Surface and grain boundary analysis of doped zirconia ceramics studied by AES and XPS

摘要

The surface- and grain boundary composition of Y, Ce and Ti doped zirconia were studied by X-ray Photoelectron Spectroscopy and Auger Electron Spectroscopy/Scanning Auger Microscopy. The grain boundaries and free surfaces showed the same enrichment levels. After heat treatment ge 1000 DaggerC all yttria doped samples showed yttrium enrichment. In the ZrO2-Y2O3 system the yttrium enrichment did not depend on the bulk concentration and amounted 30–34 mol% YO1.5 in all cases. As a consequence the segregation factor increases with decreasing solute concentration in the bulk. The thickness of the segregation layer was about 2–4 nm. In the ternary Y doped systems yttrium is the main segregant. In ceria-doped tetragonal zirconia polycrystals (Ce-TZP) systems significant segregation of cerium starts atTge1300DaggerC and is mainly attributed to Ce3+. In Y,Ti-TZP systems also strong segregation of Ti4+ occurs. The absolute value of the increase of the surface concentration in fine grained material is smaller than in coarse grained material. This is mainly due to depletion of the bulk.