JPH09110532A - Heat resistant material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat resistant material containing AlN and/or AlON, capable of having both excellent heat impact resistance and corrosion resistance simultaneously and also inexpensive. SOLUTION: This heat resistant material is obtained by nitriding a formed material containing >=85wt.% aluminum dross powder at 550-2,000 deg.C. Thus, the heat resistant material containing >=90wt.% AlN or AlON, or both of them and having 3-35vol.% air bubble containing ratio, is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to AlN and / or
Alternatively, the present invention relates to a heat-resistant material containing AlON or BN, and a method for producing the same.

[0002]

2. Description of the Related Art AlN decomposes when contacted with water and NH
_Although it evolves ₃ gases and changes to Al ₂ O ₃ , it has relatively high thermal conductivity and relatively low Young's modulus, so it is relatively resistant to thermal shock, can withstand rapid cooling from 300 ° C to room temperature, and can be used for molten steel, etc. It is known as a material resistant to erosion by molten metal. On the other hand, Al ₂ O ₃ is weak against thermal shock, but chemically stable, and is known as a material resistant to erosion by molten metal with molten steel. Further, AlON is a general term for a solid solution composed of Al, O and N, has intermediate properties between AlN and Al ₂ O _3, and is inferior in thermal shock resistance to AlN, but this is also a molten steel. It is known as a material resistant to erosion by molten metal such as. This AlON is obtained, for example, by mixing AlN powder and Al ₂ O ₃ powder and heating at a high temperature of 1400 ° C. or higher, and AlON having various compositions can be produced depending on the powder composition and firing conditions. .

From the above characteristics, AlN and Al
A composite material containing ON is also proposed. JP 63
-84750 discloses boron nitride (BN) 20-7.
Disclosed is a continuous casting nozzle suitable for continuous casting of deoxidized steel containing 0 part by weight, 10 to 40 parts by weight of aluminum nitride and 10 to 30 parts by weight of graphite (C). Further, since the nozzle in which BN, AlN, and C are blended in a predetermined ratio in this way has a low wettability with molten steel, it is shown that inclusions can be prevented from adhering to the inner surface of the nozzle.

Also, page 70 of Interceram, Special Issue (1987) shows that a BN-based continuous casting nozzle is 52.6w.
t% BN, 27.0 wt% AlN, 2.0 wt% SiO
₂ , a composition of 17.5 wt% in total of C and SiC is disclosed.

Further, in Japanese Patent Application Laid-Open No. 5-2777643, BN is contained in an amount of 20 wt% or more, preferably 40 wt% or more, and glass is preferably 2 wt% or more, and the balance is S.
iAlON, AlN, Al ₂ O ₃ , ZrO ₂ , MgO,
A break ring for horizontal continuous casting made of a material having high erosion resistance against molten steel such as CaO is disclosed.

Furthermore, FC Report, vol 11 (1993) No. 8
Pp. 168, the starting materials are Al ₂ O ₃ and Al
It is disclosed that an AlON-BN sintered body formed by using N, BN, and Y ₂ O ₃ as a sintering aid has excellent molten steel resistance and thermal shock resistance.

As described above, these materials usually use the powder corresponding to the components constituting the product as a starting material. However, since AlN powder is expensive, such a material has been used only for a limited number of applications, even though the heat-resistant material using this as a starting material has excellent corrosion resistance.

On the other hand, in Japanese Patent Laid-Open No. 59-8669, a molded body made of metal silicon (Si), metal aluminum (Al) and metal oxide is nitrided and sintered in a nitrogen atmosphere. Excellent corrosion resistance against molten metal,
A method for obtaining a silicon nitride composite sintered body having excellent workability and its material are disclosed. Specifically, Si20-
90 wt%, Al1 to 20 wt%, and Al ₂ O ₃ ,
5 to 60 wt% of at least one oxide selected from ZrO ₂ , Y ₂ O ₃ , Cr ₂ O ₃ , TiO ₂ , and MgO is kneaded and molded, and then this molded body is subjected to
After pre-baking at a temperature of 000 to 1300 ° C., nitriding sintering is performed under a nitrogen atmosphere at a temperature of 1500 ° C. or less under a metal silicon nitriding condition to obtain a target silicon nitride composite sintered body. The obtained sintered body was subjected to a nitriding reaction between the metal components of Si and Al and the oxide to produce Si ₃ N ₄ —AlN—Al ₂ O.
_{It is a 3} type or Si ₃ N ₄ -AlN-oxide type composition and exhibits a strong bond structure.

