The Mechanism of Oxide Growth on Pure Aluminum in Ultra-High-Temperature Steam

Abstract

A high-temperature water steam (H2 O(g)) between 300◦ C and 1000◦ C reacted with the Al surface in this study. The Al surface states were characterized and analyzed using XRD◦ C, XPS, and SEM after and before the reaction, and the effects and mechanism of H2 O(g) on the Al surface morphology and chemical composition were studied. The experiment showed that for an Al sheet reacting with H2 O(g), its oxide layer morphology changed from nano-needle to flaky and granular oxides gradually with the rise of temperature, and finally the Al surface became porous as a whole. Its oxide crystals were amorphous and were determined to be aluminum oxide (Al2 O3) using XPS. The needle-like oxide in the Al sheet surface tended to grow toward the surface, and no obviously inward oxidizing corrosion layer occurred in the aluminum substrate; the oxide layer between the oxide and Al sheet substrate was compact, and could effectively prevent the infiltration and corrosion of water molecules.