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I have an aluminum sample stored about 1 month ago. I am going to couple it for galvanic current and potential measurements. I think the Al sample grew an oxide film due to exposure to air. Would the aluminum oxide film can affect the measurements? Should I remove it first? How?

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    $\begingroup$ Aluminium electrode is going to corrode anyway, depending on the current it may even be thick layers of $\ce{Al2O3}$/$\ce{Al(OH)3}$ that peel off over time as the electrode is consumed. If aqueous electrolyte is used, also expect hydrogen evolution and corresponding pH change which may affect measured potential. If these are undesired processes, you probably want to use alloyed aluminium (say, with tin). $\endgroup$
    – andselisk ♦
    Commented Aug 22, 2017 at 6:37

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sure it's going to affect the test so you have to remove the oxide layer Generally, we adopt the method of alkali corrosion to remove the oxide layer on the surface of the aluminum.The purpose of alkali corrosion is removing the oxide layer on the surface of the aluminum. (Note: Technological process of the method is as follows: under normal temperature, 20% nitric acid; the process parameters is about 0.5 minutes. Pre-degrease--degrease--rinsing--rinsing--alkali corrosion--rinsing--rinsing--bright dipping--rinsing--rinsing--pure rinsing. The purpose of bright dipping is to remove surface residual black ash after alkali corrosion.Temperature:50-60 degrees; time:0.5-1 minutes.The purpose of degreasing is to remove grease on the surface of the aluminum.The process parameters is 0.5-1 minutes. You can use acid to wash it

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  • $\begingroup$ Can I use a dilute solution of HCl that has the same ph with the nitric acid? $\endgroup$
    – Acid
    Commented Aug 22, 2017 at 14:33
  • $\begingroup$ Can mechanically polishing it using abrasive paper remove the oxide layer? $\endgroup$
    – Acid
    Commented Aug 22, 2017 at 14:35
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    $\begingroup$ I prefer using the first method of HCl not the mechanical way $\endgroup$
    – JaafarMehrez
    Commented Aug 22, 2017 at 14:37
  • $\begingroup$ What concentration would do? $\endgroup$
    – Acid
    Commented Aug 22, 2017 at 14:38
  • $\begingroup$ Use a concentration of 3% $\endgroup$
    – JaafarMehrez
    Commented Aug 22, 2017 at 14:49

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