Patent US4847221A successfully refreshed from Google Patents.
US4847221A
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AlN sintered body having high thermal conductivity and a method of fabricating the same
Assignee: Toshiba Corp
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Filing: 1988-01-11
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Granted: 1989-07-11
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Expires: 2008-01-11
Abstract
Abstract According to the present invention, there is provided an aluminum nitride sintered body having a high thermal conductivity and essentially consisting of a AlN single-phase, containing 0.01 to 8,000 ppm of rare earth elements and less than 2,000 ppm of oxygen. According to the present invention, there is provided a method of fabricating an aluminum nitride sintered body having a high thermal conductivity and essentially consisting of AlN single-phase, containing 0.01 to 8,000 ppm of rare earth elements and less than 2,000 ppm of oxygen, wherein a molded body prepared by mixing and molding an aluminum nitride power having less than 7 wt % of oxygen and an average particle size of 0.05 to 5 μm and with rare earth compounds of 0.01 to 15 wt % of based on rare earth elements content, or a sintered AlN body containing oxide grain boundary phases of 0.01 to 15 wt % of rare earth elements and 0.01 to 20 wt % of oxygen and (rare earth element)--Al--O compounds phases and/or (rare earth element)--O compounds phases, is fired in a reducing atmosphere at a temperature of 1,550 to 2,050° C. for 4 hours or more.
Inventors
- 👤 Akihiro Horiguchi
- 👤 Fumio Ueno
- 👤 Mitsuo Kasori
- 👤 Yoshiko Sato
- 👤 Masaru Hayashi
- 👤 Hiroshi Endo
- 👤 Kazuo Shinozaki
- 👤 Akihiko Tsuge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:35
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/581
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
45 words
An aluminum nitride sintered body consisting essentially of: (a) an AlN single-phase; and (b) a second phase containing rare earth elements, the contents of rare earth elements and oxygen in the entire sintered body being 0.01 to 8,000 ppm, and less than 2,000 ppm, respectively.
Claim 2
Dependent Claim
45 words
An aluminum nitride sintered body consisting essentially of: (a) an AlN single-phase; and (b) a second phase containing rare earth elements, the contents of rare earth elements and oxygen in the entire sintered body being 0.01 to 8,000 ppm, and less than 2,000 ppm, respectively.
Claim 3
Dependent Claim
19 words
The sintered body according to claim 1, wherein the content of rare earth elements is 0.01 to 3,000 ppm.
Claim 4
Dependent Claim
19 words
The sintered body according to claim 1, wherein the content of rare earth elements is 10 to 3,000 ppm.
Claim 5
Dependent Claim
28 words
The sintered body according to claim 1, wherein the rare earth element is at least one element selected from the group consisting of Y, Ce, Sc, and Dy.
Claim 6
Dependent Claim
14 words
The sintered body according to claim 1, wherein the rare earth element is Y.
Claim 7
Dependent Claim
21 words
The sintered body according to claim 1, wherein the sintered body has a density of 3.120 to 3.285 g/cm 3 .
Claim 8
Dependent Claim
21 words
The sintered body according to claim 1, wherein the sintered body has a density of 3.259 to 3.264 g/cm 3 .
Claim 9
Dependent Claim
27 words
The sintered body according to claim 1, wherein the sintered body essentially consists of AlN grains having an average particle size of not less than 7 μm.
Claim 10
Dependent Claim
27 words
The sintered body according to claim 1, wherein the sintered body essentially consists of AlN grains having an average particle size of not less than 10 μm.
Claim 11
Dependent Claim
24 words
The sintered body according to claim 1, wherein a total content of impurities excluding the rare earth element is not more than 1,000 ppm.
Claim 12
Dependent Claim
23 words
The sintered body according to claim 1, wherein the sintered body has a thermal conductivity of not less than 200 W/m·K (25° C).
Claim 13
Dependent Claim
46 words
The sintered body according to claim 1, wherein the sintered body has a porosity of not more than 1%, a lattice constant of 497.95 to 498.20 pm along a c-axis of an aluminum nitride hexagonal lattice, and a density of 3.255 to 3.275 g/cm 3 .
