CA1247326A - Process for production of silicon nitride - Google Patents
Process for production of silicon nitrideInfo
- Publication number
- CA1247326A CA1247326A CA000512074A CA512074A CA1247326A CA 1247326 A CA1247326 A CA 1247326A CA 000512074 A CA000512074 A CA 000512074A CA 512074 A CA512074 A CA 512074A CA 1247326 A CA1247326 A CA 1247326A
- Authority
- CA
- Canada
- Prior art keywords
- silicon nitride
- production
- frm
- polycarbosilane
- ammonia
- 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
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
- C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
- C04B35/589—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride obtained from Si-containing polymer precursors or organosilicon monomers
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
- C30B25/005—Growth of whiskers or needles
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/38—Nitrides
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Crystallography & Structural Chemistry (AREA)
- Ceramic Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Structural Engineering (AREA)
- Inorganic Fibers (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Ceramic Products (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for the production of a whisker of silicon nitride comprising the step of: firing polycarbosilane in the form of powder or spun fibers at 1300° or above in an ammonia gas atmosphere or in a stream of nitrogen and ammonia gases within a firing furnace.
A process for the production of a whisker of silicon nitride comprising the step of: firing polycarbosilane in the form of powder or spun fibers at 1300° or above in an ammonia gas atmosphere or in a stream of nitrogen and ammonia gases within a firing furnace.
Description
3L,'~7326 TITLE OF THE INVENTION
PROCESS FOR PRODUCTION OF SILICON NITRIDE
S BACKGROUND OF THE INVENTION
1. Field of the Invention This invention xelates to a process for the production of a whisker of silicon nitride, and more particularly to a process for the production of a whisker of silicon nitride which is well compatible with metal at the time of producing a fiber reinforced metal.
PROCESS FOR PRODUCTION OF SILICON NITRIDE
S BACKGROUND OF THE INVENTION
1. Field of the Invention This invention xelates to a process for the production of a whisker of silicon nitride, and more particularly to a process for the production of a whisker of silicon nitride which is well compatible with metal at the time of producing a fiber reinforced metal.
2. Prior Art In order to produce silicon nitride, various kinds of methods have heretofore been carried out as shown in the following chemical reaction formulas. The methods so carried out include a method comprising the reduction of silica having a high purity with coke at a high temperature according to the chemical reaction formula (1), a method comprising the reaction of silicon tetrachloride with ammonia in a vapor phase according to the reaction formula (23, a method comprising the decomposition of ~ilicon imide in a vapor phase (formula
(3)1 and a method comprising the direct nitriding of silicon metal (formula (4)):
3SiO2 t 6C + 2N2 ~ Si3N4 ~ 6CO ... (1) 3SiC14+ 4NH3 iSi3N4 t 12HCl ... (2) 3Si(NH)2 -~ Si3N4 ~ 2NH3 ... (3) 3Si ~ 2N2- > Si3N4 -- ( ) To produce silicon nitride by the conv~ntional methods, it is difficult to perfectly separate the product from starting materials therefor. Accordingly, highly pure silicon nitride is not obtained. When such lZ~32~
less pure silicon nitride is used as a reinforcing material for fiber reinforced metals ~hereinafter referred to as "FRM"~, the silicon nitride will not be compatible with the metal whereby a FRM having excellent characteristics is not obtained.
The present inventors further studied in attempts -to find a process for the production of excellent fibrous silicon nitride and, as a result, they found that when poycarbosilane in the form of powder or spun fibers is fired at 1300C or above in an atmosphere o ammonia, a whisker of silicon nitride will be obtained and that when the whisker thus obtained is used in the produc-tion of a fiber-reinforced metal ~FRM), a FRM having excellent characteristics will be obtained.
Thus, they accomplished the present invention.
SUMMARY OF THE INVENTION
The cxux of the present invention is to obtain - a whisker of silicon nitride by baking or firing ; 20 polycarbosilane in the form of powder or spun fibers at 1300C or above in an atmosphere of ammonia gas.
The polycarbosilane is shown by the following formula R
~Si-CH2~n .. , R2 wherein R1 and R2 are each an alkyl group having 1 to 5 carbon atoms or a phenyl group, they may be identical with each other at the same time, and n is an integer of 1 to 5. The reaction for obtaining the desired silicon nitride is shown by the following reaction formula at least Rl 1300C
~Si-CH2~ t NH3 ~Si3N4 .. . .
~73Z6 BRIEF DESCRIPTION OF THE DRAWINGS
. .
This invention will be better understood by reference to the accompanying drawings in which~
Fig. 1 is a diffraction pattern of X-rays of silicon nitride obtained according to this invention;
Fig. 2 is a photomicrograph (magnification:
3000) of the silicon nitride in Fig. 1; and Fig. 3 shows an arrangement of an apparatus for producing the silicon nitrideO
DETAILED DESCRIPTION OF THE INVENTION
Now, an ordinary apparatus for the syntheses of silicon nitride will be explained with reference to the accompanying drawings.
