Abstract: A method and composition for non-destructive testing of a magnetizable workpiece in which the surface of the workpiece is coated with a composition containing discrete magnetic particles consisting of a ferromagnetic particle core, fluorescent pigment particles attached to said core and a cascading opacifier combined therewith, preferably by means of a film-forming encapsulating resin. The particles of the daylight fluorescent pigment are sufficiently large so that they fluoresce with sufficient intensity to be seen in normal lighting conditions. Consequently, the magnetizable pieces to be inspected can be simultaneously inspected under ultra-violet and white light excitation to reveal both fine cracks and large voids.

Abstract: A method for testing a magnetizable workpiece for flaws by the magnetic particle inspection method wherein a coating of finely divided, hydrophobic particles is electrostatically applied onto the surface of a workpiece to be tested after which an aqueous suspension of magnetizable particles is applied over the resulting coating. The magnetized workpiece is then inspected for deposits of magnetizable particles which have become lodged in the flaws. The hydrophobic nature of the coating repels the water from the suspension, and permits the indications to appear promptly after application of the magnetizable particle suspension.