According to this technique, Al as a starting material
Is cheaper than AlN, so AlN, AlON
It is advantageous for expanding the application of the contained material. However, it is difficult to completely convert Al into AlN by nitriding,
Unreacted Al remains in the sintered body. Therefore, there is a problem that the high temperature strength of the sintered body is lowered. Further, if the content of metallic aluminum is too large, a phenomenon occurs in which Al in the molded body is melted at 660 ° C. and flows out of the molded body.
Therefore, the content of metallic aluminum is limited to 30 wt% or less.

[0010]

As described above,
It is conceivable to form inexpensive Al as a starting material instead of expensive AlN or AlON powder as a starting material for AlN and AlON which have excellent corrosion resistance, particularly excellent corrosion resistance to molten metal. If the compounding ratio of Al is increased, there is a problem that Al melts and blows out,
Conventionally, auxiliary Al powder has been added only.

The present invention has been made in view of the above circumstances, and it is possible to achieve both excellent thermal shock resistance and excellent corrosion resistance at the same time, and at a low cost, AlN and / or A
An object of the present invention is to provide a heat resistant material containing 1ON and a method for producing the same.

[0012]

In order to solve the above-mentioned problems, the present invention firstly contains 90% by weight or more of AlN or AlON or both of them, and has a bubble content of 3 to 10.
A heat-resistant material having a content of 35 vol% is provided.

Secondly, 85 w of aluminum dross powder
Provided is a method for producing a heat-resistant material containing AlN and / or AlON, which comprises nitriding a compact containing t% or more at 530 to 2000 ° C.

Third, 85 w of aluminum dross powder
AlN and / or AlO obtained by nitriding a compact containing t% or more at 530 to 2000 ° C.
A heat-resistant material containing N is provided.

Fourth, 30 to 80 wt% of AlN or AlON or both of them, and 10 to 60 w of BN.
Provided is a heat-resistant material characterized by containing t%, the total amount of both being 90 wt% or more, and the bubble content being 3 to 35 vol%.

Fifth, aluminum dross powder of 40 to
AlN and / or AlON and BN characterized by nitriding a molded body of a mixed powder containing 75% by weight and 10 to 45% by weight of B ₄ C powder, the total amount of which is 85% by weight or more at 1300 to 2000 ° C. Provided is a method for producing a heat-resistant material containing the same.

Sixth, aluminum dross powder of 40 to
AlN and / or AlON and BN obtained by nitriding a molded body of a mixed powder containing 75 wt% and B ₄ C powder in an amount of 10 to 45 wt% and a total amount of 85 wt% or more at 1300 to 2000 ° C. To provide a heat resistant material.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. In the present invention, aluminum dross is used as a starting material. Aluminum dross is a by-product generated in the process of melting and refining aluminum scrap to regenerate it into metal. The aluminum dross contains 40 to 70 wt% of metal Al, as well as metal Si and A.
1N, Al ₂ O ₃ , MgO, MgCl ₂ , NaCl, N
Including aF and the like.

The inventors of the present invention have found that aluminum dross powder is easily nitrided by nitrogen gas at a temperature of 530 ° C. or higher, and that a molded product containing aluminum dross powder as a main component has a pure Al melting point of 660. The present invention has been completed by finding that molten aluminum does not flow out of the molded body even when heated to a temperature of not less than 0 ° C.

In one embodiment of the present invention, a compact containing 85 wt% or more of aluminum dross powder is nitrided at 530 to 2000 ° C. to obtain a heat resistant material containing AlN and / or AlON.

Aluminum dross powder particles are made of metallic Al.
A main part consisting of an alloy in which a small amount of metallic Si is solid-solved,
It is composed of a nitriding or oxide layer (having AlN or Al ₂ O ₃ as a main component) on the surface layer and a portion to which MgCl ₂ , NaCl, NaF or the like added as a flux adheres to the particle surface. These non-metal components contained in the aluminum dross have an effect of preventing movement, coalescence, and outflow to the outside of the molded body of droplets generated by melting Al of the main part.
By thus preventing the movement and coalescence of the droplets, the surface area of the molten aluminum is maintained at a high level. This provides favorable conditions for the progress of the nitriding reaction that occurs on the surface of the aluminum dross particles, and the residual of unreacted Al is minimized. Therefore, by applying the aluminum dross powder as the Al source, the above-mentioned problems of melting aluminum and problems of incomplete nitriding of Al are solved.

As a result, the proportion of metallic aluminum in the starting material can be set to a level exceeding 30 wt%, and a material having a high proportion of AlN or AlON having good corrosion resistance can be obtained. For example, aluminum dross alone containing 40 to 70 wt% of metallic aluminum is used as a starting material. From the viewpoint of obtaining a material having high corrosion resistance, it is preferable that the content of aluminum dross is high, and in the present invention, the content is 85 wt% or more.

