An XPS study on the degradation of lead magnesium niobate-based relaxor ferroelectrics during nickel electroplating

Resistance degradation of Pb(Mg1/3Nb2/3)O-3-Pb(Zn1/3Nb2/3)O-3-PbTiO3 (PMZNT ) relaxor ferroelectrics during nickel electroplating was investigated by r esistivity measurement and X-ray photoelectron spectroscopy (XPS) through t he appearance of changes in Nb 3d and Pb 4f spectra. It was found that the insulation resistance of the PMN-based ceramics decreased after electroplat ing. 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 N b5+ reduction was prior to Pb2+ reduction. On the basis of our experiments, two conduction mechanisms involved in the hydrogen-induced resistance degr adation were established.