Electrochemical Behavior of Chemical Conversion of Coated Aluminum 1100Al in a Neutral Tartrate Solution
Engineering and Technology Journal,
2010, Volume 28, Issue 18, Pages 5640-5650
Abstract1100 Al specimens were anodically oxidized in different concentrations of
tartaric acid-tartrate solution (pH=7) in 1, 1.75, 3.25 and 4 wt % at temperatures of
30, 37.5, 52.5 and 60 ºC by applying a range of potentials of 30, 37.5, 52.5 and 60
V at exposure times of 40, 47.5, 62.5 and 70 min.. These four variables are
manipulated through the experimental work using Box – Wilson experimental
design where second order polynomial model was proposed to correlate the studied
variables with the thickness of anodic film of aluminum alloy (1100) to estimate
the coefficients of the proposed polynomial adopted via statistica software.
Optimum conditions for achieving the maximum film thickness are obtained from
optimizing the above correlation and are found as follows: temp. = 44ºC, acid conc.
= 2.8 wt %, voltage = 43.6 V, time = 54.6 min.. Stagnate Solutions of 3, 5, 10 and
25 wt % Nacl at 25ºC have been investigated using polarization technique at
optimum conditions for anodizing. The most important feature achieved was the
great difference in behavior between the anodic polarization curves for bare and
anodized aluminum in different concentrations of Nacl solutions. The corrosion
rates for anodized specimens are lower than those for unanodized ones. The
polarization behavior of anodizing specimens shows that the breakdown potentials
are shifted to more noble direction than bare specimens which is more pronounced
in 25 wt % Nacl solution due to anodizing.
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