The potential of a corroding surface in an electrolyte, relative to a reference electrode. Also called rest potential, open circuit potential, or freely corroding potential.

A linear imperfection in a crystalline array of atoms. Two basic types are recognized: (1) an edge dislocation corresponds to the row of mismatched atoms along the edge formed by an extra, partial plane of atoms within the body of a crystal; (2) a screw d ...

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

The property of a material by virtue of which deformation caused by stress disappears upon removal of the stress. A perfectly elastic body completely recovers its original shape and dimensions after release of stress.

(1) Permanently damaging a metal or alloy by heating to cause either incipient melting or intergranular oxidation. See also over-heating. (2) In grinding, getting the work hot enough to cause discoloration or to change the microstructure by tempering or h ...

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

The condition of an electrode when the rate of anodic dissolution just balances the rate of cathodic plating.885

A chromate conversion coating produced on magnesium alloys in a boiling solution of sodium dichromate.

A surface treatment at elevated temperature, generally carried out in pack, vapor, or salt bath, in which an alloy is formed by the inward diffusion of chromium into the base metal.

The electrode of an electrolytic cell at which reduction is the principal reaction. (Electrons How toward the cathode in the external circuit.) Typical cathodic processes are cation' taking up electrons and being discharged, oxygen being reduced. and the ...

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

The lowest value of oxidizing potential at which pits nucleate and grow. It is dependent on the test method used.

A metastable aggregate of ferrite and cementite resulting from the transformation of austenite at temperatures below the pearlite range but above M

Deforming metal plastically under conditions of temperature and strain rote that induce strain hardening. Usually, hut not necessarily, conducted at room temperature. Contrast with hot working.

The relative humidity above which the atmospheric corrosion rate of some metals increases sharply.

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

(1) An iron mineral crystallizing in therhombohedral system; the most important oreof iron. (2) An iron oxide, Fe,O,, corrcsponding to an iron content of approximately 70%.

Any interruption in the normal physical structure or configuration of a part, such as cracks, laps, seams, inclusions, or porosity. A discontinuity may or may not affect the usefulness of the part.

Heating a metal or alloy to such a high temperature that its properties are impaired. When the original properties cannot be restored by further heat treating, by mechanical working, or by a combination of working and heat treating, the overheating is kno ...

Corrosion occurring under or around a discontinuous deposit on a metallic surface. Also called poultice corrosion.