5. Corrosion Flashcards
Corrosion
The chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties.
Anode
The electrode at which oxidation reactions occur in a corrosive cell, leading to the loss of material.
Cathode
The electrode at which reduction reactions occur in a corrosion cell, where typically no material loss happens.
Electrolyte
A liquid or gel that contains ions and can be decomposed by electrolysis, e.g., saltwater around ships.
Rust
A form of corrosion that occurs with iron-containing materials due to oxidation, typically resulting in red oxides.
Galvanic Corrosion
Corrosion that occurs when two different metals are in electrical contact in a corrosive environment; the more anodic metal corrodes.
Pitting Corrosion
A localized form of corrosion that leads to the creation of small holes or pits in the metal.
Crevice Corrosion
A localized corrosion occurring in confined spaces to which the access of the working fluid from the environment is limited.
Intergranular Corrosion
Corrosion that occurs along the grain boundaries of a metal, often due to impurities or depletion of alloying elements.
Stress Corrosion Cracking (SCC)
The growth of crack formation in a corrosive environment. It can be accelerated by tensile stress in a corrosive environment.
Uniform Corrosion
Also known as general corrosion, it occurs uniformly across the surface of a material.
Erosion Corrosion
Accelerated corrosion caused by the relative movement between a corrosive fluid and a metal surface.
Selective Leaching
Also known as parting, it occurs when one element is removed from a solid alloy through corrosion processes.
Oxidation
The loss of electrons during a reaction by a molecule, atom, or ion.
Reduction
The gain of electrons during a reaction by a molecule, atom, or ion.
Corrosion Inhibitor
A chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material.
Cathodic Protection
A technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell.
Sacrificial Anode
A piece of a more reactive metal attached to the metal to be protected; it corrodes in place of the protected metal.
Passivation
The process of making a material ‘passive,’ usually by the deposition of a surface layer that prevents further corrosion.
Inhibitor
A substance that slows down or prevents a chemical reaction or corrosion.
Corrosion Fatigue
The weakening of a material due to the cyclic stress and corrosive environment.
Microbial Corrosion
Corrosion caused or promoted by microorganisms, often known as microbiologically influenced corrosion (MIC).
Fretting Corrosion
Damage at the asperities of contact surfaces that are exposed to repeated relative motion and high contact pressure.
Atmospheric Corrosion
Corrosion that occurs on metal surfaces exposed to the atmosphere.
