Polishing method and polishing composition
Provided is a method for polishing a material having a Vickers hardness of 1500 Hv or higher. The polishing method comprises a step of carrying out preliminary polishing using a preliminary polishing composition that comprises an abrasive A PRE and a step of carrying out final polishing using a final polishing composition that comprises an abrasive A FIN lower in hardness than the abrasive A PRE .
1. A method for polishing a material comprising the steps of:
providing a material having a Vickers hardness of 1500 Hv or higher;
preliminarily polishing the material using a preliminary polishing composition comprising an abrasive A PRE and a water-soluble polishing aid B PRE ; and
final polishing the material using a final polishing composition that comprises an abrasive A FIN lower in hardness than the abrasive A PRE ;
wherein the polishing aid B PRE comprises a composite metal oxide CMO PRE , the composite metal oxide CMO PRE having a monovalent or divalent metal (but not a transition metal, and a transition metal in the fourth period of the periodic table.
2. The polishing method according to claim 1 wherein the abrasive A PRE has a Vickers hardness in a range of 800 Hv to 3000 Hv, and the abrasive A FIN has a Vickers hardness in a range of 200 Hv to 1500 Hv.
3. The polishing method according to claim 1 wherein the mean secondary particle diameter P PRE of the abrasive A PRE is greater than the mean secondary particle diameter P FIN of the abrasive A FIN .
4. The polishing method according to claim 1 wherein the final polishing composition comprises a water-soluble polishing aid B FIN .
5. The polishing method according to claim 4 wherein the polishing aid B FIN comprises a composite metal oxide CMO FIN , the composite metal oxide CMO FIN having a monovalent or divalent metal (but not a transition metal) or ammonia, and a transition metal in group 5 or 6 of the periodic table.
6. The polishing method according to claim 5 wherein the polishing aid B FIN further comprises an oxygen-containing substance capable of supplying oxygen to the composite metal oxide CMO FIN .
7. A method for polishing a material comprising the steps of:
providing a material having a Vickers hardness of 1500 Hv or higher;
preliminarily polishing the material using a preliminary polishing composition, and
final polishing the material using a final polishing composition, wherein
the preliminary polishing composition has an oxidation-reduction potential ORP PRE vs. standard hydrogen electrode, and the final polishing composition has an oxidation-reduction potential ORP FIN vs. standard hydrogen electrode, satisfying a relation ORP PRE >ORP FIN ; and
the oxidation-reduction potential ORP PRE of the preliminary polishing composition is in a range of 700 mV to 1500 mV, and the oxidation-reduction potential ORP FIN of the final polishing composition is in a range of 300 mV to 650 mV.
8. The polishing method according to claim 7 having a ratio ORP PRE :ORP FIN of the oxidation-reduction potential ORP PRE of the preliminary polishing composition to the oxidation-reduction potential ORP FIN of the final polishing composition, satisfying 1.2≤ORP PRE :ORP FIN ≤4.0.