How do bi-metal lugs prevent galvanic corrosion?
Bi-metallic lugs stop galvanic corrosion from happening in the first place by acting as a controlled junction between two different metals, which are usually aluminum conductors and copper terminals, that would otherwise react negatively if placed in direct contact.

The process of galvanic corrosion happens when two metals of different types are connected and there is moisture or an electrolyte present. In aluminum-to-copper connections, aluminum is the more anodic metal and as a result it tends to corrode quickly and cause an increase in resistance, overheating, and eventually the failure of the joint. Bi-metal lugs are the solution to this problem.

To create a bi-metal lug, an aluminum barrel and a copper palm are joined together permanently through methods such as friction welding or molecular bonding. The result is a strong metallurgical bond where the metals are welded together without any voids or surfaces that could hold moisture. The aluminum conductor is crimped only into the aluminum barrel and the copper terminal only comes in contact with the copper palm, therefore there is no direct aluminum-to-copper contact at the point of installation.

Besides, a number of bi-metal lugs get treatment with anti-corrosive substances and protective coating on the copper palm. These actions contribute less to the occurrence of oxidation, moisture penetration, and electrochemical reactions.

By separating metals that are not alike, keeping contact resistance low, and offering a strong mechanical bond, bi-metal lugs have the power to stop galvanic corrosion from taking place and thus, they provide long-term safety and reliability in the electrical installations involving mixed-metal.