US4559270A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oxidation prohibitive coatings for carbonaceous articles
Assignee: Graftech Technology LLC
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Filing: 1983-07-28
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Granted: 1985-12-17
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Expires: 2003-07-28
Abstract
Abstract A carbonaceous article, e.g., a carbon or graphite crucible or mold, is provided with an oxidation prohibitive coating comprising a rigid, glassy, ceramic, refractory material containing mullite and silicon carbide or boron carbide or both. The carbonaceous article has a coefficient of thermal expansion which is greater than about 1.5×10 -6 inch/inch/°C.
Inventors
- 👤 Raymond V. Sara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:48
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B41/45; C04B41/50; C04B41/5053; C04B41/5057; C04B41/5059; C04B41/5076; C04B41/5089; C04B41/80; C04B41/81; C04B41/85; C04B41/87; Y; Y10; Y10T; Y10T428/00; Y10T428/30
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
64 words
An article comprising a carbonaceous substrate having a coefficient of thermal expansion greater than about 1.5×10 -6 inch/inch/° C. and an oxidation prohibitive coating overlying and bonded to said substrate, said coating comprising a rigid, glossy, ceramic, refractory material containing mullite as a major ingredient along with a metallic carbide selected from the group consisting of silicon carbide and boron carbide and mixtures thereof.
Claim 2
Dependent Claim
64 words
An article comprising a carbonaceous substrate having a coefficient of thermal expansion greater than about 1.5×10 -6 inch/inch/° C. and an oxidation prohibitive coating overlying and bonded to said substrate, said coating comprising a rigid, glossy, ceramic, refractory material containing mullite as a major ingredient along with a metallic carbide selected from the group consisting of silicon carbide and boron carbide and mixtures thereof.
Claim 3
Dependent Claim
22 words
An article according to claim 1 wherein said carbonaceous substrate has a coefficient of thermal expansion of about 4×10 -6 inch/inch/° C.
Claim 4
Dependent Claim
21 words
An article according to claim 2 wherein said coating has a coefficient of thermal expansion of about 5.5×10 -6 inch/inch/° C.
Claim 5
Dependent Claim
86 words
An article comprising a carbonaceous substrate having a coefficient of thermal expansion of about 4×10 -6 inch/inch/° C. and an oxidation prohibitive coating overlying and bonded to said substrate, said coating comprising a rigid, glassy, ceramic, refractory material containing mullite as a major ingredient along with a metallic carbide selected from the group consisting of silicon carbide and boron carbide, said coating having a coefficient of thermal expansion of about 5.5×10 -6 inch/inch/° C. and being plastic and flowable at a temperature above about 1100° C.
Claim 6
Dependent Claim
86 words
An article comprising a carbonaceous substrate having a coefficient of thermal expansion of about 4×10 -6 inch/inch/° C. and an oxidation prohibitive coating overlying and bonded to said substrate, said coating comprising a rigid, glassy, ceramic, refractory material containing mullite as a major ingredient along with a metallic carbide selected from the group consisting of silicon carbide and boron carbide, said coating having a coefficient of thermal expansion of about 5.5×10 -6 inch/inch/° C. and being plastic and flowable at a temperature above about 1100° C.
Claim 7
Dependent Claim
17 words
A graphite crucible or mold having a coating according to any one of claims 1 to 4.
Claim 8
Dependent Claim
15 words
A furnace lining brick having a coating according to anyone of claims 1 to 4.
Claim 9
Dependent Claim
87 words
An article comprising a carbonaceous substrate having an oxidation prohibitive coating thereon which can be rendered resistant to thermal shock upon heating to elevated temperature above about 1100° C., said coating comprising between about 20 and 70% by weight mullite, between about 5 and 14% by weight silica, between about 5 and 70% by weight silicon carbide or boron carbide or both and between about 5 and 14% by weight of a silicon-containing binder material, all percentages being based upon the total weight of the dry ingredients.
Claim 10
Dependent Claim
87 words
An article comprising a carbonaceous substrate having an oxidation prohibitive coating thereon which can be rendered resistant to thermal shock upon heating to elevated temperature above about 1100° C., said coating comprising between about 20 and 70% by weight mullite, between about 5 and 14% by weight silica, between about 5 and 70% by weight silicon carbide or boron carbide or both and between about 5 and 14% by weight of a silicon-containing binder material, all percentages being based upon the total weight of the dry ingredients.
Claim 11
Dependent Claim
25 words
An article according to claim 7 wherein said carbonaceous substrate has a coefficient of thermal expansion which is greater than about 1.5×10 -6 inch/inch/° C.
Claim 12
Dependent Claim
27 words
An article according to claim 7 wherein said silicon-containing binder material is selected from the group consisting of sodium silicate, potassium silicate, ethyl silicate and colloidal silica.
Claim 13
Dependent Claim
33 words
An article according to claim 7 wherein said coating comprises about 57.7% by weight mullite, about 11.4% by weight silica, about 20.3% by weight silicon carbide and about 10.6% by weight sodium silicate.
Claim 14
Dependent Claim
93 words
An article comprising a carbonaceous substrate having a coefficient of thermal expansion of about 4×10 -6 inch/inch/° C. and having an oxidation prohibitive coating thereon which can be rendered resistant to thermal shock upon heating to elevated temperature above about 1100° C., said coating comprising between about 48 and 60% by weight mullite, between about 9 and 12% by weight silica, between about 16 and 35% by weight silicon carbide and between about 8 an 11% by weight of sodium silicate, all percentages being based upon the total weight of the dry ingredients.
Claim 15
Dependent Claim
93 words
An article comprising a carbonaceous substrate having a coefficient of thermal expansion of about 4×10 -6 inch/inch/° C. and having an oxidation prohibitive coating thereon which can be rendered resistant to thermal shock upon heating to elevated temperature above about 1100° C., said coating comprising between about 48 and 60% by weight mullite, between about 9 and 12% by weight silica, between about 16 and 35% by weight silicon carbide and between about 8 an 11% by weight of sodium silicate, all percentages being based upon the total weight of the dry ingredients.
Claim 16
Dependent Claim
17 words
A graphite crucible or mold having a coating according to any one of claims 7 to 11.
Claim 17
Dependent Claim
17 words
A graphite furnace lining brick having a coating according to any one of claims 7 to 11.
Claim 18
Dependent Claim
70 words
A coating composition for applying an oxidation prohibitive coating onto a carbonaceous substrate, which comprises between about 20 and 70% by weight mullite, between about 5 and 14% by weight silica, between about 5 and 70% by weight silicon carbide or boron carbide or both and between about 5 and 14% by weight of a silicon-containing binder material, all percentages being based upon the total weight of the dry ingredients.
Claim 19
Dependent Claim
70 words
A coating composition for applying an oxidation prohibitive coating onto a carbonaceous substrate, which comprises between about 20 and 70% by weight mullite, between about 5 and 14% by weight silica, between about 5 and 70% by weight silicon carbide or boron carbide or both and between about 5 and 14% by weight of a silicon-containing binder material, all percentages being based upon the total weight of the dry ingredients.
Claim 20
Dependent Claim
28 words
A coating composition according to claim 14 wherein said silicon-containing binder material is selected from the group consisting of sodium silicate, potassium silicate, ethyl silicate, and colloidal silica.
Claim 21
Dependent Claim
31 words
A coating composition according to claim 15 comprising about 47.4% by weight mullite, about 9.4% by weight silica, about 16.7% by weight silicon carbide and about 26.1% by weight sodium silicate.
Claim 22
Dependent Claim
62 words
A coating composition for applying an oxidation prohibitive coating onto a carbonaceous substrate, which comprises between about 48 and 60% by weight mullite, between about 9 and 12% by weight silica, between about 16 and 35% by weight silicon carbide and between about 8 and 11% by weight sodium silicate, all percentages being based upon the total weight of the dry ingredients.
Claim 23
Dependent Claim
62 words
A coating composition for applying an oxidation prohibitive coating onto a carbonaceous substrate, which comprises between about 48 and 60% by weight mullite, between about 9 and 12% by weight silica, between about 16 and 35% by weight silicon carbide and between about 8 and 11% by weight sodium silicate, all percentages being based upon the total weight of the dry ingredients.
Claim 24
Independent Claim
115 words
A method of protecting a carbonaceous article against oxidation and erosion at elevated temperature above about 1100° C., which comprises: (a) applying to the surfaces of said carbonaceous article a particulate mixture comprising between about 20 and 70% by weight mullite, between about 5 and 14% by weight silica, between about 5 and 70% by weight of a metallic carbide selected from the group consisting of silicon carbide and boron carbide, and between about 5 and 14% by weight of a silicon-containing binder material, all pecentages being based upon the total weight of the dry ingredients; and (b) heating said particulate mixture to a temperature at which a rigid, glassy, ceramic, refractory coating is formed.
Claim 25
Independent Claim
115 words
A method of protecting a carbonaceous article against oxidation and erosion at elevated temperature above about 1100° C., which comprises: (a) applying to the surfaces of said carbonaceous article a particulate mixture comprising between about 20 and 70% by weight mullite, between about 5 and 14% by weight silica, between about 5 and 70% by weight of a metallic carbide selected from the group consisting of silicon carbide and boron carbide, and between about 5 and 14% by weight of a silicon-containing binder material, all pecentages being based upon the total weight of the dry ingredients; and (b) heating said particulate mixture to a temperature at which a rigid, glassy, ceramic, refractory coating is formed.
