Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by __________.

Correct Answer: Option A — cavitation

Pitting on centrifugal pump impellers is a classic symptom of cavitation. When vapor bubbles collapse near the metal surface, the resulting high-pressure micro-jets cause localized fatigue and material removal. This mechanical damage is distinct from chemical corrosion or electrolysis, appearing as a rough, honeycombed surface on the suction vanes.