Fluorescent cobalt ferrite nanoparticles for non-destructive magnetic particle testing

Magnetic particle testing is one of the popular methods to detect very small surface or near-surface defects in engineering parts. Successful defect detection depends on the physical properties of the particles. This work aims to synthesize cobalt ferrite-fluorescent polymer particles to detect finer defects located in deeper places. For this purpose, cobalt ferrite (CoFe₂O₄) nanoparticles were synthesized and the next step, fluorescence pigment was incorporated into CoFe₂O₄ nanoparticles. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibration magnetometer (VSM), and Fourier transform infrared spectroscope (FTIR) were used to examine the effects of various parameters. CoFe₂O₄ nanoparticles with a size of about 55 nm and suitable magnetic properties were chosen. The presence of pigment reduced the saturation magnetization to 25.17 emu/g, although this value is still within the suitable range. Finally, the stability of the pigment on CoFe₂O₄ nanoparticles in water was investigated, and synthesized nanocomposite was successfully used to reveal defects.