GB967933A - Improvements in or relating to methods of preparing crystalline silicon carbide - Google Patents
Improvements in or relating to methods of preparing crystalline silicon carbideInfo
- Publication number
- GB967933A GB967933A GB37968/61A GB3796861A GB967933A GB 967933 A GB967933 A GB 967933A GB 37968/61 A GB37968/61 A GB 37968/61A GB 3796861 A GB3796861 A GB 3796861A GB 967933 A GB967933 A GB 967933A
- Authority
- GB
- United Kingdom
- Prior art keywords
- graphite
- silicon
- temperature
- silicon carbide
- million
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
- C01B32/963—Preparation from compounds containing silicon
- C01B32/984—Preparation from elemental silicon
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
Crystalline silicon carbide is prepared by forming, in a graphite crucible, a body of molten silicon having a hot zone at a temperature of at least 2,100 DEG C. separated from a cold zone at a temperature of not greater than 1,900 DEG C. by a temperature gradient of at least 100 DEG C., graphite being dissolved from the crucible in the hot zone and deposited as silicon carbide in the cold zone. The graphite has a density of at least 1.8 gm./c.c. It may have an impurity of 100 parts/million. The molten silicon may be produced from polycrystalline silicon containing less than 1 part/million of impurity. The process may be carried out by induction heating in an atmosphere of argon at atmospheric pressure. Silicon may be separated from the product by dissolution with a mixture of nitric and hydrofluoric acid. The crystal structure of the product is mainly cubic with a small proportion of hexagonal and rhombohedral crystals. In an example, a middle layer of molten silicon is heated at 2,300 DEG C., the temperature above and below falling off at an initial rate of 300 DEG C./c.m. to 1,800 DEG C.ALSO:Crystalline silicon carbide is prepared by forming, in a crucible of graphite having a density of at least 1,8 gm./c.c., a body of molten silicon having a hot zone at a temperature of at least 2100 DEG C. separated from a cold zone at a temperature of not greater than 1900 DEG C. by a temperature gradient of at least 100 DEG C., graphite being dissolved from the crucible in the hot zone and deposited as silicon carbide in the cold zone. The middle layer may be heated to 2300 DEG C., the temperature above and below falling off at an initial rate of 300 DEG C./cm. to 1800 DEG C. The graphite may have an impurity of 100 parts/million. The molten silicon may be produced from polycrystalline silicon containing less than 1 part/million of impurity. The process may be carried out by induction heating in an atmosphere of argon at atmospheric pressure. Silicon may be separated from the product by dissolution with a mixture of nitric and hydrofluoric acid. The crystal structure of the product is mainly cubic with a small proportion of hexagonal and rhombohedral crystals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB37968/61A GB967933A (en) | 1961-10-23 | 1961-10-23 | Improvements in or relating to methods of preparing crystalline silicon carbide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB37968/61A GB967933A (en) | 1961-10-23 | 1961-10-23 | Improvements in or relating to methods of preparing crystalline silicon carbide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB967933A true GB967933A (en) | 1964-08-26 |
Family
ID=10400287
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB37968/61A Expired GB967933A (en) | 1961-10-23 | 1961-10-23 | Improvements in or relating to methods of preparing crystalline silicon carbide |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB967933A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3254955A (en) * | 1962-08-28 | 1966-06-07 | George R Bird | Method of preparing a tantalum carbide crystal |
| US3438729A (en) * | 1965-07-16 | 1969-04-15 | Harold A Ohlgren | Preparation of finely divided crystalline metal carbides |
| GB2216145A (en) * | 1988-02-23 | 1989-10-04 | T & N Technology Ltd | Protecting graphite based articles with silicon carbide |
| CN117585679A (en) * | 2024-01-19 | 2024-02-23 | 昆明理工大学 | Method for preparing high-purity semi-insulating SiC powder by high-temperature solution method |
-
1961
- 1961-10-23 GB GB37968/61A patent/GB967933A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3254955A (en) * | 1962-08-28 | 1966-06-07 | George R Bird | Method of preparing a tantalum carbide crystal |
| US3438729A (en) * | 1965-07-16 | 1969-04-15 | Harold A Ohlgren | Preparation of finely divided crystalline metal carbides |
| GB2216145A (en) * | 1988-02-23 | 1989-10-04 | T & N Technology Ltd | Protecting graphite based articles with silicon carbide |
| GB2216145B (en) * | 1988-02-23 | 1992-06-03 | T & N Technology Ltd | Coatings |
| CN117585679A (en) * | 2024-01-19 | 2024-02-23 | 昆明理工大学 | Method for preparing high-purity semi-insulating SiC powder by high-temperature solution method |
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