JPH04214068A - Green compact of aluminum nitride powder, binder used for the green compact, and production of sintered body of aluminum nitride - Google Patents

Abstract

PURPOSE:To offer a sintered aluminum nitride compact manufacturing method, which is capable of producing a sintered body of aluminum nitride with high dimensional accuracy by uniformly dispersing a powdered raw material of aluminum nitride in a solvent and improving the density of the resulting green compact and also producing a high quality sintered body of aluminum nitride excellent in volatility and minimal in residual carbon content when heat-treated in a nonoxidizing atmosphere, so as to offer a sintered body of aluminum nitride powder used in the above-mentioned manufacturing method and a binder used for this green compact. CONSTITUTION:The green compact of aluminum nitride powder is characterized by incorporating, as a binder, an acrylic copolymerization high polymer or a mixture of acrylic copolymerization high polymer and polybutylmethacrylate. Further, the binder consists of a copolymer of 1-5 mole% monomer containing carboxyl group and 99-55 mole% of at least one monomer of acrylic alkylester and acrylic alkoxyester.

Description

[Detailed description of the invention]

[Object of the invention]

0002

[Industrial Application Field] The present invention relates to a method for producing an aluminum nitride sintered body and an aluminum nitride powder compact, and in particular, to an easy production method of an aluminum nitride sintered body that is dense, has high dimensional accuracy, and has high strength. The present invention relates to a method for manufacturing an aluminum nitride sintered body and an aluminum nitride powder compact used in the manufacturing method.

The present invention also relates to a binder for molding aluminum nitride powder used to form a molded body of aluminum nitride ceramics before firing, and in particular, it is capable of uniformly dispersing raw aluminum nitride powder, and is capable of uniformly dispersing aluminum nitride raw material powder, The present invention relates to a binder for aluminum nitride powder molding, which is capable of forming a high quality sintered body with almost no residual carbon during degreasing of the body.

0004

[Prior Art] Ceramics prepared by molding raw material powders such as nitrides, carbides, borides, and silicides into a predetermined shape and then sintering them generally have good hardness, insulation, abrasion resistance, heat resistance, and corrosion resistance. It has been put into practical use in a wide range of fields in recent years because it has superior properties such as elasticity compared to conventional metal materials.

For example, a sintered body made of alumina (Al2O3) has conventionally been generally used as an insulating substrate material for semiconductors and integrated circuits. However, since the substrate made of alumina sintered body has low thermal conductivity and a high coefficient of thermal expansion compared to silicon, the adhesion of large silicon chips to the substrate is poor, and the silicon chips are easy to peel off. It also had the disadvantage of poor heat dissipation characteristics.

[0006] Therefore, sintered aluminum nitride (AlN), which has extremely high thermal conductivity and electrical insulation, and has a coefficient of thermal expansion close to that of silicon, is viewed as a promising material for electronic circuit boards.

Conventionally, AlN sintered bodies are produced by adding a sintering aid, a dispersant, a binder, a plasticizer, and a solvent to fine AlN raw material powder to prepare a uniform slurry, and shaping the resulting slurry into a predetermined shape. It is manufactured by molding to obtain an AlN powder compact, and then heating and sintering the obtained AlN powder compact at a temperature range of 1700 to 2000°C.

By the way, since AlN powder does not have good sinterability, yttrium oxide (Y2O3), calcium oxide (CaO), alkaline earth metals, metal oxides, and the like are added as sintering aids. As a result, an aluminum nitride sintered body that is relatively dense and has high strength under normal pressure is obtained.

[0009] Dispersants are added to improve the wettability of the AlN raw powder to solvents and to uniformly disperse the raw material powder in the solvent. agent is used.

[0010] Furthermore, a binder is added to bind the raw material powders together and hold them in a certain shape. In particular, the binder is used to hold the powder compact in a predetermined shape to improve shape accuracy, and also to improve its handling. It is added to improve properties. Conventionally, organic polymer compounds such as acrylic resin, PVB (polyvinyl butyral) resin, and cellulose resin are generally used as this binder.

