## 3 Results and Discussion  
### Dispersion Stability Analysis  
In the polishing solutions with abrasive concentrations of 20 g/dm\({}^{3}\), 60 g/dm\({}^{3}\), and 100 g/dm\({}^{3}\), various concentrations of Na(PO3)6 were added, and the sedimentation conditions after standing for 30 min are depicted in Figure 3. The corresponding photos are presented in Figure A1 in Appendix A, where reagent bottle numbers 1, 2, 3, 4, and 5, respectively, represent Na(PO3)6 concentrations of 0, 0.5 wt%, 1.0 wt%, 1.5 wt%, and 2.0 wt%. It can be observed from Figure A1 that, at the same Na(PO3)6 concentration, the sedimentation degree of the polishing solution increased, and delamination became more pronounced as the abrasive concentration rose. With different Na(PO3)6 concentrations at the same abrasive concentration, the sedimentation degree of the polishing solution varied. As shown in Figure 3, when the Na(PO3)6 concentration was 0.5 wt% and the abrasive concentration was 20 g/dm\({}^{3}\), the abrasive particles hardly sedimented, indicating good dispersion stability in the polishing solution. However, at abrasive concentrations of 60 g/dm\({}^{3}\) and 100 g/dm\({}^{3}\), the abrasive particles showed slight sedimentation, and noticeable sedimentation occurred when the Na(PO3)6 concentration exceeded 1.0 wt%. At the same abrasive concentration, an increase in the Na(PO3)6 concentration initially improved and later decreased the dispersion stability of the polishing solution. Conversely, at the same Na(PO3)6 concentration, an increase in abrasive concentration intensified particle sedimentation, accentuated delamination, and deteriorated the dispersion stability. PEG, as a dispersant, was introduced into the polishing solution with varying abrasive concentrations, and the sedimentation patterns after 30 min are depicted in Figure 4. Actual photographs are presented in Figure A2 in Appendix A, with reagent bottle numbers 1, 2, 3, 4, 5, and 6 corresponding to PEG concentrations of 0, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, and 3.0 wt%, respectively. In comparison to samples with abrasive concentrations of 60 g/dm\({}^{3}\) and 100 g/dm\({}^{3}\), the dispersion stability of the polishing solution was slightly superior at an abrasive concentration of 20 g/dm\({}^{3}\), with the delamination phenomenon becoming more pronounced as the abrasive concentration increased. At an abrasive concentration of 100 g/dm\({}^{3}\), all of the samples approached a complete sedimentation state in approximately 15 min. Through analysis, it can be concluded that, at low abrasive concentrations, the content of abrasive particles in the polishing solution is lower, resulting in a reduced probability of particles coalescing into larger particles compared to high abrasive concentrations. Consequently, the sedimentation rate of particles at a low abrasive concentration is relatively slow. Under the same abrasive concentration, there was almost no significant difference between the samples with different PEG concentrations. Therefore, the static sedimentation experiments were analyzed, leading to the conclusion that changes  
Figure 3: Sedimentation conditions of polishing solution at different abrasive and Na(PO3)6 concentrations. in abrasive concentration influence the sedimentation rate of the polishing solution, but PEG has a limited impact on the dispersion stability of the alumina polishing solution. The results of the static sedimentation experiment for the polishing solution with added phosphoric ester compounds are depicted in Figure 5. Actual photographs are displayed in Figure A3 in Appendix A, with reagent bottle numbers 1, 2, 3, 4, 5, and 6 corresponding to phosphoric ester compounds concentrations of 0, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, and 3.0 wt%, respectively. A shown in Figures 5 and A3, when the phosphoric ester compounds concentration was 0, the sedimentation level of the polishing solution increased with the rise in abrasive concentration.