Optimizing processing performance of Fe-6.5 wt%Si–SiC magnetic abrasive particles by in-situ formation of FexSiy interlayer

Abstract

The Magnetic Abrasive Finishing (MAF) technology has demonstrated significant potential for precision machining due to its adaptable processing characteristics. However, the current methods for preparing Magnetic Abrasive Particles (MAPs) suffer from issues such as high cost, uneven particle size distribution, and unsatisfactory structure. In this paper, a two-step ball milling method is proposed to address these problems and produce MAPs with a uniform core-shell structure. During the ball milling process, nanoscale iron powder (NIP) is added and forms a coated intermediate bonding layer on the Fe-6.5 Si powder core, increasing the adhesion between the ferromagnetic phase core and the abrasive hard phase. The study found that the addition of 10 wt% NIP as a mass percentage can optimize the MAP structure. During the sintering process at 1169.7 °C, the NIP interface transforms into a metallic interface layer, namely FexSiy (Fe5Si3 and Fe3Si), between the hard phase and the ferromagnetic phase. This intermediate layer combines the hard phase with the ferromagnetic phase, enhancing the magnetic saturation intensity while reducing the coercivity. The developed MAPs were applied to the polishing of Zr alloy tubes and effectively removed localized defects on the outer surface of the tubes. After six polishing cycles, the surface roughness decreased from 0.361 µm to 0.085 µm. This study establishes the correlation between interface behavior and magnetic properties and proposes a new strategy for the preparation of high-performance MAPs.