Influence of Ferric Chloride–Oxalic Acid Polishing Slurry on the Chemical Mechanical Polishing of 304 Stainless Steel

The effects of mass fractions of ferric chloride (FeCl3) and oxalic acid (H2C2O4) in polishing slurry on the polishing of 304 stainless steel were studied. The stainless steel polishing experiments with different compositions of polishing liquids were designed, the material removal rate was calculated, the surface roughness value was measured, and the Fe2+ content in the polishing waste liquid was determined by spectrophotometry. The mechanism of FeCl3 on stainless steel polishing was investigated. The results indicated the existence of the reaction 2Fe3+ + Fe → 3Fe2+ during the polishing process; Fe3+ in the polishing slurry promoted the reaction and significantly increased the material removal rate; and the composition ratio of the FeCl3-H2C2O4 slurry for polishing 304 stainless steel was optimized. After optimization, the material removal rate achieved more than 200 nm/min, and the surface roughness after polishing was reduced to less than 10 nm. Qualitative analysis of the surface material of the polished 304 stainless steel with FeCl3 polishing slurry by XRD proved that the phase of the matter was basically unchanged. This experiment provides reference value for the preparation of polishing slurry for 304 stainless steel.