US5143522A — Abrasive products containing fused alumina zircon…

Claim 1

Independent Claim 87 words

An abrasive grit comprising from about 20 to about 50% by weight of zirconia of which more than 25% by weight of the zirconia present is in tetragonal crystal form; from 1.5 to about 10%, expressed as titanium dioxide, of reduced titania; from 0.03 to about 0.5% total carbon; impurities, if any, in an amount on analysis expressed as the oxides of not more than 3% by weight, including less than 1% SiO 2 ; and a balance of alumina, said abrasive grain being a fused grit.

Claim 2

Dependent Claim 87 words

An abrasive grit comprising from about 20 to about 50% by weight of zirconia of which more than 25% by weight of the zirconia present is in tetragonal crystal form; from 1.5 to about 10%, expressed as titanium dioxide, of reduced titania; from 0.03 to about 0.5% total carbon; impurities, if any, in an amount on analysis expressed as the oxides of not more than 3% by weight, including less than 1% SiO 2 ; and a balance of alumina, said abrasive grain being a fused grit.

Claim 3

Dependent Claim 81 words

An abrasive grit comprising from about 27 to about 35% by weight of zirconia of which more than 25% by weight of the zirconia present is in the tetragonal crystal form; from 1.5 to about 10%, expressed as titanium dioxide, of reduced titania; from 0.03 to about 0.5% total carbon; impurities, if any, in an amount on analysis expressed as the oxides of not more than 3% by weight, including less than 1% SiO 2 ; and a balance of alumina.

Claim 4

Dependent Claim 81 words

An abrasive grit comprising from about 27 to about 35% by weight of zirconia of which more than 25% by weight of the zirconia present is in the tetragonal crystal form; from 1.5 to about 10%, expressed as titanium dioxide, of reduced titania; from 0.03 to about 0.5% total carbon; impurities, if any, in an amount on analysis expressed as the oxides of not more than 3% by weight, including less than 1% SiO 2 ; and a balance of alumina.

Claim 5

Dependent Claim 21 words

An abrasive grit according to claim 2, containing from about 2.4 to about 5%, expressed as titanium dioxide, of reduced titania.

Claim 6

Dependent Claim 54 words

An abrasive grit comprising about 31% zirconia, about 4.5%, expressed as titanium dioxide, of reduced titania; from 0.03 to about 0.5% total carbon; impurities, if any, in an amount on analysis expressed as the oxides of not more than 3% by weight, including less than 0.5% SiO 2 ; and a balance of alumina.

Claim 7

Dependent Claim 54 words

An abrasive grit comprising about 31% zirconia, about 4.5%, expressed as titanium dioxide, of reduced titania; from 0.03 to about 0.5% total carbon; impurities, if any, in an amount on analysis expressed as the oxides of not more than 3% by weight, including less than 0.5% SiO 2 ; and a balance of alumina.

Claim 8

Dependent Claim 16 words

An abrasive grit according to claim 2, containing from about 0.08 to about 0.25% total carbon.

Claim 9

Dependent Claim 16 words

An abrasive grit according to claim 3, containing from about 0.08 to about 0.25% total carbon.

Claim 10

Dependent Claim 21 words

An abrasive grit according to any one of claims 1 to 3, comprising less than 0.5% by weight SiO 2 .

Claim 11

Dependent Claim 146 words

A fused abrasive grit material comprising from about 20 to about 50%, by weight of said abrasive grit material, of zirconia, of which at least 25% by weight of said zirconia is in the tetragonal crystal form; from 0.9 to 6.0%, by weight of said abrasive grit material, of titanium, at least some of which is dissolved in said abrasive grit material, said dissolved titanium existing in a form having compounded therewith less oxygen than titania, with the balance of said titanium, undissolved, existing in at least one compound form having less oxygen than titania; from about 0.03 to about 0.5%, by weight said abrasive grit material, of total carbon; and impurities of not more than about 3.0% by weight of said abrasive grit material; the balance of said abrasive grit material being essentially alumina; wherein said abrasive grit material comprises an alumina-zirconia eutectic microstructural phase.

Claim 12

Dependent Claim 146 words

A fused abrasive grit material comprising from about 20 to about 50%, by weight of said abrasive grit material, of zirconia, of which at least 25% by weight of said zirconia is in the tetragonal crystal form; from 0.9 to 6.0%, by weight of said abrasive grit material, of titanium, at least some of which is dissolved in said abrasive grit material, said dissolved titanium existing in a form having compounded therewith less oxygen than titania, with the balance of said titanium, undissolved, existing in at least one compound form having less oxygen than titania; from about 0.03 to about 0.5%, by weight said abrasive grit material, of total carbon; and impurities of not more than about 3.0% by weight of said abrasive grit material; the balance of said abrasive grit material being essentially alumina; wherein said abrasive grit material comprises an alumina-zirconia eutectic microstructural phase.

Claim 13

Dependent Claim 29 words

The invention of claim 8 wherein said alumina-zirconia eutectic microstructural phase is a matrix having embedded therein primary alumina crystals with said matrix containing essentially no primary zirconia crystals.

Claim 14

Dependent Claim 29 words

The invention of claim 8 wherein said alumina-zirconia eutectic microstructural phase is a matrix having embedded therein primary zirconia crystals with said matrix containing essentially no primary alumina crystals.

