Page 24 - Liquid Penetration Inspection

Diploma in Mechanical Engineering (Material)

LIQUID PENETRATION INSPECTION

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Penetrant Materials

1. Surface energy

2. Specific gravity
Surface energy is also known as surface wetting
3. Viscosity
capability where the penetrant is to freely wet the

4. Colour and fluorescence brightness
surface of the object being inspected.
5. Removability

How does it occur?

At the liquid-solid surface interface, if the molecules

of the liquid have a stronger attraction to the

molecules of the solid surface than to each other (the

adhesive forces are stronger than the cohesive

forces), wetting of the surface occurs.

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