A controversial topic in our sector, it is truly one of those issues you don’t want to face when you receive a call about a nonconformity due to corrosion.

Next, I will briefly explain the catastrophic impact that galvanic corrosion can have with an example based on true events:

In 1763, the English frigate called “Alarm” suffered the consequences of galvanic corrosion. The situation was that they decided to apply a copper coating on the ship to protect the wooden hull from marine worms and barnacles. The problem arose when they attached the copper coating using iron nails. Due to the potential difference between these two elements and the presence of the electrolyte (saltwater), galvanic corrosion formed, endangering the ship’s functionality, structural integrity, and therefore the safety of the crew on board.

What is galvanic corrosion?

In this post, we will discuss galvanic corrosion, an electrochemical phenomenon that, if not considered, can have significant consequences on the durability and performance of metallic materials. It can ruin everything simply due to the poor selection of metals in contact with each other.

Carbon steel pipe connected to 316 stainless steel pipe
Carbon steel pipe connected to 316 stainless steel pipe

How does it occur?

The following conditions must be met:

  • Direct contact of different metals (e.g., carbon steel and stainless steel)
  • Presence of an electrolyte (moisture, a corrosive environment, seawater are examples)
  • Closed electrical circuit (physical or electrical connection between the metals). Be careful! This doesn’t mean the pipe is plugged into electricity; simply contact between metals can cause it.

So, what factors influence the occurrence of galvanic corrosion?

  • Metal compatibility: Essentially, in this section, the focus should be on the potential. In other words, the larger the difference in potentials, the higher the likelihood of galvanic corrosion occurring. But don’t worry about this part; we’ve designed a very easy-to-use tool, which we will look at later.
  • Surface area: If the anode, which is the part that corrodes, has a small surface area compared to the cathode, the corrosion will be faster. That is, if you have two pieces of different metals, one smaller and one larger, the smaller piece will corrode faster because the corrosion is concentrated in that small area instead of being distributed over the larger piece.
  • Electrolyte: An electrolyte acts like an enzyme that accelerates a chemical or biochemical reaction. Its presence severely influences galvanic corrosion. An example of an electrolyte can be saltwater, a plant near the sea, an installation in a humid area, or an outdoor area exposed to rain.

Therefore, as observed throughout this explanation, galvanic corrosion is highly relevant in industries that come into contact with electrolytes such as seawater. This includes industries such as shipbuilding, desalination plants, wastewater treatment plants, and any facility located near environments where saltwater is present.

But let’s get to the interesting part…

Galvanic corrosion

Will galvanic corrosion occur if I mix different types of materials?

Next, we provide a system that allows you to accurately determine whether the combination of these materials will result in galvanic corrosion or if, on the contrary, you can forget about this problem.

Galvanic Corrosion EN

At Redfluid, we offer a wide variety of materials for practically everything you’re looking for related to fittings and valves, whether for low or high pressure (a sector in which we specialize).

I hope everything is much clearer now, and you know, if you have any questions, feel free to contact us so we can clarify them for you 🙂