Among the most common surface defects derived from casting, die casting and sintering processes are microporosities. These defects are caused by the release of previously absorbed gases during the metal's transition from liquid to solid state, causing the material to shrink.

The presence of microporosities in castings can compromise their tightness, leading to the rejection of large quantities of material.

To solve this problem, one of the most popular methods is vacuum impregnation. In this process, components are immersed in a catalyzed thermosetting resin that seals the microporosities, making them compliant with leak tests and suitable for eventual processing such as coating.