High K low firing temperature capacitors based on lead niobate

Abstract

Dielectric formulations based on lead magnesium niobate and lead iron niobate which achieve a Z5U temperature characteristic with a dielectric constant of 12000 have been developed for the manufacture of multilayer ceramic capacitors. A low-melting-temperature glass frit was added to the formulation to achieve a firing temperature of between 975 degrees C and 1050 degrees C, allowing the use of silver electrodes with from 18% to 25% palladium added. The addition of lead iron tungstate and cadmium titanate further reduced the firing temperature to between 850 degrees C and 900 degrees C, which allowed the use of pure silver electrodes. An insulation resistance of 10000 ohm-farads and a dissipation factor of 1% were achieved with excellent long-term life reliability and an aging rate of less than 2%. High-quality capacitors can be manufactured using standard manufacturing techniques and very careful safety and environmental procedures. >