Corrosion that occurs under organic films in the form of randomly distributed threadlike filaments or spots. In many cases this is identical to filiform corrosion.

An electrolytic cell, the electromotive force of which is due to a difference in air (oxygen) concentration at one electrode as compared with that at another electrode of the same material; an oxygen concentration cell (a cell resulting from a potential d ...

A compound of iron and carbon, known chemically as iron carbide and having the approximate chemical formula Fe3C. It is characterized by an orthorhombic crystal structure. When it occurs as a phase in steel, the chemical composition will be altered by the ...

Material placed in a drilled hole to fill space around anodes, vent pipe, and buried components of a cathodic protection system.

A coating developed on a metal surface by a high temperature diffusion process (as carburization, calorizing, or chromizing).

A list of elements arranged according to their standard electrode potentials, with "noble" metals such as gold being positive and "active" metals such as zinc being negative.

Embrittlement under creep conditions of, for example, aluminum alloys and steels that results in abnormally low rupture ductility. In aluminum alloys, iron in amounts above the solubility limit is known to cause such embrittlement; in steels, the phenomen ...

Occurs in the base metal adjacent to weldments due to high through-thickness strains introduced by weld metal shrinkage in highly restrained joints. Tearing occurs by decohesion and linking along the working direction of the base metal; cracks usually run ...

The size of a flaw (defect) in a structure that will cause failure at a particular stress level.

The least noble potential where pitting or crevice corrosion, or both, will initiate and propagate.

The maximum stress that a material is capable of sustaining without any permanent strain (deformation) remaining upon complete release of the stress.

A raised area, often dome shaped, resulting from (1) loss of adhesion between a coating or deposit and the base metal or (2) delamination under the pressure of expanding gas trapped in a metal in a near-subsurface zone. Very small blisters may be called p ...

A factor of proportionality representing the amount of substance diffusing across a unit area through a unit concentration gradient in unit time.

(1) Water having salinity values ranging from approximately 0.5 to l7 parts per thousand. (2) Water having less salt than seawater, but undrinkable.

A segregated structure consisting of alternating nearly parallel bands of different composition, typically aligned in the direction of primary hot working.

(1) A reduction of the anodic reaction rate of an electrode involved in corrosion. (2) The process in metal corrosion by which metals become passive. (3) The changing of a chemically active surface of' a metal to a much less reactive state. Contrast with ...

An electrode widely used as a reference electrode of known potential in electrometric measurement of acidity and alkalinity, corrosion studies, voltammetry, and measurement of the potentials of other electrodes. See also electrode potential, reference ele ...

Zinc oxide: the powdery product of corrosion of zinc or zinc-coated surfaces.

Evidence of plastic deformation in structural materials. Also called plastic flow or creep. See also flow.

The condition of being electrically separated from other metallic structures or the environment.