Shaped abrasive particles, methods of making, and abrasive articles including the same

Patent metadata

Field	Value
Publication number	US-11530345-B2
Application number	US-202016878851-A
Country	US
Kind code	B2
Filing date	May 20, 2020
Priority date	Oct 31, 2012
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

A method of making abrasive particles includes: providing a slurry comprising non-colloidal solid particles and a liquid vehicle; forming at least a portion of the slurry into shaped bodies contacting a substrate; at least partially drying the shaped bodies to provide shaped abrasive precursor particles; separating at least a portion of the shaped abrasive precursor particles from the substrate; and converting at least a portion of the shaped abrasive precursor particles into shaped abrasive particles. The shaped abrasive particles comprise alpha alumina having an average crystal grain size of 0.8 to 8 microns and an apparent density that is at least 92 percent of the true density. Each shaped abrasive particle has a respective surface comprising a plurality of smooth sides that form at least four vertexes. Shaped abrasive particles, abrasive articles including them, and methods of using are also disclosed.

First claim

What is claimed is:

1. A method of making shaped abrasive particles, the method comprising:
providing a slurry comprising non-colloidal solid particles and a liquid vehicle, wherein at least some of the non-colloidal solid particles comprise aluminum oxide powder, and wherein the non-colloidal solid particles comprise at least 30 percent by volume of the slurry;
forming at least a portion of the slurry into shaped bodies contacting a substrate, wherein the shaped bodies are formed substantially according to a predetermined shape;
at least partially drying the shaped bodies to provide shaped abrasive precursor particles;
separating at least a portion of the shaped abrasive precursor particles from the substrate; and
converting at least a portion of the shaped abrasive precursor particles into shaped abrasive particles, wherein the shaped abrasive particles comprise alpha alumina having an average crystal grain size of 1.1to 2.1 microns and an apparent density that is at least 92 percent of the true density, and wherein the shaped abrasive particles contain 0.0008 to 0.001 percent of sodium oxide based on the total weight of the shaped abrasive particles.

2. The method of claim 1 , wherein the substrate has cavities on a surface thereof, and wherein said forming the slurry into shaped abrasive precursor particles contacting the substrate comprises urging the slurry into at least a portion of the cavities.

3. The method of claim 1 , wherein said shaping the slurry comprises urging the slurry through a screen onto the substrate.

4. The method of claim 1 , wherein said converting at least a portion of the shaped abrasive precursor particles into the shaped abrasive particles comprises:
sintering the shaped abrasive precursor particles to provide the shaped abrasive particles.

5. The method of claim 1 , wherein said converting at least a portion of the shaped abrasive precursor particles into the shaped abrasive particles comprises:
calcining the shaped abrasive precursor particles to provide calcined shaped abrasive precursor particles; and
sintering the calcined shaped abrasive precursor particles to provide the shaped abrasive particles.

6. The method of claim 1 , wherein said converting at least a portion of the shaped abrasive precursor particles into the shaped abrasive particles comprises:
impregnating the shaped abrasive precursor particles with a metal salt solution to provide impregnated shaped abrasive precursor particles; and
sintering the impregnated shaped abrasive precursor particles to provide the shaped abrasive particles.

7. The method of claim 1 , wherein said converting at least a portion of the shaped abrasive precursor particles into the shaped abrasive particles comprises:
calcining the shaped abrasive precursor particles to provide calcined shaped abrasive precursor particles;
impregnating the calcined shaped abrasive precursor particles with a metal salt solution to provide impregnated calcined shaped abrasive precursor particles; and
sintering the impregnated calcined shaped abrasive precursor particles to provide the shaped abrasive particles.

8. The method of claim 1 , wherein the non-colloidal alpha alumina precursor particles comprise aluminum oxide powder.

9. The method of claim 1 , wherein the non-colloidal alpha alumina precursor particles comprise milled aluminum trihydrate particles.

10. The method of claim 1 , wherein the non-colloidal alpha alumina precursor particles have an average particle diameter of at least 0.2 microns.

11. The method of claim 1 , wherein the slurry further comprises a thickener.

12. The method of claim 11 , wherein the thickener comprises colloidal boehmite.

13. The method of claim 1 , wherein the non-colloidal alpha alumina precursor particles comprise at least 40 percent by volume of the slurry.

14. Shaped abrasive particles made according to the method of claim 1 .

15. Shaped abrasive particles comprising alpha alumina, wherein the alpha alumina has an average crystal grain size of 1.1to 2.1 microns, wherein the alpha alumina has an apparent density that is at least 92 percent of the true density, wherein the shaped abrasive particles conform to a nominal predetermined shape, and wherein the shaped abrasive particles contain 0.0008 to 0.001 percent of sodium oxide based on the total weight of the shaped abrasive particles.

16. An abrasive article comprising shaped abrasive particles retained in a binder, wherein the shaped abrasive particles comprising alpha alumina, wherein the alpha alumina has an average crystal grain size of from 1.1to 2.1 microns, wherein the alpha alumina has an apparent density that is at least 92 percent of the true density, wherein the shaped abrasive particles conform to a nominal predetermined shape, and wherein the shaped abrasive particles contain 0.0008 to 0.001 percent of sodium oxide based on the total weight of the shaped abrasive particles.

17. The abrasive article of claim 16 , wherein the nominal predetermined shape is a truncated trigonal pyramid.

18. A method of abrading a workpiece, the method comprising contacting the abrasive article of claim 16 with the workpiece, and moving at least one of abrasive article or the workpiece relative to the other to abrade at least a portion of the workpiece.

Assignees

• 3M Innovative Properties Company

Inventors

• Rosenflanz Anatoly Z
• Adefris Negus B

Classifications

• C04B2235/72

  Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics · CPC title

• B24D11/00

  Constructional features of flexible abrasive materials; Special features in the manufacture of such materials · CPC title

• C04B2235/5445

  submicron sized, i.e. from 0,1 to 1 micron · CPC title

• C04B2235/3201

  Alkali metal oxides or oxide-forming salts thereof · CPC title

• C09K3/1409 Primary

  Abrasive particles per se (preparation of diamond C01B32/25) · CPC title