Patent US5525134A successfully refreshed from Google Patents.
US5525134A
Expired / Lapsed
US
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Silicon nitride ceramic and cutting tool made thereof
Assignee: Kennametal Inc
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Filing: 1995-01-12
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Granted: 1996-06-11
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Expires: 2015-01-12
Abstract
Abstract Provided is a silicon nitride based ceramic which is particularly useful for use as a cutting tool in the high speed chip forming machining of metallic materials. The ceramic is preferably composed of at least 85 volume percent (v/o) beta silicon nitride phase and less than about 5 v/o intergranular phase. The ceramic has greater than 0.2 weight percent (w/o) magnesia, greater than 0.2 w/o yttria, where the sum of magnesia and yttria is less than 5 w/o. The ceramic preferably has less than 0.2 v/o porosity.
Inventors
- 👤 Pankaj K. Mehrotra
- 👤 Robert D. Nixon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:34
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; B; B22; B22F; B22F1/00
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
129 words
A ceramic cutting tool for high speed chip forming machining of a metallic material, said ceramic cutting tool comprising: a rake face over which chips formed during said chip forming machining of said metallic material will flow; a flank face; a cutting edge, for cutting into said metallic material at high speeds to form said chips, formed at a junction of said rake face and said flank face; said ceramic consisting essentially of beta silicon nitride phase; and an intergranular phase wherein said ceramic has at least 0.2 w/o yttria and at least 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o, and wherein said ceramic has 1.3 w/o to 2.2 w/o oxygen and a density of at least 3.19 g/cm 3 .
Claim 2
Dependent Claim
129 words
A ceramic cutting tool for high speed chip forming machining of a metallic material, said ceramic cutting tool comprising: a rake face over which chips formed during said chip forming machining of said metallic material will flow; a flank face; a cutting edge, for cutting into said metallic material at high speeds to form said chips, formed at a junction of said rake face and said flank face; said ceramic consisting essentially of beta silicon nitride phase; and an intergranular phase wherein said ceramic has at least 0.2 w/o yttria and at least 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o, and wherein said ceramic has 1.3 w/o to 2.2 w/o oxygen and a density of at least 3.19 g/cm 3 .
Claim 3
Dependent Claim
22 words
The ceramic cutting tool according to claim 1 wherein the beta silicon nitride phase forms at least 85 v/o of said ceramic.
Claim 4
Dependent Claim
20 words
The ceramic cutting tool according to claim 1 wherein the sum of yttria and magnesia is at least 1.5 w/o.
Claim 5
Dependent Claim
32 words
The ceramic cutting tool according to claim 1 having a hardness at room temperature greater than 1700 kg/mm 2 and at 1000° C. the hardness is greater than 800 kg/mm 2 .
Claim 6
Dependent Claim
17 words
The ceramic cutting tool according to claim 1 having a transverse rupture strength greater than 150 Ksi.
Claim 7
Dependent Claim
16 words
The ceramic cutting tool according to claim 1 having a Weibull modulus of at least 15.
Claim 8
Dependent Claim
30 words
The ceramic cutting tool according to claim 1 having a thermal diffusivity of at least 0.2 cm 2 /s and a thermal conductivity of at least 0.1 calorie/sec.-cm 0 C.
Claim 9
Dependent Claim
19 words
The ceramic cutting tool according to claim 1 having a Young's Modulus of elasticity of at least 300 GPa.
Claim 10
Dependent Claim
74 words
The cutting insert according to claim 1 wherein the yttria is 0.5 to 1.5 w/o, and the magnesia is 0.5 to 1.5 w/o; wherein the hardness at room temperature is at least 1700 kg/mm 2 and at 1000° C. hardness is at least 900 kg/mm 2 ; wherein the transverse rupture strength is greater than 160 Ksi; wherein the Weibull modulus is at least 15; and wherein Young's modulus is at least 300 GPa.
Claim 11
Dependent Claim
24 words
The ceramic cutting tool according to claim 1 wherein the sum of yttria and magnesia is less than or equal to about 2 w/o.
Claim 12
Dependent Claim
24 words
The ceramic cutting tool according to claim 9 wherein the sum of yttria and magnesia is less than or equal to about 2 w/o.
Claim 13
Dependent Claim
24 words
The ceramic cutting tool according to claim 1 wherein the yttria is 0.5 to 1.5 w/o, and the magnesia is 0.5 to 1.5 w/o.
