We have investigated the interaction between Ti and SiO2in the temperature range of 400° to about 1000°C. The reaction proceeds in a layer-by-layer fashion and consists of SiO2reduction followed by the formation of a Ti-rich silicide at the interface. At higher temperatures, a Ti-rich oxide is formed near the surface. The reaction starts at approximately 400°C, and the loss of SiO2becomes significant above 500°C. A strong interaction between Ti and SiO2takes place at 700°C and above. The thicker the SiO2the higher resistance it has to degradation due to elevated temperature effects. © 1984, The Electrochemical Society, Inc. All rights reserved.