Sol-gel titania films on YHfAl foils and their influence on inhibition of transition aluminas during oxidation at high temperatures.
Résumé
In this experimental work, sol-gel technique was used as surface coating of YHfAl alloys to avoid the formation of transition aluminas (delta and theta). This technique has an advantage of low cost and rapidity. The preparation conditions of TiO(2) sol-gel coatings were presented with a description of their evolution with temperature during the first stages of YHfAl oxidation. It is noted that the rutile is the only detected phase at 800 degrees C. The sol-gel thin films were prepared in order to inhibit the formation of transition aluminas. An important gain mass was recorded at a temperature of 875 degrees C and the first grains of aluminas were appeared after 0.5 h of oxidation. A sol-gel TiO(2) film of nearly 60nm thick has proven its efficiency and has allowed to reduce the presence of transition aluminas. (C) 2010 Elsevier B.V. All rights reserved.