JPH04132666A - Aluminum nitride sintered compact and production thereof - Google Patents

Abstract

PURPOSE:To provide a dense sintered compact and improve high thermal conductivity, strength and light shielding properties by mixing AlN powder with a specific metallic compound, forming the resultant mixture and sintering the formed compact. CONSTITUTION:An AlN sintered compact is obtained by mixing 0.01-30wt.% (expressed in terms of metals) AlN powder having >=1mum grain diameter and one or two or more metallic compounds, selected from Ti, Zr, Hf, V, Nb, Ta, Mo, W, Fe, Co and Ni and having <=1mum grain diameter, as necessary, 0.01-10wt.% sintering assistant (e.g. stearic acid), forming the resultant mixture and then sintering the formed compact at 1600-2000 deg.C in a nonoxidizing atmosphere containing nitrogen. Thereby, the aforementioned sintered compact containing compound grains other than a wurtzite structure finely dispersed in AlN particles having hexagonal system wurtzite structure having >=30kg/mm<2> tensile strength, >=50cm<-1> apparent absorption coefficient at 500nm and >=70W/mk thermal conductivity is obtained.

Description

[Detailed Description of the Invention] (Object of the Invention) [Field of Application of Pi' The present invention relates to an aluminum nitride sintered lambda that is dense, has high thermal conductivity, high strength, and excellent light-shielding properties, and a method for producing the same.

[Prior Art] Technological progress has been remarkable in recent years, mainly in the electronics industry, and the properties required of the materials used are becoming increasingly strict.

For example, in semiconductors, as the degree of integration and processing speed increases, the amount of heat generated and the heat density are rapidly increasing, and the heat dissipation characteristics required of substrate materials have become stricter. Therefore, the conventional Aρ203 substrate has low thermal conductivity and insufficient heat dissipation, making it unable to cope with the increase in the amount of heat generated by semiconductors. For this reason, beryllium oxide (CO) can be used as an alternative substrate material to Aρ203, but CO has the drawback of being toxic and difficult to handle. New materials are therefore required.

Furthermore, in the automobile field, in order to improve engine efficiency due to the need to protect the global environment, efforts are being made not only to reduce the weight of vehicle bodies, but also to reduce the weight and improve the efficiency of engine systems. Particularly in high-temperature parts, lightweight, highly heat-resistant, high-strength, and high-thermal-conducting materials are required, and conventional metal materials are no longer suitable, so ceramic materials are being considered.

However, there was no conventional ceramic that could satisfy both strength and thermal conductivity.

On the other hand, aluminum nitride (ARN) is a material with high thermal conductivity and high insulation properties, is non-toxic, and has abundant resources, so if a sintered body can be obtained at a low cost, it will be useful.''-2 Since ancient times, research and development has been carried out on scale 2, which satisfies the required characteristics described in . ARN is poorly made by sintering, and it is difficult to densify it with Al2N alone. Therefore, sintering aids are added, for example, in JP-A-60-7157.
5, densification is carried out using a compound of one or more metals from the group consisting of alkaline earth metals, yttrium and lanthanum group metals. Research and development aimed at exploiting the material properties of AffN and making it a useful material has been carried out in the following three directions based on the premise of such a dense sintered body. The first approach was to obtain high-strength materials and use them as structural materials. A high-strength A(2N) sintered body was obtained by adding .

However, this is achieved at the expense of heat conduction, and AR
It is difficult to say that the characteristics of the N were fully developed in one car.

The second direction is development that prioritizes high thermal conductivity, and Japanese Patent Laid-Open No. 60-71575 describes the use of high-purity AβN powder to produce a highly thermally conductive sintered body with translucent properties. A sintered body having an absorption coefficient of 6 μm infrared light of about 20 cm −′ and a thermal conductivity exceeding 60 w/n+k has been obtained. Furthermore, in JP-A-63-303863,
It is said that by extending the sintering time and deriving the added sintering aid, an ARN with even higher thermal conductivity can be obtained. The following translucency has been achieved:

All of these had high thermal conductivity, but the grains of Al2N were extremely coarse, resulting in low material strength and low reliability.

