JP2001240463A - Sintered body of chromia and process for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dense and uniform sintered body of chromia having high purity, and to provide a process for producing the sintered body of chromia using single component of chromia and in industrially feasible scale. SOLUTION: This sintered body of chromia is produced by firing chromia powder in vacuum or an inert atmosphere with pressure so as to result in dense form having a relative density of 97% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chromia sintered body having excellent denseness and a uniform structure, and a method for producing the same.

[0002]

_2. Description of the Related Art Chromia (Cr ₂ O ₃ ) is difficult to wet and dissolve in a slag melt at a high temperature. Therefore, sintering materials utilizing chromia are used in glass melting furnaces, general and industrial wastes, and the like. It is widely used as a lining furnace material such as a melting furnace for waste treatment effective for volume reduction and detoxification. When chromia is fired in the atmosphere, excessive grain growth occurs due to the evaporation-condensation mechanism, and it is difficult to sinter densely with a single chromia component (see Fig. 3). In addition, sintering aids such as TiO ₂ and clay are added to chromia, and sintering is promoted by firing at a high temperature in the air. For example, JP-A-6-3216
No. 28 describes that a chromia sintered body produced using a sintering aid such as TiO ₂ is applied to a refractory as a corrosion-resistant aggregate.

[0003] However, such a sintered body has many voids and is inferior in density, and furthermore, a sintering aid exists as a liquid phase at the grain boundaries of chromia. In addition, the structure of the sintered body is significantly disintegrated due to the diffusion of the characteristic components in the slag, and there is a problem that the excellent corrosion resistance function of chromia is not utilized and as a result, the erosion proceeds.

On the other hand, as for densification sintering of a single component of chromia, for example, a production method described in Japanese Patent Publication No. 63-387 is known. In this method, a chromia compact is fired in a carbon-reducing atmosphere to generate an appropriate amount of a low-melting-point composition inside the compact during the sintering process, and a dense sintered body having a relative density of 95% or more is obtained. ing. However, the conventional manufacturing method described in the above publication includes a two-step process of molding and firing, and when firing, it is necessary to embed the molded body in carbon powder, which is more troublesome than the conventional firing method. However, there is a practical problem.

[0005] Chromia hardly shrinks during sintering, and the filling property during molding is greatly reflected in the density of the sintered body. Is also important. However, commercially available high-purity chromia is generally a fine powder having a size of several μm. To form such a fine powder under high pressure, the presence of an air layer formed inside the molded body except in a vacuum is required. However, in order to make the powder hard to enter, it is necessary to perform a pre-treatment such as further granulating the powder raw material with a spray drier or the like. As described above, in the conventional densification sintering of a single chromia component, molding and sintering were troublesome, so that development of a simple and practical manufacturing method from the raw material stage to the sintering process is expected. It is rare.

[0006]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-mentioned problems of the prior art and to obtain a dense, homogeneous and homogeneous chromia sintered body of high purity.
A further object of the present invention is to provide a method for producing a chromia sintered body that can easily obtain the above-described excellent chromia sintered body using a chromia single component.

[0007]

The above objects are achieved by the present invention described below. That is, the present invention is characterized in that the chromia powder has a dense form having a relative density of 97% or more, and is obtained by firing a chromia powder under pressure in a vacuum or an inert atmosphere. A sintered body, and a method for producing a chromia sintered body for producing the chromia sintered body, wherein the chromia powder is heated and fired while being pressed in a vacuum or an inert atmosphere. This is a method for producing a chromia sintered body.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to preferred embodiments. The chromia sintered body of the present invention is obtained by firing under pressure in a vacuum or in an inert atmosphere, and is characterized by having a relative density of 97% or more and a high density. Such a chromia sintered body can be easily obtained by the production method of the present invention in which chromia powder is heated and baked while applying pressure in a vacuum or an inert atmosphere. Hereinafter, this will be described.

The chromia sintered body of the present invention has a relative density of 9
Since it is 7% or more, it is preferable to use a high-purity chromia powder raw material for producing the same. Preferably, a powder raw material having a purity of 99.5% by weight or more is used. Commercially available chromia powder having such a purity is usually prepared to have an average particle size in the range of 1 to 3 μm, but in the present invention, this can be used as it is. In order to obtain a more uniform chromia sintered body, it is preferable to use a uniform chromia fine powder having a sharper particle size distribution as a raw material.

