A Study of the Microstructure and Electric Properties of Ba2Ti9O20-based Multilayer Ceramic Capacitors by Microwave Sintering

Abstract

In this study, the effects of microwave sintering on the sintering behaviour, the microstructure and the silver diffusion of Ba2Ti9O20-based multilayer ceramic capacitors (BT MLCCs) with 95Ag-5Pd electrodes were investigated. The energy dispersive spectroscopy results showed that the silver ions diffused into the dielectric layer significantly when BT MLCC was sintered directly up to 940°C (conventional sintering). However, BT MLCC was fired at 940°C using microwave sintering; it was found to effectively suppress silver ion diffusion into the dielectric layer. According to the EDS analysis, the concentration of Ag in the Ba2Ti9O20-based dielectrics using microwave sintering is below 0.4 at.%, whereas the use of conventional sintering results in an Ag ion concentration of approximately 2.3 at.%. The result for this may be due to different sintering kinetics between conventional and microwave sintering. To prove the effect of silver ion diffusion on the insulation resistance of BT MLCCs, the insulation resistance under different sintering conditions was measured at 85°C and 95% relative humidity atmosphere. The insulation resistance of BT MLCCs with conventional sintering was degraded obviously, which was compared with that with the microwave sintering.