US5188908A — Al2 O3 Based ceramics

Claim 1

Independent Claim 227 words

An Al 2 O 3 -based ceramic consisting essentially of: 5% to 50% by weight of a hard dispersed phase composed of at least one compound which is selected from the group consisting of metal carbide, metal nitride, metal carbonitride, metal oxy-carbide, metal oxynitride and metal carbo-oxynitride, and is represented by M(CNO), wherein M is at least one metal selected from the group consisting of Ti, Zr and Hf; no greater than 25% by weight of ZrO 2 ; and balance Al 2 O 3 matrix containing an additive dissolved in the Al 2 O 3 grains so as to form a solid solution therewith, said additive being contained in an amount of 0.01% to 12% by weight with respect to the Al 2 O 3 matrix and being composed of at least one oxide of an element selected from the group consisting of Y, Mg, Cr, Ni, Co and rare earth elements; said Al 2 O 3 grains having an average grain size of no larger than 1.0 μm while said hard phase constituent has an average grain size of no larger than 0.6 μm, wherein said hard phase constituent is present at the grain boundary of and within the Al 2 O 3 grains and the resulting Al 2 O 3 -based ceramic having a three-point bending strength of at least 112 kg/mm 2 .

Claim 2

Dependent Claim 227 words

An Al 2 O 3 -based ceramic consisting essentially of: 5% to 50% by weight of a hard dispersed phase composed of at least one compound which is selected from the group consisting of metal carbide, metal nitride, metal carbonitride, metal oxy-carbide, metal oxynitride and metal carbo-oxynitride, and is represented by M(CNO), wherein M is at least one metal selected from the group consisting of Ti, Zr and Hf; no greater than 25% by weight of ZrO 2 ; and balance Al 2 O 3 matrix containing an additive dissolved in the Al 2 O 3 grains so as to form a solid solution therewith, said additive being contained in an amount of 0.01% to 12% by weight with respect to the Al 2 O 3 matrix and being composed of at least one oxide of an element selected from the group consisting of Y, Mg, Cr, Ni, Co and rare earth elements; said Al 2 O 3 grains having an average grain size of no larger than 1.0 μm while said hard phase constituent has an average grain size of no larger than 0.6 μm, wherein said hard phase constituent is present at the grain boundary of and within the Al 2 O 3 grains and the resulting Al 2 O 3 -based ceramic having a three-point bending strength of at least 112 kg/mm 2 .

Claim 3

Dependent Claim 37 words

An Al 2 O 3 based ceramic according to claim 1, wherein said compound M(CNO) of said hard dispersed phase is the one represented by M(C x N y O z ), wherein 0.95≦x+y+z≦1, 5/95≦x/y≦70/30 and 0≦z≦0.1.

Claim 4

Dependent Claim 29 words

An Al 2 O 3 based ceramic according to claim 2, wherein residual compressive stress exerted on said Al 2 O 3 matrix is no less than 20 MPa.

Claim 5

Dependent Claim 47 words

An Al 2 O 3 based ceramic according to claim 2, wherein said hard phase constituent is composed of at least one compound selected from the group consisting of titanium carbide, titanium nitride and titanium carbo-nitride, and is represented by Ti(C x N y ), wherein 5/95≦x/y≦70/30.

Claim 6

Dependent Claim 60 words

An Al 2 O 3 based ceramic according to claim 2, further comprising a hard coating vapor-deposited thereon, said hard coating having a thickness of 0.3 to 30 μm and being comprised of one or more layers of at least one composition selected from the group consisting of carbide, nitride, carbo-nitride, oxy-carbide of titanium, and Al 2 O 3 .

Claim 7

Dependent Claim 60 words

An Al 2 O 3 based ceramic according to claim 4, further comprising a hard coating vapor-deposited thereon, said hard coating having a thickness of 0.3 to 30 μm and being comprised of one or more layers of at least one composition selected from the group consisting of carbide, nitride, carbo-nitride, oxy-carbide of titanium, and Al 2 O 3 .

Claim 8

Dependent Claim 31 words

An Al 2 O 3 based ceramic according to claim 1, wherein said additive is dissolved in said Al 2 O 3 grains so as to form a solid solution herewith.

Claim 9

Dependent Claim 226 words

An Al 2 O 3 -based ceramic consisting of: 5% to 50% by weight of a hard dispersed phase composed of at least one compound which is selected from the group consisting of metal carbide, metal nitride, metal carbonitride, metal oxy-carbide, metal oxynitride and metal carbo-oxynitride, and is represented by M(CNO), wherein M is at least one metal selected from the group consisting of Ti, Zr and Hf; no greater than 25% by weight of ZrO 2 ; and balance Al 2 O 3 matrix containing an additive dissolved in the Al 2 O 3 grains so as to form a solid solution therewith, said additive being contained in an amount of 0.01% to 12% by weight with respect to the Al 2 O 3 matrix and being composed of at least one oxide of an element selected from the group consisting of Y, Mg, Cr, Ni, Co and rare earth elements; said Al 2 O 3 grains having an average grain size of no larger than 1.0 μm while said hard phase constituent has an average grain size of no larger than 0.6 μm, wherein said hard phase constituent is present at the grain boundary of and within the Al 2 O 3 grains and the resulting Al 2 O 3 -based ceramic having a three-point bending strength of at least 112 kg/mm 2 .

Claim 10

Dependent Claim 226 words

An Al 2 O 3 -based ceramic consisting of: 5% to 50% by weight of a hard dispersed phase composed of at least one compound which is selected from the group consisting of metal carbide, metal nitride, metal carbonitride, metal oxy-carbide, metal oxynitride and metal carbo-oxynitride, and is represented by M(CNO), wherein M is at least one metal selected from the group consisting of Ti, Zr and Hf; no greater than 25% by weight of ZrO 2 ; and balance Al 2 O 3 matrix containing an additive dissolved in the Al 2 O 3 grains so as to form a solid solution therewith, said additive being contained in an amount of 0.01% to 12% by weight with respect to the Al 2 O 3 matrix and being composed of at least one oxide of an element selected from the group consisting of Y, Mg, Cr, Ni, Co and rare earth elements; said Al 2 O 3 grains having an average grain size of no larger than 1.0 μm while said hard phase constituent has an average grain size of no larger than 0.6 μm, wherein said hard phase constituent is present at the grain boundary of and within the Al 2 O 3 grains and the resulting Al 2 O 3 -based ceramic having a three-point bending strength of at least 112 kg/mm 2 .

Claim 11

Dependent Claim 24 words

An aluminum based ceramic as defined in claim 1, wherein the ZrO 2 is present in an amount of 1 to 25% by weight.

Claim 12

Dependent Claim 225 words

An Al 2 O 3 -based ceramic consisting of: 5% to 50% by weight of a hard dispersed phase composed of at least one compound which is selected from the group consisting of metal carbide, metal nitride, metal carbonitride, metal oxycarbide, metal oxynitride and metal carbo-oxynitride, and is represented by M(CNO), wherein M is at least one metal selected from the group consisting of Ti, Zr and Hf; 1 to 25% by weight of ZrO 2 ; and balance Al 2 O 3 matrix containing an additive dissolved in the Al 2 O 3 grains so as to form a solid solution therewith, said additive being contained in an amount of 0.01% to 12% by weight with respect to the Al 2 O 3 matrix and being composed of at least one oxide of an element selected from the group consisting of Y, Mg, Cr, Ni, Co and rare earth elements; said Al 2 O 3 grains having an average grain size of no larger than 1.0 μm while said hard phase constituent has an average grain size of no larger than 0.6 μm, wherein said hard phase constituent is present at the grain boundary of and within the Al 2 O 3 grains and the resulting Al 2 O 3 -based ceramic having a three-point bending strength of at least 112 kg/mm 2 .

Claim 13

Dependent Claim 225 words

An Al 2 O 3 -based ceramic consisting of: 5% to 50% by weight of a hard dispersed phase composed of at least one compound which is selected from the group consisting of metal carbide, metal nitride, metal carbonitride, metal oxycarbide, metal oxynitride and metal carbo-oxynitride, and is represented by M(CNO), wherein M is at least one metal selected from the group consisting of Ti, Zr and Hf; 1 to 25% by weight of ZrO 2 ; and balance Al 2 O 3 matrix containing an additive dissolved in the Al 2 O 3 grains so as to form a solid solution therewith, said additive being contained in an amount of 0.01% to 12% by weight with respect to the Al 2 O 3 matrix and being composed of at least one oxide of an element selected from the group consisting of Y, Mg, Cr, Ni, Co and rare earth elements; said Al 2 O 3 grains having an average grain size of no larger than 1.0 μm while said hard phase constituent has an average grain size of no larger than 0.6 μm, wherein said hard phase constituent is present at the grain boundary of and within the Al 2 O 3 grains and the resulting Al 2 O 3 -based ceramic having a three-point bending strength of at least 112 kg/mm 2 .

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-02-23	1996-08-24	1997-02-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-02-23	2000-08-24	2001-02-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-02-23	2004-08-24	2005-02-23	$7700.00	Window Closed / Lapsed

Al2 O3 Based ceramics

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