On the other hand, in order to improve the thermal conductivity of aluminum nitride, it is necessary to prevent solid solution of oxygen into the aluminum nitride powder and prevent oxidation. Therefore, conventionally, in manufacturing processes such as degreasing and sintering, the molded body has been treated in a non-oxidizing atmosphere so as not to oxidize the aluminum nitride itself.

0012

[Problem to be solved by the invention] However, resin materials such as PVB resin added as a binder have extremely poor degreasing properties, and it is difficult to completely volatilize aluminum nitride powder in a non-oxidizing atmosphere such as the above. However, even after the degreasing operation, some carbon remains in the molded body, which inhibits the sintering of the aluminum nitride. Therefore, a method has also been adopted in which a high-strength aluminum nitride sintered body is formed by sufficiently degreasing in an oxidizing atmosphere, even at the expense of some degree of deterioration of aluminum nitride in the degreasing process.

However, in this case, the high thermal conductivity of aluminum nitride tended to be impaired. This trend is
This problem was particularly noticeable in electronic AlN co-sintered substrates, which are produced by forming a circuit wiring pattern on the surface of an aluminum nitride molded body using a metal paste and then sintering the same together with the molded body.

[0014] Further, the above residual carbon easily reacts with metal tungsten used as a conductor in the ceramic multilayer substrate to form high-resistance tungsten carbide (WC). As a result, there was a problem in that the wiring resistance of the aluminum nitride multilayer substrate after firing increased.

[0015] In order to solve the above problems, a method of using an acrylic resin with excellent volatility as a binder has been implemented, but in this case, it is difficult to sufficiently disperse the aluminum nitride raw material powder in the solvent slurry. However, this method has the disadvantage that only a low-density molded body can be obtained, and as a result, the amount of shrinkage of the molded body before and after firing increases, and the dimensional error of the sintered body increases.

On the other hand, if an attempt is made to reduce the amount of residual carbon as much as possible by using only a small amount of a binder with a large dispersing power, the lamination adhesive strength of the molded article will be significantly reduced. In particular, when forming a ceramic multilayer board by layering aluminum nitride green sheets, the adhesion between the green sheets is insufficient, which tends to cause short circuits, poor continuity, poor insulation, etc. of the wiring in the board. This caused a significant drop in the yield of electronic products.

On the other hand, various surfactants have been used as dispersants for ceramic powders, but there have been no detailed studies on specific examples of surfactants suitable for aluminum nitride powders for substrate molding. There weren't many.

In order to sufficiently disperse each ceramic powder in a solvent, it is necessary to improve the wettability of the powder surface to the solvent.
It is desirable to use a surfactant that can increase the ζ potential (zeta potential) on the powder surface, increase the repulsive force between the powders, and prevent reagglomeration. Such surfactants are determined depending on the type of ceramic powder, but in the past, various surfactants have often been used on a trial basis.

[0019] Therefore, surfactants that are difficult to dissolve in solvents may be used incorrectly. In this case, the aluminum nitride powder conversely aggregates and dispersion of the aluminum nitride powder in the solvent is inhibited. If dispersion is inhibited and aggregation occurs in this way, it becomes difficult to mold green sheets, which are raw materials for multilayer substrates. Further, even if molding is possible to a certain extent, the density of the molded product is low and the variation in density becomes large, making it difficult to obtain an electronic substrate that requires high dimensional accuracy.

[0020] Furthermore, in the case of a surfactant containing metal ions such as Na+, the metal ions may become contaminants and cause a decrease in the quality and thermal conductivity of the substrate.

[0021] Also, in recent years, with the increase in high-speed operation of electronic components,
BACKGROUND ART While there is an increasing demand for reducing the conductive resistance of a substrate, and as electronic components become smaller and more highly integrated, there is a demand for a substrate material that causes less deterioration in the dimensional accuracy of the substrate after firing. In particular, aluminum nitride, which has excellent heat transfer properties, has good dispersibility of the raw material powder and can form dense compacts, reduces conductor resistance, and forms high-quality sintered compacts. There is a need for a method for producing an aluminum nitride sintered body that can achieve this.

