How does stainless steel’s resistance to pitting compare to aluminum in saltwater?
Stainless steel and aluminum are both widely used in marine environments, but their resistance to pitting corrosion in saltwater differs significantly. Stainless steel, particularly grades like 316 with added molybdenum, offers superior pitting resistance due to its passive oxide layer, which reforms quickly when damaged. Aluminum, while lightweight and corrosion-resistant in many conditions, is more prone to pitting in saltwater, especially without protective coatings or alloys like 5052 or 6061. Chloride ions in saltwater aggressively attack aluminum, leading to localized corrosion. For long-term durability in saltwater, stainless steel is generally the better choice, though proper alloy selection and maintenance are crucial for both metals.
