高温电容器用BNT-NN纳米瓷料合成与介电性能研究

Preparation and Dielectric Properties of BNT-NN Nano-powders and Ceramics for High Temperature Capacitor

高能球磨法是一类简单有效制备陶瓷纳米颗粒的粉体技术,在多层陶瓷电容器制造领域可以实现高活性介电瓷料可控合成,有利于降低流延膜厚,提升电容密度。以Bi_(0.5)Na_(0.5)Ti O_3-Na Nb O_3(BNT-NN)二元体系为研究目标,在先期煅烧成相的基础上,采用高能球磨技术对BNT-NN煅烧粉体进行细化。研究表明,高能球磨法可以快速实现煅烧粉体尺度由微米级向纳米级转变,利用纳米瓷料致密化烧结获得的陶瓷晶粒尺寸相对于常规瓷料制备的陶瓷减小1/3,且电容温度稳定性在-60到300℃的宽广温区小于±15%,有望应用于高温多层陶瓷电容器。

High energy ball milling is a simple and effective method in preparing nano-particles,which can be used to lower the size of starting dielectric powder for building thin casting film,favoring to enhance the capacitance density of multilayer ceramic capacitors.In this paper,Bi_(0.5)Na_(0.5)TiO_3-Na Nb O_3(BNT-NN)binary system has been selected as research goal.After high temperature calcining,the obtained pure phase BNT-NN coarse powder was further pulverized by the high energy milling method.The results reveal that high energy milling method can realize the refinement of BNT-NN nano-powders in a short time.Using these nano-powders as precursor,the grain size of the densified ceramics decreases by about one third in comparison with those derived from normal coarse powders.Moreover,the temperature stability of capacitance of fine ceramics is below±15%in a wide temperature region between-60 ^(o )C to 300 ^(o )C,showing potential application in high-temperature multilayer ceramic capacitors.