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Previously i asked this question in Engineering SE: What aluminum grade is the most resistant to corrosion in alkaline environment?

Some input from others seem indicating that no mass-produced aluminum grade suitable for alkaline aqueous environment (sodium hydroxide). So I was thinking if there is a way to produce it?

Any suggestion of what might be added to pure aluminum to make it highly resistant to corrosion in alkaline?

Other parameter (strength, workability, etc) is not significant thus can be neglected

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    $\begingroup$ I can't say for sure this is impossible but it is going to be hard (and fairly certainly not worth the cost). Al is very reactive to alkalis like NaOH as is the normal oxide coating that protects Al from other forms of corrosion. There are even well known reactions where Al is dissolved out of other alloys by using NaOH! $\endgroup$
    – matt_black
    Jan 4 at 9:45

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Here is an idea based on the concept of a sacrificial anode. Per Wikipedia, to quote:

A galvanic anode, or sacrificial anode, is the main component of a galvanic cathodic protection (CP) system used to protect buried or submerged metal structures from corrosion.They are made from a metal alloy with a more "active" voltage (more negative reduction potential / more positive electrochemical potential) than the metal of the structure. The difference in potential between the two metals means that the galvanic anode corrodes, so that the anode material is consumed in preference to the structure.

So perhaps, experiment with adding to the aluminum alloy, or introducing surface strips of pure Zinc, which is more anodic than Aluminum, as noted in this source. Now, Zn must all be removed before Al corrodes, and with a large surface area anode of zinc relative to say an incidental (or provided spot) of carbon (serving as the noble cathode), the galvanic reaction, at least, will be slow.

Related concept: Galvanizing Steel, which per a source, to quote:

Galvanizing, or galvanization, is a manufacturing process where a coating of zinc is applied to steel or iron to offer protection and prevent rusting. There are several galvanizing processes available, but the most commonly offered and used method is called hot-dip galvanizing.

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  • $\begingroup$ Galvanized aluminum? $\endgroup$
    – Ed V
    Jan 4 at 1:10
  • $\begingroup$ Thanks Ed V, Galvanizing aluminum helps protect metal from oxidation and corrosion. ... Cold galvanizing aluminum surfaces with zinc fusion provides effective metal protection in extreme temperatures and environments containing high concentrations of corrosive elements at a fraction of the cost for hot galvanizing.Apr 24, 2017 here sciencing.com/galvanize-aluminum-8664634.html $\endgroup$
    – AJKOER
    Jan 4 at 1:19
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    $\begingroup$ But why not just use one of the many zinc alloys that are available now? Nickel-plated aluminum is common in some applications, e.g., electrodes for excimer lasers, and nickel-plated zinc is commonly used for fasteners and such at my local hardware store. If cost is not a major factor, titanium is an option. $\endgroup$
    – Ed V
    Jan 4 at 1:25
  • $\begingroup$ Nickel is at the wrong end of the anodic index (see zygology.com/cms/upload_area/pdf/Zyg-Anodic-Index.pdf). $\endgroup$
    – AJKOER
    Jan 4 at 2:05
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    $\begingroup$ But nickel would not be acting as sacrificial anode: it would be like the tin on a steel can, not like zinc on a galvanized trashcan. $\endgroup$
    – Ed V
    Jan 4 at 12:54

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