Corrosion behaviour of Ni–Al composite coating in 3.5% NaCl + 0.05 M H2SO4 solution

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Author(s) B.I. Onyeachu | E.E. Oguzie | X. Peng | C.E. Ogukwe | I. Digbo
Pages 711-716
Volume 3
Issue 11
Date November, 2014
Keywords Ni–Al composite; co–electrodeposition; XPS; corrosion rate.

The electrochemical corrosion behaviour of electrodeposited Ni–Al composite coating, containing 1μm–size Al particles, was studied in 3.5% NaCl + 0.05 M H2SO4 solution using electrochemical and surface probe techniques. Open circuit potential measurement revealed that the Al particles shift the Ni corrosion potential to more negative regions. Potentiodynamic polarization characterization showed that the Al particles increase the corrosion rate of the Ni coating by increasing both cathodic and anodic half–reactions. XPS characterization confirmed that the Al corrosion products are highly dissoluble in the 3.5% NaCl + 0.05 M H2SO4 solution. This dissolution disturbs the easy linkage of the Ni corrosion product based on SEM characterization.

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