The Study Of High Dielectric Constant And BaTiO₃-based Ceramics

BaTiO₃-based X7R dielectric materials have gotten close attention in the field of X7R ceramics. In this paper, it was investigated that the effect of additive on the dielectric properties and microstructure of the system, and the studies on X7R systems were conducted by using nanoscaled powders additives. The goal of this work is to obtain X7R materials with both good sinterability and excellent dielectric properties.1. Mg mainly taking place of Ti site can enhance dielectric constant and also increaseΔe/e.2. Nb and Co were used as a pair of additives, which took place of Ti site in the form of [Nb_2/3⁵⁺Co_1/3²⁺]⁴⁺, and form"core-cell"structure. When Nb and Co sintered at 750℃, the thickness of average grain-shell was larger, the curve of dielectric constant– temperature at low temperature was enhanced, andΔe/e increased.3. The BaTiO₃ ceramics doped with 0.046 wt %MnCO₃ holds superior dielectric properties. It was found that Mn additive practices as sintering agent, which improves the dielectric constant of the system. When manganese ion transcribes from 2+ to 3+ valence, tan d reduces, the materials fit EIA X7R specification. The main process and dielectric properties are as follows: sintering temperature 1 240℃for 6h, e⁵800, tan d=1.5%, -15%<Δe/e<15%,?v=1×10¹²Î©Â·cm(measured at 1 kHz). 4,Namo BaTiO₃ powder were obtained by sol- gel method. Sintered at 800℃, the namo powders were obtained. The nano BaTiO₃ powder can increase the dielectric constant to 5500, and also increaseΔe/e. the BaTiO₃ ceramics doped with namo BaTiO₃ powder and Nb and Co sintered at 750℃, holds both good sinterability and superior dielectric properties. The main process and dielectric properties are as follows: sintering temperature 1 260℃for 6h, e⁴200,tan d=1.5%, -15%<Δe/e<15%,?_v=1×10¹²Î©Â·cm(measured at 1 kHz).