JP6968653B2 - Method for manufacturing Al4SiC4 powder - Google Patents

Description

The present invention relates to a method for producing _{Al 4} SiC _{4 powder.}

Generally, antioxidants such as metallic Al, metallic Si, and Al—Mg alloys are added to refractories such as bricks and heat resistant paints for the purpose of suppressing deterioration due to oxidation. For example, in a refractory material containing carbon (MgO-C brick), when exposed to a high temperature, the carbon in the refractory material reacts with oxygen in the atmosphere and disappears as a carbon oxide-based gas. When such carbon oxidation reaction proceeds, voids are formed in the refractory material, and the refractory material is worn out. In order to prevent such an oxidation reaction, for example, if a metal Al is added to the refractory as an antioxidant, the metal Al can reduce carbon oxide and suppress the reduction of carbon due to the oxidation reaction. Can be done.

However, the metal Al may _{be changed to aluminum carbide (Al 4} C ₃ ) when carbon oxide is reduced, or may be changed to aluminum nitride (Al N) by reacting with nitrogen in the air. These aluminum compounds have the property of easily reacting with water, and if they are contained in the refractory material, they may absorb moisture and lead to the collapse of the refractory material.

_{Therefore, in recent years, Al 4} SiC ₄ has been attracting attention as an antioxidant that does not change to aluminum carbide or aluminum nitride. Al ₄ SiC ₄ has a high melting point of 2037 ° C. and is expected to be applied as a high temperature and structural material. In addition to its antioxidant effect, it is also expected to improve its mechanical properties.

As _{disclosed in Patent Document 1, Patent Document 2 and Patent Document 3, Al 4} SiC ₄ can be produced by mixing a raw material composed of an aluminum source, a carbon source and a silicon source and firing the raw material. .. In Patent Document 1, the crystal structure is hexagonal, describes _Al 4 SiC ₄ powder particle shape is a hexagonal plate shape, Patent Document 2, an average particle diameter of 1μm or less of _Al 4 SiC ₄ powder is described ing. _{In Patent Document 3, Al 4} SiC ₄ powder is obtained by calcining an alumina component or a silica component-containing substance and a carbon raw material.

Japanese Patent No. 5152654 Japanese Patent No. 6131625 Japanese Unexamined Patent Publication No. 2009-199061

However, as a result of studies by the present inventors, it has been found that, in general, Al ₄ SiC _{4 powder contains aluminum carbide (Al 4} C ₃ ) as a by-product during firing. As mentioned above, since aluminum carbide has the property of easily reacting with water, Al ₄ SiC ₄ powder containing aluminum carbide has reduced water resistance and moisture resistance, and such powder is used as an antioxidant for refractories and heat-resistant paints. When blended in, there is a risk of degrading the performance of refractories and heat-resistant paints.

Further, if _{the crystallinity size of the Al 4} SiC ₄ powder is small and the crystallinity is low, it easily reacts with the constituent materials of the refractory material and the heat-resistant paint, and there is a possibility that the effect as an antioxidant cannot be exhibited.

In view of the above situation, it is an object of the present invention to provide a production method for producing _{Al 4} SiC _{4 powder which does not substantially contain aluminum carbide (Al 4} C ₃ ) and has a large crystallite size. And.

The present inventors have succeeded in producing _{an Al 4} SiC _{4 powder which is substantially free of aluminum carbide (Al 4} C ₃ ) and has a large crystallite size.

The present invention comprises a step of firing a mixture of an aluminum source, a silicon source, a carbon source, and silicon carbide to _{produce Al 4} SiC ₄ powder, the aluminum contained in the aluminum source, the silicon source, and the carbide. Also in a method for producing _{Al 4} SiC ₄ powder using the aluminum source, the silicon source, and the silicon carbide in an amount such that the molar ratio Al / Si with silicon contained in silicon is 3.76 to 3.94. Related. Preferably, the firing is carried out in an inert atmosphere at a temperature of 1650 to 1900 ° C. for 1 to 10 hours.

_{The Al 4} SiC ₄ powder produced by the present invention is used as an antioxidant. Preferably, the antioxidant is used to be incorporated into refractory or heat resistant paints.