Referring to Fig. 3, reference numeral 1 designates a bomb of nitrogen gas having a high purity, 2 a bomb of ammonia gas having a high purity, 3 and 4 flow meters respectively, and 5 and 6 stop valves respectively. Reference numeral 7 designates a gas blender of ammonia and nitrogen gases, tubes for supplying the ammonia and nitrogen gases to said blender being provided with check valves 8,9, respectively. A
mixture of the nitrogen and ammonia gases is dried in a dry column 10 to be supp~ied in a firing furnace 11.
When fired in a firing furnace 11, polycarbosilane is charged into a boat put therein, after which said furnace is reduced in pressure with the aid of a vacuum pump 12 and then heated while passing a mixture of the ammonia and nitrogen gases into said furnace, thereby converting the polycarbosilane in the furnace to a desired silicon nitride. Further, reference numeral 13 in the drawings designates a manometer and 14 a stopper for preventing a reverse flow.
The silicon nitride obtained according to the present invention is in the form of a whisker and when it is used in producing a FRM, it will be well , ~æ~3~
compatible with a metal due to its low content of impurities, thereby being able to obtain a FR~ having a high strength. Further, ~he pr~cass for the production of silicon nitride according to the present in~ention is simple co~paring with the conventional processes. More specifically, it only compri~es treating a polycarbosilane at 1300C or above in an atmosphere of ammonia.
The whis~er FRM sf the present invention may be subjected to a conventional technique of processi~g aluminium. It may thus be extrusion molded, roll molded and forged to obtain round bars, sheets, deformed articles and pipes which are all high in tensile modulus, tensile streng~h and fibrous volume.
Example One hundred grams (lOOg) o~ particulate polycarbosilane (average molecular weight is about 2000, and melting point is 220 to 230C) were charged in an ZO almina boat which is place in a small-sized tubular ~urnace (Siliconit th rmogenic element) and then fired therein for one hour at 1400 while flowing 005Q
/min. of each of high puri~y ammonia ga~ and high purity nitrogen gas thereby to obtain a ~ired ~Oay.
The ~ired body thus obtained was subjected to X-rays di~fraction thereby to find peaks at 43~4, 38.9, 35.3, 34.8~, 31.0, 22.9 a~d 20.6 at 20 respectively as shown in Fig~ 1 and was confirmed to be ~-Si3N4. Fur~her, a pho~omicrograph of 3000 magnification of the fired body indicated that the fibers were in the whisker form and were 0.1 to 2.2~m in diameter and at least 0.2 mm, in length as shown in Fig.
o Experiment 1 (Whisker FRM) co~lta~ning ~h~ n,o~-~id~h~iske~
was producëd by a high pressure forgoing method ~2~73Z6 according to JIS Matrix A-6061. The FRM thus obtained was measured for its volume of fibers (vf) with the result of 30~. The observation of the inner part of the FRM revealed that the FRM had no voids and both the fibers and the matrix were bonded together enough to form a secure composite thereof.
The FRM was also measured for mechanical properties at room temperature (293K) with the result that the tensile strength was 80 Kg/mm2 and the tensile modulus 15 ton/mm2.
On the other hand, the vf of the conventional product was lS~ and the tensile strength thereof was 20 Kg/mm2.
Experiment 2 A sheet-like FRM containing silicon nitride whisker was obtained from the FRM billet made in Experiment 1 by means of roll forming. The result of measuremen~ of vf of the product thus obtained was 30%.
The observation of the inner part of the product revealed that the product had a secure composite structure in which no voids existed and the adhesion of the fibers to the matrix was satisfactory~ The result of the measurement of the mechanical characteristics of the product at room temperature (293K~ was 80 Xg/mm2 in tensile strength and 15 ton/mm2 in tensile modulus.
Experiment 3 A bar-shaped FRM containing the silicon nitride whisker was produced from the FRM billet made in Experiment 1 by means of extrusion forming. The result of the measurement of vf of the product thus obtained was 30%. The product was confirmed to be a good composi~e scarcely having fibrous break and having the fibers oriented in the extruding direction. The mechanical properties measured at room temperature (293K) were 100 Kg/mm2 in tensile strength and 18 ~Z9~73~i ton/mm2 in tensile modulus.
Further, the high temperature property of the product was found to be 80 Kg/mm2 at 300C, which was a very high strength as compared with those of conventional aluminium alloys.