Other raw materials for aluminum dross include
It is necessary that the material is relatively excellent in corrosion resistance and heat resistance, and for example, oxides, nitrides having a melting point of 1700 ° C. or higher,
Oxynitride, boride, and carbide can be applied.

As the oxide, TiO ₂ , ZrO ₂ , C
Examples thereof include one or more oxides selected from r ₂ O ₃ , Al ₂ O ₃ , MgO, and SiO ₂ , and complex oxides containing at least one of these oxides. 2MgO · SiO ₂ , 3MgO · 2 as the complex oxide
SiO ₂ , MgO / SiO ₂ , MgO / CaO, MgO
・ Cr ₂ O ₃ , MgO / Al ₂ O ₃ , 2MgO / TiO
₂ , MgO.ZrO ₂ , 3Al ₂ O ₃ .2SiO _{2 and the} like. As the nitride, TiN, ZrN, Cr ₂ N,
AlN may be mentioned. AlON is mentioned as an oxynitride. As boride, MgB ₂ , CaB ₆ , Ti
One or more boride compounds selected from B ₂ , ZrB ₂ and AlB ₂ may be mentioned. As carbide,
SiC, TiC, ZrC, Cr ₃ C ₂ , Cr ₇ C ₃ , A
One or more carbides selected from l ₄ C ₃ can be mentioned. In addition, a metal such as Al or Si that is converted into ceramics by nitriding or carbonization during the sintering process may be added.

AlON contained as an oxynitride is A
It is a general term for solid solutions of 1, O, and N, but the composition is not particularly limited, and any composition may be used. Further, part of Al in AlON may be replaced with Si. However, the Si / Al molar ratio is preferably 1.0 or less from the viewpoint of corrosion resistance. This is because if it exceeds 1.0, the corrosion resistance to the melt, particularly the molten steel and the molten slag, is lowered. Examples of such AlON include Al ₁₁ O ₁₅ N, AlON, Al ₁₉₈ O ₂₈₈ N ₄ , A
l ₂₇ O ₃₉ N, Al ₁₀ N ₈ O ₃ , Al ₉ O ₃ N ₇ , SiA
_{l 7 O 2 N 7, Si} 3 Al 3 O 4.5 N 5 , and the like.

In the present invention, Al in the aluminum dross as a starting material is nitrided with a nitriding gas such as nitrogen, ammonia, or an ammonia decomposition gas. A furnace temperature of 530 ° C. or higher is selected for the progress of nitriding. Preferably. The reaction when nitrogen is used is Al + 1 / 2N ₂ → AlN.

The reason why the temperature is 530 ° C. or higher is that the nitriding speed is low and it cannot be said to be practical if the temperature is lower than this temperature. Here, the nitridation of Al is an exothermic reaction, and the temperature of the processed material becomes higher than the furnace temperature. When the furnace temperature is raised, the progress of nitriding is accelerated, so that the processing time can be shortened. Furnace temperature is 1
At temperatures above 300 ° C, nitriding of metallic Si also occurs, resulting in Si ₃ N ₄
Is generated. The reaction at this time is Si + 2 / 3N ₂ → 1 / 3Si ₃ N ₄ .

At a temperature of 1400 ° C. or higher, AlN reacts with Al ₂ O ₃ to produce AlON. Partly Si ₃
It also reacts with N ₄ to become SiAlON. AlON is Al
As with N, it has excellent corrosion resistance to molten metal,
You may heat-process above 1400 degreeC and aim at AlON conversion. Although SiAlON is inferior in corrosion resistance to AlON, SiA has a large Al ratio of 1.0 or less in Si / Al atomic ratio.
The concept is in a broad sense, including lON. It is not necessary to exceed 2000 ° C for conversion to AlON. Therefore, the temperature condition is selected so that the temperature during nitriding falls within the temperature range of 530 to 2000 ° C.

In this way, a heat resistant material having a high content of AlN and / or AlON having excellent heat resistance can be obtained. By further compounding this with BN, the thermal shock resistance can be dramatically improved. it can.

That is, in another embodiment of the present invention, a molded body of a mixed powder containing ₄₀ to 75 wt% of aluminum dross powder and 10 to 45 wt% of B ₄ C powder, the total of both being 85 wt% or more. 1300 to 20
Nitriding is performed at 00 ° C. to obtain a heat resistant material containing AlN and / or AlON and BN.

Since BN powder is extremely expensive, its application is extremely limited as long as BN is used as a starting material. Therefore, in the present invention, relatively inexpensive B ₄ C is used as a starting material, and a heat-resistant material containing AlN and / or AlON and BN is manufactured by a method of synthesizing BN at the same time when a compact is sintered. That is, a molded body of a mixed powder containing aluminum dross and B ₄ C in the above range is heated to produce AlN and / or AlON.
And BN are generated.

