Influence d'un Revetement de Silice sur la Reactivite d'un Alliage FeCrAl

摘要

The multimaterial FeCrAl/plasma coat FeCrAlY/SiO_2 is elaborated from the FeCrAl alloy to increase its resistance to hot oxidation. The scale of silica is obtained by HIP. This scale is very adherent to the plasma spraying deposit FeCrAlY, which separates the metal FeCrAl from the glass. The reactivity of the lamellar composite is studied between 800deg C and 1300deg C. Two types of behavior are visible: the oxidation is either continuous and accelerated or it tends to a constant mass gain. The presence of silica does not modify deeply the mechanism of oxidation. Silica does not prevent oxidation for this thin thickness, but it slows down the reaction rate. From 1100deg C, there is a partial disappearance of the cristallized silica and, probably, a beginning of amorphisation.