Papers by Author: Lei Chen

Abstract: In this paper, the influence of nickel (Ni) nano-powders addition on the microstructures and dielectric properties of Ba(Ti,Zr)O3 based Y5V non-reducing ceramics were investigated. The X-ray diffraction (XRD) analysis indicated that the primary phase was Ba(Ti,Zr)O3 and no Ni phase appeared until the amount of Ni exceeded 5mol%. Scanning electron microscope (SEM) observation showed that the Ni particles distributed homogenously throughout BTZ ceramic matrix. The incorporation of Ni altered the perovskite lattice parameters and thus led to the change of polarization degree under electric field and the improvement of the dielectric constant at Curie temperature.

Abstract: Ce3+-doped SrGa2O4 was synthesized by citrate-gel with citric acid as chelate agent and sintered in a slightly reduced atmosphere of hydrogen and nitrogen mixture. It was found that the phosphor synthesized by citrate-gel can be sintered at relatively lower temperature. The luminescent properties of Ce3+-activated SrGa2O4 and the complex Sr(Ga-Al)2O4 were studied.

Abstract: Titanate ferroelectric materials play more and more important roles in electronic industry due to their particular performances, so the synthesis of ultra-fine ferroelectric powder with high purity is the key issue to improve the performance of electronic components. In this paper, Ba(Ti0.85Zr0.15)O3 nano-powder with perovskite structure and homogeneous granularity was prepared by oxalate precipitation method, the particle size of the powder calcined at 800oC is about 50 nm. The sintering ability of the powder is excellent so that the compact ceramics can be obtained at sintering temperature of 1200°C, which is much lower than that of the powder prepared by the conventional solid method. With the powder prepared by oxalate precipitation method, we developed an ultrafine-grained dielectric material showing Y5V characteristics with the room temperature dielectric constant over 14,000, which can be used in base metal electrodes multilayer chip capacitors.