What is meant by crevice corrosion?
Crevice corrosion refers to the attack of metal surfaces by a stagnant solution in crevices, for example around the edges of nuts and rivet heads. When dust, sand and other corrosive substances are deposited on surfaces, they create an environment where water will accumulate and corrode the part.
How can you tell if a crevice is corroded?
The critical crevice temperature is the minimum temperature (°C) to produce crevice attack and CCT is usually lower than the critical pitting temperature (CPT). Computer software such as CRA-Compass can be used to assess the crevice corrosion resistance of an alloy for a given temperature and chloride concentration.
What causes crevice corrosion?
Crevice corrosion is caused on contact of metals with metals or metals with nonmetals, for example, gaskets, couplings, and joints. It may occur also at washers, under barnacles, at sand grains, under applied protective films, and at pockets formed by threaded joints.
How is a crevice formed?
Abstract. Crevice corrosion is a form of localized corrosion on hard-to-reach metal surfaces, such as interstices in which a solution is trapped and not renewed. Unlike some alloys, including stainless steel, aluminium is not very sensitive to crevice corrosion.
What is the difference between pitting and crevice corrosion?
Whereas pitting corrosion occurs across the surface of a component, crevice corrosion is associated with a crevice, be that one that forms around a fastener, washer or joint, in a sharp corner or in an area where the flow of a liquid is slowed i.e. a dead spot.
How do you treat crevice corrosion?
Addition of inhibiting substances to bulk solution is also a protection method. Application of passivating compounds such as chromate and nitrate is well practiced to prevent crevice corrosion. Overlaying susceptible areas with an alloy which is more resistant to crevice corrosion is another protective measure.
How can crevice corrosion be prevented?
Use butt weld joints instead of bolted or threaded joints for new equipment. Use continuous welding or soldering to eliminate crevices in lap joints. Ensure complete vessel drainage where possible and design any non-draining areas to allow sufficient solution flow to prevent stagnation.
Is stainless steel susceptible to crevice corrosion?
Many metals and alloys are susceptible to crevice corrosion, but in stainless steel, crevices are the first and most common place for corrosive attack to begin.
How do you control crevice corrosion?
What are the effects of crevice corrosion?
This anodic imbalance can lead to the creation of highly corrosive micro-environmental conditions in the crevice, conducive to further metal dissolution. This results in the formation of an acidic micro-environment, together with a high chloride ion concentration.
What is a crevice in a rock?
Word forms: crevices A crevice is a narrow crack or gap, especially in a rock.
What is the most effective means of corrosion?
The most widely used and effective methods for corrosion prevention and mitigation are Materials Selection and Design, Protective Coatings, Measurement and Inspection, Cathodic Protection, Chemical Inhibitors, and Corrosion Management. The Importance of Corrosion Management
What are the methods to prevent corrosion?
Reviewing Corrosion. We have learned that three things are required for the anodic and cathodic steps of corrosion to occur: an electrolyte,an exposed metal surface,and an electron acceptor.
What are the disadvantages of corrosion?
Weakens material due to prolonged corrosive action.
What is corrosion and how to prevent it?
chemistry and carefully chosen barrier packaging materials to prevent the corrosion of firearms, firearm parts, and ammunition during storage for 5 years or more depending on use. Arms