3SiO2 t 6C + 2N2 ~ Si3N4 ~ 6CO ... (1) 3SiC14+ 4NH3 iSi3N4 t 12HCl ... (2) 3Si(NH)2 -~ Si3N4 ~ 2NH3 ... (3) 3Si ~ 2N2- > Si3N4 -- ( ) To produce silicon nitride by the conv~ntional methods, it is difficult to perfectly separate the product from starting materials therefor. Accordingly, highly pure silicon nitride is not obtained. When such lZ~32~
less pure silicon nitride is used as a reinforcing material for fiber reinforced metals ~hereinafter referred to as "FRM"~, the silicon nitride will not be compatible with the metal whereby a FRM having excellent characteristics is not obtained.
The present inventors further studied in attempts -to find a process for the production of excellent fibrous silicon nitride and, as a result, they found that when poycarbosilane in the form of powder or spun fibers is fired at 1300C or above in an atmosphere o ammonia, a whisker of silicon nitride will be obtained and that when the whisker thus obtained is used in the produc-tion of a fiber-reinforced metal ~FRM), a FRM having excellent characteristics will be obtained.
Thus, they accomplished the present invention.
SUMMARY OF THE INVENTION
The cxux of the present invention is to obtain - a whisker of silicon nitride by baking or firing ; 20 polycarbosilane in the form of powder or spun fibers at 1300C or above in an atmosphere of ammonia gas.
The polycarbosilane is shown by the following formula R
~Si-CH2~n .. , R2 wherein R1 and R2 are each an alkyl group having 1 to 5 carbon atoms or a phenyl group, they may be identical with each other at the same time, and n is an integer of 1 to 5. The reaction for obtaining the desired silicon nitride is shown by the following reaction formula at least Rl 1300C
~Si-CH2~ t NH3 ~Si3N4 .. . .
~73Z6 BRIEF DESCRIPTION OF THE DRAWINGS
. .
This invention will be better understood by reference to the accompanying drawings in which~
Fig. 1 is a diffraction pattern of X-rays of silicon nitride obtained according to this invention;
Fig. 2 is a photomicrograph (magnification:
3000) of the silicon nitride in Fig. 1; and Fig. 3 shows an arrangement of an apparatus for producing the silicon nitrideO
DETAILED DESCRIPTION OF THE INVENTION
Now, an ordinary apparatus for the syntheses of silicon nitride will be explained with reference to the accompanying drawings.
Referring to Fig. 3, reference numeral 1 designates a bomb of nitrogen gas having a high purity, 2 a bomb of ammonia gas having a high purity, 3 and 4 flow meters respectively, and 5 and 6 stop valves respectively. Reference numeral 7 designates a gas blender of ammonia and nitrogen gases, tubes for supplying the ammonia and nitrogen gases to said blender being provided with check valves 8,9, respectively. A
mixture of the nitrogen and ammonia gases is dried in a dry column 10 to be supp~ied in a firing furnace 11.
When fired in a firing furnace 11, polycarbosilane is charged into a boat put therein, after which said furnace is reduced in pressure with the aid of a vacuum pump 12 and then heated while passing a mixture of the ammonia and nitrogen gases into said furnace, thereby converting the polycarbosilane in the furnace to a desired silicon nitride. Further, reference numeral 13 in the drawings designates a manometer and 14 a stopper for preventing a reverse flow.
The silicon nitride obtained according to the present invention is in the form of a whisker and when it is used in producing a FRM, it will be well , ~æ~3~
compatible with a metal due to its low content of impurities, thereby being able to obtain a FR~ having a high strength. Further, ~he pr~cass for the production of silicon nitride according to the present in~ention is simple co~paring with the conventional processes. More specifically, it only compri~es treating a polycarbosilane at 1300C or above in an atmosphere of ammonia.
The whis~er FRM sf the present invention may be subjected to a conventional technique of processi~g aluminium. It may thus be extrusion molded, roll molded and forged to obtain round bars, sheets, deformed articles and pipes which are all high in tensile modulus, tensile streng~h and fibrous volume.
Example One hundred grams (lOOg) o~ particulate polycarbosilane (average molecular weight is about 2000, and melting point is 220 to 230C) were charged in an ZO almina boat which is place in a small-sized tubular ~urnace (Siliconit th rmogenic element) and then fired therein for one hour at 1400 while flowing 005Q
/min. of each of high puri~y ammonia ga~ and high purity nitrogen gas thereby to obtain a ~ired ~Oay.
The ~ired body thus obtained was subjected to X-rays di~fraction thereby to find peaks at 43~4, 38.9, 35.3, 34.8~, 31.0, 22.9 a~d 20.6 at 20 respectively as shown in Fig~ 1 and was confirmed to be ~-Si3N4. Fur~her, a pho~omicrograph of 3000 magnification of the fired body indicated that the fibers were in the whisker form and were 0.1 to 2.2~m in diameter and at least 0.2 mm, in length as shown in Fig.
o Experiment 1 (Whisker FRM) co~lta~ning ~h~ n,o~-~id~h~iske~
was producëd by a high pressure forgoing method ~2~73Z6 according to JIS Matrix A-6061. The FRM thus obtained was measured for its volume of fibers (vf) with the result of 30~. The observation of the inner part of the FRM revealed that the FRM had no voids and both the fibers and the matrix were bonded together enough to form a secure composite thereof.
