Abrasive particles and production method thereof

Patent metadata

Field	Value
Publication number	US-9850413-B2
Application number	US-201314406143-A
Country	US
Kind code	B2
Filing date	Jun 10, 2013
Priority date	Jun 13, 2012
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

In order to use less cerium oxide and achieve higher durability and polishing speeds, these abrasive particles used in an abrasive have: a shell layer ( 3 ) which is the outermost shell layer of the abrasive particles and is formed with cerium oxide as the main component; and a middle layer ( 2 ) which contains cerium oxide and an oxide of at least one element selected from Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and the alkali earth metals, and which is formed closer to the center of the abrasive particles than the shell layer ( 3 ).

First claim

The invention claimed is:

1. An abrasive particle to be used as an abrasive material, comprising:
a shell layer being an outermost layer of the abrasive particle and mainly composed of cerium oxide;
an intermediate layer containing cerium oxide and an oxide of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals and formed on an inner side of the shell layer of the abrasive particle; and
a core layer formed on an inner side of the intermediate layer of the abrasive particle and including a center of the abrasive particle,
wherein the shell layer covers the entire intermediate layer, and the core layer is mainly composed of an oxide of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals,
wherein the intermediate layer contains the cerium oxide and the oxide of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals at a variation within a range of ±5 mol %.

2. The abrasive particle according to claim 1 , wherein
the intermediate layer contains a same oxide as that being the main component of the core layer.

3. The abrasive particle according to claim 1 , wherein
the intermediate layer has a concentration gradient of cerium oxide decreasing from a shell layer side toward a core layer side.

4. The abrasive particle according to claim 1 , wherein the abrasive particle is a spherical particle.

5. A method of producing abrasive particles, comprising:
forming a core layer mainly composed of a salt of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals through formation of the salt;
forming an intermediate layer containing a Ce salt and a salt of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals on an outer surface of the core layer by adding an aqueous solution containing at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals and an aqueous solution containing a Ce salt to a first dispersion containing the dispersed particles of the salt of the element formed in the core layer-forming step;
forming a shell layer mainly composed of a Ce salt on an outer surface of the intermediate layer by adding an aqueous solution containing a Ce salt to a second dispersion containing the dispersed particles provided with the intermediate layer of the salts formed in the intermediate layer-forming step;
separating the solid being an abrasive material precursor from a third dispersion prepared in the shell layer-forming step; and
firing the abrasive material precursor prepared in the separation step in the air or in an oxidizing atmosphere,
wherein the intermediate layer-forming step uses the aqueous solution containing a Ce salt and the aqueous solution containing a salt of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals such that the intermediate layer contains the Ce salt and the salt of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals at a variation within a range of ±5 mol %.

6. The method of producing abrasive particles according to claim 5 , wherein
the intermediate layer-forming step performs the addition of the aqueous solution containing a Ce salt such that the intermediate layer has a concentration gradient of the Ce salt decreasing according to a distance from an outer side of an abrasive particle toward a center of the abrasive particle.

7. The method of producing abrasive particles according to claim 5 , wherein
the salts formed in the core layer-forming, the intermediate layer-forming, and the shell layer-forming are basic carbonates.

8. The method of producing abrasive particles according to claim 7 , wherein the core layer-forming forms a core layer mainly composed of a basic carbonate of at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals by adding a urea compound to an aqueous solution containing at least one element selected from the group consisting of Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, In, Sn, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Bi, Th, and alkali earth metals.

Assignees

• Konica Minolta Inc

Inventors

• Takahashi Atsushi
• Ito Natsuki
• Maezawa Akihiro

Classifications

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• C09K3/1463

  Aqueous liquid suspensions · CPC title

• B24B37/00

  Lapping machines or devices; Accessories (B24B3/00 takes precedence) · CPC title

• C09K3/1436 Primary

  Composite particles, e.g. coated particles · CPC title

• C09G1/02

  containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)} · CPC title