Claim 14
Dependent Claim
17 words
The ceramic cutting tool according to claim 12 wherein said ceramic has 1.3 to 1.9 w/o oxygen.
Claim 15
Dependent Claim
17 words
The ceramic cutting tool according to claim 10 wherein said ceramic has 1.3 to 1.9 w/o oxygen.
Claim 16
Dependent Claim
58 words
A ceramic consisting essentially of: Beta silicon nitride phase and intergranular phase, wherein said ceramic has greater than 0.2 w/o yttria, greater than 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o, wherein said ceramic has 1.3 w/o to 2.2 w/o oxygen and a density of at least 3.19 g/cm 3 .
Claim 17
Dependent Claim
58 words
A ceramic consisting essentially of: Beta silicon nitride phase and intergranular phase, wherein said ceramic has greater than 0.2 w/o yttria, greater than 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o, wherein said ceramic has 1.3 w/o to 2.2 w/o oxygen and a density of at least 3.19 g/cm 3 .
Claim 18
Dependent Claim
24 words
The ceramic according to claim 15 wherein the magnesia is between 0.5 to 1.5 w/o, and the yttria is between 0.5 to 1.5 w/o.
Claim 19
Dependent Claim
22 words
The ceramic according to claim 15 wherein the sum of yttria and magnesia is less than or equal to about 2 w/o.
Claim 20
Dependent Claim
16 words
The ceramic according to claim 17 wherein oxygen is 1.3 to 1.9 w/o of said ceramic.
Claim 21
Dependent Claim
20 words
The ceramic according to claim 16 wherein the beta silicon nitride phase forms at least 85 v/o of said ceramic.
Claim 22
Dependent Claim
17 words
The ceramic cutting tool according to claim 1 further comprising: a refractory coating on said cutting tool.
Claim 23
Dependent Claim
18 words
The ceramic cutting tool according to claim 20 wherein said refractory coating includes Al 2 O 3 .
Claim 24
Dependent Claim
22 words
The ceramic cutting tool according to claim 1 wherein said beta silicon nitride phase forms at least 95 v/o of said ceramic.
Claim 25
Dependent Claim
28 words
The ceramic cutting tool according to claim 10 further comprising a refractory coating on said cutting tool, and wherein the refractory coating includes Al 2 O 3 .
Claim 26
Dependent Claim
22 words
The ceramic cutting tool according to claim 23 wherein said beta silicon nitride phase forms at least 95 v/o of said ceramic.
Claim 27
Dependent Claim
15 words
The ceramic cutting tool according to claim 21 wherein said refractory coating also includes TiN.
Claim 28
Dependent Claim
15 words
The ceramic cutting tool according to claim 24 wherein said refractory coating also includes TiN.
Claim 29
Dependent Claim
116 words
A ceramic cutting tool for high speed chip forming machining of metallic materials, said ceramic cutting tool comprising: a rake face over which chips formed during said chip forming machining of metallic materials will flow; a flank face; a cutting edge, for cutting into said metallic materials at high speeds to form said chips, formed at a junction of said rake face and said flank face; said ceramic consisting essentially of beta silicon nitride phase; and an intergranular phase wherein said ceramic has at least 0.2 w/o yttria and at least 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o, and a density of at least 3.19 g/cm 3 .
Claim 30
Dependent Claim
116 words
A ceramic cutting tool for high speed chip forming machining of metallic materials, said ceramic cutting tool comprising: a rake face over which chips formed during said chip forming machining of metallic materials will flow; a flank face; a cutting edge, for cutting into said metallic materials at high speeds to form said chips, formed at a junction of said rake face and said flank face; said ceramic consisting essentially of beta silicon nitride phase; and an intergranular phase wherein said ceramic has at least 0.2 w/o yttria and at least 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o, and a density of at least 3.19 g/cm 3 .
Claim 31
Dependent Claim
22 words
The ceramic cutting tool according to claim 27 wherein the beta silicon nitride phase forms at least 85 v/o of said ceramic.
Claim 32
Dependent Claim
20 words
The ceramic cutting tool according to claim 27 wherein the sum of yttria and magnesia is at least 1.5 w/o.
Claim 33
Dependent Claim
32 words
The ceramic cutting tool according to claim 27 having a hardness at room temperature greater than 1700 kg/mm 2 and at 1000° C. the hardness is greater than 800 kg/mm 2 .
