Synthesis of Fe3O4 encapsulated with lemon yellow for application in magnetic particle inspection

Magnetic particle inspection, a widely used nondestructive testing method, is employed to detect surface defects in ferromagnetic materials due to its ease of operation, low cost, and high efficiency. In this study, Fe ₃ O ₄ hollow nanospheres were synthesized by a solvothermal method. Lemon yellow (LY) pigments were successfully encapsulated on the surface of these magnetic nanospheres using E51 epoxy resin. The synthesized Fe ₃ O ₄ /E51/LY composite material was characterized in terms of its microscopic morphology, physical phase, and structural properties. The adsorption mechanism of the fluorescent materials on the particle surface was analyzed. Additionally, the photoluminescence and magnetic properties of the composite were tested and evaluated. A magnetic particle inspection test bench was then established to detect defects in the workpiece. The composite exhibited a saturation magnetization of 53.22 emu/g and emitted yellow-green fluorescence at 525 nm under ultraviolet light. The surface defects of the workpiece were accurately detected using magnetic fluorescent particles.