INSPECTION (MT): Visually observing, or looking at the surface of a part after it has been magnetized and magnetic
particles applied to assure that the part is free of discontinuities.
INTENSIFYING SCREEN (RT): A layer of material that, when placed in contact with a photographic film, improves
the efficiency of the photographic action of ionizing radiation on the film emulsion. The increased rate of absorption of
radiation energy by the emulsion enables reduction of exposure time.
INTENSITY, RADIATION (RT): The amount of energy passing per unit time per unit area at a point in a beam of
radiation, the area being perpendicular to the direction of propagation.
INTERACTION (RT): Any process in which all or part of the energy of incident radiation is transferred to the
electrons or nuclei of the atoms that constitute matter, or in which only the direction of the incident particle is altered.
INTERFACE: The physical boundary between two adjacent surfaces.
INTERGRANULAR CORROSION: Corrosion occurring preferentially at grain boundaries.
INTERLOCK (RT): A device for precluding access to an area of radiation hazard either by preventing entry or by
automatically removing the hazard.
INTERMEDIATE LAYER METHOD (ET): A method of liftoff compensation where the same eddy current indication
is obtained from bare metal and at a predetermined distance from the bare metal using a nonconductive shim
INTERNAL COIL (ET): A coil wound upon a bobbin and having a cross-sectional configuration close to that of the
internal bore or passage of the test object.
INTERNAL CONVERSION (RT): The transfer of nuclear energy directly to a bound electron in the same atom, which
causes the electron to be ejected from the atom. Subsequent filling of the vacancy thus created results in the emission
of characteristic X-rays or auger electrons.
INTERNAL STRESSES: Unseen forces existing within a part. These are forces that exist without the part being
subjected to a working load.
INTERPRETATION (Evaluation): The determination of the cause of an indication or the evaluation of the significance
of discontinuities from the standpoint of whether they are detrimental defects or superficial blemishes.
INTERPRETATION (MT): The determination of what condition in the part has caused the magnetic particle pattern.
INTERSTITIAL SOLID SOLUTION: An alloy in which small atoms of alloying elements including carbon, nitrogen
or hydrogen assume positions between the lattice sites normally occupied by the base metal.
INVERSE SQUARE LAW (RT): At constant kilovoltage or source strength, the intensity of the radiation reaching the
object is governed by the distance between the focal spot or radioactive source and the object, varying inversely with the
square of the distance.
INVERSE VOLTAGE (RT): A voltage that may appear across an X-ray tube or rectifier during one half-cycle of an
alternating current and that reverses the polarity of the electrodes relative to the previous half-cycle.
Casting metal into a mold produced by surrounding (investing) in expendable pattern with a refractory
slurry that sets at room temperature after which the wax, plastic or frozen mercury pattern is removed through the use
of heat. Also called precision casting or lost-wax process.