Reactions in TiO2/Ti3Al and TiO2/TiAl bilayers:: application of target-factor analysis in Auger electron spectroscopy

Bilayers of TiO2/Ti3Al and TiO2/TiAl were heated up to 973 K, The resulting concentration-depth profiles were determined using Auger electron spectroscopy in combination with ion sputtering. By applying target-factor analysis it was possible to distinguish between different states of chemical bonding of the elements analysed. In both TiO2/Ti3Al and TiO2/TiAl heating causes decomposition of titanium dioxide at the bilayer interface, as revealed by the associated oxygen diffusion into the metallic layer. In a certain depth range near to the original bilayer, interface oxygen is bonded to both Ti and Al. In the original Ti3Al layer oxygen dissolves homogeneously, whereas Al2O3 was formed in the original TiAl layer, particularly in the central region. Copyright (C) 2000 John Wiley & Sons, Ltd.