Corrosion of Aluminum-Uranium Alloys in Water Vapor at 200 °C

Abstract

AbstractSpecimens of aluminum-uranium alloys at 10 and 18 weight percent uranium were exposed to a saturated water vapor condition at 200 °C up to about 12 weeks and compared to previous results for aluminum 1100. The aluminum-uranium materials exhibited a range of initial corrosion rates and approached similar rates with the formation of a passive film of boehmite (Al2O3·H2O). The initial corrosion rates of the aluminum-uranium materials were one to four times higher than that for aluminum 1100. It is postulated that a micro-galvanic coupling between the large UA14 particles and the aluminum matrix has caused this difference. Sectioning the exposed specimens shows different characteristics of the oxide layers. In the oxide on the aluminum-10% uranium alloy (Al-10%U), small uranium aluminide particles can be seen in a boehmite matrix and do not seem to be corroded. The oxide film on the aluminum- 18% uranium alloy (Al-18%U) appears to have two distinct oxide layers. The outer layer has mass aggregates in a boehmite matrix, while the inner layer contains UA14 particles as in the case of Al-10%U.