Journal of Advanced Dielectrics

Journal of Advanced Dielectrics, Ahead of Print. <br/> Dielectrics with high permittivity and temperature stability are important for the development of high-temperature multilayer ceramic capacitors (MLCCs). In this study, Ca[math]NaxTi[math]NbxSiO5 (abbreviated as CTS[math]NN) ceramics were prepared by solid-phase reaction method. The introduction of NN weakens the long-range ordered displacement of Ti, leading to a significant increase in the dielectric temperature stability. The CTS−2%NN samples exhibit high permittivity (53) and TCC [math] ppm/∘C in the range of [math]C to 300∘C. The CTS-based ceramics behave high dielectric temperature stability. In addition, the bandgap of the CTS-based ceramics increased significantly, which is favorable for improving the breakdown strength of the material. For [math]% samples, the breakdown strength reaches 621[math]kV/cm. Thus, the designed CTS-based dielectrics are promising for high-temperature capacitors.

Journal of Advanced Dielectrics, Volume 14, Issue 04, August 2024. <br/>

Journal of Advanced Dielectrics, Volume 14, Issue 04, August 2024. <br/> Statins are widely used in the treatment of hyperlipidemia disease, which are refractory in the municipal sewage treatment plant. The photocatalytic degradation of statins by the Z-scheme heterostructured photocatalyst is confirmed, but the degradation mechanism of statins needs to be further revealed. In this study, the effects of photocatalyst dosage, solution pH and humic acid (HA) on the photocatalysis of fluvastatin by ZnIn2S4/Bi2WO6 Z-scheme heterostructured photocatalyst (ZIS/BWO photocatalyst) were investigated and the degradation mechanism was proposed. Results showed that adsorption of fluvastatin was improved with the increase of photocatalyst dosage, but photoinduced desorption and light scattering resulted in the decrease of the removal of fluvastatin with high dosage. 0.2[math]g/L of the ZIS/BWO photocatalyst was optimal dosage. 65.21% of fluvastatin was removed at pH=9, because high concentration of OH− was conducive to produce ⋅OH. The change of pH, competition of photons and active sites, and trapping of reactive oxygen species (ROS) by carboxyl group of HA combined to inhibit the photocatalysis of fluvastatin in the presence of HA. The C–C, C[math]C and C–N bonds of fluvastatin were attacked by a variety of ROS to generate degradable intermediates that were easily mineralized to H2O and CO2.

Journal of Advanced Dielectrics, Volume 14, Issue 04, August 2024. <br/> Calcium bismuth niobate (CBN) ceramic, as a core element of high-temperature piezoelectric sensors, has attracted widespread attention due to its high Curie temperature within the class of Aurivillius compounds. However, CBN usually faces two shortcomings: poor piezoelectric constant and low resistivity. In this work, CBN-based ceramics with donor–acceptor ions (W/Co) co-substituted at B-site were prepared by solid-state reaction method, and structure–property relationship of ceramics was studied in detail. Co-substitution of W/Co ions effectively improved the electrical property and hardness of CBN ceramics. CaBi2Nb[math](W[math]Co[math]O9 exhibits enhanced electrical and mechanical properties including high resistivity of [math]cm at 500°C, piezoelectric constant of [math] pC/N and hardness value of [math][math]GPa. These values are two orders of magnitude, over two times, and 1.36 times higher than those of pure CBN ceramic, respectively. This work provides a reference for exploring other bismuth-layered structural ceramics.

Journal of Advanced Dielectrics, Ahead of Print. <br/> Yttrium oxide–magnesium oxide (Y2O3–MgO) composite nanopowders were synthesized via three distinct methods: sol–gel, co-precipitation and glycine–nitrate process. The synthesized powders were calcined at various temperatures, and their microstructure, specific surface area and particle size were characterized. A comparative study was conducted to assess the impact of the synthesis method on the microstructure and transparency of the resulting ceramic sintering. Notably, the powder synthesized by the sol–gel technique exhibited the highest specific surface area and superior light transmittance, reaching a maximum of 85.33% at a wavelength of 5.31[math]m.