Structural Variation and Microwave Dielectric Properties of ZrO_2 Added Ba(Zn_(1/3)Ta_(2/3))O_3 Ceramics

摘要

Ba(Zn_(1/3)Ta_(2/3))O_3 (BZT) ceramic has 1 : 2 ordered hexagonal structure, but was destroyed with the addition of ZrO_2. The 1:1 ordered cubic structure was developed when a large amount of ZrO_2 was added. BZT has a porous and inhomogeneous microstructure with a Ba_5Ta_4O_(15) second phase. When ZrO_2 was added, a new Ba_(0.5)TaO_3 second phase formed and grain growth occurred. Presence of liquid phase which is related to the Ba_(0.5)TaO_3 second phase could be responsible for the grain growth. Q value of BZT was greatly enhanced with the addition of ZrO_2. The improvement of Q value can be explained by the increase of relative density and grain size. Especially, grain size is considered to be one of the crucial factors for the improvement of Q value of BZT ceramic.