National Physical Laboratory


X-ray image obtained using an absorbent penetrant to identify a crack in a plastic mouldingĀ 
In complex components where it might be difficult to used other techniques radiography maybe employed. Radiography uses localised differences in attenuation under x-ray illumination to provide a cross-sectional picture of the density of a component. Images are typically recorded on film and increasingly digital or real-time recording systems are being used. Radiography is best suited to large volumetric defects and it can sometimes be difficult to detect the small crazes.

Enhanced resolution can be achieved by using an x-ray absorbing penetrant. This involves applying a penetrant to the polymer that will absorb x-rays more readily than the polymer. When the component is illuminated the x-rays are absorbed more by the penetrant in the cracks than it is elsewhere. However, this technique is not particularly popular because of health and safety issues although new low intensity systems are now available, which reduce the environmental hazards.

Last Updated: 25 Mar 2010
Created: 22 Aug 2007


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