Furthermore, because of its light-transmitting properties, it is considered undesirable as a material for semiconductor packaging, for example. A third direction is to improve the second direction by adding a specific compound to impart light-shielding properties or to improve metallizability. For example, JP-A-62-1531
73 includes the periodic table 4a, 5a, 6a, 7a,
By adding Group 8 elements, it is possible to obtain colored ARN that is dense and has high thermal conductivity and can be sintered at low temperatures. However, the thermal conductivity is at most about 100w/mk, and the bending strength is at most 6.
It is 0 kg/mm2. In JP-A-61-270262, in order to improve metallization strength, periodic table 4a,
A containing borides, nitrides, and carbides of group 5a and 6a elements
A ρN sintered body is shown in which these compounds exist at grain boundaries and improve metallizability.

However, the thermal conductivity is as low as about 120 w/mk, and the strength of the sintered body is unknown. Furthermore, there is no description regarding light transmission. JP-A-2-124772 has ARN as the main component, Ti, Zr, Iff, V, Nb, T
a, Cr, Mo, W.

A ΔρN sintered body containing one or more metal elements selected from Mn, Pe, Co, Ni, Nd, and llo and having a power of 150 w/mk or more is disclosed.

However, although it has light blocking properties and high thermal conductivity, its strength remains low.

In other words, the research direction of AffN is centered on pursuing high thermal conductivity by reducing impurities, mainly oxygen, in AffN sintered bodies as much as possible, and in part, improving strength and changing the grain boundary phase by checking additives. Therefore, improvements in metallization strength and coloring have been studied. Furthermore, attempts to improve mechanical strength have been abandoned.

(Problems to be solved by the invention) The development of AffN to date has focused on pursuing 80N heat conduction, and has not been able to fully utilize the characteristics of ARN, and has not been able to satisfy the practically necessary characteristics. It is difficult to say that there are any.

In other words, it cannot be said that ARN has been developed that satisfactorily meets the requirements for aluminum nitride that is dense, has high thermal conductivity, has high strength, and has excellent light-shielding properties, and the present invention satisfies these combined requirements. It is something.

[Structure of the invention] (Means and effects for solving the problem) The present inventors
In order to achieve the above object, we conducted various studies on ARN sintered bodies and conducted experiments including ARN raw materials. As a result, we discovered an AρN sintered body with a new structure and completed the present invention.

In other words, a fine compound with a specific crystal structure is ^ρN
It has become clear that unique characteristics can be achieved by AρN sintered bodies with a unique structure dispersed within particles, and these characteristics have never existed before.As a result of various studies on the necessary matters, the present invention was developed. was completed.

Generally, AffN belongs to a hexagonal system and has a wurtzite crystal structure. The present invention is accomplished by sintering an AρN crystal in which a compound belonging to a different crystal system is finely dispersed. That is, it is necessary that the finely dispersed compound has a crystal structure other than hexagonal or wurtzite, and compounds having a cubic crystal structure, particularly a NaCA structure, are preferable. This suggests that AρN crystal and Af
It is thought that the difference in the structure of the crystals dispersed within the fN grains is effective.

Crystals such as BeO or Ti82 with the same structure are AffN.
It is difficult to distribute within the grains, and the properties are not sufficiently improved.

The relationship in particle size between the AρN particles and the dispersed particles is one of the most important items, and it is particularly desirable that the AβN particles be fine crystals of 175 or less. This means that the dispersed particles are AQN
This is because if the particle size is 175 or more, the effect of the dispersed particles becomes smaller, and the finer the dispersed particles, the greater the effect. In particular, particles at minute 11 are preferably 1μ or less.
It is preferable that the N grains have an average size of 1 μ or more. This is Af
The finer the fN grains, the greater the strength of the fired body, but the incorporation of finely dispersed particles becomes insufficient and precipitation of dispersed grains to the ρN grain boundaries increases, so the average size of AρN particles should be 1μ or more. is preferred. Moreover, the most preferable average particle size of the dispersed particles is 0.3 μm or less.

Finely dispersed particles are mostly present within ARN grains, and A
Although finely dispersed particles are present in most of the RN grains, preferably the majority of the dispersed particles are within the AffN grains, with the remainder being within the AffN grains.
Exists at grain boundaries. The higher the ratio of dispersed particles within the A72N grains, the better. This is because, if dispersed within the grains, the decrease in thermal conductivity will be small, the light-shielding property will increase, and the contribution to the strength of the sintered body will be large.

The finely dispersed particles are Ti, Zr, Ti, V, N.
b, Ta, Mo, W, Fe.

It is preferable to use one or more compounds selected from Co and Ni, but Au, Pt, etc., for example, are also effective and are not limited thereto. In particular, these elements have a large light absorption effect and greatly contribute to light shielding properties.

