Low-sintering composite multilayer ceramic capacitors with X7R specification

Abstract

The low-sintering composite multilayer ceramic capacitors (CMLCCs) having K value in excess of 7200 with X7R characteristics (−55 to +125°C, ±15%) has been successfully developed. The CMLCCs incorporate four PMN–PNN–PT or PMN–PT based ceramics with different Curie temperatures as the principal components. The green tapes and inner electrode are stacked during green printing according to a certain order and co-fired to prepare this kind of multimaterials multilayer chip component with a usual co-firing technique. The property of the dielectric constant ( K) over a temperature range from −55 to +125°C can be determined approximately by the proportion of the four dielectrics with different Curie temperatures according to the parallel connecting model of capacitance. The small difference between the calculative curve and testing curve can be explained by the mutual diffusion among different dielectrics via the inner 30%Pd–70%Ag electrode. The CMLCCs have good microstructure. The research results show that it is feasible to produce chip components with high performance by co-firing multiphases materials.