Claim 14
Dependent Claim
42 words
The sintered body according to claim 1, wherein the sintered body has an apparent absorption coefficient of not more than 50 cm -1 at a wavelength of 500 nm, and not more than 70 cm -1 at a wavelength of 330 nm.
Claim 15
Dependent Claim
41 words
The sintered body according to claim 1, wherein the sintered body has an apparent absorbance of not more than 20 cm -1 at a wavelength of 500 nm, and not more than 50 cm -1 at a wavelength of 330 nm.
Claim 16
Dependent Claim
22 words
The sintered body according to claim 1, wherein the sintered body further contains a (rare earth element)--N compound as a second phase.
Claim 17
Dependent Claim
22 words
The sintered body according to claim 1, wherein the sintered body further contains a (rare earth element)--C compound as a second phase.
Claim 18
Dependent Claim
33 words
The sintered body according to claim 1, wherein the sintered body further contains a (rare earth element) --Al--C compound and (rare earth element) --O compound or a combination thereof as a second phase.
Claim 19
Dependent Claim
21 words
The sintered body according to claim 1, wherein the sintered body contains a (rare earth element)--Al--O compound as a second phase.
Claim 20
Independent Claim
181 words
A method of fabricating an aluminum nitride sintered body consisting essentially of an AlN single-phase, and a second phase containing rare earth elements, the contents of rare earth elements and oxygen in the entire sintered body being 0.01 to 8,000 ppm and less than 2,000 ppm of oxygen, respectively, which comprises firing in a reducing atmosphere in a sintering housing producing vaporized carbon during sintering at a temperature of 1,550° to 2,050° C. for at least four hours either: (a) a molded body prepared by mixing and molding an aluminum nitride powder having less than 7 wt. % of oxygen and an average particle size of 0.05 to 5 μm and with one or more rare earth compounds in the amount of 0.01 to 15 wt. %, based on the rare earth element content, or (b) a sintered AlN body containing oxide grain boundary phases having 0.01 to 15 wt. % of rare earth elements and 0.01 to 20 wt. % of oxygen and (rare earth element) --Al--O compound phases and (rare earth element) --O compound phases or a combination thereof.
Claim 21
Independent Claim
181 words
A method of fabricating an aluminum nitride sintered body consisting essentially of an AlN single-phase, and a second phase containing rare earth elements, the contents of rare earth elements and oxygen in the entire sintered body being 0.01 to 8,000 ppm and less than 2,000 ppm of oxygen, respectively, which comprises firing in a reducing atmosphere in a sintering housing producing vaporized carbon during sintering at a temperature of 1,550° to 2,050° C. for at least four hours either: (a) a molded body prepared by mixing and molding an aluminum nitride powder having less than 7 wt. % of oxygen and an average particle size of 0.05 to 5 μm and with one or more rare earth compounds in the amount of 0.01 to 15 wt. %, based on the rare earth element content, or (b) a sintered AlN body containing oxide grain boundary phases having 0.01 to 15 wt. % of rare earth elements and 0.01 to 20 wt. % of oxygen and (rare earth element) --Al--O compound phases and (rare earth element) --O compound phases or a combination thereof.
Claim 22
Dependent Claim
31 words
The method according to claim 19, wherein the reducing atmosphere contains nitrogen and at least one element selected from the group consisting of hydrogen, carbon monoxide, carbon gas, and solid-state carbon.
Claim 23
Dependent Claim
26 words
The method according to claim 19, wherein the sintering housing contains a material which produces carbon gas or housing material itself produces carbon gas during sintering.
Claim 24
Dependent Claim
27 words
The method according to claim 19, wherein the rare earth element is at least one element selected from the group consisting of Y, Ce, Sc, and Dy.
Claim 25
Dependent Claim
13 words
The method according to claim 19, wherein the rare earth element is Y.
Claim 26
Dependent Claim
35 words
The method according to claim 19, wherein a sintering housing is made of carbon or is a carbon housing having an aluminum nitride, BN or tungsten bottom plate for supporting the molded or sintered body.
Claim 27
Dependent Claim
33 words
The method according to claim 19, wherein a ratio of an inner volme of a sintering housing to a volume of the molded or sintered body is 1×10 0 to 1×10 7 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |