Abstract

Resistance degradation of Pb(Mg_1/3Nb_2/3)O₃–Pb(Zn_1/3Nb_2/3)O₃–PbTiO₃ (PMZNT) relaxor ferroelectrics during nickel electroplating was investigated by resistivity measurement and X-ray photoelectron spectroscopy (XPS) through the appearance of changes in Nb 3d and Pb 4f spectra. It was found that the insulation resistance of the PMN-based ceramics decreased after electroplating. The XPS analysis showed that the ceramic materials had been reduced by hydrogen during electroplating and Nb⁴⁺ and metallic Pb were generated. As a result, oxygen vacancies and free electrons were created and, therefore, increased the conductivity of the ferroelectrics. It was also found that Nb⁵⁺ reduction was prior to Pb²⁺ reduction. On the basis of our experiments, two conduction mechanisms involved in the hydrogen-induced resistance degradation were established.