Pitting Corrosion

Pitting corrosion occurs when pits form on the inside of pipes or machines due to corrosion. It typically results from galvanic corrosion, which happens when two different metals and water come together as electrolytes. This creates an electrochemical reaction similar to a battery, where electrons flow from the base metal to the noble metal, producing small pits.

The process often begins when impurities such as iron particles enter a water system and meet nobler metals like copper alloys or stainless steel. These particles form many small galvanic elements in localized areas, immediately triggering corrosion. Over time, pitting builds up a pit that eats through the pipe, eventually creating leaks and holes that require repair or replacement.

The decisive factor in pitting is the potential difference between the pipe material and foreign particles, not the pipe material itself. Classical corrosion prevention methods like corrosion inhibitors and cathodic protection are often ineffective because chemicals cannot reach the corrosion pit. Prevention strategies include installing dirt filters at water inlets and using technologies like the Merus Ring, which forms a protective oxide film (magnetite) on metal surfaces to increase corrosion resistance and reduce pitting frequency by over 90%.