Abrasive grain containing alumina and zirconia
AssigneeMinnesota Mining and Manufacturing Company
InventorHenry A. Larmie
Life of this patent
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Abstract
A method of preparing preferred abrasive grain includes: preparing a dispersion including alpha alumina oxide monohydrate and zirconia sol therein; converting the dispersion to base grit material; and sintering the base grit to form abrasive grains. The presence of the zirconia sol within the dispersion from which the base grits are formed provides an improved abrasive grain. The improved abrasive grain are useful in abrasive products.
Claims25
A method of preparing abrasive grain material;
- said method comprising the steps of:
- (a) preparing a dispersion of alumina hydrate and zirconia particles, wherein at least about 97% by weight of said zirconia particles are less than about 0.2 micrometer in size;
- (b) forming alumina base grits from said dispersion;
- and
- (c) sintering said alumina base grits to provide abrasive grain comprising about 70 to about 99.9 percent by weight alumina and at least about 0.1 percent by weight zirconia, based on the total weight of said abrasive grain, said alumina being present as one of alpha alumina, alumina reaction product, or a combination thereof, said zirconia being present as one of zirconia or zirconia and zirconia reaction product,
- with the proviso that said zirconia particles are present in said dispersion in an amount sufficient to increase densification of said abrasive grain of step (c) as compared to an abrasive grain made according to steps (a), (b), and (c) without the presence of zirconia in said abrasive grain.
A sintered abrasive grain comprising alpha alumina, including alpha alumina domains comprised of alpha alumina crystallites, and about 0.05 to about 1 micrometer particles of zirconia, said particles of zirconia being substantially uniformly distributed throughout said abrasive grain, and a majority of said zirconia particles in said alpha alumina domains being randomly and uniformly distributed between said alpha alumina crystallites.
Dependencies are inferred from the claim text.