First, when aluminum dross melts at 530 to 600 ° C., Al reacts with B ₄ C to form AlB ₂ . The reaction at this time is as follows. B ₄ C + 2Al → 2AlB ₂ + C Excessive Al is nitrided at this stage according to the following reaction to become AlN.

Al + 1 / 2N ₂ → AlN At temperatures above 1300 ° C., AlB ₂ is nitrided to form BN together with AlN. The reaction at this time is as follows.

Part or all of AlB ₂ + 3 / 2N ₂ → AlN + 2B N C reacts with Si in the aluminum dross in the following manner to form SiC.

Si + C → SiC In this way, AlN, BN, and SiC are newly generated, and constitute the material together with Al ₂ O ₃ , MgO, etc. contained in the starting material. The B ₄ C remaining in the initial stage of nitriding without becoming AlB ₂ is nitrided at a temperature of 1400 ° C. or higher to generate BN and C. Also, AlN and A
To react with l ₂ O ₃ to achieve AlON formation, 14
It is necessary to set the temperature to 00 ° C. or higher, but the temperature higher than 2000 ° C. is not necessary. Therefore, AlN and /
Alternatively, in order to obtain a heat resistant material containing AlON and BN, temperature conditions are selected so that the temperature during nitriding falls within the temperature range of 1300 to 2000 ° C.

BN has excellent thermal shock resistance and is a soft material. In order to obtain such a material containing BN, B ₄ C powder is blended as described above.
If the amount of B ₄ C powder is too small, the amount of BN will be insufficient and the thermal shock resistance will be insufficiently improved. On the other hand, if the amount is excessive, the thermal shock resistance will be improved, but the hardness of the material will be reduced and the fluidized wear due to molten metal The weakening defect becomes remarkable. Therefore, B ₄
The blending amount of C powder is 10 to 45 so that such a problem does not occur.
The amount of aluminum dross powder is 40-
It is set to 75 wt%. Further, in order to combine such corrosion resistance and thermal shock resistance, AlN and / or AlO
It is necessary to increase the total amount of N and BN. For this purpose, the total amount of aluminum dross powder and B ₄ C powder is 8
It is necessary to increase it to 5 wt% or more.

Even when BN is contained in this way, as the other raw material, a material having relatively excellent corrosion resistance and heat resistance as described above, for example, an oxide, a nitride or an oxynitride having a melting point of 1700 ° C. or higher. , Boride, and carbide can be applied.

In the present invention, it is necessary to sufficiently carry out the above-mentioned various reactions. For this reason, it is preferable to remove coarse particles from the aluminum dross powder.
A mesh (mesh opening of 590 μm) that passes through the sieve mesh is preferable. More preferably, 325 mesh (opening 44 μm is obtained by removing coarse particles or crushing.
Use the one that has passed through the sieve mesh of m).

When a mixed powder of aluminum dross powder and B ₄ C powder is applied, it is preferable to use a B ₄ C powder having a mesh size of 325 mesh (opening 44 μm). This is because the reaction of producing AlB ₂ from Al and B ₄ C is sufficiently performed. If coarse powder B
_{When 4} C is contained, B ₄ C remains unreacted, which is not preferable. From this viewpoint, it is more preferable to grind the B ₄ C raw material so that the maximum particle diameter is 10 μm or less. In addition, the refinement of the raw material powder brings about the refinement of the crystal structure, so that the material strength is also improved.

In this way, AlN and / or A
A heat resistant material containing 1ON or a heat resistant material further containing BN is obtained. The present invention also relates to AlN or A
A heat-resistant material containing 90 wt% or more of lON or both of them and having a bubble content of 3 to 35 vol%, and A
30 to 80 wt% of IN or AlON or both
%, And 10 to 60 wt% of BN, the total of both is 90 wt% or more, and the bubble content is 3 to 35 vo
It provides a heat resistant material which is 1%. These heat resistant materials are obtained by the above-mentioned method and have excellent corrosion resistance to molten metal and thermal shock resistance. The latter material has particularly good thermal shock resistance.

