Reliability improvement of PMZNT relaxor ferroelectrics through surface modification by MnO2 doping against electroplating-induced degradation

Electroplating treatment, scanning electron microscopy (SEM) observation, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses were conducted to investigate the reliability improvement of lead magnesium niobate-based ceramics (PMZNT) through MnO2 vaporous doping against hydrogen reduction during electroplating. The results showed that manganese dopant was reduced to be +3 oxidation state during the sintering and Mn3+ was incorporated into the perovskite lattice; however, only the outermost ceramics surface was doped while 50 mum beneath kept unchanged. This technique proved to enhance the reliability of PMZNT against electroplating significantly without changing the dielectric properties of ceramics body. Based on the above results, the modification mechanism of MnO2 vaporous doping was analyzed from the viewpoint of defect chemistry. (C) 2002 Elsevier Science B.V. All rights reserved.