US5693305A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for synthesizing aluminum nitride whiskers
Assignee: Advanced Refractory Technologies Inc
•
Filing: 1995-10-19
•
Granted: 1997-12-02
•
Expires: 2015-10-19
Abstract
Abstract A method for making aluminum nitride whiskers comprising reacting a reactant bed of aluminum, alumina, ammonium chloride, with a metal-containing carbon catalyst in the presence of a nitrogen gas flow, such that a direct nitridation reaction, a carbothermal reaction and a transport species reaction occur concurrently.
Inventors
- 👤 Vithal Revankar
- 👤 Arvind Goel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:46
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/10; C30B29/40; C30B29/403; C30B25/00; C30B25/005
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
78 words
A method for making aluminum nitride whiskers comprising: in concurrent reactions in a reactant bed, reacting aluminum in the presence of nitrogen in a direct nitridation reaction under conditions necessary to make aluminum nitride whiskers; reacting alumina in the presence of nitrogen in a carbothermal nitridation reaction under conditions necessary to make aluminum nitride whiskers; and reacting aluminum and alumina in the presence of nitrogen in a transport species reaction under conditions necessary to make aluminum nitride whiskers.
Claim 2
Independent Claim
78 words
A method for making aluminum nitride whiskers comprising: in concurrent reactions in a reactant bed, reacting aluminum in the presence of nitrogen in a direct nitridation reaction under conditions necessary to make aluminum nitride whiskers; reacting alumina in the presence of nitrogen in a carbothermal nitridation reaction under conditions necessary to make aluminum nitride whiskers; and reacting aluminum and alumina in the presence of nitrogen in a transport species reaction under conditions necessary to make aluminum nitride whiskers.
Claim 3
Dependent Claim
20 words
The method according to claim 1, wherein the reactant bed comprises: aluminum, alumina, ammonium chloride and a metal-containing carbon catalyst.
Claim 4
Dependent Claim
16 words
The method according to claim 2, wherein the reactant bed is placed into a reaction vessel.
Claim 5
Dependent Claim
22 words
The method according to claim 2, wherein the reactant bed is heated in a furnace filled with a flow of nitrogen gas.
Claim 6
Dependent Claim
25 words
The method according to claim 2, wherein the reactant bed is heated at a heating rate of from about 10° C./min. to about 25° C./min.
Claim 7
Dependent Claim
24 words
The method according to claim 3, wherein the reactant bed is heated to a temperature of from about 900° C. to about 1600° C.
Claim 8
Dependent Claim
21 words
The method according to claim 2, wherein the aluminum is provided to the reactant bed in the form of aluminum fibers.
Claim 9
Dependent Claim
24 words
The method according to claim 2, wherein the metal-containing carbon catalyst comprises carbon selected from the group consisting of carbonized cotton, and carbon powder.
Claim 10
Dependent Claim
29 words
The method according to claim 2, wherein the metal-containing carbon catalyst comprises a metal-containing compound selected from the group consisting of nickel, magnesium, cobalt, manganese, iron and combinations thereof.
Claim 11
Dependent Claim
13 words
The method according to claim 9, wherein the metal-containing compound is nickel nitrate.
Claim 12
Dependent Claim
18 words
The method according to claim 9, wherein the metal-containing compound is a nickel nitrate and magnesium nitrate mixture.
Claim 13
Dependent Claim
23 words
The method according to claim 2, wherein the reactant bed has a mass density of from about 0.05 g/cc to about 0.20 g/cc.
Claim 14
Dependent Claim
19 words
The method according to claim 2, further comprising providing a flow of hydrogen chloride gas to the reactant bed.
Claim 15
Dependent Claim
80 words
The method according to claim 1 further comprising: heating the reactant bed at a heating rate of from about 10° C./min. to about 25° C./min. to a reaction temperature of from about 900° C. to about 1600° C., under conditions effective to produce aluminum nitride whiskers wherein the reactant bed comprises aluminum, alumina, a metal-containing carbon catalyst, and ammonium chloride in the presence of nitrogen, said bed having a mass density of from about 0.05 g/cc to about 0.2 g/cc.
