Investigation of BaTiO_3 System Nonlinear Ceramics

摘要

The nonlinear ceramics of BaTiO_3-BaZrO_3, BaTiO_3-BaSnO_3, BaTiO_3-SrTiO_3,BaTiO_3-SnO_2 were investigated. The DC bias and AC voltage were applied to the samples in order to research the dielectric constant (ε) behavior of these materials. The breakdown field strength and the effects of temperature and frequency on the dielectric constant and dielectric loss (tg δ) were studied as well. The results show that all of these materials have strong nonlinearity, for example, their e can change 2.7 times when DC bias is applied and 2.2 times when AC voltage is applied. In addition, both BaSn_(0.06)Ti_(0.94)O_3 and BaZr_(0.13)Ti_(0.87)O_3 have high dielectric constant (ε = 2000 ～ 3500 at 0 bias) and high breakdown field strength (>2500V/mm), so they can be used as the materials of nonlinear capacitive turn-off snubber for power electronic switches. Morever Ba_(1-x) Sr_xTiO_3(x=0.6～0.7) has lower dielectric constant and dielectric loss, higher temperature-stability and better high-frequency properties, so it can be used as the material of phase shifter for phased-array antennas. In contrast, because 0.94BaTiO_3-0.06SnO_2 has lower breakdown field strength, it can not be used in the above field even if it has low dielectric loss and good temperature-stability.