The bubbles defined here can be generated by the evaporation of volatile components contained in the aluminum dross. That is, low-boiling components such as MgCl ₂ , NaCl, and NaF contained in the aluminum dross powder start to evaporate when the temperature exceeds 1000 ° C., and the degree of evaporation becomes extremely violent when the temperature exceeds 1400 ° C. Is generated, and these bubbles remain.
Here, the bubbles are nearly spherical in shape and have a diameter of 30 to 1000.
Although it is about μm, in the present invention, by positively allowing such bubbles to exist in the material, thermal shock resistance,
Improves mechanical shock resistance. That is, when such bubbles are present inside the material, even if a crack is generated and propagates due to thermal shock or mechanical shock, the fracture energy is absorbed there when the tip of the crack reaches one of the bubbles. The crack propagation can be stopped at the location of the bubbles, and the presence of the bubbles improves the thermal shock resistance and mechanical shock resistance of the material.

One of the features of the heat-resistant material of the present invention is the presence of such bubbles. Since such bubbles form a part of the pores contained in the material, the porosity of the material is increased. , Brings about a decrease in the strength of the material. Therefore, the content of bubbles is set to 5 to 35 vol% in consideration of the above. Further, since the strength itself depends on the total porosity (the ratio of all the pores including bubbles), it is preferable to set the porosity to 10 to 60% in consideration of this point. The bubble content can be adjusted by adjusting the particle size distribution of the starting raw material powder and the molding pressure before the heat treatment.
When the porosity of the molded body is increased, the steam that causes bubbles during the heat treatment is likely to escape to the outside, and the residual bubbles are reduced. On the other hand, when the porosity of the molded body is lowered, on the contrary, the vapor easily escapes to the outside, and the residual bubbles increase.

Next, the method for producing the heat-resistant material of the present invention will be described more specifically. As the main raw material, an aluminum dross powder that passes through 28 mesh or a B ₄ C powder that passes through 325 mesh in addition to this is prepared and crushed if necessary. A known method such as a jet mill or a ball mill can be applied to the pulverization. The ball mill may be a dry type or a wet type, and may be a container rolling type, a container vibrating type, or a ball stirring type. In the case of a wet ball mill, a non-aqueous solvent is suitable as the dispersion medium. This is because when water is used, in the case of aluminum dross, the oxidation of Al progresses during the crushing process, and B ₄ C
In this case, H ₂ O is adsorbed on the surface, which oxidizes B ₄ C in the subsequent heating process, which is not preferable.

As the non-aqueous solvent, alcohols such as methanol, ethanol and iso-propanol, alkanes such as hexane, and heterocyclic compounds such as tetrahydrofuran can be used.

85 wt% of aluminum dross powder was ground.
% Or more mixed powder and aluminum dross powder 4
It may be performed in the state of a mixed powder containing 0 to 85 wt% and 10 to 45 wt% of B ₄ C powder, and the total amount of both is 85 wt% or more. In this case, the effect of uniform mixing of different kinds of powder can be expected together with the pulverization. When wet pulverization is carried out, drying is carried out. For this drying, known methods such as various vacuum dryers and various spray dryers can be applied.

The raw material powder prepared as described above is
It is filled in a mold and pressure-molded. In this case, uniaxial press molding may be carried out using a mold, or CIP (cold isotropic pressing) may be carried out using a rubber mold. A molding pressure of 20 to 1000 kg / cm ² is suitable. this is,
If it is less than 20 kg / cm ^2, it is difficult to maintain the shape, and 1000
This is because if it exceeds kg / cm ² , cracks are likely to occur in the object to be processed due to volume expansion accompanying nitriding during the nitriding processing performed after molding.

Next, the molded body thus obtained is placed in a nitriding furnace and subjected to a nitriding treatment. The molded body may be loaded into the furnace as it is, or may be housed in a heat-resistant container, for example, a graphite container, and the gap may be filled with powder. It is an essential condition that such a powder be difficult to sinter, for example,
BN powder and graphite powder can be applied. The inside of the nitriding furnace is, for example, a nitrogen atmosphere of 0.3 to 1.1 MPa (absolute pressure). From the viewpoint of accelerating the reaction, a pressurized atmosphere is preferable.

[0048]

Embodiments of the present invention will be described below. (Example 1) Pass through 32 mesh sieve mesh (opening 500μ
The aluminum dross powder of m) was prepared. This powder contains 54.8 wt% metallic Al and 9.8 wt% metallic Si. Elemental analysis of this with EDX (energy dispersive X-ray analyzer) revealed that Al, Si, Mg, Cl,
The presence of elements such as Na and Ca was confirmed. In addition, XRD
When analyzed by (X-ray diffraction), Al, Si, AlN,
The existence of Al ₂ O ₃ and MgO crystals was confirmed.

Next, a mold made up of a graphite cylinder having an inner diameter of 60 mm and a height of 100 mm and two graphite disks having an outer diameter of 60 mm and a thickness of 10 mm was prepared, one of which was inserted into the cylinder. 100 g of the powder was filled therein, and another disk was inserted into the cylinder so as to be positioned above the powder, and the powder was sandwiched between the two disks. Then, by a uniaxial press, a load of 3 t was applied through a disc to perform molding.