In the present invention, as described above, preferably, chromia fine powder having a purity of Cr ₂ O ₃ of 99.5% by weight or more is used as a raw material. It is characterized by firing under pressure in an inert atmosphere. At that time, the firing temperature is preferably set to 120
0-1600 degreeC, More preferably, 1300-1.
The temperature may be in the range of 500 ° C. As the pressure, the pressure sintering is preferably performed at a pressure of 10 to 60 MPa, more preferably at a pressure of 20 to 40 MPa.

According to the study of the present inventors, in order to obtain a chromia sintered body having a higher density, the sintering temperature must be set to 1200.
It has been found that the temperature is desirably not less than 1 ° C., more preferably not less than 1300 ° C. On the other hand, the firing temperature is 1600 ° C
If it is higher than this, the growth of particles tends to be remarkable, and the strength of the obtained chromia sintered body will be reduced. For this reason, 1600 ° C. or lower, more preferably 1
It was found that firing at a temperature of 500 ° C. or less was good.
Further, even if the pressing force is larger than 60 MPa, the effect of the pressing on the sinterability is not significantly changed and is not economical.
When the pressing force is smaller than a, the pressing effect may not be sufficiently obtained unless the pressing force is applied for a long time. Therefore, in practice, pressure sintering is preferably performed in the range of 20 to 40 MPa. Furthermore, the actual firing conditions are determined by a balance between the two, and firing at a higher temperature can reduce the pressure, and by increasing the pressure, firing at a lower temperature becomes possible.

The chromia sintered body of the present invention can be obtained by pressure firing in a vacuum or an inert atmosphere under suitable firing conditions selected from the ranges of firing temperature and pressure as described above. However, as the pressure sintering method used in this case,
A hot press method in which sintering is promoted by an external pressure without relying on the force of a sintering aid, or a conventional pulsed current heating and pressure sintering method can be used. It is particularly preferable that the chromia sintered body of the present invention is manufactured by using a pulse current heating and pressure sintering method. As the pulse current heating method, there are various methods that use the pulse current directly or indirectly, or simultaneously use the direct and indirect methods, and any of them can be used. Further, as the pressurizing method, the powder material may be uniaxially pressurized, or may be uniaxially pressurized while performing the entire pressurization using an inert gas introduced into the chamber. Good. Hereinafter, the pressure firing method will be specifically described.

In the hot press method, a sintering die (die) made of graphite or the like for filling a chromia powder raw material and a chromia powder filled in the sintering mold are configured to apply at least pressure. Using the upper and lower punches, baking is performed by Joule heat transmitted from the die and the upper and lower punches while uniaxially pressing the chromia powder filled in the die.

In the pulse current heating / pressure sintering method, a pulse current is applied to a powder filled in a conductive firing mold (die) made of a material such as graphite while uniaxially pressing the powder with upper and lower punches. Firing is performed by the heat generation effect of the powder itself caused by flowing through the die and Joule heat transmitted from the die and the upper and lower punches.

In the present invention, when any of the above sintering methods is used, the sintering is performed in a vacuum or in an atmosphere inert to chromia. At this time, any inert gas can be used in order to make the atmosphere inert. Above all, the process is generally performed in an argon gas.

Further, in the present invention, as shown in FIG. 2, upper and lower punches are provided for the purpose of improving the engagement between the die and the punch, and to uniformly heat the chromia powder raw material. Graphite powder may be thinly arranged between the green compact forming surface and firing. According to the study of the present inventors, in particular, when pressure firing using a pulse current heating and pressure sintering method in which the heat generation of the die and the punch is greatly affected by the current characteristics, the state where the graphite powder is disposed It was found that it was desirable to heat and pressurize at. The filling amount of the graphite powder at this time may be appropriately set in accordance with the pressing force so that the thickness is in the range of about 0.5 to 5 mm at the time of applying the maximum pressing force.

