A method for the detection of porosity in protective coatings and materials was presented. The defects were marked by bubbles rising from the immersed surface under low vacuum. The appearance of bubbles from surface defects was supported by electrical resistance and capacitance changes of the coating. Anodized aluminium, sprayed metal coating, paint film, and plastic molded IC were used for the tests. The variation of resistance, obtained by a moisture meter, showed a good correlation with the effective properties of the coatings.
