That portion of the polarization of a cell produced by concentration changes resulting from passage of' current through the electrolyte.

A reaction in which there is a decrease in valence resulting from a gain in electrons. Contrast with oxidation.

Chromium plated for engineering rather than decorative applicactions.

Forming an adherent phosphate coating on a metal by immersion in a suitable aqueous phosphate solution. Also called phosphatizing. See also conversion coating.

A glass membrane electrode used to measure pH or hydrogen-ion activity.

(1) A molecular structure in which a heterocyclic ring can he formed by the unshared electrons of neighboring atoms. (2) A coordination compound in which a heterocyclic ring is formed by a metal bound to two atoms of the associated ligand. See also comple ...

Any of several processes in which both nitrogen and carbon are absorbed into the surface layers of a ferrous material at temperatures below the lower critical temperature and, by diffusion, create a concenteration gradient. Nitrocarburizing is performed p ...

An electrolytic cell, the electromotive force of which is caused by a difference in concentration of some component in the electrolyte. This difference leads to the formation of discrete cathode and anode regions.

A chemical compound with one or more carboxyl radicals (COOH) in its structure; examples are butyric acid, CH3(CH2)2COOH; maleic acid, HOOCCH-CHCOOH; and benzoic acid, C6H5COOH.

An obsolete historical term usually applied to stress-corrosion crackling of brass.

Depositing filler metal on a surfsae by welding, spraying, or braze welding to increase resistance to abrasion, erosion, wear, galling. impact, or cavitation damage.

The potential of an electrode in an electrolyte as measured against a reference electrode. The electrode potential does not include any resistance losses in potential in either the solution or external circuit. It represents the reversible work to move a ...

The electromotive force generated in a circuit containing two dissimilar metals when one junction is at a temperature different from that of the other. see also thermocouple.

Accelerated corrosion of a metal because of an electrical contact with a more noble metal or nonmetallic conductor in a corrosive electrolyte.

An equation that expresses the exact electromotive force of a cell in terms of the activities of products and reactants of the cell.

A metal having an extremely high melting point, for example, tungsten, molybdenum, tantalum, niobium, chromium, vanadium, and rhenium. In the broad sense, this term refers to metals having melting points above the range for iron, cobalt, and nickel.

The electric current that flows between metals or conductive nonmetal in a galvanic couple.

Water that contains certain salts, such as those of calcium or magnesium, which form insoluble deposits in boilers and form precipitates with soap.

See auxiliary electrode.

Surface discoloration of a metal caused by formation of a thin film of corrosion product.