Polarization of the cathode; change of the electrode potential in the active (negative) direction due to current flow; a reduction from the initial potential resulting from current flow effects at or near the cathode surface. Potential becomes more active ...

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 selective leaching or corrosion of a specific constituent (Al, Ni, Mo, Ni) from an alloy.

A strongly alkaline solution into which metal is immersed for etching. for neutralizing acid, or for removing organic materials such as greases or paints.

The maximum stress (tensile. compressive, or shear) a material can sustain without fracture, determined by dividing maximum load by the original cross-sectional area of the specimen. Also called nominal strength or maximum strength.

The potential difference at the junction of two dissimilar substances.

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

Change of electrode potential with respect to a reference value. Often the free corrosion potential is used as the reference value. The change may be caused, for example, by the application of an external electrical current or by the addition of an oxidan ...

An electrode in an electrolytic cell that is not mechanically connected to the power supply, but is so placed in the electrolyte, between the anode and cathode, that the part nearer the anode becomes cathodic and the part nearer the cathode becomes anodic ...

The formation and instantaneous collapse of innumerable tiny voids or cavities within a liquid subjected to rapid and intense pressure changes. Cavitation produced by ultrasonic radiation is sometimes used to effect violent localized agitation. Cavitation ...

The fracture toughness determined under dynamic loading conditions; it is used as an approximation of KIc for very tough materials.

The minimum value of Kc for any given material and condition, which is attained when rapid crack propagation in the opening mode is governed by plane-strain conditions.

A chemical substance or mixture that prevents or reduces the rate of the cathodic or reduction reaction by physical, physico-chemical or chemical action.

A fractographic pattern of radial marks (shear ledges) that look like nested letters "V"; sometimes called a herringbone pattern. Chevron patterns are typically found on brittle fracture surfaces in parts whose widths are considerably greater than their t ...

Whitening and loss of gloss of a usually organic coating caused by moisture. Also called blooming.

Corrosion resulting from an electrochemical cell caused by a thermal gradient.

(1) Injection of air or water under high pressure through a tube to the anode area for the purpose of purging the annular space and possibly correcting high resistance caused by gas blocking. (2) In connection with boilers or cooling towers, the process o ...

An obsolete historical term denoting a form of stress-corrosion cracking most frequently encountered in carbon steels or iron-chromium-nickel alloys that are exposed to concentrated hydroxide solutions at temperatures of 200 to 250

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