According to the present invention, it is possible to produce _{an Al 4} SiC _{4 powder which is substantially free of aluminum carbide (Al 4} C ₃ ) and has a large crystallite size. _{The Al 4} SiC ₄ powder obtained by the present invention is excellent in water resistance and moisture resistance because it does not substantially contain aluminum carbide (Al ₄ C ₃ ), and in addition, it has a large crystallinity size and excellent crystallinity. It can be suitably used as an antioxidant.

Chart obtained by X-ray diffraction analysis of _{Al 4} SiC ₄ produced in Example 2. Chart obtained by X-ray diffraction analysis of _{Al 4} SiC ₄ manufactured in Comparative Example 4. SEM photograph of _{Al 4} SiC ₄ manufactured in Example 2.

Hereinafter, embodiments of the present invention will be described in detail.
First, a _{method for producing the Al 4} SiC ₄ powder of the present invention will be described.

According to the present invention, an aluminum source, a silicon source, a carbon source, and silicon carbide are weighed and then sufficiently mixed, and the obtained mixture is calcined and pulverized to produce Al ₄ SiC ₄ powder. can do.

As the raw material aluminum source, metallic Al, aluminum compounds such as aluminum oxide and aluminum hydroxide can be used. From the viewpoint of purity, it is preferable to use metal Al.

As the raw material silicon source, metallic Si, a silicon compound such as silicon dioxide, or the like can be used. From the viewpoint of purity, it is preferable to use metallic Si.

As the carbon source of the raw material, scaly graphite, synthetic graphite, carbon black or the like can be used. It is preferable to use scaly graphite from the viewpoint of cost and availability.

These aluminum source, silicon source, and carbon source may be weighed in such an amount that the molar ratio of aluminum, silicon, and carbon contained therein is 4: 1: 4.

According to the production method of the present invention, in addition to these aluminum sources, silicon sources, and carbon sources, silicon carbide (SiC) is further weighed and added. By adding silicon carbide, the molar ratio Al / Si of Al and Si contained in the whole raw material after the addition is made to be lower than the theoretical ratio of 4.0 in _{Al 4} SiC _4. Specifically, it is carbonized in such an amount that the molar ratio Al / Si of aluminum contained in the aluminum source and the total silicon contained in the silicon source and silicon carbide is in the range of 3.76 or more and 3.94 or less. Add silicon. By adding silicon carbide, _{Al 4} C ₃ that deteriorates the water resistance of the _{Al 4} SiC ₄ powder is less likely to remain. When the molar ratio Al / Si is 3.95 or more, Al ₄ C ₃ is likely to remain, and when it is 3.75 or less, _{the crystallite size of the obtained Al 4} SiC ₄ powder becomes small. The lower limit of the molar ratio Al / Si is preferably 3.78 or more, more preferably 3.80 or more, and even more preferably 3.82 or more. The upper limit of the molar ratio Al / Si is preferably 3.92 or less, more preferably 3.90 or less, and even more preferably 3.89 or less.

When mixing the aluminum source, the silicon source, the carbon source, and silicon carbide, it is preferable to mix them as uniformly as possible. The specific mixing method is not particularly limited, but a container rotary mixer such as a V-type mixer, a ribbon mixer, a Henschel mixer, a professional share mixer, a dry ball mill and the like can be used. It is preferable to mix using a dry ball mill because the mixing of impurities can be reduced at low cost. The mixing conditions in the dry ball mill are not particularly limited, but the mixing is preferably carried out at room temperature for 5 hours or more. If the mixing time is shorter than 5 hours, the raw materials may not be mixed uniformly, which may adversely affect the properties of _{the obtained Al 4} SiC _{4 powder.}

Next, the obtained mixed raw material is calcined to synthesize _{Al 4} SiC _4. The firing may be any as long as it can be fired at 1650 to 1900 ° C. in an inert atmosphere, and is not particularly limited. Inductive heating furnaces, direct energization type electric furnaces, etc. can be used. The synthesis of Al ₄ SiC ₄ by calcination proceeds in a two-step reaction. First, Al, Si and C react to form Al ₄ C ₃ and SiC (Formula II). Next, in a temperature range of 1300 ° C. or higher, Al ₄ C ₃ reacts with SiC _{to synthesize Al 4 SiC 4} (Formula III).
Formula II: 4Al (s) + Si (s) + 3C (s) → Al 4 C 3 (s) + SiC (s)
Equation III: Al ₄ C ₃ (s) + SiC (s) → Al ₄ SiC ₄ (s)

Since the reaction of formula III proceeds slowly below 1650 ° C. and Al ₄ C ₃ tends to remain after the reaction, the calcination temperature is preferably 1650 ° C. or higher. When the firing temperature exceeds 1900 ° C, _{a part of Al 4} SiC ₄ is thermally decomposed. Therefore, the upper limit of the firing temperature is preferably 1900 ° C or lower, more preferably 1800 ° C or lower, and further preferably 1750 ° C or lower. The firing time may be appropriately adjusted according to the firing temperature, but is preferably about 1 to 10 hours.