Furthermore, these metal elements may be compounds such as oxides, carbides, nitrides, or metals, but they must be separated and dispersed rather than being solidly dissolved in the AQN lattice. Solid solution into AffN grains must be avoided because it greatly reduces the thermal conductivity of AβN.

It is necessary that most of the metal elements in the finely dispersed particles do not form a solid solution in the AffN grains in a substitutional or interstitial manner. The dispersed particles are in particular Ti, Zr, Iff, V
.

Preferably, it is a compound containing an element selected from Nb Ta. These compounds have a NaC11 type structure and exist in the form of, for example, nitrides, carbides, borides, oxides, or solid solutions thereof. This is particularly effective in the case of compounds mainly consisting of nitrides. The metal element of the dispersed particles is 0.01 to 30% by weight, preferably 0.0
1 to 5.0 weight percent.

Although it is preferable for the content to be large, it may cause a decrease in electrical insulation properties and a decrease in density, so it is necessary to keep the content within limits. If the dispersed particles are fine, sufficient effects can be obtained with up to 50% by weight.

In particular, it is possible to obtain sufficient light-shielding mechanical strength with high thermal conductivity and insulation properties at 1.0 weight percent or less. It is also possible to use a sintering aid added to improve the sinterability of AffN particles. As the sintering aid, it is preferable to use compounds of known alkaline earth and rare earth elements, and in the sintered body, the compound of 8ρ and 0 contained in AQN can be used without solid solution in AQ and N. can be formed and present at the grain boundaries of ARN. If the amount of the sintering aid is small, the thermal conductivity will be low and the density of the sintered body will be difficult to increase. On the other hand, if the amount is too large, the thermal conductivity of the sintered body will decrease, and the surface quality of the sintered body will deteriorate. Therefore, a compound containing an alkaline earth or rare earth element in an amount of 0.01 to 10.0 weight percent, preferably 0 to 3.0 weight percent, is used. In particular, oxides, carbonates, hydroxides, stearic acid compounds, alkoxides, etc. are used, and these exist mainly as oxides in the sintered body.
It often forms compounds with ρ203.

Next, the characteristics of the obtained sintered body will be described.

The sintered body of the present invention has a transverse rupture strength of 30 kg/mm2 or more.

The transverse rupture strength is determined by measuring a 4 mm rl JX 0.635 mm thick plate-shaped specimen in a 3-point bending span of 20 m 1 Tl.

By selecting preferable conditions, it is possible to obtain a strength of 50 kg/mm2 or more, and even more than 80 kg/mm2. This is especially true for example if the AρN grain size is 5
μm or less, it can be obtained by dispersing finely dispersed particles in AρN particles with a size of 0.3 μm or less and also existing at AρN grain boundaries. Such high strength is considered to be due to moderate inhibition of AffN grain growth, AffN grain strengthening, and grain boundary strengthening.

The apparent absorption coefficient of light is 50c+n-' or more at 500 nm, and it is colored black, brown, etc., and exhibits light-shielding properties. The absorption coefficient is measured using a spectrophotometer using a plate specimen with a thickness of 0.5 mm.The absorption coefficient is simply calculated as I: I oe-JJ-L IO = Intensity of incident light ■ = Intensity of transmitted light β: Thickness of sintered body t: Apparent absorption coefficient As shown above, except for the dispersed particles and sintering aid, AffN is of high purity.
The reason why the absorption coefficient is high despite the high thermal conductivity is thought to be due to the high light absorption ability of the dispersed particles. Finely A72N with the effect of the elements of the dispersed particles
This is thought to be because it is distributed within the grain and thus contributes to the absorption of incident light efficiently.

The thermal conductivity is 70 w/mk or more, the bending strength is 30 kg/mm2 or more, and the absorption coefficient for 50 nm light is 50 cm-' or more.

Preferably a strength of more than 50 kg/+nn2 is obtained. The sintered body preferably has a thermal conductivity of 120 w/mk or more, most preferably 150 w/mmL or more, and preferably has a high transverse rupture strength of 70 kg/mm2 or more.

The AffN particles of the sintered body in the present invention have extremely high purity except for finely dispersed particles, and there are extremely few impurity atoms dissolved in the AρN lattice. Therefore, the lattice constant of AQN is 49798 to 4983 people in the C-axis direction and 3.1 in the a-axis direction.
10 people - 3,1138 had a c/a of 1.602 or less.

The full width at half maximum is 0.15 deg or less in 2θ. Half price 1]
Although it is large due to the influence of finely dispersed particles, the lattice constant c/a is small and it is considered that there is very little solid solution in the lattice of ΔρN. This is thought to be the reason why thermal conductivity, light shielding properties, and strength can be improved at the same time.