The present invention was made to solve the above-mentioned problems, and it is possible to uniformly disperse aluminum nitride raw material powder in a solvent slurry to improve the density of a compact and produce aluminum nitride sintered products with high dimensional accuracy. The aluminum nitride sintered body has excellent volatility and has low residual carbon even when heat treated in a non-oxidizing atmosphere, making it possible to produce a high-quality aluminum nitride sintered body. The object of the present invention is to provide a manufacturing method, an aluminum nitride powder molded body used in the manufacturing method, and a binder used in the molded body. [Structure of the invention]

[0023]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present application have proposed the types and amounts of surfactants and solvents used as binders and dispersants to be added when producing aluminum nitride powder compacts. Comparative investigation was carried out on the dispersibility of the raw material powder in the solvent, the formability, adhesion and degreasing properties of the powder compact, and the strength characteristics of the aluminum nitride sintered body obtained by firing the powder compact, using various methods. The experiment was repeated to find out.

As a result, a copolymer formed by copolymerizing a monomer containing a carboxyl group or an ester group as a binder and at least one monomer of an acrylic acid alkyl ester and an acrylic acid alkoxyl ester in a predetermined ratio. When combining or using a mixture of the above acrylic copolymer and polybutyl methacrylate, a powder compact with excellent degreasing properties, high density, and high adhesive strength can be obtained, as well as low residual carbon and electrical resistance. It was found that an aluminum nitride sintered body with a small

Furthermore, when at least one of an alkyl ether phosphate surfactant and an alkyl ether acetate surfactant is used as a dispersant, the dispersibility of the aluminum nitride raw material powder becomes extremely good, resulting in a powder having a high density. It has been found that when a compact is obtained and the powder compact is fired, an aluminum nitride sintered body with little shrinkage and high dimensional accuracy can be obtained.

The present invention has been completed based on the above findings.

That is, the aluminum nitride powder compact according to the present invention is a nitride powder obtained by adding and mixing a binder, a dispersant, a plasticizer, and a solvent to aluminum nitride powder, and molding the resulting mixture into a predetermined shape. The aluminum powder compact is characterized in that the binder contains an acrylic copolymer or a mixture of an acrylic copolymer and polybutyl methacrylate. The acrylic copolymer polymer may be composed of a copolymer of at least one monomer of an acrylic acid alkyl ester and an acrylic acid alkoxy ester, and a monomer containing a carboxyl group or an ester group.

In particular, monomers 1 to 1 containing carboxyl groups
5 mol% and at least one monomer of acrylic acid alkyl ester and acrylic acid alkoxy ester 99
An aluminum nitride powder molding binder comprising a copolymer with ~95 mol % of aluminum nitride may be used.

The present invention is further characterized in that the dispersant contains at least one of an alkyl ether phosphate surfactant and an alkyl ether acetic acid surfactant.

On the other hand, in the method for producing an aluminum nitride sintered body according to the present invention, a binder and a binder are added to aluminum nitride powder.
Aluminum nitride is produced by adding and mixing a dispersant, plasticizer, and solvent, molding the resulting mixture into a predetermined shape to form an aluminum nitride powder compact, and then heating and sintering the resulting compact. The method for producing a sintered body is characterized in that an acrylic copolymer polymer or a mixture of an acrylic copolymer polymer and polybutyl methacrylate is used as the binder. Further, the present invention is characterized in that at least one of an alkyl ether phosphate surfactant and an alkyl ether acetic acid surfactant is used as the dispersant.

[0031]

[Action] Acrylic copolymer has polar acrylic acid or methacrylic acid groups in its molecular structure in order to impart dispersibility to aluminum nitride powder, and destroys agglomeration of aluminum nitride powder. It acts as a deflocculant and at the same time has the effect of promoting the dispersion of powder into a solvent.

However, polar groups such as carboxyl groups or hydroxyl groups in the acrylic copolymer have the property of easily causing a polymerization reaction during the degreasing process. Therefore, acrylic copolymer polymers have the disadvantage that they are difficult to volatilize in an atmosphere where aluminum nitride and conductive metals do not oxidize, and carbon content tends to remain in the molded product. This residual carbon reacts with the conductor metal in the subsequent firing process to form a high-resistance compound, which may increase the conductor resistance of the final product.

