Fundamental performance of magnetic compound fluid polishing liquid in contact-free polishing of metal surface

The present work proposed a new contact-free surface finishing method for metal surface with micro-3D structure utilizing magnetic compound fluid (MCF) polishing liquid, a functional liquid composed of nano-sized magnetite particle, micro-sized iron particle, several 10 μm-sized α-cellulose fiber, and sub-micro-sized abrasive particle that reacts to the magnetic field. As a step to completely develop the technique, this article deals with the experimental investigation on the effects of the magnetic field applying, the abrasive particle size, the blend ratios of abrasive particle and the iron powder on the polishing characteristics (i.e., surface roughness and material removal) of stainless steel (SUS304) specimen. The obtained results showed that (1) when the magnetic field is applied only by installing the upper magnet, a better work surface is obtained but the material removal becomes smaller compared with that both the upper and lower magnets are installed; (2) a better surface and a larger material removal are obtained when larger-sized abrasive particles are used for polishing; (3) the respective optimum concentrations of the abrasive particle and the iron powder within the MCF polishing liquid exist in terms of the polishing characteristics; in the current experimental conditions, the optimum values for the concentrations of abrasive and iron powder were 20 and 20–40 wt.%, respectively.