Chemical compatibility between silver electrodes and low-firing binary-oxide compounds: Conceptual study

The chemical compatibility of silver electrodes and low-firing ceramics has been considered, in terms of the existence of a tie line between silver (a nd/or Ag2O) and the binary oxide compound in the corresponding ternary phas e diagram. The probability of the existence of the tie line is related to t he conditions in the subordinated silver-based isothermal binary systems. G reater probabilities have been calculated for the systems with fewer silver -based binary compounds. Based on the concepts that have been developed, se veral silver-based isothermal binary systems have been investigated to iden tify the oxides suitable for the development of low-temperature cofired cer amics. The developed concept has been tested by investigating the phase rel ations in the Bi2O3-Nb2O5 and Bi2O3-V2O5 ternary systems with silver. X-ray and microstructural investigations of bismuth niobates and bismuth vanadat es reveal that, as a result of the inertness of Bi2O3 and the reactivity of Nb2O5 and V2O5 toward silver, compounds that are rich in niobium or vanadi um react with silver to form ternary Nb/V-Bi-Ag oxide compounds, whereas fo r compounds that are rich in bismuth, tie lines to silver and Ag2O do exist .