Black magnetic ink, pre-mixed, high sensitivity. Magnetic Particle Inspection for the detection of surface and near surface defects in ferro-magnetic materials. Ardrox 800/3 is a ready-to-use high sensitivity black magnetic ink consisting of black iron oxide with a controlled, fine particle size, mineral oil and a suspending agent in a high flash, low aromatic petroleum distillate. Ardrox 800/3 is used for revealing surface and near surface defects in ferro-magnetic materials.