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

CORROSION 101 · PART ONE

Corrosion is the deterioration of a material—usually metal—caused by a chemical or electrochemical reaction with its environment. Moisture, oxygen, salts, acids, and other conditions can drive these reactions, gradually weakening materials and reducing asset life.

An introduction to corrosion science, risk, and materials protection

Imagine a water main weakening from the inside out after years of undetected corrosion. Or a storage tank lining blistering and failing, exposing the steel underneath to corrosive chemicals. On bridges, pipelines, industrial equipment, and other critical infrastructure, corrosion can begin quietly before becoming a much larger maintenance, reliability, or safety problem.

The economic impact is enormous. Corrosion costs industries and governments billions of dollars each year through inspection, maintenance, repair, downtime, replacement, and failures. Explore AMPP’s research on the cost of corrosion →

What Is Corrosion?

Corrosion is the process by which a material—usually metal—deteriorates through chemical or electrochemical interaction with its surrounding environment.

At its core, corrosion is a natural process. Refined metals tend to move toward more chemically stable states, such as oxides or hydroxides. Electrochemical reactions drive that transformation and can gradually reduce a material’s thickness, integrity, strength, or ability to perform its intended function.

How Does Corrosion Happen?

A basic electrochemical corrosion process requires several elements working together. One simple way to understand the process is to think of it as a small battery operating on the surface of an asset.

Why Is Corrosion a Global Problem?

Corrosion is much more than a maintenance issue. Its effects reach asset reliability, business continuity, infrastructure investment, environmental protection, and public safety.

AMPP research has estimated global corrosion-related costs at more than $2.5 trillion annually, representing approximately 3–4% of global GDP. Research also indicates that a significant share of corrosion-related costs can be reduced through existing technologies and good corrosion-management practices.

Corrosion-related failures can contribute to pipeline ruptures, water-system problems, equipment failures, chemical releases, structural deterioration, and other serious consequences. Understanding the corrosion mechanism is an important first step toward managing those risks.

Where Does Corrosion Happen?

Corrosion affects almost every industry that depends on metals, concrete, infrastructure, transportation, energy, water, or industrial equipment. The environment and corrosion mechanism may change, but the need to understand and control deterioration remains the same.

Corrosion Terms to Know

New to corrosion? These foundational terms will make it easier to understand how electrochemical corrosion works.

Term	What It Means
Oxidation	A reaction in which a material loses electrons. At the anodic area of a corrosion cell, oxidation of the metal occurs.
Electrolyte	A conductive medium that allows ionic movement and helps complete the electrochemical circuit.
Anode	The area where oxidation occurs and metal is consumed during the corrosion process.
Cathode	The area where the corresponding reduction reaction occurs and electrons are consumed.
Galvanic Corrosion	Corrosion that can occur when dissimilar metals are electrically connected in the presence of an electrolyte.

Can Corrosion Be Prevented?

Corrosion cannot always be eliminated completely, but it can often be significantly slowed, controlled, or managed. Effective corrosion management begins with understanding the material, environment, exposure conditions, and expected service life of the asset.

Common Questions About Corrosion

Quick answers to some of the most common introductory questions about corrosion.

What causes corrosion?

Corrosion is caused by chemical or electrochemical reactions between a material and its environment. Moisture, oxygen, salts, acids, contaminants, temperature, and other exposure conditions can influence how quickly corrosion develops.

Is corrosion the same thing as rust?

Not exactly. Rust is a familiar corrosion product associated with iron and steel, but corrosion can affect many different metals and materials and may appear in forms other than visible rust.

What are the effects of corrosion?

Corrosion can cause material loss, cracking, reduced strength, leaks, equipment failure, increased maintenance costs, downtime, environmental consequences, and safety risks.

Can corrosion be prevented?

Corrosion can often be significantly slowed or controlled through protective coatings, cathodic protection, appropriate material selection, corrosion inhibitors, good design, inspection, monitoring, and maintenance.

What industries are most affected by corrosion?

Corrosion affects virtually every infrastructure and industrial sector, including oil and gas, water and wastewater, transportation, maritime, manufacturing, energy, defense, chemical processing, utilities, bridges, and reinforced concrete structures.