When nitrogen is present in the atmosphere in the firing furnace, the nitrogen may react with the metal Al to produce aluminum nitride (AlN) as a by-product. Therefore, the firing is preferably performed in an atmosphere of an inert gas such as argon, and more specifically, the firing is performed while the inert gas such as argon is allowed to flow in the firing furnace. The firing furnace to be used is preferably filled with an inert gas in advance to remove residual nitrogen and carbon.

_{The Al 4} SiC ₄ powder obtained by firing is preferably pulverized by pulverization. The crushing method is not particularly limited, but a jaw crusher, a cone crusher, an impact crusher, a roll crusher, a cutter mill, a stamp mill, a ring mill, a jet mill, a hammer mill, a pin mill, a dry ball mill, a vibration mill, a bead mill and the like can be used. It is preferable to use a dry ball mill because it can reduce the mixing of impurities at low cost. Grinding with a dry ball mill is preferably carried out for 1 hour or more. When the crushing time is shorter than 1 hour, the average particle size of the obtained aluminum silicon carbide powder tends to be large, and the specific surface area tends to be small.

By the above steps, _{Al 4} SiC _{4 powder which does not substantially contain aluminum carbide (Al 4} C ₃ ) and has a large crystallite size can be produced, but the production method of the present invention is shown above. It is not limited to the details.

_{Next, the Al 4} SiC ₄ powder produced by the present invention will be described.
_{Al 4} SiC ₄ in the present invention does not mean that the molar ratio of Al, Si and C is exactly 4: 1: 4. The significant figure of the molar ratio is one digit, and for example, the case where Al / Si is in the range of 3.76 or more and 3.94 or less as described above is also included in the range of the composition formula.

_{The Al 4} SiC ₄ powder produced by the present invention exhibits excellent water resistance and moisture resistance, and is substantially free of the _{by-product Al 4} C _3. This point is specified by comparing the peak height of _{the principal component Al 4} SiC _{4 with} the peak height of the by-product Al ₄ C ₃ by powder X-ray diffraction analysis using CuKα rays. That is, the peak height near 2θ = 56.03 ° caused by the main component Al ₄ SiC _{4 is I 56.03 °,} and the peak height near 2θ = 55.11 ° caused by the by-product Al ₄ C _{3 is set.} When I is _{56.03 °} , _{the value of I 55.11 °} / I _{56.03 °} is preferably 0.001 or less, more preferably 0.0005 or less, and 0.0001 or less. Is even more preferable. Most preferably, _{the value of I 55.11 °} / I _{56.03 °} is 0, that is, no peak near 2θ = 55.11 ° due to the _{by-product Al 4} C _{3 is observed.}

Further, the growth of the Al ₄ SiC ₄ powder in the crystal orientation (0010) direction improves the packing property, fluidity, and dispersibility of the particles, so that the strength is not impaired even when added to a refractory material. Further, since it can be uniformly dispersed in the paint, it has an effect of improving the antioxidant effect. Growth in the crystal orientation (0010) direction is specified by comparing the peak height due to the (101) plane with the peak height due to the (0010) plane by powder X-ray diffraction analysis using CuKα rays. do. That is, the peak height near 2θ = 31.74 ° caused by the (101) plane is I _{31.74 °,} and the peak height near 2θ = 41.54 ° caused by the (0010) plane is I _{41.54 °.} When _{°, I} value of _{31.74 °} / _{I 41.54 °} is preferably at greater than 1.0 and 1.5 or less, more preferably greater than 1.0 1.4 or less, It is more preferably larger than 1.0 and 1.3 or less.

The powder X-ray diffraction analysis by CuKα ray was performed using MiniFlex 600 (manufactured by Rigaku Co., Ltd.). The measured diffraction intensity is plotted on a graph with the horizontal axis as the X-ray incident angle 2θ (unit: °) and the vertical axis as the diffraction intensity (unit: cps), and the specific incident angle and the peak height of the diffraction intensity are calculated. I read it. The measurement was performed under the conditions of an X-ray source CuKα ray (0.154 nm), a scanning speed of 2 ° / min, a scanning range of 2θ = 3 to 90 °, and a sampling interval of 0.02 °.

