Fig. 1. Schematic of scratch formation. (a) Complete scratch; (b) interrupted scratch

Fig. 2. Schematic of residual indentation marked by rigid ball

Fig. 3. Effect of polishing-powder mass fraction in polishing solution on polishing rate and surface roughness

Fig. 4. Measured results of surface roughness polished by polishing solutions with different polishing-powder mass fractions. (a) Mass fraction of 2%; (b) mass fraction of 6%

Fig. 5. Micrographs of different types of scratches. (a) Plastic scratches; (b) composite scratches with brittleness and plasticity; (c) brittle scratches; (d) extra-long scratches

Fig. 6. Actual statistical results of scratches formed by impurity particles with 2-μm and 3-μm intermediate particle sizes and simulated 3-μm results based on scratch lengths generated by 2-μm impurity particles

Fig. 7. Microporous pitch-polishing pad. (a) Physical picture; (b) optical micrograph

Fig. 8. Effects of polishing-powder mass fraction in polishing solution on polishing rate for normal polishing pad and microporous polishing pad