Magnetic and luminescent properties of bifunctional composite Fe3O4@Y2O2S:Eu3+

Abstract

As a kind of non-destructive testing method, magnetic particle inspection is widely used in the fields of aviation and high-speed rail. The properties of magnetic fluorescent bifunctional composites, such as fluorescence intensity and magnetic properties, have increasing demands in magnetic particle inspection. Rare earth compounds offer potential as novel materials for fluorescent magnetic bifunctional composites due to their excellent optical properties and extremely narrow emission spectra. In this work, the rare earth fluorescent material Y₂O₂S:Eu³⁺ was synthesized by solid-state reaction method. Fe₃O₄ nanoparticles prepared by hydrothermal method were uniformly coated on the Y₂O₂S:Eu³⁺ particles through physical adsorption of surfactants. The obtained Fe₃O₄@Y₂O₂S:Eu³⁺ exhibits dark red color under the ultraviolet light. In addition, X-ray diffraction, morphology, photoluminescence and hysteresis loop of Fe₃O₄@Y₂O₂S:Eu³⁺ were investigated. The luminescence mechanism of Y₂O₂S:Eu³⁺ is described in detail. Fe₃O₄@Y₂O₂S:Eu³⁺ displays good paramagnetism and has a good controllability under a magnetic field. The magnetic particle inspection of Fe₃O₄@Y₂O₂S:Eu³⁺ was performed using a 4-pole electromagnet and a test piece shim. The magnetic fluorescent bifunctional composite presented in this work can be applied for non-destructive testing.