Next, the manufacturing method of the present invention will be explained.

The AρN powder used in the present invention contains an element and/or a compound thereof that becomes finely dispersed particles, a compound that serves as a sintering aid, oxygen, and carbon. The compound and carbon may be added to and mixed with the AffN powder. In that case, a highly purified AffN powder is used. To achieve high purity, the ffN powder must have excellent sinterability and moldability, and preferably has an average particle diameter of 2 μm or less and an acid content of 2.0 weight percent or less. Although excessively fine ρN powder has high sinterability, it has poor formability (sheet forming, extrusion, press forming, etc.), and requires an appropriate particle size. The amount of oxygen is added or A
Although it is permissible in a wide range by varying the amount of carbon contained in the ρN powder, the presence of oxygen, carbon, unreacted Aρ203, etc. dissolved in the M7N powder is not preferable. A
During synthesis of the ρN powder, an element and/or a compound thereof that becomes finely dispersed particles, a compound that becomes a sintering aid, and carbon may be included in advance. This can be easily obtained by adding these precursors to the raw material for AρN synthesis and then synthesizing 812N.

The obtained powder may further be mixed with a predetermined amount of an element and/or compound that becomes finely dispersed particles, a compound that becomes a sintering aid, and carbon.

For example, according to the ρ203 reduction method, carbon or its precursor, a precursor of an element and/or its compound that becomes finely dispersed particles, and a precursor of a compound that becomes a sintering aid are added to Al2203 powder, and then mixed in a nitrogen-containing atmosphere. 1400℃ inside
It can be obtained by heating at a temperature above. Regardless of the method of synthesizing AβN, for example, direct nitriding or gas phase reaction may be employed. Addition of fine fractions ii &1'M, child elements and/or their compounds, compounds serving as sintering aids, etc. to high purity AffN powder is done by adding a predetermined amount of substances containing these elements and mixing. It will be done.

The substances containing these elements may be powders of oxides, hydroxides, carbonates, oxalates, etc., or solutions of alkoxides, etc. dissolved in alcohol.

Preferably, it is necessary to finely mix the 7M2N powder with a fine powder having an average particle diameter of 0°2 μm or less, or a solution.

The elements that form finely dispersed particles are Ti, Zr, Iff,
V, Nb.

Ta, Mo, W, Tc, Co, and Ni are preferred, especially Ti and Zr.

If, V, Nb, and Ta are preferred.

Powders of these metals, oxides, carbides, and nitrides are added to AffN powder or added in advance during MN synthesis, and
It is contained by synthesizing ffN or the like.

0.01 to 30% by weight in terms of elements in the sintered body,
It is preferably present in an amount of 0.01 to 5.0 weight percent. The compound serving as a sintering aid contains 0.0% alkaline earth or rare earth element in the sintered body. Old~]0w1
Add the amount necessary to make 0 present. Oxides, carbonates, hydroxides, etc. of these elements, and compounds such as stearic acid and oleic acid are also effective. Carbon is released as free carbon during heating of the compact, for example, at 1000°C.
present at ~5.0 weight percent. This is free carbon pre-existing in Al2N powder, free carbon added to AρN powder (such as acetylene black graphite, etc.), or organic substances that leave free carbon when heated.
phenolic resin, etc.). Furthermore, resins (such as PVB) added as molding aids may also decompose upon heating, leaving free carbon behind. Free carbon removes oxygen present on the surface or inside the AρN powder. (Remove O as CO gas, e.g. Af
20- is reduced, releasing CO gas or evaporating as lower oxides) and reducing finely dispersed elements and compounds. For example, the added or contained TiO2 powder is reduced and immediately nitrided by the N2 atmosphere to become TiN, which is dispersed within the MNN circle.

Molding and sintering of AρN is performed by a known method, and there are no restrictions on the molding method. Further, the sintering is performed in a nitrogen-containing non-oxidizing atmosphere at a temperature north of 1600°C and 2000°C, and there are no restrictions on these manufacturing methods.

The embodiments described below with reference to examples are merely examples of manufacturing methods, etc., and the present invention is not limited thereto in any way.

Measurement method in this specification.

