Papers by Author: Gang Yang

Abstract: xBST-(1-x)YIG composite ceramics with x=0~1 were prepared by solid-state reaction method. The variations for phase compositions were determined by XRD, and the magnetic and dielectric properties of the composites were studied in the frequency range of 100Hz~1GHz. The results showed that the composites (x=0.1~0.9) are consisted of BST phase and YIG phase and no significant chemical interaction occurs between these two phases. The composite materials exhibit excellent frequency dependences of dielectric and magnetic properties. The resonance frequency and high frequency characteristics of YIG are improved by additions of BST, and when x=0.3, xBST-(1-x)YIG has the best dielectric and magnetic properties.

Abstract: (1-X)BaTiO3-XCaCu2.94Mn0.06Ti4O12 (BTO-CCMTO) composite ceramics with X =0.1 and 0.2 were prepared through solid state reaction route. X-ray diffraction (XRD) analyses showed that a co-existence structure of BTO and CCMTO phase can be realized when the sample was sintered at 950°C. Furthermore, influences of CCMTO on the dielectric behaviors of the BTO-CCMTO composite ceramics were investigated. The results showed that the dielectric permittivity of the BTO-CCMTO composite ceramics increases with increasing amounts of CCMTO and the Curie peak of the pure BTO ceramics is greatly suppressed due to the addition of CCMTO. The dielectric loss of the BTO-CCMTO composite ceramics can be kept in the same magnitude order as that of the BTO ceramics.

Abstract: Ultrafine-grained ceramics based on nano-scale barium titanate for BME-MLCC applications have been prepared. Relationships of milling time, microstructures and dielectric properties have been investigated. With processing selected carefully, the present ceramics show ultrafine grain size (180nm) and homogeneous microstructures, well with high dielectric constant (ε25=2550), low dielectric loss (<0.02), high resistivity, high breakdown field and X7R temperature specifications, which would be promising materials for the next generation BME-MLCC applications.