多种添加剂对高压X8R介质材料的改性研究

Dielectric Properties of High-voltage X8R Dielectric Material with Different Kinds of Dopants

研究了综合添加NiNb_2O_6、CaZrO_3和MnCO_3对细晶BaTiO_3系统介电及耐压性能的影响.NiNb_2O_6可使BaTiO_3居里峰展宽并产生双峰效应;CaZrO_3改善了系统的电容变化率,有效抑制了铁电相,提高了耐压强度.MnCO_3的加入可有效地阻止晶粒过度长大,改善了微观结构,降低了介质损耗,提高了耐压强度.当NiNb_2O_6、CaZrO_3和MnCO_3添加量为2.5mol%、1.5mol%、1.0mol%时,本实验获得了满足X8R温度特性的低频高压MLC瓷料系统.该瓷料可达到如下介电性能:介电常数ε≥2600,ΔC/C_(20℃)≤±15%(-55～+150℃),损耗tgδ≤0.7%,耐压强度Eb≥15kV/mm.

The doping effects of NiNb2O6, CaZrO3 and MnCO3 on the dielectric properties and breakdown voltages of fine grain BaTiO3 systems were studied. NiNb2O6 can shift the Curie temperature and broaden it, and makes contributions to double peaks; CaZrO3 may improve the temperature coefficiency characteristic greatly and enhance the withstand voltage; adding MnCO3 can restrain the overgrowth of particles, which can decease the dielectric dissipation and improve the withstand voltage greatly. With adding 2.5mol% NiNbO6, 1.5mol% CaZrO3 and 0.1mol% MnCO3, a kind of MLC ceramic with low frequent and high voltage can be got, which also meets X8R requirement, and its dielectric properties are as follows： E ≥2600, △C/C20^oc ≤ ±15% （-55 ±150℃）, tgδ ≤0.7%, Eb≥15kV/mm.