Synthesis nano core-shell material Fe₃O₄@SiO₂ for magnetorheological finishing with Halbach array and regenerative abrasive system

Abstract

Fe3O4@SiO2 nanomaterials hold significant promise for diverse applications across various fields. This study aims to elucidate the feasibility and effectiveness of Fe3O4@SiO2 in surface finishing processes. Utilizing the co-precipitation method, SiO2 shells were successfully coated onto Fe3O4 nanoparticles. The abrasive properties of Fe3O4@SiO2 were analyzed for their efficiency in surface finishing. Leveraging the magnetic field generated by a Halbach array, combined with an abrasive particle replacement system, we propose a robust and highly effective polishing process using Fe3O4@SiO2 abrasives. This study details the formation of a magnetorheological fluid (MRF) polishing tool incorporating Fe3O4@SiO2 abrasive particles. Practical experiments were conducted on Sapphire workpieces to validate the proposed polishing process. The experimental setup was designed to assess the surface finishing capabilities and material removal behaviour. Results demonstrated that the Sapphire surface achieved nanometer-scale smoothness with a roughness average (Ra) of 1.145 nm, free of surface damage, after just 100 min of processing. The underlying mechanisms of material removal were also investigated and discussed. The findings suggest that MRF polishing using Fe3O4@SiO2 abrasive particles is a promising and efficient method for surface finishing across various materials.