[0033] Therefore, in order to maintain good thermal decomposition properties of the binder component in a non-oxidizing atmosphere, it is necessary to set the content of polar groups in the acrylic copolymer to 5 mol% or less. However, acrylic copolymer polymers that do not contain any polar groups have extremely low dispersing power for aluminum nitride powder, and at least 1 mol% of polar groups is required in order to exhibit a certain degree of dispersing power. . In other words, in order to promote the dispersion of the raw material powder and also exhibit thermal decomposition properties in a non-oxidizing atmosphere, the amount of polar groups contained in the acrylic copolymer polymer should be in the range of 1 to 5 mol%. It is necessary to set it within

When the above acrylic copolymer polymer is used alone as a binder, high dispersibility of the raw material powder and
Although high thermal decomposability of the binder can be obtained, by using a mixture of polybutyl methacrylate, which has better thermal decomposition properties, and the above acrylic copolymer polymer as the binder, the amount of residual carbon can be further reduced, and the high thermal decomposability can be obtained. It is possible to produce high quality aluminum nitride sintered bodies.

Here, although polybutyl methacrylate has the advantage that thermal decomposition proceeds almost completely during degreasing and the amount of residual carbon is extremely low, when its content is increased, the density ratio of the molded product decreases and sintering There is a drawback that the amount of shrinkage increases when it is made into a solid body, resulting in large dimensional errors.

Therefore, the blending ratio of the acrylic copolymer and polybutyl methacrylate is determined by taking into consideration the density ratio and residual carbon content required for the molded article. That is, it is determined in the range of 3 to 99 mol% of polybutyl methacrylate to 97 to 1 mol% of the acrylic copolymer polymer.

The acrylic copolymer as a binder contains at least one monomer of acrylic acid alkyl ester and acrylic acid alkoxy ester.
9 mol% and 70 to 1 monomer containing carboxyl group
It is preferable to prepare a copolymer by copolymerizing mol % of mol%.

In particular, as a binder for aluminum nitride molding, it maintains dispersion power for aluminum nitride powder and has good thermal decomposition properties in a non-oxidizing atmosphere.
A binder comprising a copolymer of 1 to 5 mol % of a monomer containing a carboxyl group and 99 to 95 mol % of at least one of an acrylic acid alkyl ester and an acrylic acid alkoxy ester is useful.

[0039] When the mixture of the acrylic copolymer and polybutyl methacrylate is used as a binder, it is possible to form a high-density compact without reducing the dispersibility of aluminum nitride powder in a non-aqueous solvent. and
Moreover, since it has excellent volatility, a molded article with a small amount of residual carbon after the degreasing process can be obtained.

In particular, by reducing the proportion of the acrylic copolymer polymer relative to that of polybutyl methacrylate, the density and adhesive strength of the molded product do not decrease, and the strength of the multilayer substrate can be further increased. ,
By reducing the amount of residual carbon, the conductor resistance in the substrate can be further reduced.

On the other hand, the alkyl ether phosphate surfactant or alkyl ether acetate surfactant used as a dispersant is made from aluminum nitride powder 1, which is the raw material.
It is added at a ratio of about 0.1 to 2 parts by weight per 00 parts by weight. These surfactants effectively adsorb onto the aluminum nitride powder surface due to their inherent polar groups, resulting in
The raw material aluminum nitride powder is uniformly dispersed in a non-aqueous solvent. Therefore, by using these surfactants, it is possible to obtain a slurry in which the raw material powder is uniformly dispersed, and by molding and drying this slurry, it has become possible to manufacture aluminum nitride powder compacts with high density. Ta.

Furthermore, when firing and sintering a high-density aluminum nitride powder compact, the proportion of dimensional shrinkage before and after firing becomes smaller, making it possible to obtain an aluminum nitride sintered body with high dimensional design accuracy. , high quality ceramic substrates can be manufactured.

