Anode Material

FreeBeeTony

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May 15, 2002
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Kinda surprised/comfused......can't quite understand why an aluminum anode would be used on an aluminum outdrive...:confused:
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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because it lasts a bit longer than zinc. I still prefer a new zinc every year.
 

QBhoy

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Also that the aluminium anode isn’t just quite all aluminium, or at least the same make up as the outdrive. Slightly different make up and maybe a bit miss leading in calling it so. The anode and it’s make up is made to be of a more sacrificial make up than the drive. If you know what I mean. I remember looking into this I’m great detail previously, one of the reasons was just the same question as you.
 

dingbat

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Kinda surprised/comfused......can't quite understand why an aluminum anode would be used on an aluminum outdrive...:confused:
The short answer is most aluminum is not aluminum.

Most aluminums are alloyed with a number of different elements to give it specific electrical and mechanical properties.

A number of the elements commonality alloyed are more “active” than the aluminum. Therefore, you can change the nobility of the material by changing the compostion.

As long as the anode has a higher nobility than the out drive, your good

https://performancemetals.com/pages/...luminum-anodes
 

achris

More fish than mountain goat
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May 19, 2004
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...As long as the anode has a higher nobility than the out drive, your good...[/URL]

Errr, no. You want the LEAST noble metal to be the anode.

Galvanic series (most noble at top)


The following is the galvanic series for stagnant (that is, low oxygen content) seawater. The order may change in different environments.[SUP][1][/SUP]
 

QBhoy

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You want the anode less noble for sure. Check the galvanic scale. All the best.
 
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