Corrosion Authority
Part of
Foundations of Cathodic Protection

Concept Bridge Series: CP3 Foundations

This series is a structured reading path that connects core electrochemical concepts to CP3-style interpretation and design thinking.

Each guide stands alone, but the sequence is intentional: it builds from circuit fundamentals to measurement logic, corrosion rate theory, interference logic, and finally distribution/attenuation design implications.

Recommended reading order

1) From Driving Voltage to Polarization

How applied voltage becomes current, current density, and protective polarization at the metal–electrolyte interface.

2) Why Instant-Off Matters

How instant-off isolates polarization from IR drop so your measurements represent true surface condition.

3) Understanding Corrosion Using Mixed Potential Theory

How coupled anodic and cathodic reactions set corrosion potential and how the intersection current relates to corrosion rate.

4) Why AC Can Still Cause Corrosion

How alternating current can produce localized corrosion risk despite near-zero average current over time.

5) Current Distribution and Attenuation Explained

Why protection is never uniform, how attenuation occurs, and what that means for design and verification.

How to use this series

  • Read in order for fastest comprehension.
  • After each guide, review the linked glossary terms (especially Potential, IR Drop, Polarization, Current Density).
  • Then apply the ideas in practice problems and case-style questions.

What this series enables

  • Translate “numbers on a meter” into surface reaction meaning.
  • Separate circuit effects (IR, voltage drop) from true polarization.
  • Connect corrosion rate to coupled anodic/cathodic behavior.
  • Recognize why interference and attenuation create localized risk.