The in situ growth of ZnO nanosheets has been demonstrated by our research group and the excellent electrical contact between the ZnO nanosheets and brass substrate enables many potential applications in gas sensing and photocatalytic degradation. However, problems arising from corrosion, especially that arising from chloride ions, are inevitable in the field. In this work, the corrosion behavior of these ZnO nanosheets is investigated in chloride solutions. Our results show that in a NaCl solution, the chloride ions can react with ZnO to form ZnCl2. When the NaCl concentration is relatively low (1 wt%), the structure exhibits a strong passivation behavior but a higher concentration of chloride ions can accelerate the transformation from ZnO to ZnCl2. The results also disclose that a high concentration of NaCl weakens the passivation performance and when the concentration reaches 3 wt%, the passivation ability vanishes completely. (C) 2008 Elsevier B.V. All rights reserved.