Abrasive-Free Polishing of Hard Disk Substrate with H<sub>2</sub>O<sub>2</sub>-K<sub>2</sub>S<sub>2</sub>O<sub>8</sub>-NaHSO<sub>3</sub> Slurry

Abstract

The effect of potassium peroxydisulfate-sodium hydrogensulfite (K2S2O8- NaHSO3) as an initiator system in H2O2 –based slurry for the abrasive-free polishing (AFP) of hard disk substrate was investigated. The polishing experimental results showed that the H2O2-K2S2O8-NaHSO3 slurry had ten times higher material removal rate (MRR) than the H2O2 slurry in AFP of the hard disk. Further, the polishing mechanism of H2O2-K2S2O8-NaHSO3 slurry was investigated. Compared with the H2O2 slurry, electron spin-resonance spectroscopy (EPR) analysis showed that the H2O2-K2S2O8-NaHSO3 slurry provides twenty times higher concentration of hydroxyl free radical. Potentiodynamic polarization measurement showed that the corrosion current of disk substrate in the H2O2-K2S2O8-NaHSO3 slurry is larger than that in the H2O2 slurry. The results imply that K2S2O8-NaHSO3 as an initiator system for H2O2–based slurry has application prospects in abrasive-free polishing.