Claim 16
Independent Claim
56 words
A method for making aluminum nitride whiskers comprising: in concurrent reactions in a reactant bed, reacting aluminum in the presence of nitrogen in a direct nitridation reaction under conditions necessary to make aluminum nitride whiskers; and reacting aluminum in the presence of nitrogen in a transport species reaction under conditions necessary to make aluminum nitride whiskers.
Claim 17
Independent Claim
56 words
A method for making aluminum nitride whiskers comprising: in concurrent reactions in a reactant bed, reacting aluminum in the presence of nitrogen in a direct nitridation reaction under conditions necessary to make aluminum nitride whiskers; and reacting aluminum in the presence of nitrogen in a transport species reaction under conditions necessary to make aluminum nitride whiskers.
Claim 18
Dependent Claim
29 words
The method according to claim 15, wherein the reactant bed comprises: aluminum, aluminum chloride and a metal-containing carbon catalyst, said bed having a bulk density of about 0.05 g/cc.
Claim 19
Dependent Claim
25 words
The method according to claim 16, wherein the reactant bed is heated at a heating rate of from about 10° C./min. to about 25° C./min.
Claim 20
Dependent Claim
24 words
The method according to claim 16, wherein the reactant bed is heated to a temperature of from about 900° C. to about 1600° C.
Claim 21
Dependent Claim
21 words
The method according to claim 16, wherein the aluminum is provided to the reactant bed in the form of aluminum fibers.
Claim 22
Dependent Claim
24 words
The method according to claim 16, wherein the metal-containing carbon catalyst comprises carbon selected from the group consisting of carbonized cotton and carbon powder.
Claim 23
Dependent Claim
29 words
The method according to claim 16, wherein the metal-containing carbon catalyst comprises a metal-containing compound selected from the group consisting of nickel, magnesium, cobalt, manganese, iron and combinations thereof.
Claim 24
Dependent Claim
13 words
The method according to claim 21, wherein the metal-containing compound is nickel nitrate.
Claim 25
Dependent Claim
18 words
The method according to claim 21, wherein the metal-containing compound is a nickel nitrate and magnesium nitrate mixture.
Claim 26
Dependent Claim
19 words
The method according to claim 16, further comprising providing a flow of hydrogen chloride gas to the reactant bed.
Claim 27
Independent Claim
111 words
A method for making aluminum nitride whiskers comprising: providing a reactant bed comprising an amount of ammonium chloride as a first layer, an amount of aluminum as a second layer, an amount of alumina mixed with a metal-containing carbon catalyst applied to the aluminum, and optionally, an additional amount of ammonium chloride as a final top layer in the bed; providing a flow of nitrogen gas to the reactant bed; and heating the reactant bed to a temperature sufficient to conduct a first direct nitridation reaction concurrently with a second carbothermic nitridation reaction concurrently in the presence of a third transport species reaction, under conditions effective to produce aluminum nitride whiskers.
Claim 28
Independent Claim
111 words
A method for making aluminum nitride whiskers comprising: providing a reactant bed comprising an amount of ammonium chloride as a first layer, an amount of aluminum as a second layer, an amount of alumina mixed with a metal-containing carbon catalyst applied to the aluminum, and optionally, an additional amount of ammonium chloride as a final top layer in the bed; providing a flow of nitrogen gas to the reactant bed; and heating the reactant bed to a temperature sufficient to conduct a first direct nitridation reaction concurrently with a second carbothermic nitridation reaction concurrently in the presence of a third transport species reaction, under conditions effective to produce aluminum nitride whiskers.
References Cited (Backward Citations)
JPS61124626A
Cited
JPS61261203A
Cited
JPS62283900A
Cited
JPS6375000A
Cited
JPH01308898A
Cited
JPH0264100A
Cited
US5192720A
Cited
JPH02192408A
Cited
US5153057A
Cited
US5335712A
Cited
JPH03187998A
Cited
JPH03215399A
Cited
JPH0465100A
Cited
JPH0497998A
Cited
US5214005A
Cited
JPH04321504A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-01 | 2001-06-02 | 2001-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-01 | 2005-06-02 | 2005-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-01 | 2009-06-02 | 2009-12-02 | $7700.00 | Window Closed / Lapsed |