Abrasive grits formed of ceramic containing oxides of aluminum and rare earth metal, method of making and products made therewith
AssigneeMinnesota Mining and Manufacturing Company
InventorsLarry D. Monroe, William P. Wood
Life of this patent
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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.
Claims46
Alumina-based ceramic abrasive grits having a ceramic composition selected from the group consisting of
- (a) a first composition consisting of (1) up to 30% by weight yttria, (2) 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, and (3) alpha alumina making up the balance of 100% by weight;
- and
- (b) a second composition comprising (1) up to 30% by weight of yttria, (2) 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, ytterbium, neodymium, lanthanum, gadolinium, dysprosium, erbium and mixtures of two or more of such rare earth metals, and (3) alpha alumina making up the balance of 100% by weight.
A coated abrasive sheet material comprising a backing having bonded to at least one side thereof abrasive grits in coarse and fine size grades with at least a portion of the coarse grits being alumina-based ceramic abrasive grits having a ceramic composition selected from the group consisting of
- (a) a first composition consisting of (1) up to 30% by weight yttria, (2) 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 meals, and (3) alpha alumina making up the balance of 100%;
- and
- (b) a second composition comprising (1) up to 30% by weight of yttria, (2) 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, ytterbium, neodymium, lanthanum, gadolinium, dysprosium, erbium and mixtures of two or more of such rare earth metals, and (3) alpha alumina making up the balance of 100% by weight.
A method of making ceramic abrasive grits, said method comprising the steps of:
- (1) selecting a mixture from the group consisting of (1) a mixture consisting of alumina hydrate, 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 and optionally yttria or the precursor of said oxide or yttria if used in a liquid vehicle to produce a blend in an amount to provide up to 30% by weight yttria, at least about 0.5% by weight rare earth metal oxide, and alpha alumina making up the balance of 100% by weight after firing the solids of said blend, and (2) a mixture comprising alumina hydrate, the oxide of a rare earth metal selected from the group consisting of praseodymium, ytterbium, neodymium, lanthanum, gadolinium, dysprosium, erbium and mixtures of two or more of such rare earth metals, and optionally yttria or the precursor of said oxide or yttria if used on a liquid vehicle to produce a blend in an amount to provide up to 30% by weight yttria, at least about 0.5% by weight rare earth metal oxide and alpha alumina making the balance of 100% by weight, after firing the solids of said blend;
- (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.
Dependencies are inferred from the claim text.