Suppression of ZnO Nanowire Formation in High Temperature Oxidation by Sandblasting Brass

Abstract

By exerting sandblasting onto brass (Cu0.7Zn0.3) substrates, we show that the increased sandblasting can gradually suppress ZnO nanowire formation during the thermal oxidation of the Cu–Zn alloy. Detailed surface composition analysis by EDS and depth-resolved XPS shows that both ZnO and CuO form initially on the surface upon oxidation but the CuO phase decreases from the surface to the subsurface region. It is shown that sandblasting leads to more even chemical composition of the brass substrate, which results in more uniform formation of the CuO phase across the surface. The subsequent reduction of the less stable CuO phase by Zn in the coalesced oxide layer results in uniformly accumulated pure Cu in the subsurface region, which suppresses ZnO nanowire formation by blocking the supply of Zn atoms from the brass substrate.