NONDESTRUCTIVE EVALUATION OF CORRODED NEEDLES BY MIRAGE EFFECT.

Abstract

Thermal wave methods of investigating solid, opaque materials in a nondestructive, noncontact way using the mirage effect, or optical beam deflection (OBD) detection method, have been shown to be sensitive to both surface and subsurface variations in the thermal properties of those materials. The technique of using thermal waves as an NDE method is useful for the detection of localized defects such as voids, cracks, and delaminations or debonding, for the determination of thermal properties such as thermal diffusivity and anisotropy, and for interrogating thin films/coatings, and surface studies. Corrosion is a problem which has only recently been investigated with thermal wave methods.