Claim 34
Dependent Claim
17 words
The ceramic cutting tool according to claim 27 having a transverse rupture strength greater than 150 Ksi.
Claim 35
Dependent Claim
16 words
The ceramic cutting tool according to claim 27 having a Weibull modulus of at least 15.
Claim 36
Dependent Claim
30 words
The ceramic cutting tool according to claim 27 having a thermal diffusivity of at least 0.2 cm 2 /s and a thermal conductivity of at least 0.1 calorie/sec.-cm 0 C.
Claim 37
Dependent Claim
19 words
The ceramic cutting tool according to claim 27 having a Young's Modulus of elasticity of at least 300 GPa.
Claim 38
Dependent Claim
74 words
The cutting insert according to claim 27 wherein the yttria is 0.5 to 1.5 w/o, and the magnesia is 0.5 to 1.5 w/o; wherein the hardness at room temperature is at least 1700 kg/mm 2 and at 1000° C. hardness is at least 900 kg/mm 2 ; wherein the transverse rupture strength is greater than 160 Ksi; wherein the Weibull modulus is at least 15; and wherein Young's modulus is at least 300 GPa.
Claim 39
Dependent Claim
24 words
The ceramic cutting tool according to claim 27 wherein the sum of yttria and magnesia is less than or equal to about 2 w/o.
Claim 40
Dependent Claim
24 words
The ceramic cutting tool according to claim 27 wherein the sum of yttria and magnesia is less than or equal to about 2 w/o.
Claim 41
Dependent Claim
24 words
The ceramic cutting tool according to claim 27 wherein the yttria is 0.5 to 1.5 w/o, and the magnesia is 0.5 to 1.5 w/o.
Claim 42
Dependent Claim
48 words
A ceramic consisting essentially of: Beta silicon nitride phase and intergranular phase, wherein said ceramic has greater than 0.2 w/o yttria, greater than 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o and a density of at least 3.19 g/cm 3 .
Claim 43
Dependent Claim
48 words
A ceramic consisting essentially of: Beta silicon nitride phase and intergranular phase, wherein said ceramic has greater than 0.2 w/o yttria, greater than 0.2 w/o magnesia, wherein the sum of yttria and magnesia is less than 3.5 w/o and a density of at least 3.19 g/cm 3 .
Claim 44
Dependent Claim
23 words
The ceramic according to claim 39 wherein the magnesia is between 0.5 to 1.5 w/o, the yttria is between 0.5 to 1.5 w/o.
Claim 45
Dependent Claim
22 words
The ceramic according to claim 39 wherein the sum of yttria and magnesia is less than or equal to about 2 w/o.
Claim 46
Dependent Claim
20 words
The ceramic according to claim 40 wherein the beta silicon nitride phase forms at least 85 v/o of said ceramic.
Claim 47
Dependent Claim
17 words
The ceramic cutting tool according to claim 27 further comprising: a refractory coating on said cutting tool.
Claim 48
Dependent Claim
18 words
The ceramic cutting tool according to claim 43 wherein said refractory coating includes Al 2 O 3 .
Claim 49
Dependent Claim
22 words
The ceramic cutting tool according to claim 27 wherein said beta silicon nitride phase forms at least 95 v/o of said ceramic.
Claim 50
Dependent Claim
28 words
The ceramic cutting tool according to claim 38 further comprising a refractory coating on said cutting tool, and wherein the refractory coating includes Al 2 O 3 .
Claim 51
Dependent Claim
22 words
The ceramic cutting tool according to claim 46 wherein said beta silicon nitride phase forms at least 95 v/o of said ceramic.
Claim 52
Dependent Claim
15 words
The ceramic cutting tool according to claim 44 wherein said refractory coating also includes TiN.
Claim 53
Dependent Claim
15 words
The ceramic cutting tool according to claim 47 wherein said refractory coating also includes TiN.
Claim 54
Dependent Claim
27 words
The ceramic cutting tool according to claim 27 wherein said chip forming machining consists essentially of milling and said metallic material consists essentially of a cast iron.
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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) | 1999-06-11 | 1999-12-11 | 2000-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-11 | 2003-12-11 | 2004-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-11 | 2007-12-11 | 2008-06-11 | $7700.00 | Window Closed / Lapsed |