High thermal conductivity ceramic body

Claim 2

A process for producing a sintered polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C. which comprises the steps: (a) forming a mixture comprised of oxygen-containing aluminum nitride powder, yttrium oxide, and free carbon, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges from point F5 up to point F4 of FIG. 4, said yttrium ranging from about 2.1 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 97.9 equivalent % to less than about 99.75 equivalent %, said compact having an equivalent % composition of, Y, Al, O and N outside the composition defined and encompassed by polygon A4F5F6F4 of FIG. 4, (b) heating said compact in a nitrogen-containing nonoxidizing atmosphere at a temperature ranging from about 1350° C. to a temperature sufficient to deoxidize the compact but below its pore closing temperature reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, said free carbon being in an amount which produces said deoxidized compact, and (c) sintering said deoxidized compact in a nitrogen-containing nonoxidizing atmosphere at a temperature of at least about 1830° C. producing said polycrystalline body.

Claim 3

The process according to claim 1 wherein said nitrogen-containing atmosphere in step (b) contains sufficient nitrogen to facilitate deoxidation of the aluminum nitride to produce said sintered body.

Claim 4

The process according to claim 1 wherein said nitrogen-containing atmosphere in step (c) contains sufficient nitrogen to prevent significant weight loss of said aluminum nitride.

Claim 5

The process according to claim 1 wherein said process is carried out at about ambient pressure.

Claim 6

The process according to claim 1 wherein said aluminum nitride in step (a) has a specific surface area ranging up to about 10 m 2 /g and said free carbon has a specific surface area greater than about 10 m 2 /g.

Claim 7

The process according to claim 1 wherein said process is carried out at about ambient pressure in an atmosphere comprised of nitrogen and from about 0.5% by volume to about 5% by volume of hydrogen.

Claim 8

A process for producing a sintered polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C. which comprises the steps: (a) forming a mixture comprised of an oxygen-containing aluminum nitride powder, yttrium oxide, and free carbon, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges from point F up to point F4 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 98.4 equivalent % to less than about 99.75 equivalent %, said compact having an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4FF2F4 of FIG. 4, (b) heating said compact in a nitrogen-containing nonoxidizing atmosphere at a temperature ranging from about 1350° C. to a temperature sufficient to deoxidize the compact but below its pore closing temperature reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said free carbon being in an amount which produces said deoxidized compact, and (c) sintering said deoxidized compact in a nitrogen-containing nonoxidizing atmosphere at a temperature of at least about 1830° C. producing said polycrystalline body.

Claim 9

A process for producing a sintered polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C. which comprises the steps: (a) forming a mixture comprised of an oxygen-containing aluminum nitride powder, yttrium oxide, and free carbon, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges from point F up to point F4 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 98.4 equivalent % to less than about 99.75 equivalent %, said compact having an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4FF2F4 of FIG. 4, (b) heating said compact in a nitrogen-containing nonoxidizing atmosphere at a temperature ranging from about 1350° C. to a temperature sufficient to deoxidize the compact but below its pore closing temperature reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said free carbon being in an amount which produces said deoxidized compact, and (c) sintering said deoxidized compact in a nitrogen-containing nonoxidizing atmosphere at a temperature of at least about 1830° C. producing said polycrystalline body.

Claim 10

The process according to claim 7 wherein said nitrogen-containing atmosphere in step (b) contains sufficient nitrogen to facilitate deoxidation of the aluminum nitride to produce said sintered body.

Claim 11

The process according to claim 7 wherein said nitrogen-containing atmosphere in step (c) contains sufficient nitrogen to prevent significant weight loss of said aluminum nitride.

Claim 12

The process according to claim 7 wherein said process is carried out at about ambient pressure.

Claim 13

The process according to claim 7 wherein said aluminum nitride in step (a) has a specific surface area ranging up to about 10 m 2 /g and said free carbon has a specific surface area greater than about 10 m 2 /g.

Claim 14

The process according to claim 7 wherein said process is carried out at about ambient pressure in an atmosphere comprised of nitrogen and from about 0.5% by volume to about 5% by volume of hydrogen.

Claim 15

The process according to claim 7 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F up to point F3 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to greater than about 0.5 equivalent %, said aluminum ranging from about 98.4 equivalent % to less than about 99.5 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon F1FF2F3 of FIG. 4, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined and encompassed by polygon F1FF2F3 but excluding line F2F3 of FIG. 4.

Claim 16

The process according to claim 7 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F1 to line F7F3 excluding point F3 of FIG. 4, said yttrium ranging from about 1.25 equivalent % to about 0.5 equivalent %, said aluminum ranging from about 98.75 equivalent % to about 99.5 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon F7F1F3 of FIG. 4, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined and encompassed by polygon F7F1F3 but excluding point F3 and line F1F3 of FIG. 4.

Claim 17

The process according to claim 7 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from line F7F3 excluding point F3 up to point F4 of FIG. 4, said yttrium ranging from about 0.5 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 99.5 equivalent % to less than about 99.75 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4F7F3F4 of FIG. 4, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined and encompassed by polygon A4F7F3F4 but excluding line F3F4 of FIG. 4.

Claim 18

The process according to claim 7 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F to point F5 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to about 2.1 equivalent %, said aluminum ranging from about 98.4 equivalent % to about 97.9 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line FF5, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined by line FF5 of FIG. 4.

Claim 19

The process according to claim 7 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F1 to point F of FIG. 4, said yttrium ranging from about 1.25 equivalent % to about 1.6 equivalent %, said aluminum ranging from about 98.75 equivalent % to about 98.4 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line F1F, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined by line F1F of FIG. 4.

Claim 20

The process according to claim 7 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F7 to point F1 of FIG. 4, said yttrium ranging from about 0.5 equivalent % to about 1.25 equivalent %, said aluminum ranging from about 99.5 equivalent % to about 98.75 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line F7F1, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined by line F7F1 of FIG. 4.

Claim 21

The process according to claim 7 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point A4 to point F7 of FIG. 4, said yttrium ranging from about 0.3 equivalent % to about 0.5 equivalent %, said aluminum ranging from about 99.7 equivalent % to about 99.5 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line A4F7 and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined by line A4F7 of FIG. 4.

Claim 22

A process for producing a sintered polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C. which comprises the steps: (a) forming a mixture comprised of an oxygen-containing aluminum nitride powder, yttrium oxide or precursor therefor, and a carbonaceous additive selected from the group consisting of free carbon, a carbonaceous organic material and mixtures thereof, said carbonaceous organic material thermally decomposing at a temperature ranging from about 50° C. to about 1000° C. to free carbon and gaseous product of decomposition which vaporizes away, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges from point F5 up to point F4 of FIG. 4, said yttrium ranging from about 2.1 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 97.9 equivalent % to less than about 99.75 equivalent % aluminum, said compact having an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4F5F6F4 of FIG. 4, (b) heating said compact in a nonoxidizing atmosphere at a temperature up to about 1200° C. thereby providing yttrium oxide and free carbon, (c) heating said compact in a nitrogen-containing nonoxidizing atmosphere at a temperature ranging from about 1350° C. to a temperature sufficient to deoxidize the compact but below its pore closing temperature reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, said free carbon being in an amount which produces said deoxidized compact, and (d) sintering said deoxidized compact in a nitrogen-containing nonoxidizing atmosphere at a temperature of at least about 1830° C. producing said polycrystalline body.

Claim 23

A process for producing a sintered polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C. which comprises the steps: (a) forming a mixture comprised of an oxygen-containing aluminum nitride powder, yttrium oxide or precursor therefor, and a carbonaceous additive selected from the group consisting of free carbon, a carbonaceous organic material and mixtures thereof, said carbonaceous organic material thermally decomposing at a temperature ranging from about 50° C. to about 1000° C. to free carbon and gaseous product of decomposition which vaporizes away, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges from point F5 up to point F4 of FIG. 4, said yttrium ranging from about 2.1 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 97.9 equivalent % to less than about 99.75 equivalent % aluminum, said compact having an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4F5F6F4 of FIG. 4, (b) heating said compact in a nonoxidizing atmosphere at a temperature up to about 1200° C. thereby providing yttrium oxide and free carbon, (c) heating said compact in a nitrogen-containing nonoxidizing atmosphere at a temperature ranging from about 1350° C. to a temperature sufficient to deoxidize the compact but below its pore closing temperature reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, said free carbon being in an amount which produces said deoxidized compact, and (d) sintering said deoxidized compact in a nitrogen-containing nonoxidizing atmosphere at a temperature of at least about 1830° C. producing said polycrystalline body.

Claim 24

The process according to claim 20 wherein said nitrogen-containing atmosphere in step (c) contains sufficient nitrogen to facilitate deoxidation of the aluminum nitride to produce said sintered body.

Claim 25

The process according to claim 20 wherein said nitrogen-containing atmosphere in step (d) contains sufficient nitrogen to prevent significant weight loss of said aluminum nitride.

Claim 26

The process according to claim 20 wherein said process is carried out at about ambient pressure.

Claim 27

The process according to claim 20 wherein said aluminum nitride in step (a) has a specific surface area ranging up to about 10 m 2 /g and said free carbon has a specific surface area greater than about 10 m 2 /g.

Claim 28

The process according to claim 20 wherein said process is carried out at about ambient pressure in an atmosphere comprised of nitrogen and from about 0.5% by volume to about 5% by volume of hydrogen.

Claim 29

A process for producing a sintered polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C. which comprises the steps: (a) forming a mixture comprised of an oxygen-containing aluminum nitride powder, yttrium oxide or precursor therefor, and a carbonaceous additive selected from the group consisting of free carbon, a carbonaceous organic material and mixtures thereof, said carbonaceous organic material thermally decomposing at a temperature ranging from about 50° C. to about 1000° C. to free carbon and gaseous product of decomposition which vaporizes away, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges from point F up to point F4 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 98.4 equivalent % to less than about 99.75 equivalent % aluminum, said compact having an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4FF2F4 of FIG. 4, (b) heating said compact in a nonoxidizing atmosphere at a temperature up to about 1200° C. thereby providing yttrium oxide and free carbon, (c) heating said compact in a nitrogen-containing nonoxidizing atmosphere at a temperature ranging from about 1350° C. to a temperature sufficient to deoxidize the compact but below its pore closing temperature reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said free carbon being in an amount which produces said deoxidized compact, and (d) sintering said deoxidized compact in a nitrogen-containing nonoxidizing atmosphere at a temperature of at least about 1830° C. producing said polycrystalline body.

Claim 30

A process for producing a sintered polycrystalline aluminum nitride ceramic body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C. which comprises the steps: (a) forming a mixture comprised of an oxygen-containing aluminum nitride powder, yttrium oxide or precursor therefor, and a carbonaceous additive selected from the group consisting of free carbon, a carbonaceous organic material and mixtures thereof, said carbonaceous organic material thermally decomposing at a temperature ranging from about 50° C. to about 1000° C. to free carbon and gaseous product of decomposition which vaporizes away, shaping said mixture into a compact, said mixture and said compact having a composition wherein the equivalent % of yttrium and aluminum ranges from point F up to point F4 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 98.4 equivalent % to less than about 99.75 equivalent % aluminum, said compact having an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4FF2F4 of FIG. 4, (b) heating said compact in a nonoxidizing atmosphere at a temperature up to about 1200° C. thereby providing yttrium oxide and free carbon, (c) heating said compact in a nitrogen-containing nonoxidizing atmosphere at a temperature ranging from about 1350° C. to a temperature sufficient to deoxidize the compact but below its pore closing temperature reacting said free carbon with oxygen contained in said aluminum nitride producing a deoxidized compact, said deoxidized compact having a composition wherein the equivalent % of Al, Y, O and N is defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said free carbon being in an amount which produces said deoxidized compact, and (d) sintering said deoxidized compact in a nitrogen-containing nonoxidizing atmosphere at a temperature of at least about 1830° C. producing said polycrystalline body.

Claim 31

The process according to claim 26 wherein said nitrogen-containing atmosphere in step (c) contains sufficient nitrogen to facilitate deoxidation of the aluminum nitride to produce said sintered body.

Claim 32

The process according to claim 26 wherein said nitrogen-containing atmosphere in step (d) contains sufficient nitrogen to prevent significant weight loss of said aluminum nitride.

Claim 33

The process according to claim 26 wherein said process is carried out at ambient pressure.

Claim 34

The process according to claim 26 wherein said aluminum nitride in step (a) has a specific surface area ranging up to about 10 m 2 /g and said free carbon has a specific surface area greater than about 10 m 2 /g.

Claim 35

The process according to claim 26 wherein said process is carried out at about ambient pressure in an atmosphere comprised of nitrogen and from about 0.5% by volume to about 5% by volume of hydrogen.

Claim 36

The process according to claim 26 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F up to point F3 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to greater than about 0.5 equivalent %, said aluminum ranging from about 98.4 equivalent % to less than about 99.5 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon F1FF2F3 of FIG. 4, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined and encompassed by polygon F1FF2F3 but excluding line F2F3 of FIG. 4.

Claim 37

The process according to claim 26 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F1 to line F7F3 excluding point F3 of FIG. 4, said yttrium ranging from about 1.25 equivalent % to about 0.5 equivalent %, said aluminum ranging from about 98.75 equivalent % to about 99.5 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon F7F1F3 of FIG. 4, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined and encompassed by polygon F7F1F3 but excluding point F3 and line F1F3 of FIG. 4.

Claim 38

The process according to claim 26 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from line F7F3 excluding point F3 up to point F4 of FIG. 4, said yttrium ranging from about 0.5 equivalent % to greater than about 0.25 equivalent %, said aluminum ranging from about 99.5 equivalent % to less than about 99.75 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined and encompassed by polygon A4F7F3F4 of FIG. 4, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined and encompassed by polygon A4F7F3F4 but excluding line F3F4 of FIG. 4.

Claim 39

The process according to claim 26 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F to point F5 of FIG. 4, said yttrium ranging from about 1.6 equivalent % to about 2.1 equivalent %, said aluminum ranging from about 98.4 equivalent % to about 97.9 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line FF5, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined by line FF5 of FIG. 4.

Claim 40

The process according to claim 26 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F1 to point F of FIG. 4, said yttrium ranging from about 1.25 equivalent % to about 1.6 equivalent %, said aluminum ranging from about 98.75 equivalent % to about 98.4 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line F1F, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined by line F1F of FIG. 4.

Claim 41

The process according to claim 26 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point F7 to point F1 of FIG. 4, said yttrium ranging from about 0.5 equivalent % to about 1.25 equivalent %, said aluminum ranging from about 99.5 equivalent % to about 98.75 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line F7F1, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O and N is defined by line F7F1 of FIG. 4.

Claim 42

The process according to claim 26 wherein said mixture and said compact have a composition wherein the equivalent % of yttrium and aluminum ranges from point A4 to point F7 of FIG. 4, said yttrium ranging from about 0.3 equivalent % to about 0.5 equivalent %, said aluminum ranging from about 99.7 equivalent % to about 99.5 equivalent %, wherein said compact before said deoxidation has an equivalent % composition of Y, Al, O and N outside the composition defined by line A4F7, and wherein said sintered body and said deoxidized compact are comprised of a composition wherein the equivalent percent of Al, Y, O, and N is defined by line A4F7 of FIG. 4.

Claim 43

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, said body being comprised of from about 2.1 equivalent % yttrium to greater than about 0.25 equivalent % yttrium, from about 97.9 equivalent % aluminum to less than about 99.75 equivalent % aluminum, from about 4.95 equivalent % oxygen to about 1.4 equivalent % oxygen and from about 95.05 equivalent % nitrogen to about 98.6 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 44

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4F5F6F4 but excluding line F6F4 of FIG. 4, said body being comprised of from about 2.1 equivalent % yttrium to greater than about 0.25 equivalent % yttrium, from about 97.9 equivalent % aluminum to less than about 99.75 equivalent % aluminum, from about 4.95 equivalent % oxygen to about 1.4 equivalent % oxygen and from about 95.05 equivalent % nitrogen to about 98.6 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 45

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said body being comprised of from greater than about 0.25 equivalent % yttrium to about 1.6 equivalent % yttrium, from less about 99.75 equivalent aluminum to about 98.4 equivalent % aluminum, from about 1 4 equivalent % oxygen to about 4.0 equivalent % oxygen and from about 98.6 equivalent % nitrogen to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 46

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said body being comprised of from greater than about 0.25 equivalent % yttrium to about 1.6 equivalent % yttrium, from less about 99.75 equivalent aluminum to about 98.4 equivalent % aluminum, from about 1 4 equivalent % oxygen to about 4.0 equivalent % oxygen and from about 98.6 equivalent % nitrogen to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 47

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said body being comprised of from greater than about 0.25 equivalent % yttrium to about 1.6 equivalent % yttrium, from less than about 99.75 equivalent aluminum to about 98.4 equivalent % aluminum, from about 1.4 equivalent % oxygen to about 4.0 equivalent % oxygen and from about 98.6 equivalent % nitrogen to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 2% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 48

