Definition - What does Sweet Corrosion mean?
Sweet corrosion is a type of corrosion that occurs without high levels of hydrogen sulfide or other types of sulfide. Carbon dioxide and carbonic acid are usually the causes of sweet corrosion. Sweet corrosion is a term normally used in the oilfield, oil storage, and oil transportation industries to differentiate between corrosion caused by fossil fuels containing a high amount of sulfides and those that do not.
Sweet corrosion is also known as CO2 corrosion.
Corrosionpedia explains Sweet Corrosion
Sweet corrosion (CO2 corrosion) is one of two terms used in the oil and gas industry to define what type of corrosion will occur based on the amount of sulfides in the fossil fuel. The other term is sour corrosion, which occurs when a fossil fuel relatively high in sulfides and sulfuric acid attacks the metal (usually steel) in contact with it. Sweet corrosion is usually less aggressive than sour corrosion.
Sweet corrosion is a major concern for companies involved with oil and other fossil fuels because it can cause pitting, which if allowed to continue can ultimately result in material failure. Fortunately, sweet corrosion involves weak acids such as carbonic acid and acetic acid. These weak acids take longer than stronger acids to create substantial material deterioration.
There are many ways to prevent sweet corrosion and its detrimental effects. Perhaps the most popular way is the use of corrosion inhibitors, which are compounds that slow or completely impede the corrosive process caused by some acids. Special coatings can be used to prevent sweet corrosion, as well as alloys specially formulated to stymie sweet corrosion.