Multilayer capacitors with base metal electrodes BME

3 Multilayer capacitors with base metal electrodes (BME) 

With reductions in ceramic sintering temperature, the cost of electrodes has been reduced by the use of Ag-Pd alloys, typically 70at.% Ag/30at.% Pd. The reduction in palladium content is limited to about 15 at.% because at lower levels silver migration becomes a problem. The drive to lower cost has led to efforts to avoid it entirely. One approach is based upon the injected or fugitive electrode (see Section 5.4.3 and Fig. 5.12) and the other on the use of the base metals nickel or copper for the electrodes (BME) combined with dielectrics resistant to the reduction firing necessary to retain the electrodes in the metallic state. 

Although the fugitive electrode approach is viable it is presently little used, if at all. In contrast BME technology presently accounts for about 50% of MLCC production. 

Technical BaTi03 normally contains sufficient acceptors in the form of Al, Fe etc. to render it insulating after firing at atmospheric pressure, but it requires 

The BME process cannot be applied to compositions containing lead because of the ease of reduction to metallic lead. 

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