_{In addition, the Al 4} SiC ₄ powder produced according to the present invention has excellent crystallinity and has a relatively large crystallinity size. Specifically, it is preferable that the crystallite size of the (101) plane in the powder X-ray diffraction analysis using the CuKα ray is 800 Å or more. The crystallite size of the Al ₄ SiC ₄ powder _is associated with the reactivity of the Al 4 SiC _4, when said binding crystallite size _decreases, there is a tendency that the reactivity of the Al 4 SiC ₄ becomes high. _{Therefore, the Al 4} SiC ₄ powder having a small crystallite size easily reacts with a carbon oxide-based gas generated by thermal decomposition such as a refractory material containing the powder, a base material of a heat-resistant paint, or a binder. The reaction consumes the original antioxidant effect expected of _{Al 4} SiC _{4, which is not preferable.} From the above viewpoint, the crystallite size of the (101) plane is preferably 800 Å or more, more preferably 810 Å or more, and further preferably 820 Å or more.

On the contrary, when the crystallite size of _{Al 4} SiC _{4 powder becomes large, the reactivity of Al 4} SiC ₄ tends to be low. Therefore, if the reactivity becomes too low, the _{antioxidant effect of Al 4} SiC ₄ is sufficiently exhibited. Will not be done. The upper limit of the crystallite size for use as an antioxidant is preferably less than 1000 Å, more preferably less than 980 Å, still more preferably less than 950 Å.

The crystallite size of Al ₄ SiC ₄ powder is determined by measuring the half width of the peak near 2θ = 31.74 ° caused by the (101) plane in the powder X-ray diffraction analysis using the CuKα ray described above, and using the Scherrer equation. It is calculated using.

_{The particle size of the Al 4} SiC ₄ powder produced by the present invention is not particularly limited and can be appropriately determined according to its use. However, in applications of blending into refractories and heat-resistant paints as antioxidants, the cumulative 50% particle size on a volume basis is preferably 5 to 100 μm, more preferably 10 to 80 μm, and 15 to 50 μm. It is more preferable to have.

If the particle size is less than 5 μm, it becomes difficult to handle the powder, the viscosity of the paint increases when it is blended into the paint, and it cannot be used as a paint, and the reactivity becomes too high to react with the base material and oxidize. Cannot be used as an inhibitor. When the particle size is larger than 100 μm, the density of the refractory decreases and the strength of the refractory decreases when the _{Al 4} SiC _{4 powder produced by the present invention is added to the refractory.} Further, when the particles are added to the heat-resistant paint, the particles tend to settle in the paint, so that the finish of the coating film deteriorates and its characteristics deteriorate.

The cumulative 50% particle size based on the volume is measured by a laser diffraction / scattering method, and specifically, is measured using a laser diffraction / scattering type particle size distribution measuring device MT3300 (manufactured by Nikkiso Co., Ltd.). Methanol is used as a solvent, and the powder is dispersed at 120 W for 3 minutes with an ultrasonic homogenizer US-300T (manufactured by Nissei Tokyo Office Co., Ltd.), and then the particle size is measured.

_{Further, the specific surface area of the Al 4} SiC ₄ powder produced according to the present invention is not particularly limited and can be appropriately determined according to its use. However, from the viewpoint of effectively fully exhibited as an antioxidant, it is preferable that the BET specific surface area is 0.01~10m ² / g, more preferably 0.05~5m ² / g, 0 It is more preferably 1 to ^{2 m 2 / g.} If the BET specific surface area is ^{less than 0.01 m 2} / g, the reactivity becomes too low and the _{antioxidant effect of Al 4} SiC ₄ is not exhibited. If the BET specific surface area is ^{larger than 10 m 2} / g, it becomes difficult to handle the powder, and the reactivity becomes too high to react with the base material, so that it cannot be used as an antioxidant.

The BET specific surface area is measured by a gas adsorption method (BET method) using a specific surface area measuring device (trade name: Macsorb1210, manufactured by Mountain Co., Ltd.).

_{The particle shape of the Al 4} SiC ₄ powder produced by the present invention was observed using a scanning electron microscope (SEM) (manufactured by JSM6510LA JEOL Ltd.).

