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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 Aug 22 '17 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 Aug 22 '17 at 14:33
  • $\begingroup$ Can mechanically polishing it using abrasive paper remove the oxide layer? $\endgroup$ – Acid Aug 22 '17 at 14:35
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    $\begingroup$ I prefer using the first method of HCl not the mechanical way $\endgroup$ – Jaafar Mehrez Aug 22 '17 at 14:37
  • $\begingroup$ What concentration would do? $\endgroup$ – Acid Aug 22 '17 at 14:38
  • $\begingroup$ Use a concentration of 3% $\endgroup$ – Jaafar Mehrez Aug 22 '17 at 14:49

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