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4FF2F4 but excluding line F2F4 of FIG. 4, said body being comprised of from greater than about 0.25 equivalent % yttrium to about 1.6 equivalent % yttrium, from less than about 99.75 equivalent aluminum to about 98.4 equivalent % aluminum, from about 1.4 equivalent % oxygen to about 4.0 equivalent % oxygen and from about 98.6 equivalent % nitrogen to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 2% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 49

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon F1FF2F3 but excluding line F2F3 of FIG. 4, said body being comprised of from greater than about 0.5 equivalent % yttrium to about 1.6 equivalent % yttrium, from less than about 99.5 equivalent % aluminum to about 98.4 equivalent % aluminum, from greater than about 2.5 equivalent % oxygen to about 4.0 equivalent % oxygen and from less than about 9.75 equivalent % nitrogen to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 6.00 W/cm.K at 25° C.

Claim 50

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon F1FF2F3 but excluding line F2F3 of FIG. 4, said body being comprised of from greater than about 0.5 equivalent % yttrium to about 1.6 equivalent % yttrium, from less than about 99.5 equivalent % aluminum to about 98.4 equivalent % aluminum, from greater than about 2.5 equivalent % oxygen to about 4.0 equivalent % oxygen and from less than about 9.75 equivalent % nitrogen to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 6.00 W/cm.K at 25° C.

Claim 51

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon F7F1F3 but excluding point F3 and line F1F3 of FIG. 4, said body being comprised of from about 0.5 equivalent % yttrium to about 1.25 equivalent % yttrium, from about 99.5 equivalent % aluminum to about 98.75 equivalent % aluminum, from about 1.8 equivalent oxygen to about 3.3 equivalent % oxygen and from about 98.2 equivalent % nitrogen to about 96.7 equivalent % nitrogen, said body having a porosity of less than 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 52

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon F7F1F3 but excluding point F3 and line F1F3 of FIG. 4, said body being comprised of from about 0.5 equivalent % yttrium to about 1.25 equivalent % yttrium, from about 99.5 equivalent % aluminum to about 98.75 equivalent % aluminum, from about 1.8 equivalent oxygen to about 3.3 equivalent % oxygen and from about 98.2 equivalent % nitrogen to about 96.7 equivalent % nitrogen, said body having a porosity of less than 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 53

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4F7F3F4 but excluding line F3F4 of FIG. 4, said body being comprised of from greater than about 0.25 equivalent % yttrium to about 0.5 equivalent % yttrium, from less than about 99.75 equivalent % aluminum to about 99.5 equivalent % aluminum, from about 1.4 equivalent % oxygen to less than about 2.5 equivalent % oxygen and from greater than about 97.5 equivalent % nitrogen to about 98.6 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 54

A polycrystalline aluminum nitride body having a composition defined and encompassed by polygon A4F7F3F4 but excluding line F3F4 of FIG. 4, said body being comprised of from greater than about 0.25 equivalent % yttrium to about 0.5 equivalent % yttrium, from less than about 99.75 equivalent % aluminum to about 99.5 equivalent % aluminum, from about 1.4 equivalent % oxygen to less than about 2.5 equivalent % oxygen and from greater than about 97.5 equivalent % nitrogen to about 98.6 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 55

A polycrystalline aluminum nitride body having a composition defined by line FF5 of FIG. 4, said body being comprised of from about 1.6 equivalent % to about 2.1 equivalent % yttrium, from about 98.4 equivalent % to about 97.9 equivalent % aluminum, from about 4.0 equivalent % to about 4.95 equivalent % oxygen and from about 96.0 equivalent % to about 95.05 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 56

A polycrystalline aluminum nitride body having a composition defined by line FF5 of FIG. 4, said body being comprised of from about 1.6 equivalent % to about 2.1 equivalent % yttrium, from about 98.4 equivalent % to about 97.9 equivalent % aluminum, from about 4.0 equivalent % to about 4.95 equivalent % oxygen and from about 96.0 equivalent % to about 95.05 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 57

A polycrystalline aluminum nitride body having a composition defined by line F1F of FIG. 4, said body being comprised of from about 1.25 equivalent % to about 1.6 equivalent % yttrium, from about 98.75 equivalent % to about 98.4 equivalent % aluminum, from about 3.3 equivalent % to about 4.0 equivalent % oxygen and from about 96.7 equivalent % to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 58

