What Does External Corrosion Mean?
External corrosion refers to a type of electrochemical degradation mechanism that occurs on the surface of metals. It is caused primarily due to environmental factors such as soil, water and air.
External corrosion is prevalent in pipeline applications but may occur in any circumstance. Adequate protective mechanisms such as coatings, cathodic protection (CP) and in-line pipeline inspections can be used to reduce the corrosion rate.
Corrosionpedia Explains External Corrosion
External corrosion mechanisms often occur in metal applications used in the following environmental circumstances:
- Soil profiles and topographies
- Ocean floor
- Seawater, surface underwater and splash zones
- Moist atmospheric exposure (onshore and offshore)
Further environmental classifications are made for these environments according to their relative climates (temperature), distance above sea level (pressure) and acidity. High temperature and high acidity locations facilitate greater corrosion rates.