_{The Al 4} SiC ₄ powder produced by the present invention has excellent water resistance and moisture resistance, and as an index showing this, the pH value indicated by the suspension when the powder is suspended in water is used. Can be used. Since Al ₄ SiC ₄ does not react with water, the pH value does not change even if _{Al 4} SiC _{4 is suspended in water, indicating neutrality. However, when Al 4} C ₃ which deteriorates water resistance is contained in the powder, when this powder is suspended in water, Al ₄ C ₃ reacts with water and Al (OH) as shown in the following formula I. _{Since 3} is generated, the pH value of the suspension changes to the alkaline side.
Formula I: Al ₄ C ₃ + 12H ₂ O → 4Al (OH) ₃ + 3CH ₄

Therefore, the fact that the pH of the suspension obtained by suspending the powder in water is close to neutral means that the powder does not substantially contain _{Al 4} C _{3 that lowers the water resistance, and the powder is water resistant.} It is an index showing that it has excellent properties and moisture resistance. From the above viewpoint, when the Al ₄ SiC ₄ powder produced by the present invention is suspended in pure water at 25 ° C., the pH value of the suspension is 6.5 to 7.5. It is preferably 6.5 to 7.3, more preferably 6.5 to 7.0, and even more preferably 6.5 to 7.0.

Specifically, the pH value is measured by the following method. 50 ml of pure water is placed in a 100 cc chemical resistant glass beaker and kept at a temperature of 25 ° C. 5 g of the sample powder is put into this, and the mixture is stirred with a stirrer for 1 minute and allowed to stand for 5 minutes. The pH value after 5 minutes is measured using a pH meter (glass electrode type hydrogen ion concentration indicator D-54, manufactured by Horiba STEC Co., Ltd.). The pH meter used was calibrated with a known buffer solution.

(Use)
_{The Al 4} SiC ₄ powder produced by the present invention can be used as an antioxidant to be added to refractories such as MgO-C bricks. It can also be applied to the surface of steel materials (particularly steel slabs) and used as an antioxidant to be added to heat-resistant paints used to prevent the generation of scale in a high-temperature oxidizing atmosphere. Alternatively, it can also be used as an antioxidant to be blended in a carbon / carbon composite material.

_{The amount of Al 4} SiC ₄ powder added in these applications is not particularly limited and can be appropriately set according to the purpose. For example, when used as an antioxidant to be added to a refractory, the weight is 1 to 10 weight. % Range is preferred. _{The method for producing a refractory containing Al 4} SiC ₄ powder produced according to the present invention can follow a known method, for example, the method disclosed in Patent Document 2.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

In the following Examples and Comparative Examples, the method for measuring each physical property followed the above-mentioned method.

<Example 1>
A raw material composed of metallic Al (purity 99%, particle size 50 μm or less), metallic Si (purity 98%, particle size 50 μm or less), and scaly graphite (purity 98%, particle size 100 μm or less) is converted into molars of Al: Si: C = 44. Weighed so as to be .44 mol%: 11.11 mol%: 44.44 mol%. Further, SiC (purity 99%, particle size 50 μm or less) was weighed so that the Al / Si molar ratio in the whole raw material was 3.82.

These raw materials were dry-mixed for 10 hours using a ball mill. The obtained mixed raw material was put into a firing furnace and fired at 1700 ° C. for 5 hours while flowing argon gas. After firing, it was pulverized with a dry ball mill for 10 hours to obtain _{Al 4} SiC _{4 powder.}

The obtained Al ₄ SiC ₄ powder had I _{55.11 °} / I _{56.03 °} = 0, I _{31.74 °} / I _{41.54 °} = 1.17, and (101) plane crystallite size 817 Å. The cumulative 50% particle size on a volume basis was 21.18 μm, and the BET specific surface area was 0.40 m ² / g.

<Example 2>
_{Al 4} SiC ₄ powder was obtained by the same method as in Example 1 except that the amount of SiC added was changed so that the Al / Si molar ratio in the whole raw material was 3.89.

The obtained Al ₄ SiC ₄ powder had I _{55.11 °} / I _{56.03 °} = 0, I _{31.74 °} / I _{41.54 °} = 1.04, and (101) plane crystallite size 949 Å. The cumulative 50% particle size on a volume basis was 19.49 μm, and the BET specific surface area was 0.48 m ² / g.

<Example 3>
_{Al 4} SiC ₄ powder was obtained by the same method as in Example 2 except that the firing temperature was set to 1650 ° C.

The obtained Al ₄ SiC ₄ powder had I _{55.11 °} / I _{56.03 °} = 0, I _{31.74 °} / I _{41.54 °} = 1.14, crystallite size of (101) plane, 937 Å. The cumulative 50% particle size on a volume basis was 20.93 μm, and the BET specific surface area was 0.53 m ² / g.

<Comparative Example 1>
The raw materials composed of metallic Al, metallic Si, and scaly graphite were weighed so as to have Al: Si: C = 44.44 mol%: 11.11 mol%: 44.44 mol% in terms of molars. The Al / Si molar ratio in the whole raw material is 4.0.

These three raw materials were dry-mixed for 10 hours using a ball mill. The obtained mixed raw material was put into a firing furnace and fired at 1700 ° C. for 5 hours while flowing argon gas. After firing, it was pulverized with a dry ball mill for 10 hours to obtain _{Al 4} SiC _{4 powder.}

The obtained Al ₄ SiC ₄ powder had I _{55.11 °} / I _{56.03 °} = 0.0043, I _{31.74 °} / I _{41.54 °} = 1.18, and (101) plane crystallite size. The cumulative 50% particle size on a volume basis was 20.81 μm, and the BET specific surface area was 0.47 m ² / g.

<Comparative Example 2>
_{Al 4} SiC ₄ powder was obtained by the same method as in Example 1 except that the amount of SiC added was changed so that the Al / Si molar ratio in the whole raw material was 3.95.

The obtained Al ₄ SiC ₄ powder had I _{55.11 °} / I _{56.03 °} = 0.0024, I _{31.74 °} / I _{41.54 °} = 1.12, and (101) plane crystallite size. The cumulative 50% particle size on a volume basis was 832 Å, the particle size was 20.99 μm, and the BET specific surface area was 0.40 m ² / g.

<Comparative Example 3>
_{Al 4} SiC ₄ powder was obtained by the same method as in Example 1 except that the amount of SiC added was changed so that the Al / Si molar ratio in the whole raw material was 3.75.

The obtained Al ₄ SiC ₄ powder had I _{55.11 °} / I _{56.03 °} = 0, I _{31.74 °} / I _{41.54 °} = 1.04, and (101) plane crystallite size 790 Å. The cumulative 50% particle size on a volume basis was 21.71 μm, and the BET specific surface area was 0.38 m ² / g.

<Comparative Example 4>
_{Al 4} SiC ₄ powder was obtained by the same method as in Example 2 except that the firing temperature was set to 1600 ° C.

The obtained Al ₄ SiC ₄ powder had I _{55.11 °} / I _{56.03 °} = 0.0088, I _{31.74 °} / I _{41.54 °} = 0.95, and (101) plane crystallite size. The cumulative 50% particle size on a volume basis was 20.29 μm, and the BET specific surface area was 0.62 m ² / g.
The above results are summarized in Table 1.

_{In the Al 4} SiC ₄ powders obtained in Examples 1 to _{3 , the peak of Al 4} C 3 was not observed in the powder X-ray diffraction _{, I 55.11 °} / I _{56.03 °} was 0, and I was 0. The crystallinity size of the (101) plane was 800 Å or more, which was excellent in crystallinity.

_{On the other hand, the Al 4} SiC ₄ powders obtained in Comparative Examples 1, 2 and 4 had I _{55.11 °} / I _{56.03 °} exceeding 0.001 and contained a considerable amount of _{Al 4} C _{3. It was judged that the Al 4} SiC ₄ powder obtained in Comparative Examples 3 and 4 had a crystallinity size of the (101) plane of less than 800 Å and was inferior in crystallinity.

Claims (1)

Including the step of calcining a mixture consisting of an aluminum source, a silicon source, a carbon source, and silicon carbide to _{produce Al 4} SiC _{4 powder.}
The aluminum source, the silicon source, and the silicon carbide in an amount such that the molar ratio Al / Si of the aluminum contained in the aluminum source to the silicon source and the silicon contained in the silicon carbide is 3.76 to 3.94. Using ,
The method for producing Al ₄ SiC ₄ powder, wherein the firing is carried out in an inert atmosphere at a temperature of 1650 to 1900 ° C. for 1 to 10 hours.

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