Surface compositional changes of ZrO2 in H2O, H2 and atomic hydrogen, investigated by aes and eels

Abstract The surface of polycrystalline ZrO 2 was found to be stable in pure H 2 at 900 Torr pressure and temperatures up to 1170 K, but was significantly modified by H 2 O (at ∽ 10 Torr) and by atomic hydrogen at very low concentrations as observed by the O and Zr AES signals. Atomic hydrogen caused reduction of the surface at temperatures above 1020 K. Contrary to the unreduced surface, the reduced surface readily absorbed hydrogen also in molecular hydrogen. Heating in H 2 O at 1070 K and pressures around 10 Torr caused segregation of low concentration bulk silicon to the surface. Heating in H 2 O and O 2 is tentatively proposed to cause the formation of a ZrSiO 4 surface layer. Electron beam reduction of the surface by electron stimulated desorption of oxygen was found to be significant, and the conditions (maximum current density and electron dose density) required to avoid interpretation errors due to this effect were investigated.