Diffusional penetration of silver from electrodes into PZT ceramics

Abstract

Diffusion of silver was studied in a ceramic based on lead zirconate-titanate, Pb_0.95Sr_0.05(Zr_0.53Ti_0.47)O₃+1 wt%. Nb₂O₅ (PZT), by means of a radio-tracer method. Parameters of silver diffusion and silver content in PZT after continuous diffusion saturation of the ceramic by this impurity were determined in the temperature range 500–850 °C. Concentration-depth profiles and silver content in the ceramic were obtained as a result of metal diffusion from the electrode during ceramic silvering. Our results show that silver has a high diffusivity. No evaporation of silver during metallization (T _max=750 °C) was found, but part of it (∼ 0.1 mg cm⁻²) penetrates into the ceramic from the electrode to a depth of more than 1000 μm, and the silver concentration varies from ∼2×10¹⁹ to ∼2×10¹⁸ at cm⁻³. The silver concentration does not exceed 0.2 at% at diffusion saturation of the ceramic during 100–120 h over the temperature range 650–850 °C.