What is Galvanic Corrosion?

Galvanic corrosion (also called “dissimilar metal corrosion”) occurs when two or more dissimilar materials are brought into contact under water. When this happens, one of the metals becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone. This happens even if both metals would not corrode by themselves.

This phenomenon was first discovered and put into practical application by Alessandro Volta who built, in 1800, the first electrical cell, or battery: a series of metal disks of two kinds, separated by cardboard disks soaked with acid or salt solutions. This principle is the basis of all modern wet-cell batteries.

The sacrificial corrosion of one metal such as zinc, magnesium or aluminum is a widespread method of cathodically protecting metallic structures. Galvanic corrosion can be one of the most common forms of corrosion as well as one of the most destructive.

To counteract the effects of corrosion (galvanic or otherwise), UltraTech has commercialized a sol-gel technology called Gentoo, which revolutionizes corrosion control and protection. Gentoo is a durable, clear, hydrophobic coating that acts as a thin repellent and barrier coating, providing corrosion protection by both its dense barrier properties and its ability to shed water from the surface of the coating. Gentoo is also extremely thin (4-6 microns on average) and flexible. The following is a summary of testing performed during its development under multiple Small Business Innovation Research (SBIR) programs under different branches of the United States Military.