[0043]

Embodiments Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

As an example, 0.5 parts by weight of a dispersant and 100 parts by weight of a toluene alcohol mixture as a solvent were added to 100 parts by weight of aluminum nitride powder with an average particle size of 1.5 μm.
parts by weight, 5 parts by weight of dibutyl phthalate as a plasticizer, and further 12 parts by weight of a mixture of an acrylic copolymer and polybutyl methacrylate as a binder. The mixing ratio of the acrylic copolymer and polybutyl methacrylate was varied from 80:20 to 20:80. Each of the mixtures having the above compositions was sufficiently mixed in a ball mill to prepare each slurry. Fine air bubbles contained in the slurry were completely removed by stirring under reduced pressure. The slurry thus obtained was molded by a conventional tape casting method to obtain a tape-shaped aluminum nitride powder compact (green sheet). Next, a tungsten paste was printed on the obtained green sheet, and the green sheet was stacked in multiple layers and bonded under heat and pressure, and then cut into a multilayer substrate molded body.The obtained molded body was subjected to a degreasing treatment in a nitrogen gas atmosphere. Then, the amount of residual carbon was analyzed and measured for each of the obtained degreased molded bodies using a carbon amount analyzer.

Each degreased molded body was sintered at 1800° C. for 3 hours, and the ratio of the density of the degreased molded body to the density of the obtained sintered body (molded body density ratio) was measured.

On the other hand, as a comparative example, an aluminum nitride powder compact to which only 12 parts by weight of acrylic copolymer was added was prepared in the same process, and further degreased under the same conditions as in the example. Similarly, the amount of residual carbon and the density ratio of the compact were measured.

The above results are shown in FIGS. 1 and 2.

FIG. 1 is a graph showing the relationship between the binder mixture composition and the compact density ratio, and FIG. 2 is a graph showing the relationship between the binder mixture composition and the amount of residual carbon.

As is clear from FIG. 1, as the amount of polybutyl methacrylate added as a binder increases, the density ratio of the molded article tends to decrease somewhat. However, even when the mixing ratio of polybutyl methacrylate is increased to about 80%, the density ratio remains at 60% or more, so
The amount of shrinkage after sintering is small, and there is no risk of significant reduction in dimensional accuracy.

On the other hand, as is clear from FIG. 2, when the amount of polybutyl methacrylate added as a binder is increased, the effect of reducing the amount of residual carbon becomes remarkable, and a substrate with low conductor resistance can be obtained.

Therefore, by setting the binder mixture composition to an optimum value depending on the required level of dimensional accuracy after firing and the required degree of conductor resistance, the amount of residual carbon can be reduced without impairing the density ratio of the compact. can be effectively reduced.

[0052] An aluminum nitride powder compact formed by adding 2 parts by weight of an acrylic copolymer polymer and 10 parts by weight of polybutyl methacrylate as a binder was degreased and fired under the above conditions to produce a multilayer substrate, which was then subjected to X-ray diffraction analysis. As a result of analyzing the wiring conductor, no compound of conductor metal and carbon was detected, confirming that a high-quality multilayer board with low conductor resistance was obtained.

Here, the results of an experiment conducted to confirm the thermal decomposition properties of the acrylic copolymer constituting the binder for molding aluminum nitride powder according to the present invention will be explained.

That is, the proportions of monomers having polar groups such as carboxyl groups are 10, 8, 5, 2, and 0 mol%, respectively, while the proportions of alkyl methacrylate are 90, 92, 95, 98, Samples 1 to 5 of binders each consisting of a copolymer with a concentration of 100 mol % were prepared. Next, a predetermined amount of each binder was placed in an evaporating dish, placed in a heating furnace through which nitrogen was passed, and heat-treated at a temperature of 800°C for 2 hours to cause thermal decomposition. The residual proportion of was measured and the results shown in FIG. 3 were obtained.

As is clear from the results shown in FIG.
The binders of Samples 1 and 2 containing a large amount of polar groups (10 mol %) have an extremely large amount of residual carbide, making it difficult to obtain a high-quality sintered body. On the other hand, the binders of samples 3 to 5 in which the content of polar groups is 5 to 0 mol % have a small amount of residual carbon. The binder of sample 5, which does not contain any polar groups, had the smallest amount of residual carbide, and was almost equivalent to the binder of sample 4, which contained 2 mol % of polar groups.

However, the binder of sample 5, which does not have a polar group, had almost no dispersing power for aluminum nitride powder, and was unsuitable as a binder for molding aluminum nitride powder. Therefore, in order to promote the dispersion of aluminum nitride powder and exhibit excellent thermal decomposition properties in a non-oxidizing atmosphere,
It was confirmed that the amount of polar groups contained in the binder needs to be set in the range of 1 to 5 mol%.

