Connector Corrosion 101

Corrosion is a complicated reaction influenced by many factors such as dissimilar metals, moisture, and environmental chemicals. However; structural connectors and their fasteners are attacked by corrosion in the same basic electrochemical manner.

Internal Attack - Copper ions found in high concentrations in treated wood are positively charged and actively attack the negatively charged steel. Traditional corrosion protection is a barrier layer of zinc which is more negative than steel and attracts the copper ions, thus temporarily protecting the steel. Unfortunately, once the copper eats all the zinc away, the steel is aggressively attacked. Zinc is a sacrificial delay.

External Attack - Outside factors such as moisture (especially wet/dry cycles), acid rain and chemicals, all serve to accelerate (a catalyst) the attack on the steel.

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