Next, the mold containing the compact was placed in a nitriding furnace, the atmosphere in the furnace was replaced with nitrogen, and the gas pressure was 1.0 M.
After adjusting to Pa (absolute pressure), 7
Heat to 00 ° C and hold at this temperature for 6 hours, then
The sample was heated to 1600 ° C. at a temperature rising rate of 10 ° C./min, kept at this temperature for 1 hour and allowed to cool.

Then, the sintered body was taken out from the graphite mold.
The sintered body is disc-shaped, and the dimensions are 60 mm in outer diameter and 2 in thickness.
The weight is 5.2 mm, the weight is 125.0 g, and the bulk density is 1.
It was 75 g / cm ³ . The porosity estimated from this bulk density was 50.0%. Bubbles were observed on both the surface and the cut surface, but the amount of bubbles was greater in the cut surface. The proportion of bubbles in the material was calculated from the area percentage of bubbles on the cut surface, and it was 16 vol%.

A part of the sintered body was cut out to prepare a sample,
Analysis by XRD confirmed the presence of crystals of AlN and Al ₁₀ N ₈ O ₃ . When the contents of these were calculated, the total of both was estimated to be 94 wt%.

Next, 14Cr steel cut into a cubic shape having a side of 5 mm was placed in the center of a cut piece obtained by cutting the sintered body into 1/4 in a fan shape, and this was placed in a vacuum pressure atmosphere furnace. did. Bring the furnace to an Ar atmosphere and heat it to 1550 ° C.
After holding for a while, it was allowed to cool. After cooling to room temperature, the state of the sample was observed. The 13Cr steel was not adhered to the sample, and the contact portion of the sample with 13Cr steel was discolored but sound without pits. It was confirmed to have molten steel properties.

Next, from the ½ cut piece of the sintered body, 6
8 mm x 8 mm x 40 mm test pieces are cut out, heated in an air atmosphere, and immediately subjected to thermal shock by dropping in water at 0 ° C. Then, the bending strength is measured at a span length of 30 mm, and the thermal strength is measured. The effect of shock was investigated. Heating temperature is 30
There were three levels of 0 ° C., 500 ° C. and 700 ° C., each level was repeated twice, and the bending strength was obtained by averaging the two times and compared with the level at which no thermal shock was applied. As a result, it was 82 MPa when there was no thermal shock, but decreased to 50 MPa at 700 ° C., but 76 MPa and 85 MPa at 300 ° C. and 500 ° C. I couldn't see it. From this, the thermal shock resistance of this material by the underwater dropping method is 500 ° C or more and 700 ° C or more.
It was confirmed that it was less than 100% and was excellent in thermal shock resistance.

(Example 2) The same aluminum dross powder as in Example 1 which passed through a 32 mesh sieve mesh (opening 500 µm) was prepared. This aluminum dross powder 200
g was dispersed in 200 g of ethanol, poured into a ball stirring type ball mill, and pulverized for 10 hours using an alumina ball having a diameter of 5 mm. The slurry thus obtained was dried with a rotary evaporator and then passed through a 32 mesh sieve to crush the coarse aggregated powder. When this powder was observed with a SEM (scanning electron microscope), 1
It was confirmed to be composed of agglomerated powder of primary particles pulverized to a fine powder of 0 μm or less.

Next, a mold composed of a graphite cylinder having an inner diameter of 60 mm and a height of 100 mm and two graphite disks having an outer diameter of 60 mm and a thickness of 10 mm was prepared, one of which was inserted into the cylinder. 100 g of the powder was filled therein, and another disk was inserted into the cylinder so as to be positioned above the powder, and the powder was sandwiched between the two disks. Then, by a uniaxial press, a load of 3 t was applied through a disc to perform molding.

Next, the mold containing the compact was placed in a nitriding furnace, the atmosphere in the furnace was replaced with nitrogen, and the gas pressure was 1.0 M.
After adjusting to Pa (absolute pressure), 7 at a temperature rising rate of 10 ° C / min
Heat to 00 ° C and hold at this temperature for 6 hours, then
The sample was heated to 1600 ° C. at a temperature rising rate of 10 ° C./min, kept at this temperature for 1 hour and allowed to cool.

Then, the sintered body was taken out from the graphite mold.
The sintered body is disc-shaped, and the dimensions are 60 mm in outer diameter and 2 in thickness.
7.6 mm, weight 123.4 g, bulk density 1.
It was 58 g / cm ³ . The porosity estimated from this bulk density was 54.5%. Bubbles were observed on both the surface and the cut surface, but the amount of bubbles was larger in the cut surface, and the bubbles were finer than in Example 1. The proportion of bubbles in the material was calculated from the area percentage of bubbles on the cut surface and found to be 21 vol%.

A part of the sintered body was cut out to prepare a sample,
The presence of crystals of AlN and Al ₉ N ₇ O ₃ was confirmed by XRD analysis. When the contents of these were calculated, the total of both was estimated to be 94 wt%.

Next, 14Cr steel cut into a cubic shape with a side of 5 mm was placed at the center of a cut piece obtained by cutting the sintered body into 1/4 in a fan shape, and this was placed in a vacuum pressure atmosphere furnace. did. Bring the furnace to an Ar atmosphere and heat it to 1550 ° C.
After holding for a while, it was allowed to cool. After cooling to room temperature, the state of the sample was observed. The 13Cr steel was not adhered to the sample, and the contact portion of the sample with 13Cr steel was discolored but sound without pits. It was confirmed to have molten steel properties.

Next, from the ½ cut piece of the sintered body,
Eight mm × 8 mm × 40 mm test pieces were cut out and subjected to thermal shock in the same manner as in Example 1, and then a span length of 3
The bending strength was measured at 0 mm to examine the effect of thermal shock. The heating temperatures were three levels of 300 ° C., 500 ° C., and 700 ° C., and each level was repeated twice, and the bending strength was calculated by averaging the two times and compared with the level at which no thermal shock was applied. As a result, it was 101 MPa when there was no thermal shock, but it decreased to 45 MPa when the thermal shock was 700 ° C., but 96 MPa when the thermal shock was 300 ° C. and 500 ° C., respectively.
a, 130 MPa, no decrease in strength due to thermal shock was observed. From this, it was confirmed that the thermal shock resistance of this material was 500 ° C. or more and less than 700 ° C. by the underwater dropping method, and was excellent in thermal shock resistance. In addition, the strength of this material was improved by making the bubbles finer.

Example 3 Similar to Example 1, an aluminum dross powder having a mesh of 32 mesh (mesh opening 500 μm) and a mesh of 325 mesh (mesh opening 44 μm) were used.
m) B ₄ C powder was prepared. 200 g of these aluminum dross powders 157.6 g and B ₄ C powder 42.4 g
Dispersed in ethanol and poured into a ball-stir type ball mill.
Milled for 0 hours. The slurry thus obtained was dried with a rotary evaporator and then passed through a 32 mesh sieve to crush the coarse aggregated powder. SEM this powder
Observation with a (scanning electron microscope) confirmed that the powder was composed of aggregated powder of primary particles pulverized into fine powder of 10 μm or less.

Next, a mold consisting of a graphite cylinder having an inner diameter of 60 mm and a height of 100 mm and two graphite disks having an outer diameter of 60 mm and a thickness of 10 mm was prepared, one of which was inserted into the cylinder. 100 g of the powder was filled therein, and another disk was inserted into the cylinder so as to be positioned above the powder, and the powder was sandwiched between the two disks. Then, by a uniaxial press, a load of 3 t was applied through a disc to perform molding.

Next, the mold containing the molded body was charged into a nitriding furnace, the atmosphere in the furnace was replaced with nitrogen, and the gas pressure was 1.0 M.
After adjusting to Pa (absolute pressure), 7 at a temperature rising rate of 10 ° C / min
Heat to 00 ° C and hold at this temperature for 6 hours, then
The sample was heated to 1600 ° C. at a temperature rising rate of 10 ° C./min, kept at this temperature for 1 hour and allowed to cool.

Then, the sintered body was taken out from the graphite mold.
The sintered body is disc-shaped, and the dimensions are 60 mm in outer diameter and 2 in thickness.
6.8 mm, weight 132.2 g, bulk density 1.
It was 75 g / cm ³ . The porosity estimated from this bulk density was 41.0%. Almost no bubbles were observed on the surface, but bubbles were observed on the cut surface. The proportion of bubbles in the material was calculated from the area percentage of bubbles on the cut surface, and it was 18 vol%.

A part of the sintered body was cut out to prepare a sample,
When analyzed by XRD, AlN, BN, SiAl ₇ O ₂
The presence of crystals of N ₇ was confirmed. When these contents were calculated, the total of the three was estimated to be 96 wt%.

Next, 14Cr steel cut into a cubic shape with a side of 5 mm was placed in the center of a cut piece obtained by cutting the sintered body into 1/4 in a fan shape, and this was placed in a vacuum pressure atmosphere furnace. did. Bring the furnace to an Ar atmosphere and heat it to 1550 ° C.
After holding for a while, it was allowed to cool. After cooling to room temperature, the state of the sample was observed. The 13Cr steel was not adhered to the sample, and the contact portion of the sample with 13Cr steel was discolored but sound without pits. It was confirmed to have molten steel properties.

Next, from the ½ cut piece of the sintered body,
Eight mm × 8 mm × 40 mm test pieces were cut out and subjected to thermal shock in the same manner as in Example 1, and then a span length of 3
The bending strength was measured at 0 mm to examine the effect of thermal shock. The heating temperatures were three levels of 300 ° C., 500 ° C., and 700 ° C., and each level was repeated twice, and the bending strength was calculated by averaging the two times and compared with the level at which no thermal shock was applied. As a result, while it was 70 MPa without thermal shock,
7 at thermal shock of 700 ℃, 300 ℃, and 500 ℃
No strength decrease due to thermal shock was observed at 2 MPa, 65 MPa, and 78 MPa. From this, it was confirmed that the thermal shock resistance of this material by the underwater dropping method was 700 ° C. or higher, which was extremely high.

(Comparative Example) An aluminum powder having a 200-mesh screen mesh (opening of 74 μm) and an Al ₂ O ₃ powder having a 325-mesh screen mesh (opening of 44 μm) were prepared. Aluminum powder 81.6g and Al ₂ O ₃ powder 11
8.4 g was put into a V-type mixer and mixed for 1 hour to obtain a mixed powder.

Next, a mold composed of a graphite cylinder having an inner diameter of 60 mm and a height of 100 mm and two graphite disks having an outer diameter of 60 mm and a thickness of 10 mm was prepared, one of which was inserted into the cylinder. 100 g of the powder was filled therein, and another disk was inserted into the cylinder so as to be positioned above the powder, and the powder was sandwiched between the two disks. Then, by a uniaxial press, a load of 3 t was applied through a disc to perform molding.

Next, the mold containing the compact was placed in a nitriding furnace, the atmosphere in the furnace was replaced with nitrogen, and the gas pressure was 1.0 M.
After adjusting to Pa (absolute pressure), 7 at a temperature rising rate of 10 ° C / min
Heat to 00 ° C and hold at this temperature for 6 hours, then
The sample was heated to 1600 ° C. at a temperature rising rate of 10 ° C./min, kept at this temperature for 1 hour and allowed to cool.

After that, an attempt was made to take out the sintered body from the graphite mold, but the sintered body was firmly bonded to the graphite mold and could not be taken out. When the graphite mold was cut vertically and the cross-section was observed, it was confirmed that molten Al was blown to the outer surface of the molded body, reacted with the graphite mold, and was fixed. The inside of the sintered body had a structure with many pores, and a layer having a dense metallic luster was formed near the surface. in this way,
It was difficult to produce a material containing AlN and / or AlON by using metallic aluminum as a starting material.

[0073]

As described above, according to the present invention, by using aluminum dross powder as a starting material,
Even if the Al blending ratio is increased, Al is not melted or blown out, the AlN and / or AlON blending ratio can be dramatically increased, and an appropriate amount of bubbles can be left. Therefore, it is possible to achieve both excellent thermal shock resistance and excellent corrosion resistance, and at the same time, inexpensive AlN
A refractory material containing and / or AlON can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C04B 35/58 302G

Claims (6)

[Claims] 1. AlN, AlON, or both of them are contained in an amount of 90 wt% or more, and a bubble content rate is 3 to 35 vo.
A heat resistant material characterized by being 1%. 2. A method for producing a heat-resistant material containing AlN and / or AlON, which comprises nitriding a molded body containing aluminum dross powder in an amount of 85 wt% or more at 530 to 2000 ° C. 3. A heat resistant material containing AlN and / or AlON, which is obtained by nitriding a compact containing aluminum dross powder in an amount of 85 wt% or more at 530 to 2000 ° C. 4. AlN, AlON, or both of them are contained in an amount of 30 to 80 wt%, and BN in an amount of 10 to 60 wt%, the total amount of both is 90 wt% or more, and the bubble content is 3 to 35 vol%. Characteristic heat resistant material. 5. Aluminum dross powder in the range of 40-75 w
of a mixed powder containing t% and B ₄ C powder in an amount of 10 to 45 wt% and the total amount of both is 85 wt% or more.
A method for producing a heat-resistant material containing AlN and / or AlON and BN, which comprises nitriding at 0 to 2000 ° C. 6. An aluminum dross powder of 40 to 75 w
of a mixed powder containing t% and B ₄ C powder in an amount of 10 to 45 wt% and the total amount of both is 85 wt% or more.
AlN obtained by nitriding at 0 to 2000 ° C
And / or a heat resistant material containing AlON and BN.