Ba(Zn 1/3Nb 2/3)O 3 sintering temperature lowering for silver co-sintering applications

Abstract

The complex perovskite oxide Ba(Zn 1/3Nb 2/3)O 3 have been broadly studied due to its attractive dielectric properties which place this material as a good candidate for manufacturing type I capacitors or hyperfrequency resonators. The development of Base Metal Electrodes Multi Layer Ceramic Capacitors (BME-MLCC) require a low sintering temperature to be co-sintered with a low cost metal such as copper or silver. Unfortunately, BZN requires a high temperature (1350 °C according to the literature) to reach a satisfactory density (>90% of the theoretical one). The aim of this work is to lower the BZN sintering temperature to allow a co-sintering with copper or silver electrodes. For this goal, different sintering agents (lithium salts and glass phases) have been tested on the nominal compound. It is shown that an addition of 10 molar% B 2O 3 combined with 5 molar% LiF authorises a sintering temperature lowering near to 350 °C. If a slight non-stoichiometry in A site is combined to these sintering agents, it is possible to reach a sintering temperature lower than 950 °C without affecting the basic material properties. For each composition obtained, the ceramic is characterised in terms of final density, microstructure and dielectric properties. The silver co-sintering is also performed.