Corrosion 101: Essentials for Asset Protection: What is corrosion?

What Is Corrosion? A Simple Definition and Why It Matters

Imagine a water main that weakens from the inside out, thinned by years of undetected corrosion. Or a storage tank’s protective lining that blisters and fails, exposing the steel to corrosive chemicals. We’ve all seen stories of bridge collapses and infrastructure failures—not from overuse, but from rust eating away at its structure. These are the everyday consequences of corrosion—and it costs billions of dollars per year.

Corrosion is the process by which a material—usually metal—deteriorates due to a chemical or electrochemical reaction with its environment. Most often, that reaction is caused by moisture, oxygen, salts, or other corrosive agents that trigger a breakdown over time. Here’s a deep dive into corrosion science and the importance of materials protection.

Corrosion: Definition and Meaning

At its core, corrosion is a natural chemical process. It transforms refined metals into more chemically stable compounds, such as oxides or hydroxides. This transformation happens through electrochemical reactions and gradually reduces the material’s integrity and strength.

Typical forms of corrosion include:

• Rust on steel
• Pitting on stainless steel
• Concrete cracking from rebar corrosion

These forms of corrosion are more than surface blemishes—they can lead to infrastructure failure, downtime, and even public safety hazards over time.

How Does Corrosion Happen?

Corrosion begins when three conditions are present:

• A metal surface (e.g., steel)
• An electrolyte (e.g., water with salts or acids)
• An oxidizing agent (typically oxygen)

Together, these form a corrosion cell. In straightforward terms, the metal gives up electrons and becomes oxidized. Those electrons flow to something called the cathode, and the electrolyte completes the circuit. It’s similar to a battery in action.

Corrosion is like a hidden battery on an asset. One part corrodes (anode), while the other is protected (cathode), and the surrounding environment powers the reaction. If it’s not managed correctly, this process leads to loss of material, thinning, and structural failure. It can lead to catastrophic failures in mission-critical infrastructure.

Why Corrosion is a Global Problem

Corrosion isn’t just a minor maintenance concern—it’s a global economic and safety issue.

• AMPP research has shown that over $2.5 trillion USD is lost annually to corrosion-related costs, accounting for 3–4% of global GDP.
• In the United States alone, corrosion damage exceeds $449 billion annually, according to Federal Highway Administration Corrosion Reports.
• Up to 35% of corrosion-related costs could be prevented with existing technologies and best practices.

Failures from corrosion have led to pipeline ruptures, bridge collapses, water contamination, and chemical spills around the world. Understanding how corrosion works is the first step to stopping it.

Where Corrosion Happens

You’ll find corrosion in nearly every industrial sector on earth. Some examples include:

• Pipelines: External corrosion comes from soil moisture, while internal corrosion starts with gas contaminants.
• Storage tanks: Blistered linings and corrosion develop in high-moisture or microbial environments.
• Marine structures: Accelerated corrosion occurs from saltwater and tidal cycles.
• Bridges and reinforced concrete: Corroding rebar leads to cracking, delamination, and collapse if not mitigated.

Corrosion Terms to Know

If you’re new to corrosion, these are terms you’ll often see and hear:

Frequently Asked Questions About Corrosion

• Q: What causes corrosion?
  A: Corrosion is caused by electrochemical reactions between a metal and its environment, often involving moisture, oxygen, salts, or acids.
  
• Q: What are the effects of corrosion?
  A: Corrosion weakens materials, leads to equipment failure, and poses serious safety and environmental risks.
• Q: Can corrosion be prevented?
  A: Yes! Through protective coatings, smart material selection, cathodic protection, and routine inspection, corrosion can be significantly delayed or controlled.

Build Your Corrosion Knowledge with AMPP

Looking to take the next step in your corrosion journey? These AMPP courses are the perfect starting point:

• Basic Corrosion Course and Micro-Credential – Learn the science of corrosion, including prevention basics and inspection fundamentals.
• Fundamentals of Protective Coatings (C1) – Explore coating types, surface preparation, and best practices for protective systems.

What’s next in this corrosion series?

• Part One: What is Corrosion? (You are here)
• Part Two: Why Corrosion Happens: Types, Conditions, Risk Factors
• Part Three: How to Prevent Corrosion: Best Practices, Testing, Control Methods