Next, the effect of the dispersant will be explained in comparison with the case where a conventional dispersant is used.

0.5 parts by weight of various surfactants and 800 parts by weight of an organic solvent were mixed with 100 parts by weight of aluminum nitride powder, and a sedimentation test was conducted on the resulting mixed solution l. The dispersibility of aluminum powder was investigated.

Here, the sedimentation test is carried out by filling a graduated cylinder 1 with a constant cross-sectional area S with the above-mentioned mixed liquid 1, as shown in FIG. A clear region X1 in the upper layer of the measuring cylinder 1 where the raw material powder is hardly dispersed, and a region X2 in the middle layer of the measuring cylinder 1 where the raw material powder has settled and become semi-turbid.
In the lower part of the measuring cylinder 1, a region X3 is formed where the sedimentation and consolidation of the raw material powder has proceeded, and a sedimentation surface α1, which forms the boundary between the region X1 and the region X2, and the region X2 and the region X3 are formed.
The deposition surface α2, which is the boundary between the two changes with time t. Then, a change curve of the height H of each of the sedimentation surface α1 and the sedimentation surface α2 with respect to the standing time t is obtained, and the quality of the dispersibility is judged based on the magnitude of the slope. It can be determined that the dispersibility of the aluminum nitride powder is excellent when the sinking rate of the settling surface α1 is small, the slope of the change curve is small, and the increasing rate of the settling surface α2 is small.

[0060] And one to which dioxyethylene alkyl ether phosphoric acid was added as an alkyl ether phosphate surfactant (Example 2), and one to which polyoxyethylene alkyl ether acetic acid was added as an alkyl ether acetic acid surfactant. Mixed liquids were prepared for (Example 3) and subjected to a sedimentation test, and the results shown in FIGS. 5 and 6 were obtained.

On the other hand, for comparison, a sample containing polyoxyethylene oleylamine as a conventionally used amine surfactant (Comparative Example 2) and a sample containing sorbitan sesquioleate, which is a sorbitan fatty acid ester, were prepared (Comparative Example 2). 3) A mixed solution was prepared with the addition of polyoxyethylene sorbitan monooleate (Comparative Example 4), and a sedimentation test was conducted in the same manner as in Examples 2 and 3, with the results shown in Figures 7 to 9, respectively. I got it.

As shown in FIG. 5, it can be seen that when dioxyethylene alkyl ether phosphoric acid is used as a dispersant, the slope of the sedimentation curve is the smallest, the sedimentation rate of the raw material powder is slow, and the dispersibility of the particles is the best.

Further, as shown in FIG. 6, it can be seen that the dispersibility of the aluminum nitride powder in the solvent is also improved when polyoxyethylene alkyl ether acetic acid is used as the dispersant.

On the other hand, as shown in FIGS. 7 to 9, when an amine type or sorbitan fatty acid ester type surfactant is used as a dispersant, the slope of the sedimentation curve is large, and the sedimentation rate of the aluminum nitride powder is high. , it turns out that the dispersibility is low.

Then, the dioxyethylene alkyl ether phosphoric acid and polyoxyethylene alkyl ether acetic acid shown in FIGS. 5 and 6 were added to the aluminum nitride powder, and a mixed solution was formed by uniformly dispersing it in a solvent. When measured, they all exceeded 60%. Then, when this molded body was fired and the variation in shrinkage rate before and after firing was measured, it became possible to reduce it to about 1/2 of the conventional value. Therefore, the design and manufacture of high-precision electronic ceramic substrates becomes dramatically easier, and it is possible to sufficiently respond to miniaturization and high integration of electronic components.

[0066]

As explained above, according to the method for producing an aluminum nitride sintered body according to the present invention, the aluminum nitride powder compact used in the production method, and the binder used in the powder compact, the binder Because we use a mixture of the acrylic copolymer polymer that increases the strength of the molded product and polybutyl methacrylate that has excellent volatility, and the above acrylic copolymer polymer, it does not significantly reduce the density of the molded product. It is possible to obtain an aluminum nitride powder compact having a very small amount of residual carbon after degreasing.

