(1) The formation at high temperatures of thick corrosion product layers on a metal surface. (2) The deposition of water-insoluble constituents on a metal surface.

A metal that readily combines with oxygen at elevated temperatures to form very stable oxides, for example, titanium, zirconium, and beryllium. Reactive metals may also become embrittled by the interstitial absorption of oxygen, hydrogen, and nitrogen.

In tensile testing, the ratio of maximum load to original cross-sectional area. Also called ultimate tensile strength.

Current that flows through the earth from an anodic to a cathodic area of a continuous metallic structure. Usually used only where the areas are separated by considerable distance and where the current results from concentration-cell action.

A compound that causes reduction, thereby itself becoming oxidized.

Pitting resulting from ablation, outgassing or meteor contact.

The slope (dE/di) at the corrosion potential of a potential (E)/current density (i) curve. Also used to describe the method of measuring corrosion rates using this slope.

Deterioration of wood in contact with iron-based alloys.

A potential more cathodic (positive) than the standard hydrogen potential.

The structure of a prepared surface of a metal as revealed by a microscope at a magnification exceeding 25x.

The ratio, expressed as a percentage, of the amount of water vapor present in a given volume of air at a given temperature to the amount required to saturate the air at that temperature.

The accelerated deterioration at the interface between contacting surfaces as the result of corrosion and slight oscillatory movement between the two surfaces; Deterioration at the interface between two contacting surfaces accelerated by relative motion b ...

Spontaneous aging of a supersaturated solid solution at room temperature. See also aging. Compare with artificial aging.

Short, discontinuous internal fissures in wrought metals attributed to stresses produced by localized transformation and decreased solubility of hydrogen during cooling after hot working. In a fracture surface. flakes appear as bright silvery areas; on an ...

A metallurgical term describing the formation of graphite in iron or steel, usually from decomposition of iron carbide at elevated temperatures. Not recommended as a term to describe graphitic corrosion.

A hard, brittle, nonmagnetic intermediate phase with a tetragonal crystal structure, containing 30 atoms per unit cell, space group P42mnm, occurring in many binary and ternary alloys of the transition elements. The composition of this phase in the variou ...

Corrosion due to the action of "local cells," that is, galvanic cells resulting from inhomogeneities between adjacent areas on a metal surface exposed to an electrolyte.

(1) An isothermal reversible reaction in which a solid solution is converted into two or more intimately mixed solids on cooling, the number of solids formed being the same as the number of components in the system. (2) An alloy having the composition ind ...

Catastrophic brittle failure of a normally ductile metal when in contact with a liquid metal and subsequently stressed in tension.

A surface-active agent; usually an organic compound whose moleculei contain a hydrophilic group at one end and a lipophilic group at the other.