Dielectric properties of Ni-doped Ba_(0.5)Sr_(0.5)TiIO3 ceramics prepared with hydrothermal synthesized nanopowders

摘要

Ba_(0.5)Sr_(0.5)Ti_(1-x)Ni_xO3 (BSTN) ceramics were prepared from BSTN nanopowders synthesized by a hydrothermal method. The phase and microstructure of samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy. XRD results indicate a cubic structure of the pure BST nanopowders. The cubic structure can be converted to the orthorhombic phase with increasing of Ni content to x = 0.01 and returned to the cubic structure with the presence of Ni(OH)2 impurity phase for x = 0.03 and 0.05. However, the BSTN ceramics sintered at 1,200 °C for 3 h revealed the orthorhombic phase structure with NiO impurity phase for all Ni content. The doping of Ni in Ba_(0.5)Sr_(0.5)TiO3 structure can increase the grain size of samples from 1.47 to 3.26 urn. The dielectric constant, loss tangent (tanS) and phase transition temperature of BSTN ceramics were reduced with increasing Ni content.