Furthermore, by using this aluminum nitride powder compact, a high-quality multilayer substrate with high dimensional accuracy and sufficiently low conductor resistance can be obtained.

Furthermore, since an alkyl ether phosphate surfactant or an alkyl ether acetate surfactant is used as a dispersant, the dispersibility of the aluminum nitride powder in the solvent is extremely excellent, resulting in a high-density aluminum nitride powder compact. It is now possible to obtain
An aluminum nitride sintered body with high dimensional accuracy is obtained. Therefore, an electronic board that can be designed with high precision can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between binder mixture composition and molded body density ratio.

FIG. 2 is a graph showing the relationship between the binder mixture composition and the amount of residual carbon.

FIG. 3 is a graph showing the relationship between polar group weight ratio and carbide residual rate.

FIG. 4 is an explanatory diagram showing a method of conducting a sedimentation test.

FIG. 5 is a graph showing the height of the sedimentation surface and the change over time in the height of the sedimentation surface when a sedimentation test was performed on a mixed solution prepared using dioxyethylene ether phosphoric acid as a dispersant.

FIG. 6 is a graph showing the height of the sedimentation surface and the change over time in the height of the sedimentation surface when a sedimentation test was performed on a mixed solution prepared using polyoxyethylene alkyl ether acetic acid as a dispersant.

FIG. 7 is a graph showing the height of the sedimentation surface and the change over time in the height of the sedimentation surface when a sedimentation test is performed on a mixed liquid prepared using polyoxyethylene oleylamine as a dispersant.

FIG. 8 is a graph showing the height of the sedimentation surface and the change over time in the height of the sedimentation surface when a sedimentation test was performed on a mixed liquid prepared using sorbitan sesquioleate as a dispersant.

FIG. 9 is a graph showing the height of the sedimentation surface and the change over time in the height of the sedimentation surface when a sedimentation test was performed on a mixed liquid prepared using polyoxyethylene sorbitan monooleate as a dispersant.

[Explanation of symbols]

1 Female cylinder l Mixed liquid α1 Sedimentation surface α2 Deposition surface

Claims (6)

[Claims] [Claim 1] A binder in aluminum nitride powder,
In an aluminum nitride powder compact formed by adding and mixing a dispersant, a plasticizer, and a solvent and molding the resulting mixture into a predetermined shape, an acrylic copolymer or an acrylic copolymer is used as the binder. An aluminum nitride powder compact containing a mixture of molecules and polybutyl methacrylate. 2. The acrylic copolymer polymer comprises a copolymer of at least one monomer of an acrylic acid alkyl ester and an acrylic acid alkoxy ester, and a monomer containing a carboxyl group. aluminum nitride powder compact. [Claim 3] Carboxyl group-containing monomers 1-
5 mol% and at least one monomer of acrylic acid alkyl ester and acrylic acid alkoxy ester 99
A binder for molding aluminum powder comprising a copolymer with ~95 mol%. [Claim 4] Aluminum nitride powder with a binder;
In an aluminum nitride powder compact obtained by adding and mixing a dispersant, a plasticizer, and a solvent and molding the resulting mixture into a predetermined shape, an alkyl ether phosphate surfactant and an alkyl ether acetic acid surfactant are used as the dispersant. 1. An aluminum nitride powder compact containing a surfactant consisting of at least one of a series of surfactants. [Claim 5] A binder in aluminum nitride powder,
Aluminum nitride is produced by adding and mixing a dispersant, plasticizer, and solvent, molding the resulting mixture into a predetermined shape to form an aluminum nitride powder compact, and then heating and sintering the resulting compact. A method for producing an aluminum nitride sintered body, characterized in that the binder used is an acrylic copolymer polymer or a mixture of an acrylic copolymer polymer and polybutyl methacrylate. [Claim 6] A binder in aluminum nitride powder,
Aluminum nitride is produced by adding and mixing a dispersant, plasticizer, and solvent, molding the resulting mixture into a predetermined shape to form an aluminum nitride powder compact, and then heating and sintering the resulting compact. Production of an aluminum nitride sintered body, characterized in that the method for producing a sintered body uses at least one of an alkyl ether phosphate surfactant and an alkyl ether acetic acid surfactant as the dispersant. Method.