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Galvanic corrosion of an aluminium plate occurred when the plate was connected to a mild steel structural support.. Galvanic corrosion occurs when two different metals have physical or electrical contact with each other and are immersed in a common electrolyte, or when the same metal is exposed to electrolyte with different concentrations.
In other cases, such as mixed metals in piping (for example, copper, cast iron and other cast metals), galvanic corrosion will contribute to accelerated corrosion of parts of the system. Corrosion inhibitors such as sodium nitrite or sodium molybdate can be injected into these systems to reduce the galvanic potential. However, the application ...
The chemical compositions of the solid and liquid metals affect the severity of embrittlement. The addition of third elements to the liquid metal may increase or decrease the embrittlement and alter the temperature region over which embrittlement is seen. Metal combinations which form intermetallic compounds do not cause LME.
Liquid metal embrittlement (LME) is the embrittlement caused by liquid metals. Metal-induced embrittlement (MIE) is the embrittlement caused by diffusion of atoms of metal, either solid or liquid, into the material. For example, cadmium coating on high-strength steel, which was originally done to prevent corrosion.
Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture.Rust consists of hydrous iron(III) oxides (Fe 2 O 3 ·nH 2 O) and iron(III) oxide-hydroxide (FeO(OH), Fe(OH) 3), and is typically associated with the corrosion of refined iron.
Erosion corrosion is a form of corrosion damage usually on a metal surface caused by turbulence of a liquid or solid containing liquid and the metal surface. [67] Aluminum can be particularly susceptible due to the fact that the aluminum oxide layer which affords corrosion protection to the underlying metal is eroded away. [68] [69]
High-temperature corrosion is a mechanism of corrosion that takes place when gas turbines, diesel engines, furnaces or other machinery come in contact with hot gas containing certain contaminants. Fuel sometimes contains vanadium compounds or sulfates, which can form low melting point compounds during combustion.
In metallurgy, selective leaching, also called dealloying, demetalification, parting and selective corrosion, is a corrosion type in some solid solution alloys, when in suitable conditions a component of the alloys is preferentially leached from the initially homogenous material.