Crystalline cerium oxide and preparation method of the same
The present invention relates to crystalline cerium oxide prepared in a simple, economical, and efficient manner, of which crystal structure, shape, and size can be easily adjusted and that exhibits excellent polishing properties, and a preparation method thereof. The crystalline cerium oxide can be prepared as sub-micron crystalline cerium oxide that has a mean volume diameter and a diameter standard deviation within a predetermined range.
1. Sub-micron crystalline cerium oxide having a mean volume diameter of 70 to 120 nm and a diameter standard deviation of 8 to 12.5 nm after pulverization; wherein cerium oxide before pulverization has a mean volume diameter of 0.5 to 3 um, and includes a plurality of cerium oxide particles, a boundary formed on each cerium oxide particle defines a plurality of crystal grains, and each crystal grain includes one or more cerium oxide crystals.
2. The crystalline cerium oxide according to claim 1 , wherein the mean volume diameter and standard deviation are values measured after pulverization using a vertical mill and a horizontal mill.
3. The crystalline cerium oxide according to claim 1 , wherein before pulverization, the crystal grain has a size of 20 to 300 nm, and the cerium oxide crystal has a size of 10 to 200 nm.
4. A cerium oxide slurry comprising the crystalline cerium oxide of claim 1 as a polishing agent.
5. The cerium oxide slurry according to claim 4 , further comprising a dispersant and a pH adjuster.
6. A method for preparing a crystalline cerium oxide having a mean volume diameter of 70 to 120 nm and a diameter standard deviation of 8 to 12.5 nm, comprising the steps of:
heating lanthanite-(Ce) at 50° C. or higher to produce a cerium carbonate-based compound;
heat-treating the cerium carbonate-based compound to produce cerium oxide; and
pulverizing the cerium oxide.
7. The method according to claim 6 , wherein the reaction of lanthanite-(Ce) is performed in a liquid-phase medium.
8. The method according to claim 7 , wherein the liquid-phase medium includes water, and an aqueous solvent including alcohol, DMF, or DMSO.
9. The method according to claim 7 , wherein the reaction of lanthanite-(Ce) is performed in a liquid-phase medium at a weight ratio of lanthanite-(Ce) to liquid-phase medium of 1:0.5 to 1:20.
10. The method according to claim 6 , wherein the reaction of lanthanite-(Ce) is initiated at atmospheric pressure to 100 bar.
11. The method according to claim 6 , wherein the heat-treatment is performed at 300 to 1500° C.
12. The method according to claim 6 , wherein the pulverization is performed using a vertical mill and a horizontal mill.