The corrosion behavior of Zn coatings on Al-3103 alloy

Zinc films, 4 mum thick, were deposited on an AI-Mn alloy (Al-3103) plate u sing an ion beam-assisted deposition method. The corrosion behavior of the zinc coating samples was investigated in 0.1 M NaCl solutions in the presen ce and absence of bicarbonate/carbonate buffers. In the unbuffered NaCl sol utions, both the Al-3103 and Zn/Al-3103 samples showed active dissolution, but Zn/Al-3103 had more negative corrosion potential and bigger corrosion c urrent than the Al-3103 samples. In the buffered NaCl solutions, the Al-310 3 samples showed passivation, while Zn/Al-3103 had a noble corrosion potent ial compared to the former. The surface compositions of samples, before and after zinc deposition, were checked using Rutherford backscattering spectr oscopy. The surface chemical states for samples after corrosion were analyz ed by means of X-ray photoelectron spectroscopy. The corrosion products wer e mainly zinc oxides, zinc hydroxides and aluminum oxides. (C) 2001 Elsevie r Science B.V. All rights reserved.