A polycrystalline aluminum nitride body having a composition defined by line F1F of FIG. 4, said body being comprised of from about 1.25 equivalent % to about 1.6 equivalent % yttrium, from about 98.75 equivalent % to about 98.4 equivalent % aluminum, from about 3.3 equivalent % to about 4.0 equivalent % oxygen and from about 96.7 equivalent % to about 96.0 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 59

A polycrystalline aluminum nitride body having a composition defined by line F7F1 of FIG. 4, said body being comprised of from about 0.5 equivalent % to about 1.25 equivalent % yttrium, from about 99.5 equivalent % to about 98.75 equivalent % aluminum, from about 1.8 equivalent % to about 3.3 equivalent % oxygen and from about 98.2 equivalent % to about 96.7 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at least 25° C.

Claim 60

A polycrystalline aluminum nitride body having a composition defined by line F7F1 of FIG. 4, said body being comprised of from about 0.5 equivalent % to about 1.25 equivalent % yttrium, from about 99.5 equivalent % to about 98.75 equivalent % aluminum, from about 1.8 equivalent % to about 3.3 equivalent % oxygen and from about 98.2 equivalent % to about 96.7 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at least 25° C.

Claim 61

A polycrystalline aluminum nitride body having a composition defined by line A4F7 of FIG. 4, said body being comprised of from about 0.3 equivalent % to about 0.5 equivalent % yttrium, from about 99.7 equivalent % to about 99.5 equivalent % aluminum, from about 1.4 equivalent % to about 1.8 equivalent % oxygen and from about 98.6 equivalent % to about 98.2 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 62

A polycrystalline aluminum nitride body having a composition defined by line A4F7 of FIG. 4, said body being comprised of from about 0.3 equivalent % to about 0.5 equivalent % yttrium, from about 99.7 equivalent % to about 99.5 equivalent % aluminum, from about 1.4 equivalent % to about 1.8 equivalent % oxygen and from about 98.6 equivalent % to about 98.2 equivalent % nitrogen, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 63

A polycrystalline aluminum nitride body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 0.8% by volume to less than about 5.5% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 5.5% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 3.4% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 64

A polycrystalline aluminum nitride body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 0.8% by volume to less than about 5.5% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 5.5% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 3.4% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 65

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 0.8% by volume to less than about 4.2% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 4.2% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 2.6% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 66

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 0.8% by volume to less than about 4.2% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 4.2% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 2.6% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 67

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 1.7% by volume to less than about 4.2% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 4.2% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 2.6% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 68

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 1.7% by volume to less than about 4.2% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 4.2% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 2.6% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 69

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 1.3% by volume to less than about 3.3% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 3.3% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 1.7% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 70

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and Y 3 Al 5 O 12 wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 1.3% by volume to less than about 3.3% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 3.3% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 1.7% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 71

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 0.8% by volume to less than about 1.7% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 1.3% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 1.7% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 72

A polycrystalline body having a phase composition comprised of AlN, YAlO 3 and wherein the total amount of said YAlO 3 and Y 3 Al 5 O 12 phases ranges from greater than about 0.8% by volume to less than about 1.7% by volume of the total volume of said body, said YAlO 3 phase ranging from a trace amount to less than about 1.3% by volume of the sintered body, said Y 3 Al 5 O 12 phase ranging from a trace amount to less than about 1.7% by volume of the sintered body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 73

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase ranges from about 4.2% by volume to about 5.5% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 74

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase ranges from about 4.2% by volume to about 5.5% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 75

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase range from about 3.3% by volume to about 4.2% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 0.90 W/cm.K at 25° C.

Claim 76

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase range from about 3.3% by volume to about 4.2% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 0.90 W/cm.K at 25° C.

Claim 77

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase ranges from about 1.3% by volume to about 3.3% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 78

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase ranges from about 1.3% by volume to about 3.3% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 79

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase ranges from about 0.8% by volume to about 1.3% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.

Claim 80

A polycrystalline body having a phase composition comprised of AlN and YAlO 3 wherein the amount of said YAlO 3 phase ranges from about 0.8% by volume to about 1.3% by volume of the total volume of said body, said body having a porosity of less than about 10% by volume of said body and a thermal conductivity greater than 1.00 W/cm.K at 25° C.