What is the primary purpose of Liquid Penetrant Testing (LPT)?

The primary purpose of Liquid Penetrant Testing (LPT) is indeed to detect surface-breaking defects in non-porous materials. This method works by applying a liquid penetrant to the surface of the material, allowing it to seep into any cracks or defects. After a certain dwell time, excess penetrant is removed, and a developer is applied, which draws the penetrant out of the defects, making them visible under ultraviolet or white light. This technique is particularly effective for identifying flaws such as cracks, porosity, and other surface discontinuities that could compromise the integrity of the material.

While identifying hidden internal defects in metals sounds relevant, LPT is not suitable for detecting issues below the surface, as it is specifically designed for surface analysis. In contrast, assessing corrosion resistance and measuring the thickness of coatings are tasks typically associated with different non-destructive testing methods such as electrochemical testing or ultrasonic testing, rather than LPT. Thus, the correct focus on surface-breaking defects aligns directly with the capabilities and intended applications of Liquid Penetrant Testing.