The graphite powder used at this time is preferably as high as possible in order to prevent damage to the die and punch. In addition, the particle size is preferably as small as possible in order to enhance the filling properties of the graphite itself, but the graphite powder is solidified by sintering after pressure firing, so that the filling properties are good, and It is preferable to appropriately select a particle having such a particle size that a solid obtained by sintering can be easily crushed. By doing so, the graphite sintered body can be easily separated and removed from the upper and lower surfaces of the obtained chromia sintered body after the chromia powder is fired under pressure.

According to the method for producing a chromia sintered body of the present invention, when producing a chromia sintered body, a heating method such as the above-described hot press method or pulse current heating method is used.
Controlling the sintering process to take place in an inert atmosphere,
By sintering with further pressurization, sintering can proceed at a lower temperature than the sintering performed in the conventional atmosphere, without accompanying the grain growth of the chromia powder,
A remarkable effect that the obtained sintered body can be densified can be obtained.

Hereinafter, the effect of the present invention will be described by taking, as an example, a case where a pulse current heating and pressure sintering method is used for producing a chromia sintered body. In the pulse current heating process, when energized, a high-energy pulse current flows through the particle contact area where external stress is applied, instantaneously forming a welded neck, and sintering in a shorter time compared to the conventional hot press method There is an advantage that you can.

In general, chromia undergoes remarkable grain growth when fired in the air, and sintering proceeds while forming voids. However, in the present invention, chromia is treated in a vacuum or in an atmosphere inert to chromia. Since the firing is performed, the oxygen partial pressure in the firing atmosphere is reduced, so that sintering proceeds without significant grain growth. Further, as an additional element, since the powder is fired while applying an appropriate pressure from the outside, plastic flow is promoted during heating, and voids are effectively eliminated, so that dense sintering is performed. The body can be formed.

As a result, when the chromia powder is fired using the pulse current heating / pressurizing sintering method, a dense chromia sinter having a high purity and a relative density of 97% or more as described above is obtained. The body is easily obtained. Further, in the above method,
Since molding and firing are performed simultaneously, it is possible to perform dense sintering as fine powder without requiring a high molding pressure and without requiring pretreatment of the powder raw material.

When the chromia powder is fired by the pulse current heating / pressurizing sintering method, when a conductive die and a punch made of a material such as graphite are used, when the frequency of use becomes high, the die and the punch are worn due to wear. May be deteriorated, and uniform molding may not be performed on the charged powder raw material. In this case, there is a possibility that a difference occurs in the heating effect at the contact surface with the punch, and a non-uniform structure may be formed. In addition, local heat generation may cause deterioration of the die earlier.

In the pulse current heating / pressure sintering method, the engagement between the die and the punch affects not only the contact property between the filling powder and the punch but also the current flow from the punch to the die.
If the current does not flow uniformly through the die, a difference in the heating effect occurs on the side surface of the green compact, and a more inhomogeneous structure may be formed than in the hot pressing method relying solely on Joule heat.

However, according to the method for producing a chromia sintered body of the present invention, in which graphite powder having high conductivity is arranged between the punch and the green compact, and the powder is heated while being heated while being pressed, and then fired. Since the entire surface of the green compact is uniformly pressed and the energization point from the punch to the die is secured on the entire circumference, the current flows uniformly, and as a result, the uniform Can be heated.

From the characteristics described above, according to the method for producing a chromia sintered body of the present invention utilizing the pulse current heating and pressurizing sintering method, a highly reliable chromia sintered body as a high-temperature corrosion-resistant material can be easily obtained. can get. Further, in such a manufacturing method,
Since the molding and firing of the powder are performed simultaneously and the sintering is performed with a holding time of only about 5 minutes, it can be used industrially sufficiently. Therefore, it becomes possible to produce the chromia sintered body of the present invention on an industrial scale.

The chromia sintered body manufactured by the manufacturing method of the present invention having the above-mentioned characteristics is obtained by an electron microscope (SEM).
As a result of observation of the structure, it was confirmed that, as shown in FIG. 1, the particles were bonded in a molten state and a uniform structure having a uniform particle diameter was formed without causing local grain growth. Was. In addition, by changing the firing conditions such as firing temperature and pressure, the morphology of the obtained chromia sintered body can be controlled, and the chromia sintered body manufactured by the manufacturing method of the present invention has a particle effect due to the temperature effect. It was also found that the compactness of the sintered body was maintained by the pressing effect even if the growth proceeded in some cases.

