Composition Optimization of Slurry for Polishing TA31 Titanium Alloy with Free Abrasive

The composition of polishing slurry plays an important role in the material removal rate (MRR) and surface roughness of titanium alloy. In this study, chemical mechanical polishing (CMP) was used to polish TA31 titanium alloy, the MRR and surface roughness of the titanium alloy were used as evaluation indicators, and the abrasive concentration (A), H2O2 concentration (B), and pH (C) were used as the influencing factors to carry out the orthogonal experiment of titanium alloy free abrasive polishing. In this study, the composition of the polishing slurry was optimized, and the oxidation–reduction potential (ORP) of different polishing slurries was detected. Furthermore, the mechanism of the influence of the composition of different polishing slurries and ORP on the removal of polishing materials was discussed. The results of the study show that the best polishing rate is 43.991 nm/min, and the best surface roughness is 0.045 μm. The order of significant factors affecting the removal rate of titanium alloy is A (abrasive concentration) > B (H2O2 concentration) > C (pH), and the order of significant factors affecting the surface roughness of titanium alloy is C (pH) > A (abrasive concentration) > B (H2O2 concentration). The optimal slurry composition for material removal rate is abrasive concentration of 3%, H2O2 concentration of 5% and pH = 3, and the optimal slurry composition for surface roughness is abrasive concentration of 3%, H2O2 concentration of 5% and pH = 12. The research can lay an experimental foundation for further study on the mechanism of CMP of TA31 titanium alloy.