Alumnium Corrosion Explained

[Solittle]

I ran accross the following at an aviation web site regarding corrosion in airplanes. It should apply to our world of boating:<br /><br /> http://www.avweb.com/news/columns/189857-1.html

 

[Dunaruna]

Re: Alumnium Corrosion Explained

Good site, plain english explanation <br /><br />Aldo

 

[umblecumbuz]

Re: Alumnium Corrosion Explained

Excellent article, with clear explanation.<br /><br />One thing differs markedly between the airplane problem described, and our use of boats. The article states in part<br />

For corrosion to occur, four conditions must be present.... 3.An electrical connection between the two metals (typically metal-to-metal contact)

With boats, metal to metal contact is often secondary to proximity. For example, the stainless trim tabs, although not in contact with the aluminum prop, can still cause corrosion on the prop because of proximity in a common electrolyte.<br /><br />The article used the example of a battery. In a battery, there are both anodic and cathodic plates. They are not in contact with each other, but they are in proximity in a common electrolyte. So controlled corrosion takes place - a very useful thing in a battery, but an undesirable thing on a boat.<br /><br />We sometimes overlook the fact that dissimilar metals do not have to be in contact for corrosion to occur.