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The Questions is above. I am not a chemist but that is what I know:

  • Aluminum has an Oxide Layer normally
  • Aluminum-Oxide Layer can be broken down with NaOH
  • Zink coatings are done by galvanic coating using a certain voltage

Another way to ask: Can I do this with Aluminum?

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  • $\begingroup$ Are you asking how to electroplate aluminum onto a substrate? $\endgroup$ – blacksmith37 Jun 21 at 16:02
  • $\begingroup$ yes essentially, And if thats possible without any further difficulties/ what i should consider when doing so $\endgroup$ – RIJIK Jun 21 at 16:10
  • $\begingroup$ It may be possible to electroplate , but I have only seen vapor deposition in vacuum or "flame"spray ( actually done like electric welding) which makes a relatively coating ( used for cathodic protection. ). and Alonizing , done at very high temperature. $\endgroup$ – blacksmith37 Jun 21 at 16:51
  • $\begingroup$ Alonizing , a proprietary process, deposits aluminum vapor on steel at about 1800 F. It is used to coat high temperature equipment ( eg. furnace tubes) for oxidation and sulfidation resistance. Not decorative. $\endgroup$ – blacksmith37 Jun 21 at 16:57
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Yes, it is definitely possible, but also relatively difficult as compared to electroplating zinc onto another metal.

It is a significantly important industrial process. Although aluminium itself is reactive, it develops an impervious oxide layer that quite much renders it unreactive.

However, comparatively larger negative standard electrode potential of Al/Al(III) couple (− 1.67 V vs. SHE) precludes its deposition from the aqueous baths.

So it is usually considered impossible in aqueous (water-based) solution so is conducted in either organic liquids or fused (molten) state.

Fused: Usually a bath of an eutectic mixture of $\ce{LiBr, KBr}$ & $\ce{CsBr}$ is taken along with molten $\ce{AlBr3}$ (melts at about 94-98°C). A concentration of $80\%$ (by wt.) of $\ce{AlBr3}$ is reported to give a shiny finish.

Source $1$ reports that a satisfactory result was obtained with constant current of $1-3$ $\pu{A}$ passed for $1$ hour.

Non-aqueous solution:

From Source $2$ (emphasis mine)

..the commercial processes for electroplating of Al are based on organic solvents such as SIGAL (Siemens-Galvano-Aluminium) and REAL (Room-temperature Electroplated Aluminium) processes. In the SIGAL process which was developed in Siemens laboratories Al is electrodeposited at 100 °C from alkylaluminium compounds in toluene. In the REAL process which was developed in the laboratories of Philips $\ce{Al}$ is deposited at room temperature from $\ce{AlCl3}$ and $\ce{LiAlH4}$ in tetrahydrofurane.

The process must be conducted avoiding any traces of water, or the water would be electolysed first, leading to observable evolution of gas.

TL;DR: Electroplating aluminium is not something I would recommend trying at home.


References:

  1. Aluminum electroplating on steel from a fused bromide electrolyte, P. K. Tripathy et al, Surf. Coat. Tech., Vol. 258, 15 Nov. 2014, 652-663. DOI:10.1016/j.surfcoat.2014.08.021
  2. Electroplating of mild steel by aluminium in a first generation ionic liquid: A green alternative to commercial Al-plating in organic solvents, S. Zein El Abedin et al, Surf. Coat. Tech., Vol. 201, Issues 3–4, 5 Oct. 2006, 1352-1356. DOI:10.1016/j.surfcoat.2006.01.065
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  • $\begingroup$ Thank you very much. Very informative. I think i will then try some other material though. Thats too much of a hassle to homebrew. But I have one question left: Why do some people recommend using NaOH to destroy the oxide Layer and why isn't it possible form Al+1 or Al+2 to go into solution and then using a voltage to redirect the ions to flow to the other electrode? $\endgroup$ – RIJIK Jun 22 at 8:44
  • $\begingroup$ You're welcome. $\ce{NaOH}$ forms an aluminate complex, and hence dissolves $\ce{Al2O3}$ under moderate heat (read more here). And no, forming and stabilizing +1 or +2 states would be really challenging (and maybe impossible altogether) at room temperature. +1 state is rare but existent, while I don't believe the +2 state exists. If you've studied basic electronic configuration, you might know that Al prefers a +3 state. $\endgroup$ – William R. Ebenezer Jun 22 at 9:53
  • $\begingroup$ Yeah I had studied that, but its a while ago and i never considered one impossible. Thank you very much for the answers $\endgroup$ – RIJIK Jun 22 at 12:27

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