・Particle size: Observation using SEM or TEM in principle. Powder particle size is determined by sedimentation method. ・Elemental analysis: Quantitative analysis after alkali melting. Metal elements, carbon, and oxygen are determined by gas analysis (manufactured by 1eco). Folding force width 4m
Sample 2 with a thickness of 0.635 mm and a length of 30 mm
0mm span 3-point bending test ・Absorption coefficient measured using a spectrophotometer on a mirror-finished 0.5 mmT sample ・Thermal conductivity 2-dimensional measurement using laser flash method (
(equivalent to TC-7000 manufactured by Shinku Riko Co., Ltd.)・Porosity Calculated from the sintered density calculated with the density of AffN as 3.26 and the actual value・Density Archimedes method・Lattice constant By X-ray diffraction (si standard QL>Example 1 ARN Powder (average particle size 0.8μm, oxygen 1.5w/
o, metal impurities excluding Aρ 0.1w10 or less, carbon 0.
03w10), the additives shown in Table 1 with an average particle size of 05 μm or less and Y2O3 powder (average particle size of 0.5 μm, purity 99.9
%) was added, 1.0% by weight of phenol was added, and 10% by weight of PVB was placed in a nylon ball and nylon pot in a Torcon solvent for 10 hours. The resulting slurry was cast into a sheet shape and dried. A sheet with a thickness of 0.8 mm was obtained. A sintered body was obtained by punching out a 50 mm square and heating it in nitrogen at 50° C. in a BN crucible for 5 hours. The sample was taken out at 1000° C. during heating and analyzed for carbon, and the free carbon content was 0.6%. ? Table 1 shows the properties of the sintered body.

The slurry obtained by adding 10% by weight of PMMA (polymethyl methacrylate) and a naphtha-based solvent to a nylon pot and a nylon ball for 10 hours was cast into a sheet and dried to a thickness of 0.8 mm. I got a sheet of Punch out into 50mm squares and heat in nitrogen at 1850℃
A sintered body was obtained by heating in a BN crucible for 3 hours. The properties of the sintered body are shown in Table 2.

Table 2 * indicates comparative example Example 2 AffN powder (average particle size 0.8 μm, oxygen 1.5 w/
O%Metal impurities except Aρ 0.1w10 or less, carbon 0
．． 03w10) with TiO2 powder (average particle size 0.1 μm,
purity 99.9%) to 2.0w10. Table 2 as a sintering aid
Example 3 AffN powder (average particle size 1.0 μm, oxygen 1.2W10
, metal impurities excluding AQ 0.1w10 or less, carbon 0.0
5w10) with the additives shown in Table 3 and Y2 as a sintering aid.
O3 to 1.0W10. A slurry obtained by storing 0.8% phenol, 10% by weight of PMMA (polymethyl acrylate) as a molding binder, and a naphtha-based solvent in a nylon pot and a nylon ball for 10 hours was cast into a sheet and dried. Thickness 0.
A sheet of 8 mm was obtained. It was punched into a 50 mm square and heated in a BN crucible at 1850° C. for 3 hours in nitrogen to obtain a sintered body. The properties of the sintered body are shown in Table 3.

Table Example 4 AffN powder (average particle size 1.2 μm, oxygen 1.Ow/
o, metal impurities excluding Aβ 0.1w10 or less, carbon 0
．． 03w10) TlO2 powder average particle size 0.2 μm,
99.9%) and 0.5% Y2O as sintering aid, powder as 0.
．． 5%, various weights of graphite and phenol were added, 10% by weight of PMMA (polymethyl acrylate) as a molding binder, and a naphtha-based solvent for 10 hours using a nylon pot and a nylon ball.The obtained slurry was then molded into a sheet. After drying, the sheet was punched into 50 mm squares to obtain a square sheet with a thickness of 0.8 mm. The sheet was sintered at 1800° C. for 5 hours in a nitrogen stream to obtain a sintered body. Table 4 shows the properties of the obtained sintered body.

Table 4 Example 5 AQN powder containing various additives was synthesized by a direct nitriding method, a reductive nitriding method, and an alkyl aluminum decomposition method (characteristics are shown in Table 5) and Y2O3 powder (average particle size 0.5 μm 1 purity 99.
9%) and 0.5% by weight of TiO2 powder (particle size 0.9%).
A slurry obtained by combining 0.5w10゜phenol resin (1.0% by weight) and 10% by weight of PVB in a toluene solvent in a nylon pot and a nylon ball for 5 hours. After casting into a sheet, it was dried to obtain a sheet with a thickness of 0.7 mm. A blank obtained by punching out 50 mm squares was placed in a nitrogen stream.
It was sintered at 850° C. for 3 hours in an AaN crucible. Table 5 shows the properties of the obtained sintered body.

