Mutual diffusion at heterogeneous interfaces in co-fired composite MLCCs

Abstract

Interdiffusion at the heterogeneous interfaces in composite multilayer ceramic capacitors (MLCCs) was investigated by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results show that the movement of silver at the interface only involves physical migration, which can be controlled mainly by the sintering characteristic of the ceramic. Before the open pores in the ceramic change into closed pores, the silver migrates by vapourisation. In addition, interdiffusion between different dielectric layers may be affected by the sintering temperature and time and particularly by compositional gradients. So by lowering the sintering temperature and designing the elemental compositions of neighbouring dielectric layers, interdiffusion can be suppressed and reliable processing of composite MLCCs achieved.