Issue << content << Differential-Interference Contrast Method in Material Science Applications


DOI: 10.12737/article_5aaf9b1d1a8fe5.34130469

2018. Vol.21. No. 1, pp. 66-69

Differential-Interference Contrast Method in Material Science Applications

A. G. Anisovich

The differential-interference contrast method (DIC) is essentially a high-sensitive method ensuring optical staining to visualize surface defects with dimensions in the nanometer range. The purpose of this article is to acquaint readers with the differential-interference contrast method using reflected light. The method is based on the polarized light interference effect. The basic element in the image formation in the DIC method is the Nomarsky’s birefringent v-block splitting light beam into two plane-polarized beams — a normal beam and an abnormal beam. When interacting, these beams cause the sample portions with different heights acquire different colors accompanied by a greater contrast. The image obtained can be interpreted as a 3D surface relief pattern. The examples demonstrate the DIC applications capabilities. In metallography: visualization of weld joints, cracks and porosity, alloy phases. In non-destructive testing: in-process measurement of microcircuit elements, quality testing of hardsurfacing overlays and decorative coatings, as well as surfaces hardened by high-level exposures.
Keywords: differential-interference contrast, Nomarsky’s v-block, microscopy, visualization
 
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