Mechanical Disruption (Erosion Corrosion)

Definition

Mechanical disruption is the stripping of protective films by shear forces from flow and turbulence. It exposes anodic sites faster than they can repassivate.

As water velocity rises, shear forces at the metal surface increase, and turbulence from abrupt changes in direction, diameter, or pressure amplifies them and scours away films. This is why corrosion appears first at elbows, tees, pump impellers, control valves, and heat exchanger inlets. Understanding where mechanical disruption occurs explains why corrosion localizes and where it reappears after repair, even though geometry and fluid dynamics are rarely controllable.

Related concepts

Passivation · Repassivation · Film Saboteurs

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