Claim 15

Dependent Claim 21 words

The invention of claim 9 wherein at least a portion of said dissolved titanium is dissolved in said primary alumina crystals.

Claim 16

Dependent Claim 18 words

The invention of claim 10 wherein said dissolved titanium is essentially dissolved in said alumina-zirconia eutectic microstructural phase.

Claim 17

Dependent Claim 21 words

The invention of claim 9 wherein said primary alumina crystals vary in size from about 5 microns to about 50 microns.

Claim 18

Dependent Claim 21 words

The invention of claim 10 wherein said primary zirconia crystals vary in size from about 5 microns to about 50 microns.

Claim 19

Dependent Claim 28 words

The invention of claim 13 wherein said primary alumina crystals exhibit a dendritic type of oriented structure separated at least in part by said alumina-zirconia eutectic microstructural phase.

Claim 20

Dependent Claim 28 words

The invention of claim 14 wherein said primary zirconia crystals exhibit a dendritic type of oriented structure separated at least in part by said alumina-zirconia eutectic microstructural phase.

Claim 21

Dependent Claim 36 words

The invention of claim 15 wherein the portions of said alumina-zirconia eutectic microstructural phase, which separates said dendritic type of oriented structure of said alumina crystals, comprises rods of zirconia having a high degree of orientation.

Claim 22

Dependent Claim 36 words

The invention of claim 16 wherein the portions of said alumina-zirconia eutectic microstructural phase, which separates said dendritic type of oriented structure of said zirconia crystals, comprises rods of zirconia having a high degree of orientation.

Claim 23

Dependent Claim 23 words

The invention of claim 8 wherein said material contains from about 27% to about 35%, by weight of said material, of said zirconia.

Claim 24

Dependent Claim 23 words

The invention of claim 9 wherein said material contains from about 27% to about 35%, by weight of said material, of said zirconia.

Claim 25

Dependent Claim 23 words

The invention of claim 8 wherein said material contains from about 1.44% to about 3.0%, by weight of said material, of said titanium.

Claim 26

Dependent Claim 23 words

The invention of claim 9 wherein said material contains from about 1.44% to about 3.0%, by weight of said material, of said titanium.

Claim 27

Dependent Claim 23 words

The invention of claim 10 wherein said material contains from about 1.44% to about 3.0%, by weight of said material, of said titanium.

Claim 28

Dependent Claim 24 words

The invention of claim 8 wherein said material contains from about 0.08% to about 0.25%, by weight of said material, of said total carbon.

Claim 29

Dependent Claim 24 words

The invention of claim 9 wherein said material contains from about 0.08% to about 0.25%, by weight of said material, of said total carbon.

Claim 30

Dependent Claim 24 words

The invention of claim 10 wherein said material contains from about 0.08% to about 0.25%, by weight of said material, of said total carbon.

Claim 31

Dependent Claim 29 words

The invention of claim 8 wherein said alumina-zirconia eutectic microstructural phase comprises zirconia rots having a diameter in the range of greater than 0.2 microns to about 0.4 microns.

Claim 32

Dependent Claim 29 words

The invention of claim 8 wherein said alumina-zirconia eutectic microstructural phase comprises zirconia platelets having a thickness in the range of greater than 0.2 microns to about 0.4 microns.

Claim 33

Dependent Claim 20 words

The invention of claim 8 wherein said abrasive grit material is in a size range of 120 grit or larger.

Claim 34

Dependent Claim 56 words

The invention of claim 8 wherein said impurities contain not more than 0.1%, by weight of said abrasive grit material, of soda, not more than 1.0%, by weight of said abrasive grit material, of silica and not more than 1.5%, by weight of said abrasive grit material, of a combination of magnesia, lime and iron oxide.

Claim 35

Dependent Claim 142 words

A process of producing an abrasive grit material according to claim 8, comprising the steps of: a) combining 1) from about 40 to about 78.5 parts by weight of alumina, with 2) from about 20 to about 50 parts by weight of zirconia; b) melting said combined alumina and zirconia; c) after melting said combined alumina and zirconia, adding, to said melted alumina and zirconia, 3) from 1.5 to about 10 parts by weight of titania; and 4) from about 0.6 to about 5 parts by weight of carbon; d) after adding said titania and said carbon, heating the combined ingredients under reducing furnace conditions until said titania is melted and reduced by said carbon; and then e) casting the melted composition onto a heat sink material in such a manner that solidification of the melt is effected in under three minutes.

Claim 36

Dependent Claim 18 words

A process according to claim 31, wherein the composition combined contains from about 27 to about 35% zirconia.

Claim 37

Dependent Claim 18 words

A process according to claim 31, where the composition cast contains from about 2.4 to about 5% titania.

Claim 38

Dependent Claim 16 words

A process according to claim 33, wherein solidification of the melt is effected under one minute.

Claim 39

Dependent Claim 16 words

A process according to claim 33, wherein solidification of the melt is effected under twenty seconds.

Claim 40

Dependent Claim 15 words

A coated abrasive product comprising an abrasive grain as claimed in one of claims 8-12.

Claim 41

Dependent Claim 15 words

A bonded abrasive product comprising an abrasive grain as claimed in one of claims 8-12.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-09-01	1996-03-02	1996-09-01	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-09-01	2000-03-02	2000-09-01	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-09-01	2004-03-02	2004-09-01	$7700.00	Window Closed / Lapsed

Abrasive products containing fused alumina zirconia and reduced titania

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