Development of Composite Iron Oxide Fluorescent Nanoparticles for Nondestructive Magnetic Particle Testing

A method has been developed for modifying the surface of iron oxide nanoparticles with a fluorescent dye based on fluorescein. It is shown that iron oxide nanoparticles chemically bind with a fluorescein derivative by means of preliminary surface modification with silicon dioxide. The composition and structure of the obtained composite nanoparticles have been confirmed by the IR, UV, and NMR spectroscopy, and TEM microscopy data. Composite nanoparticles based on nanoparticles of iron oxides and fluorescein have high sensitivity when visualizing microcracks in metal products by magnetic flaw detection.