The resulting slurry was mixed with a toluene solvent in a nylon pot and a nylon ball for 5 hours, then cast into a sheet, and dried to obtain a sheet with a thickness of 0.7 mm. 5
The blank obtained by punching out a 0 mm square was placed in a nitrogen stream at 185 mm.
Sintering was performed at 0° C. for 3 hours in a crucible made of MN. Table 6 shows the properties of the obtained sintered body.

Example 6 AρN powder containing various additives was subjected to direct nitriding, reductive nitriding, and alkyl aluminum decomposition methods (characteristics are shown in Table 6), and Y
Example 7 /VN powder (average particle size Q. 3, czm, oxygen 1.0w10
, metal impurities excluding Δl 0.1w10 or less, carbon 0.0
3w10) Ti compounds of various particle sizes shown in Table 7, phenolic resin 1.0w10 as a carbon source, and PMMAIO weight percent as a 6W't binder were placed in a naphtha-based solvent for 10 hours using a nylon pot and a nylon ball. The obtained slurry was cast into a sheet shape, dried, and then punched into 50mm square sheets to obtain a square sheet with a thickness of 0.8 mm. The sheets are shown in Table 7. Sintering was performed in a N2 stream at different temperatures and times. Table 7 shows the properties of the obtained sintered body.

Example 8 MN powder (average particle size 0.8 μm, oxygen 1, Ow/.o,
Metal impurities excluding M: 0.1w10 or less, carbon: 0.03w
10) 0.1 μm TiO2 powder was mixed with 1.0W10, phenol resin 1, Owlo as a carbon source, and PMMΔ IOWlo as a molding binder in a naphtha-based solvent using a nylon pot and a nylon ball for 10 hours. After casting the slurry into a sheet and letting it dry,
A square sheet with a thickness of 0.8 mm was obtained by punching out a 50 mm square sheet. The sheets were sintered at 1850° C. for 5 hours in a nitrogen stream. The lattice constant of the obtained sintered body is a-axis 3. ]], 1
People, C axis 4.981 people, c/a is 1.601 and TiO2
It was the same as that produced under the same conditions without adding. The thermal conductivity is 170w/m and 190w/m.
It was m. Also, the half width is 0.10dcg at 2θ20
'l'i02 was larger than 0.05deg when not added.

[Brief explanation of the drawing]

Claims (9)

[Claims] (1) An aluminum nitride sintered body characterized in that particles of a compound other than wurtzite structure are finely dispersed within grains of aluminum nitride having a hexagonal wurtzite structure. (2) The aluminum nitride sintered body according to claim (1), wherein the finely dispersed particles are a compound having an NaCl structure. (3) The aluminum nitride sintered body according to claim (1), wherein the average size ratio of the aluminum nitride particles to the compound particles finely dispersed in the aluminum nitride particles is 5 or more. (4) Finely dispersed particles are Ti, Zr, Hf, V, Nb
, Ta, Mo, W, Fe, Co, and Ni, or a compound containing 0.01 to 30 weight percent of these elements as a metal element. ) The aluminum nitride sintered body described in item ). (5) The aluminum nitride sintered body according to claim (1), wherein the grain boundary phase composed of a compound phase of a sintering aid and Al_2O_3 contains a fine grain compound. (6) The apparent absorption coefficient of light at 500 nm is 50
The aluminum nitride sintered body according to claim (1), wherein the aluminum nitride sintered body has a diameter of at least cm^-^1. (7) Aluminum nitride powder and T with an average particle size of 1 μm or less
i, Zr, Hf, V, Nb, Ta, Mo, W, Fe, C
A method for producing an aluminum nitride sintered body according to claim 1, characterized in that one or more compounds selected from Ni, O, Ni, and the like are mixed, molded, and sintered. (8) Ti, Zr, Hf, V, Nb, Ta, Mo, W,
Claim (1) characterized in that aluminum nitride powder containing one or more compounds selected from Fe, Co, and Ni is synthesized, and the synthesized aluminum nitride powder is molded and sintered. A method for producing an aluminum nitride sintered body as described in 1. (9) A molding aid or an organic compound that leaves free carbon by heating is added to the powder or slurry mainly composed of aluminum nitride, and after mixing, the free carbon is reduced by 0.01 to 5.0% during the process of molding and sintering. Claim No. 7, characterized in that the composition is in the state of containing 0% by weight.
A method for producing an aluminum nitride sintered body according to item (8).