EP0293164B1
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EP
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Abrasive grits formed of ceramic containing oxides of aluminum and rare earth metal, method of making and products made therewith
Assignee: 3M Co
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Filing: 1988-05-24
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Granted: 1992-10-14
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Expires: 2008-05-24
Abstract
Abstract Ceramic abrasive grits comprising alpha alumina and at least about 0.5 percent by weight rare earth metal oxide are prepared by combining alumina hydrate and rare earth metal oxide or its precursors to produce a blend, drying the blend to produce a dried solid, crushing the dried solid to produce grits, calcining the dried grits to substantially remove bound volatile materials, and firing the grits to produce a ceramic material. The rare earth metal is selected from the group consisting of praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium, and mixtures of one or more rare earth metal.
Inventors
- 👤 William P. C/O Minnesota Mining And Wood
- 👤 Larry D. C/O Minnesota Mining And Monroe
- 👤 Stanley L. c/o Minnesota M.and M. Co. Conwell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 06:33
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/1115; C09; C09K; C09K3/00; C09K3/14; C09K3/1409; C09K3/1418
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
67 words
Ceramic abrasive grits comprising alpha alumina and at least one additional phase, one of said additional phases characterized by being a reaction product of aluminum oxide and at least about 0.5% by weight of the oxide of a rare earth metal selected from the group consisting of praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium and mixtures of two or more of such rare earth metals.
Claim 2
Dependent Claim
19 words
The ceramic abrasive grits of claim 1 further characterized by including about 0.25% to about 30% by weight yttria.
Claim 3
Dependent Claim
28 words
The ceramic abrasive grits of claim 1 further characterized by said aluminum oxide and rare earth metal oxide reaction product being in the form of a garnet phase.
Claim 4
Dependent Claim
28 words
The ceramic abrasive grits of claim 1 further characterized by said aluminum oxide and rare earth metal oxide reaction product being in the form of a perovskite phase.
Claim 5
Dependent Claim
25 words
The ceramic abrasive grits of claim 1 further characterized by the rare earth metal oxide content being from about 1 to about 30% by weight.
Claim 6
Dependent Claim
16 words
An abrasive product characterized by including said ceramic abrasive grits of any one of claims 1-5.
Claim 7
Dependent Claim
17 words
The abrasive product of claim 6 further characterized by said abrasive product being a coated abrasive product.
Claim 8
Dependent Claim
17 words
The abrasive product of claim 6 further characterized by said abrasive product being a bonded abrasive product.
Claim 9
Dependent Claim
18 words
The abrasive product of claim 6 further characterized by said abrasive product being a lofty non-woven abrasive product.
Claim 10
Independent Claim
159 words
A method of making ceramic abrasive grits, said method comprising the steps of: a. combining alumina hydrate with an additive material which forms a blend which when fired forms a ceramic comprised of alpha alumina and at least one other phase resulting from the additive material; b. drying the blend to produce a dried solid; c. crushing the dried solid to produce particles; d. calcining the dried particles to substantially remove bound volatile materials; and e. firing the particles to produce a ceramic material, characterized by the additive material being the oxide of a rare earth metal selected from the group consisting of praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium and mixtures of two or more of such rare earth metals or the precursor of said oxide in a liquid vehicle to produce a blend in an amount to provide at least about 0.5% by weight rare earth metal oxide after firing the solids of said blend;
Claim 11
Dependent Claim
27 words
The method of claim 10 further characterized by said precursor compound of said rare earth metal oxide being a rare earth metal salt of a volatile anion.
Claim 12
Dependent Claim
55 words
The method of claim 10 further characterized by said combining being by way of a sol gel method comprising first preparing a mixture of an aqueous dispersion of alumina hydrate and an oxide of said rare earth metal or a precursor thereof and then gelling said mixture to produce said blend of the gelled material.
Claim 13
Dependent Claim
88 words
The method of claim 10 modified in that the said method comprises the steps of preparing a sol of alumina hydrate, drying the sol to form a porous dried solid comprised of dried sol, crushing the porous dried solid to form particles, calcining the particles to convert the alumina hydrate to an insoluble form of alumina, preparing a homogeneous mixture of said rare earth metal oxide or its precursor in a liquid vehicle in which the calcined alumina is substantially insoluble, and impregnating said mixture into said particles.
Claim 14
Dependent Claim
20 words
The method of claim 13 further characterized by said impregnation being accomplished by impregnating said particles more than one time.
Claim 15
Dependent Claim
28 words
The method of claim 14 further characterized by the concentration of rare earth metal oxide or its precursors in the impregnation solution being the same in each impregnation.
Claim 16
Dependent Claim
18 words
The method of claim 14 further characterized by the concentration of impregnation solution being different for each impregnation.
Claim 17
Dependent Claim
20 words
The method of claim 14 further characterized by the composition of the impregnating solution being the same for each impregnation.
Claim 18
Dependent Claim
19 words
The method of claim 14 further characterized by the composition of the impregnating solution being different for each impregnation.
Claim 19
Dependent Claim
23 words
The method of claim 14 further characterized by including the step of adding a precursor of a modifying additive to the aqueous dispersion.
Claim 20
Dependent Claim
27 words
The ceramic abrasive grits of claim 1 further characterized by at least a portion of said reaction product being in the form of hexagonal rare earth aluminate.
Claim 21
Dependent Claim
26 words
The abrasive product of claim 6 further characterized by at least a portion of said reaction product being in the form of hexagonal rare earth aluminate.
References Cited (Backward Citations)
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