Claim 26
Dependent Claim
25 words
A method according to claim 18 wherein said carbonaceous article has a coefficient of thermal expansion which is greater than about 1.5×10 -6 inch/inch/° C.
Claim 27
Dependent Claim
27 words
A method according to claim 18 wherein said silicon-containing binder material is selected from the group consisting of sodium silicate, potassium silicate, ethyl silicate and colloidal silica.
Claim 28
Dependent Claim
34 words
A method according to claim 18 wherein said particulate mixture comprises about 47.4% by weight mullite, about 9.4% by weight silica, about 16.7% by weight silicon carbide and about 26.1% by weight sodium silicate.
Claim 29
Dependent Claim
26 words
A method according to claim 18 wherein said particulate mixture is applied to the surfaces of said carbonaceous article in the form of an aqueous slurry.
Claim 30
Dependent Claim
24 words
A method according to claim 22 wherein said slurry is dried under conditions to produce a hard coherent layer adhering to the carbonaceous article.
Claim 31
Dependent Claim
16 words
A method according to claim 23 wherein said slurry is dried in air at ambient temperature.
Claim 32
Dependent Claim
21 words
A method according to claim 24 wherein said dried coherent layer is heated to temperature of at least about 1100° C.
Claim 33
Independent Claim
143 words
A method of protecting a carbonaceous article having a coefficient of thermal expansion of about 4×10 -6 inch/inch/° C. against oxidation and erosion at elevated temperature above about 1100° C. which comprises: (a) applying to the surfaces of said carbonaceous article an aqueous slurry comprising between about 48 and 60% by weight mullite, between about 9 and 12% by weight silica, between about 16 and 35% by weight silicon carbide and between about 8 and 11% by weight sodium silicate, all percentages being based upon the total weight of the dry ingredients; (b) drying said slurry in air at room temperature to remove water and to form a hard coherent layer adhering to the surfaces of said article; and (c) heating said dried coherent layer to a temperature of at least about 1100° C. to thereby form a rigid, glassy, ceramic, refractory coating.
Claim 34
Independent Claim
143 words
A method of protecting a carbonaceous article having a coefficient of thermal expansion of about 4×10 -6 inch/inch/° C. against oxidation and erosion at elevated temperature above about 1100° C. which comprises: (a) applying to the surfaces of said carbonaceous article an aqueous slurry comprising between about 48 and 60% by weight mullite, between about 9 and 12% by weight silica, between about 16 and 35% by weight silicon carbide and between about 8 and 11% by weight sodium silicate, all percentages being based upon the total weight of the dry ingredients; (b) drying said slurry in air at room temperature to remove water and to form a hard coherent layer adhering to the surfaces of said article; and (c) heating said dried coherent layer to a temperature of at least about 1100° C. to thereby form a rigid, glassy, ceramic, refractory coating.
Claim 35
Dependent Claim
104 words
In an article comprising a carbonaceous substrate having a coefficient of thermal expansion greater than about 1.5×10 -6 inch/inch/° C. and an oxidation prohibitive coating on at least one surface thereof; the improvement wherein said coating comprises a layer of rigid, glassy, ceramic, refractory material overlying and bonded to the surface of said substrate, said refractory material containing mullite having a composition consisting essentially of 3Al 2 O 3 .3SiO 2 as a major ingredient along with a metallic carbide selected from the group consisting of silicon carbide and boron carbide, said layer being plastic and flowable at a temperature above about 1100° C.
Claim 36
Dependent Claim
104 words
In an article comprising a carbonaceous substrate having a coefficient of thermal expansion greater than about 1.5×10 -6 inch/inch/° C. and an oxidation prohibitive coating on at least one surface thereof; the improvement wherein said coating comprises a layer of rigid, glassy, ceramic, refractory material overlying and bonded to the surface of said substrate, said refractory material containing mullite having a composition consisting essentially of 3Al 2 O 3 .3SiO 2 as a major ingredient along with a metallic carbide selected from the group consisting of silicon carbide and boron carbide, said layer being plastic and flowable at a temperature above about 1100° C.
References Cited (Backward Citations)
DE316450C
Cited
GB894593A
Cited
US3140193A
Cited
GB955629A
Cited
US3348929A
Cited
US3852107A
Cited
US4301387A
Cited
US4384046A
Cited
US4418097A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-16 | 1989-06-17 | 1989-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-16 | 1993-06-17 | 1993-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-16 | 1997-06-17 | 1997-12-17 | $7700.00 | Window Closed / Lapsed |