium ions in the high-temperature preparation, so as to improve the density and electrical properties of KNN-based piezoelectric ceramics. This research uses traditional solid-state sintering technology, a high density, high properties lead-free piezoelectric ceramics, KNNSC-$x$, successfully prepared with sintering additives CuO. The modern test analysis of XRD and SEM shows that a moderate amount of CuO doped in the range of research can form a single perovskite structure of an orthorhombic structure, not found in any second phase, and can promote grain evenly growing and improve the sintering properties of KNN-based piezoelectric ceramics. The KNNSC-0.04 ceramics exhibit excellent electrical properties through various electrical tests such as $d_{33}$ = 238pC/N, $k_p$= 47%, ${𝜀}_r$= 1049, tan$\delta$= 2.4%, $P_r$ = 25.6 $\mu$C/cm², $E_C$ = 1.24 kV/mm, respectively. These test results show that the KNNSC-$x$ piezoelectric ceramics have great potential to be applied in middle- and low-voltage piezoelectric devices.

The paper studies the effect of temperature ($T$), ($T=300$, 3200, 4000, 5000, 6000, 7000K) at pressure $P=0$GPa; pressure ($P$), ($P=0$, 100, 200, 300, 350, 400GPa) at $T=7000$K and thermal annealing time ($t$), $t=47.8$ps (after 10⁵ steps) at $T=7000$K, $P=400$Gpa) on the structure of MgSiO₃ bulk 3000 atoms by Molecular Dynamics (MD) simulation using Born–Mayer (BM) pair interaction potential and periodic boundary conditions. The structural results are analyzed through the Radial Distribution Function (RDF), the Coordination Number (CN), the angle distribution, size ($l$), total energy of the system ($E_{\mathrm{\text{tot}}}$) and the bonding lengths. The results show that the temperature and pressure had influenced the structural properties of MgSiO₃ bulk and formation process geology of the Earth. In addition, the center of the Earth with $T=7000$K and $P=350$GPa has appearance and disappearance of the Si–Si, Si–O, O–O, Si–Mg, O–Mg, Mg–Mg bonds and SiO₄, SiO₅, SiO₆, MgO₃, MgO₄, MgO₅, MgO₆, MgO₇, MgO₈, MgO₉, MgO${}_{10}$, MgO${}_{11}$, MgO${}_{12}$ angle distributions. When increasing the depth of the Earth’s surface $(h)$ lead to size $(l)$ of MgSiO₃ decreases, total energy of the system ($E_{\mathrm{\text{tot}}}$) increases, position of first peak of Radial Distribution Function (RDF) is $(r)$, height of RDF is $g(r)$ varies greatly with $h$ from $h=0$km to $h=1820$km, gradually decreasing with $h$ from $h=2000$km to $h=3200$km and the smallest structural change with $h>3200$km that shows has influence affects on the geological formation of the Earth.

This paper studies the effect of atoms number $(N)$ of bulk Ag: $N=2916$ atoms (Ag${}_{2916}$), 4000 atoms (Ag${}_{4000}$), 5324 atoms (Ag${}_{5324})$, 6912 atoms (Ag${}_{6912})$ at temperature $T=300$K, 400K, 500K, 600K, 700K, 800K, 900K, 1000K on bulk Ag${}_{5324}$ and annealing time $t$ = 200 ps on the structure and phase transition of Ag bulk by Molecular Dynamics (MD) method with Sutton–Chen (SC) pair interaction potential, periodic boundary conditions. The structural results are analyzed through the Radial Distribution Function (RDF), the total energy of the system ($E_{tot})$, the size $(l)$, the phase transition (determined by the relationship between $E_{tot}$ and $T$), and combined with the Common Neighbors Analysis (CNA) method. The obtained results show that the first peak’s position ($r)$ of the RDF has negligible change value, $r=2.78$Å, which is completely consistent with the experimental results. For bulk Ag, there are always four types of structure: FCC, HCP, BCC, Amor and glass transition temperature $T_g=500$K. When decreasing the temperature, bulk Ag changes from liquid state to crystalline state, when increasing the annealing time at $T_g=500$K, bulk Ag changes from amorphous phase to crystalline phase state, leading to the increase of FCC, HCP, BCC structures and the decrease of Amor structure. The obtained results will be used as guide for future experiments.

The following sections are included:

• Introduction

• Experimental Designs
  • Kratky Block Collimation System
  • Pinhole Collimation System
  • Advanced Polymers Beamline
  • ChemMat CARS Undulator Beamline at the APS
    • Undulator X-Ray Source
    • ChemMat CARS Beamline
    • X-Ray Beam Delivery
    • Beamline Layout

• Theoretical Background
  • Particulate Scattering
  • Nonparticulate Scattering
  • Scattering from Semicrystalline Polymers
  • Analysis from Time Resolved Measurements

• Scientific Examples for Synchrotron Research
  • Supramolecular Structures in Complex Fluids
    • Structures of Polyelectrolyte Surfactant Complexes
    • Block Copolymer in Solution
  • Kinetics of Phase Transition
    • Semistiff Chain Polymers
    • Flexible Chain Polymers and Blends
  • Experiments under Supercritical Conditions
  • Polymers under Deformation
  • In situ Study of Fiber Spinning

• Acknowledgments

• References