The FRM was also measured for mechanical properties at room temperature (293K) with the result that the tensile strength was 80 Kg/mm2 and the tensile modulus 15 ton/mm2.
On the other hand, the vf of the conventional product was lS~ and the tensile strength thereof was 20 Kg/mm2.
Experiment 2 A sheet-like FRM containing silicon nitride whisker was obtained from the FRM billet made in Experiment 1 by means of roll forming. The result of measuremen~ of vf of the product thus obtained was 30%.
The observation of the inner part of the product revealed that the product had a secure composite structure in which no voids existed and the adhesion of the fibers to the matrix was satisfactory~ The result of the measurement of the mechanical characteristics of the product at room temperature (293K~ was 80 Xg/mm2 in tensile strength and 15 ton/mm2 in tensile modulus.
Experiment 3 A bar-shaped FRM containing the silicon nitride whisker was produced from the FRM billet made in Experiment 1 by means of extrusion forming. The result of the measurement of vf of the product thus obtained was 30%. The product was confirmed to be a good composi~e scarcely having fibrous break and having the fibers oriented in the extruding direction. The mechanical properties measured at room temperature (293K) were 100 Kg/mm2 in tensile strength and 18 ~Z9~73~i ton/mm2 in tensile modulus.
Further, the high temperature property of the product was found to be 80 Kg/mm2 at 300C, which was a very high strength as compared with those of conventional aluminium alloys.
Claims (2)
1. A process for the production of silicon nitride comprising firing polycarbosilane in the form of powder or spun fibers at 1300°C or above in an ammonia gas atmosphere, said polycarbosilane having the general formula:
wherein R1 and R2 are each an alkyl group having 1 to 5 carbon atoms or a phenyl group, they may be identical with each other at the same time, and n is an integer of 1 to 5.
wherein R1 and R2 are each an alkyl group having 1 to 5 carbon atoms or a phenyl group, they may be identical with each other at the same time, and n is an integer of 1 to 5.
2. A process for the production of silicon nitride according to claim 1, wherein the ammonia gas atmosphere consists of a stream of ammonia gas and nitrogen gas in mixture.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60134350A JPS61295298A (en) | 1985-06-21 | 1985-06-21 | Preparation of silicon nitride |
| JP134350/85 | 1985-06-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1247326A true CA1247326A (en) | 1988-12-28 |
Family
ID=15126305
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000512074A Expired CA1247326A (en) | 1985-06-21 | 1986-06-20 | Process for production of silicon nitride |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS61295298A (en) |
| CA (1) | CA1247326A (en) |
| DE (1) | DE3619888A1 (en) |
| FR (1) | FR2583734B1 (en) |
| GB (1) | GB2178417B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3707225A1 (en) * | 1987-03-06 | 1988-09-15 | Wacker Chemie Gmbh | METHOD FOR PRODUCING SILICON CARBIDE FIBER |
| US5814290A (en) * | 1995-07-24 | 1998-09-29 | Hyperion Catalysis International | Silicon nitride nanowhiskers and method of making same |
| CN102659086B (en) * | 2012-05-04 | 2014-08-20 | 中国人民解放军国防科学技术大学 | Preparation method of silicon nitride nanometer fiber felt |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3399979A (en) * | 1963-11-01 | 1968-09-03 | Union Carbide Corp | Process for producing metal nitride fibers, textiles and shapes |
| US4097294A (en) * | 1976-08-23 | 1978-06-27 | The United States Of America As Represented By The Secretary Of The Navy | Preparation of ceramics |
| US4761389A (en) * | 1985-04-01 | 1988-08-02 | Dow Corning Corporation | Process for preparing ceramic materials with reduced carbon levels |
-
1985
- 1985-06-21 JP JP60134350A patent/JPS61295298A/en active Granted
-
1986
- 1986-06-09 GB GB08613939A patent/GB2178417B/en not_active Expired
- 1986-06-13 DE DE19863619888 patent/DE3619888A1/en not_active Withdrawn
- 1986-06-20 CA CA000512074A patent/CA1247326A/en not_active Expired
- 1986-06-20 FR FR868608925A patent/FR2583734B1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB8613939D0 (en) | 1986-07-16 |
| FR2583734B1 (en) | 1990-08-31 |
| GB2178417A (en) | 1987-02-11 |
| FR2583734A1 (en) | 1986-12-26 |
| JPH0477719B2 (en) | 1992-12-09 |
| JPS61295298A (en) | 1986-12-26 |
| GB2178417B (en) | 1988-10-26 |
| DE3619888A1 (en) | 1987-01-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |