JP3290686B2 - Method for producing aluminum nitride powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing aluminum nitride powder by a reduction nitridation method, and more particularly to a method for producing aluminum nitride powder exhibiting easy sinterability.

[0002]

2. Description of the Related Art Aluminum nitride (AlN) is a non-oxide ceramic characterized by excellent thermal conductivity and electrical insulation. It is expected to be applied to substrates and packages such as ICs and LSIs, and is already in practical use. It is a new ceramic material that has begun to be used. In addition, it has been found that it can be used in some highly corrosive environments because of its excellent corrosion resistance.

[0003] However, aluminum nitride is a substance having a strong covalent bond and no melting point.
Decomposes at 400 ° C, so it is positioned as a non-sinterable substance. For this reason, high-purity fine powder is usually used, and it is possible to perform fine densification sintering using a raw material powder obtained by mixing an alkaline earth metal compound such as yttria or calcia or a rare earth element compound as a sintering aid. Is being done. Further, when the sintering aid as described above is used, the aid captures impurity oxygen in aluminum nitride, so that an effect that high thermal conductivity can be easily achieved is also obtained.

In manufacturing an aluminum nitride sintered body,
The importance of controlling the characteristics of the raw material powder is apparent from the above-described mechanism for increasing the thermal conductivity, and various studies have been conducted. Based on these facts, the raw material powder of aluminum nitride includes, for example, (a) fine powder with high purity,
(b) Oxygen impurities are controlled to be small. (c) Particle size distribution is narrow and its shape is equiaxed. (d) Easy sintering. (e) Excellent economical efficiency. (F) It is required to satisfy such as excellent reproducibility.

[0005] By the way, as a method of synthesizing aluminum nitride powder, there are generally known three kinds of methods: a direct nitridation method of aluminum, a reduction nitridation method of alumina, and a gas phase reaction method of organic aluminum and ammonia. Have been. Among them, the method is industrially used, and the method in terms of cost is the most preferable, but the method is inferior to the method in terms of quality such as particle size and particle shape.
In addition, although the method satisfies a considerable part of the above-mentioned required characteristics and is expected as a synthesis method for obtaining fine ceramics, it is compared with alumina (Al ₂ O ₃ ), which is the existing substrate and package material. In particular, it must be said that the cost is insufficient. That is, it has been difficult to reduce the variation in particle size after pulverization, and to make the particle shape spherical, which is advantageous for sintering.

On the other hand, the characteristics of the aluminum nitride sintered body are as follows:
It also depends on the dispersion state of the sintering aid added to and mixed with the aluminum nitride powder. Usually, the raw material powder of the aluminum nitride sintered body is produced by mixing the aluminum nitride powder and the sintering aid powder with a ball mill or the like,
Since the powders are mixed together, there are various problems such as a long time required to obtain a homogeneous mixed state, and an ideal mixed state cannot be obtained even after a long mixing operation. Was.

Therefore, when synthesizing aluminum nitride by the reduction nitriding method, a method of producing aluminum nitride powder in a state where a sintering aid component is already contained is disclosed in, for example, JP-A-60-65768 and JP-A-60-65768. No. 61-155209. In any of the methods described in these, alumina powder, carbon powder and a compound powder of an alkaline earth element or a rare earth element functioning as a sintering aid are simply mixed, and after the synthesis of aluminum nitride, the sintering aid is used as necessary. It is intended to leave the agent component. In any of the above-mentioned methods, the synthesis temperature is set to 1400 ° C. or higher from the viewpoint of reactivity, and specifically, the synthesis is performed at a high temperature of about 1550 ° C. to 1800 ° C. However, when calcination is performed at a high temperature such as 1550 ° C. or higher, compounds of alkaline earth elements and rare earth elements are easily volatilized in the calcination process, and it is difficult to sufficiently leave the sintering aid component after synthesis. Had a problem. Also, adding a large amount of the sintering aid component in advance leaves an unnecessary amount of additive after the Al ₂ O ₃ —CN ₂ system reduction nitridation reaction, so that the yield of aluminum nitride is reduced. Lower it. Furthermore, high-temperature sintering is economically disadvantageous, and also causes the problem that it becomes difficult to control the particle shape and the particle diameter because the crystal grains easily grow.

[0008]

As described above, in the conventional method for producing aluminum nitride by the reduction nitriding method, a sintering aid component is added from the synthesis stage to obtain an easily sinterable aluminum nitride powder. Attempts have been made to add in advance, but since firing at a high temperature such as 1550 ° C or higher was required, volatilization and grain growth of the sintering aid components were caused, and sufficient effects were obtained. Had not been.

[0009] In view of the above, in order to obtain an aluminum nitride powder containing a sintering aid component and having a controlled particle shape and particle size, it is strongly required to enable low-temperature synthesis of aluminum nitride powder. Had been.

[0010] The present invention has been made to address such problems, and enables low-temperature synthesis of aluminum nitride, minimizes volatilization of sintering aid components, and controls the particle shape and particle size. It is an object of the present invention to provide a method for producing aluminum nitride powder, which makes it possible to obtain easily sinterable aluminum nitride powder economically and with good reproducibility by improving the aluminum nitride powder.

[0011]

Manufacturing method of the first aluminum nitride powder of the present invention SUMMARY OF], the aluminum oxide powder, and carbon powder, and the mixed powder of a rare earth element compound powder powder starting material, in al ₂ O ₃ -CN ₂ system manufacturing method of the aluminum nitride powder, based on the reduction nitriding reaction of the rare earth
The lowest eutectic temperature with Al ₂ O ₃ is 178
Selected from Y ₂ O ₃ , Yb ₂ O ₃ , Eu ₂ O ₃ and Gd ₂ O ₃ below 0 ° C
Using at least one kind of the rare earth element compound powder, the total amount of the aluminum oxide powder and the carbon powder
The starting material is prepared by adding the starting material in an amount of 0.5 to 15 parts by weight based on 100 parts by weight, and the starting material is fired in a non-oxidizing atmosphere containing nitrogen at a temperature in a range of 1000 ° C to 1500 ° C. When
In both cases, the rare earth element is used as an intermediate product during the firing process.
The compound aluminate is synthesized, and from this aluminate
It is characterized by producing aluminum nitride .

[0012] The second method for producing aluminum nitride powder comprises: an aluminum oxide powder, a carbon powder, and aAl ₂ O ₃ powder.
BM _x X _y ( where M is at least one element selected from alkaline earth elements and rare earth elements, M _x X _y is the minimum eutectic temperature with Al ₂ O ₃ 1450 ° C or less for compounds containing elements, and 1780 ° C or less for compounds containing rare earth elements as M, a, b, x
Aluminate powder represented by and y is a natural number)
Mixed powder was used as a starting material, and this starting material, characterized in that <br/> fired at a temperature in the range of 1000 ° C. to 1500 ° C. at a non-oxidizing atmosphere containing nitrogen with.

The method for producing aluminum nitride powder of the present invention is based on an Al ₂ O ₃ —CN ₂ system reduction nitridation reaction, and uses alumina powder and carbon powder as main raw materials. The mixing ratio between the alumina powder and the carbon powder is preferably such that the molar ratio of Al ₂ O ₃ / C is in the range of 0.25 to 0.33. If the value of Al ₂ O ₃ / C (molar ratio) is larger than 0.33, that is, if the amount of carbon is too small, the synthesis of aluminum nitride at a low temperature cannot be sufficiently promoted. Further, if the value of Al ₂ O ₃ / C (molar ratio) is smaller than 0.25, that is, if the amount of carbon is too large, unnecessary carbon will remain, leading to a decrease in the yield of aluminum nitride. Become.

It is preferable that the alumina powder and the carbon powder have an average particle diameter of 1 μm or less. If the average particle size exceeds 1 μm, the reaction rate at low temperatures is undesirably reduced. The more preferred average particle size of the alumina powder is 0.2 μm or less, and the more preferred average particle size of the carbon powder is 0.1 μm or less. These average particle diameters are important for obtaining an intermediate product in the reaction step described later relatively easily. Further, the amount of impurities in the alumina powder and the carbon powder needs to be 1% by weight or less as a metal element amount, and particularly preferably 0.2% by weight or less.

[0015] The starting material in the production method of the present invention, the mixed powder of the alumina and carbon, adding at least one compound powder selected from the rare earth element compound further,
It is a mixture or a mixture of alumina and a composite compound (aluminate) of a compound containing at least one element selected from alkaline earth elements and rare earth elements. Then, such a starting material is put in a predetermined container, and in a non-oxidizing atmosphere containing nitrogen at 1000 ° C.
The powder is fired at a temperature in the range of 1500 ° C., and further heat-treated in an oxidizing atmosphere to oxidize and remove the remaining carbon, thereby producing a desired aluminum nitride powder.

Here, the compound containing an alkaline earth element or a rare earth element is a component that reacts with alumina before the reductive nitridation of alumina to form aluminate and promotes the synthesis of aluminum nitride at a low temperature. In order to obtain such a reaction accelerating effect, it is essential to have excellent reactivity with alumina.

Therefore, in the present invention, the minimum eutectic temperature of a compound containing an alkaline earth element or a rare earth element to be used with Al ₂ O ₃ is defined as follows:
This makes it possible to obtain the reaction promoting effect with good reproducibility.

(1) Alkaline earth metal compound: 1450 ° C. or less (2) Alkaline earth metal compound + rare earth element compound: 145
0 ° C or less (3) Rare earth element compound: 1780 ° C or less For compounds whose minimum eutectic temperature with Al ₂ O ₃ exceeds the above specified temperature, the catalytic action of Al ₂ O ₃ —CN ₂ system reductive nitriding reaction is sufficient. And cannot be reacted efficiently at a low temperature of 1500 ° C. or less. That is, by adding a compound that satisfies the conditions described above, for the first time,
Synthesis at a low temperature of 00 ° C. or less is possible. In addition, as for the reason that the above specified temperature in the rare earth element compound is set higher than the compound containing the alkaline earth element, although the mechanism of the reaction is not clear, as in the case of being used as a sintering aid, Preferred results are obtained under these selection conditions.

Compounds satisfying the above conditions include CaO (minimum eutectic temperature with Al ₂ O ₃ : 1390 ° C.)
oxides of alkaline earth elements such as aO (1425 ° C), CaF ₂
(1395 ℃), fluoride of alkaline earth element, CaO-CaF
₂ (1200 ° C-1400 ° C), CaO-Fe ₂ O ₃ (1200 ° C) and other complex compounds containing alkaline earth elements, Y ₂ O ₃ (17
60 ° C), Yb ₂ O ₃ (1750 ° C), Eu ₂ O ₃ (1630)
° C) and oxides of rare earth elements such as Gd ₂ O ₃ (1750 ° C). Of these, fluorides of alkaline earth elements and rare earth elements are particularly suitable for the present invention because they form active aluminates at lower temperatures. The powder of the compound containing the alkaline earth element or the rare earth element has an average particle diameter of 1 μm for the same reason as the alumina powder or the like.
It is preferable to use those having m or less. A more preferred average particle size is 0.8 μm or less. The amount of impurities is
The amount of the metal element must be 1% by weight or less, particularly preferably 0.2% by weight or less.

[0020] In the method for manufacturing aluminum nitride powder of the present invention, as described above, the compound containing the added rare earth element reacts with the alumina to form an aluminate prior reduction and nitridation of alumina, the 1500 ° C because the aluminate compound is subject to reductive nitridation by carbon and nitrogen
The reaction (synthesis reaction of AlN) can proceed at a low temperature and at a high speed as follows.

The compound containing an alkaline earth element or a rare earth element according to the present invention not only acts as a catalyst for accelerating the synthesis reaction of aluminum nitride, but also contains the alkaline earth element or the rare earth element in the aluminum nitride powder after firing. It can be left in the form of an oxide or a double oxide, and functions as a sintering aid.

The present invention enables the synthesis at a low temperature of 1500 ° C. or less by using the above-described additive compound. In other words, the low-temperature sintering enables the sintering to be performed. The compound functioning as an agent can be sufficiently left in the aluminum nitride powder. In the present invention, 50% by weight or more of the metal element to which the above compound is added can be left.
For this purpose, the set temperature during firing is extremely important. If the firing temperature exceeds 1500 ° C, the alkaline earth elements and rare earth elements in the added compound evaporate during firing, and the sintering aids. The required amount of the compound as an agent cannot be left. A more preferred sintering temperature is 1450 ° C. or lower, more preferably less than 1400 ° C.

The additive compound in the present invention is added in the range of 0.5 to 15 parts by weight based on 100 parts by weight of the total amount of the alumina powder and the carbon powder. Since the additive compound has the function of a reaction accelerator and the function of a sintering aid,
If the addition amount is less than 0.5 part by weight, the effect of promoting the synthesis cannot be sufficiently obtained, and the obtained aluminum nitride powder cannot have sufficient sinterability. Further, if it is added in excess of 15 parts by weight, not only no further effect can be obtained, but also an excessive amount remains, which also causes a decrease in the yield of the aluminum nitride powder. A more preferred amount is in the range of 3 to 10 parts by weight.

In the method for producing an aluminum nitride powder of the present invention, the same effect as in the case where the above-mentioned compound is added can also be obtained by using an aluminate represented by aAl ₂ O ₃ .bM _x X _y as a starting material. Can be obtained. As the M _x X _y in the aluminate, the same as the compound containing an alkaline earth element or a rare earth element that satisfies the above-described minimum eutectic temperature condition with alumina is used,
Specific examples thereof include a composite compound of the above-mentioned compound and alumina.

The above aluminate is added in an amount of M _x X _y /
The value of (Al ₂ O ₃ + M _x X _y ) is set to be 10% or less in molar ratio. When the above molar ratio exceeds 10%, the yield of aluminum nitride powder is reduced as in the case of the above-mentioned compound. The molar ratio is preferably set to 1% or more because the addition amount of aluminate is too small to sufficiently obtain the effect of promoting the synthesis reaction. The aluminate is preferably used as a powder having an average particle size of 5 μm or less.

[0026] By using a starting material containing such aluminate, in low-temperature firing of 1500 ° C. or less, and more can be more efficiently react, and M _x X _y 50% by weight or more in the amount of metal element also Can be left. Note that conditions other than these are based on the case where a compound containing an alkaline earth element or a rare earth element described above is added. It is to be noted that addition of a compound of a rare earth element or an alkaline earth element shown in the present invention separately to this system also brings about a preferable result.

[0027]

The operation will be described by taking calcium fluoride, which is one of the alkaline earth metal compounds, as an example. Al ₂ O ₃ -C-CaF ₂
When the system is calcined under specified conditions in a stream of nitrogen gas, Al ₂ O
Before the reduction nitridation reaction of ₃ proceeds, Al ₂ O ₃ and CaF ₂ react to form, for example, CaF ₂ .5Al ₂ O ₃ (Al ₂ O ₃
O ₃ + CaF ₂ = CaF ₂ · 5Al ₂ O ₃ ). This CaF ₂・ 5Al ₂ O
₃ has a melting point of 1395 ° C. and is more reactive than Al ₂ O ₃ , so the reductive nitridation reaction proceeds even at a low temperature of 1500 ° C. or less (CaF ₂ .5Al ₂ O ₃ + C + N ₂ = AlN + Ca compound + CO), aluminum nitride powder is efficiently synthesized.

Further, since firing is performed at a low temperature of 1500 ° C. or less, additives such as CaF ₂ repeat a cycling reaction without evaporating, and finally, an aluminum oxide powder or a double oxide is formed in the aluminum nitride powder. To remain. Since the remaining oxides and double oxides function as sintering aids, the resulting aluminum nitride powder can be densified and sintered without adding any new sintering aids. Furthermore, since aluminum nitride is efficiently synthesized by low-temperature sintering, aluminum nitride powder having a uniform particle shape and particle size can be obtained without causing growth of crystal grains. Further, the obtained aluminum nitride powder has a spherical shape with high sinterability. The spherical powder
The filling factor during the production of the sintered body can be improved, thereby facilitating densification sintering.

Even when aluminate is used,
A similar effect is obtained. Taking calcium fluoride aluminate as an example, based on the reaction shown below,
It becomes possible to produce aluminum nitride powder at a low temperature.

CaF ₂ .5Al ₂ O ₃ = AlN + Ca compound + CO Al ₂ O ₃ + Ca compound = (for example) CaF ₂ .5Al ₂ O ₃

[0031]

Embodiments of the present invention will be described below.

Example 1 Alumina powder having an average particle diameter of 0.2 μm and 0.02 μm
μm carbon black and Al ₂ O ₃ / C (molar ratio) = 0.
Prepare 200g of the mixture at the ratio of 29, and add the average particle size
3% by weight of 0.8μm calcium fluoride powder (in all powders)
Was added so that This powder containing CaF ₂ was mixed in a ball mill for 20 hours using ethanol as a dispersion medium.

The mixed powder (starting material) thus prepared was put in a carbon container, and the temperature was increased while flowing nitrogen gas at 500 cc / min, and calcined. The firing conditions are from room temperature to 10
The rate of temperature rise to 00 ° C was 500 ° C / hr, from 1000 ° C to 1350 ° C was 250 ° C / hr, and the temperature was maintained at 1350 ° C for a predetermined time. 1350
The holding time at 1 ° C. was 1 hour and 2 hours, respectively. Further, they were heat-treated in air at 700 ° C. for 4 hours to oxidize and remove the remaining carbon, and the product was recovered.

When the conversion rate of the reaction product thus obtained into AlN was determined, the reaction rate was 45% after firing for 1 hour and 100% after firing for 2 hours.
It was confirmed that Al ₂ O ₃ could be efficiently converted to AlN. This value is based on an average particle size of 0.2 with no calcium fluoride added.
When calcined under the same temperature condition using only a mixture of alumina powder of μm and carbon black having an average particle size of 0.02 μm in a ratio of Al ₂ O ₃ / C (molar ratio) = 0.29 (Comparative Example 1) However, from the fact that the reaction rate was only 5% after firing for 2 hours, it can be seen that the added compound exhibited an extremely effective reaction promoting effect.

Further, the reaction product obtained under the above firing conditions for 1 hour and 2 hours was subjected to powder shape measurement and component analysis. These results were compared with the above Comparative Example 1, a reaction product (Comparative Example 2) baked under the conditions of 1500 ° C. × 2 hours using starting materials having the same composition as Comparative Example 1, and a starting material having the same composition as in Example 1. The results are shown in Table 1 together with the measurement results of the reaction product (Comparative Example 3) fired at 1550 ° C. for 2 hours using the raw materials.

[0036]

[Table 1] As is evident from Table 1, it was observed that the additive remained in the aluminum nitride powder obtained in Example 1, while the additive was added when calcined at 1550 ° C.
In each case, factors causing the decrease in sinterability, such as the Ca component evaporating and hardly remaining, and as a result, the reaction being delayed and the grain growth proceeding, were overlapped. Further, the aluminum nitride powder fired at 1500 ° C. without adding an alkaline earth element compound or the like was inferior in the filling property in view of the particle shape.

Further, in Example 1 above, the respective states of the reaction product at the stage of holding at 1350 ° C. for 30 minutes and the reaction product after holding at 2350 hours were observed by a scanning electron microscope. After holding at 1350 ° C. for 30 minutes, formation of aluminate was observed. After holding for 2 hours, no aluminate was observed, and substantially spherical aluminum nitride powder was formed in a state of uniform particle diameter.

Example 2 Alumina powder having an average particle size of 0.2 μm and 0.02
μm carbon black and Al ₂ O ₃ / C (molar ratio) = 0.
Prepare 200g of the mixture at the ratio of 29, and add the average particle size
1.0 μm yttrium oxide powder was added so as to be 3% by weight (of all powders). The powder containing Y ₂ O ₃ was mixed in a ball mill for 20 hours using ethanol as a dispersion medium.

The mixed powder (starting material) thus prepared was placed in a carbon container and fired by raising the temperature while flowing nitrogen gas at 500 cc / min. The firing conditions are from room temperature to 10
The temperature was raised to 00 ° C at a rate of 500 ° C / hr, from 1000 ° C to 1450 ° C at 250 ° C / hr, and maintained at 1450 ° C for a predetermined time. 1450
The holding time at 1 ° C. was 1 hour and 2 hours, respectively. Further, they were heat-treated in air at 700 ° C. for 4 hours to oxidize and remove the remaining carbon, and the product was recovered.

The conversion rate of the reaction product thus obtained into AlN was determined. As a result, it was found that there was a reaction of 52% for 1 hour firing and 100% for 2 hour firing. This value is obtained by mixing alumina powder with an average particle size of 0.2 μm and carbon black with an average particle size of 0.02 μm without adding yttrium oxide to Al ₂ O ₃ / C
(Molar ratio) = When only one compounded in a ratio of 0.29 was used and baked under the same temperature conditions (Comparative Example 4), the reaction rate was 60% after calcination for 1 hour. It can be seen that a very effective reaction promoting effect was exhibited. Also,
When the reaction products obtained by firing for 1 hour and 2 hours were subjected to component analysis, it was confirmed that the additives remained sufficiently in each case.

Examples 3 to 12 According to the above Examples 1 and 2, aluminum nitride powders were produced under the starting materials and the firing conditions shown in Table 1 respectively. These were also evaluated for characteristics in the same manner as in Example 1. Table 2 also shows the results.

[0042]

[Table 2] Example 13 A mixture of 90 parts by weight of alumina powder having an average particle size of 0.2 μm and 10 parts by weight of CaF ₂ .5Al ₂ O ₃ aluminate powder having an average particle size of 2 μm was prepared. Carbon black with an average particle size of 0.02 μm is converted to Al ₂ O ₃ / C
(Molar ratio) = 0.29. The powder (total amount: 200 g) containing the aluminate powder was mixed in a ball mill for 20 hours using ethanol as a dispersion medium.

The mixed powder (starting material) thus prepared was placed in a carbon container, and heated and fired while flowing nitrogen gas at 500 cc / min. The firing conditions are from room temperature to 10
The rate of temperature rise to 00 ° C was 500 ° C / hr, from 1000 ° C to 1400 ° C was 250 ° C / hr, and the temperature was maintained at 1400 ° C for a predetermined time. 1400
The holding time at 1 ° C. was 1 hour and 2 hours, respectively. Further, they were heat-treated in air at 700 ° C. for 4 hours to oxidize and remove the remaining carbon, and the product was recovered.

The conversion rate of the reaction product thus obtained into AlN was determined, and it was found that both of the 1-hour firing and the 2-hour firing had a 100% reaction. This value is for alumina powder with an average particle size of 0.2 μm and carbon black with an average particle size of 0.02 μm, with no aluminate added, in a ratio of Al ₂ O ₃ / C (molar ratio) = 0.29. When the baking was carried out under the same temperature conditions (Comparative Example 5), the reaction rate was only 28% after baking for 2 hours, indicating that the added compound exhibited a very effective reaction promoting effect. . In addition, when a reaction product obtained by firing in 1 hour and 2 hours was subjected to component analysis, it was confirmed that all of the additives remained.

Examples 14 to 16 Aluminum nitride powders were produced according to Example 13 under the starting materials and the firing conditions shown in Table 3 respectively. These were also evaluated for characteristics in the same manner as in Example 13. The results are shown in Table 3.

[0046]

[Table 3]

[0047]

As described above, according to the method for producing aluminum nitride powder of the present invention, it is possible to synthesize aluminum nitride at a low temperature, so that the volatilization of alkaline earth elements and rare earth elements added during the synthesis is minimized. This can prevent the sintering aid component from remaining. In addition, since the grain growth and the like are suppressed, the controllability of the particle shape and the particle size is improved, and in particular, the packing ratio is high, and a highly reliable spherical or similar aluminum nitride powder can be stably obtained. Becomes possible. Furthermore, the synthesis of aluminum nitride by low-temperature sintering also contributes to improved economic efficiency. As described above, according to the present invention, it is possible to economically and reproducibly obtain an easily sinterable aluminum nitride powder capable of performing additive-free sintering.

[0048]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-155209 (JP, A) JP-A-2-160610 (JP, A) JP-A-62-265106 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) C01B 21/072 C04B 35/581 C04B 35/626

Claims (4)

(57) [Claims] 1. An aluminum oxide powder, a carbon powder ,
The mixed powder of a rare earth element compound powder powder as a starting material,
In a method for producing an aluminum nitride powder based on an Al ₂ O ₃ -CN ₂ system reduction nitridation reaction, as the rare earth element compound powder, the minimum eutectic temperature with Al ₂ O ₃ is 1780 ° C. or less Y ₂ O ₃ , Yb or ₂ O _3, Eu ₂ O ₃ and Gd ₂ O ₃
At least one selected from the group consisting of
The starting material is prepared by adding the element compound powder in a range of 0.5 to 15 parts by weight based on 100 parts by weight of the total amount of the aluminum oxide powder and the carbon powder, and the starting material is mixed with a non-oxidizing atmosphere containing nitrogen. While firing at a temperature in the range of 1000 ° C to 1500 ° C, and as an intermediate product during the firing process,
Rare earth element aluminate is synthesized and this aluminum
A method for producing aluminum nitride powder, which comprises producing aluminum nitride from a nitrate . 2. The method according to claim 1, wherein the aluminum oxide powder and the carbon powder are mixed in a molar ratio of Al.
_A method for producing aluminum nitride powder, wherein mixing is performed so that the value of ₂ O ₃ / C is in the range of 0.25 to 0.33. 3. An aluminum oxide powder, a carbon powder,
_{aAl 2 O 3 · bM x X} y ( provided that at least one element M is selected from alkaline earth elements and rare earth elements, M _x X _y is A
The minimum eutectic temperature with l ₂ O ₃ is 1450 ° C or less for a compound containing an alkaline earth element as M, and 1780 ° C or less for a compound containing a rare earth element as M,
a, b, x and y is expressed by a natural number) Arumine
Powder as a starting material, and the starting material is mixed in a non-oxidizing atmosphere containing nitrogen in a temperature range of 1000 ° C to 1500 ° C.
A method for producing aluminum nitride powder, characterized by firing at a temperature . 4. The method according to claim 3 aluminum nitride powder, wherein the aluminum oxide (Al ₂ O ₃₎ is the _{aAl 2 O 3 · bM x X} y
Aluminate represented by the formula: M _x X _y / (Al ₂ O ₃ + M
_x X _y ) is mixed so that the value becomes 10% or less.