[0027]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. <Example 1> The raw material chromia powder had an average particle size of 1
A commercially available product of μm (G5 manufactured by Nippon Chemical Industry Co., Ltd.) was used. The filling portion of the powder is formed by upper and lower punches and a die as shown in FIG. 2, and the shape of the punch is φ60 × 40 mm at both the upper and lower sides, and the shape of the die is an outer diameter
Those having a diameter of 0 mm, an inner diameter of 60.8 mm, and a height of 70 mm were used. These materials are all graphite. First, after inserting the lower punch into the die, the above-mentioned raw material powder is uniformly filled in the die, and the upper punch is inserted. At this time, in this embodiment, in order to prevent damage to the die caused by the reaction between the die and the punch and the powder raw material, a carbon sheet having a thickness of 0.2 mm is inserted between the upper and lower punches and the filled powder raw material. , 2
We installed.

The dice filled with the chromia powder raw material as described above was set in a chamber of a discharge plasma sintering machine (SPS-7.40, manufactured by Izmitek Co., Ltd.) and fired. First, the inside of the chamber was evacuated to 5 Pa or less, and then fired under the firing conditions shown in Table 1. Eight types of sintered bodies 1 to 8 were obtained. That is, the firing conditions are 1350 to 1450 in 19 or 20 minutes while applying a pressing force to the powder within the range of 20 to 40 MPa.
Temperature to the ultimate temperature in the range of
Pressed firing was carried out for a period of one minute. After firing in this manner, the pressure is completely released, and the product is naturally cooled.
When the temperature reached 0 ° C., it was opened to the atmosphere to obtain each sintered body.

<Comparative Example 1> Sintering aids (TiO ₂ , Si
O ₂ ) was used in a total amount of 10%, and the same powder material containing 90% of Cr ₂ O ₃ as used in Example 1 was fired at 1750 ° C. in the air to obtain a comparative example. Chromia sintered body N
o. 9 was obtained.

[0030]

[Evaluation] Nos. Of Examples and Comparative Examples obtained above. 1-9
Each of the nine types of sintered bodies was cut and subjected to relative density, bending strength, erosion tests, and surface state observations by the methods described below, and their properties were evaluated. The results are shown in Table 1 together with the firing conditions of each sintered body.

(1) Relative density The density was measured by the Archimedes method. That is,
In accordance with JIS-R2205, the obtained bulk density was divided by the theoretical density of chromia and expressed as a percentage, which was defined as a relative density.

(2) Bending strength Regarding the sintered bodies of Nos. 1 to 8, JIS-R
The three-point bending strength at room temperature was measured according to 1601.

(3) Erosion test No. The following slag erosion tests were performed on the sintered bodies 1, 2, 5, and 9. In the slag erosion test, the slag synthesized from the reagent was melted in the air at 1500 ° C., and each of the sintered bodies (6 ×
(A sample cut into a shape of 10 × 20 mm was used). After the test, the sample was cut, the slag interface was observed by SEM, and the amount of decrease in the sample was measured to determine the amount of erosion, and the corrosion resistance of each sintered body was evaluated.

(4) Observation of Surface Condition The microstructure was observed by SEM, 100 particles were taken out at random, the particle size was measured, and the surface properties were evaluated in the range of the obtained particle size.

(5) Evaluation Result No. 1 obtained by the manufacturing method of this embodiment. As shown in Table 1, the eight types of sintered bodies 1 to 8 had a relative density of 97% or more, and it was confirmed that all of them were dense chromia sintered bodies. On the other hand, No. 1 was fired in the air using a sintering aid. The sintered body of Comparative Example 9 had a relative density of 89%, indicating that the sintered body was inferior in density to that of the present example. Further, according to the present example, the relative density was 97% at a significantly lower firing temperature than the method of the comparative example.
It was also found that the above dense chromia sintered body was easily obtained.

In addition, No. The sintered bodies of this example of Nos. 1, 2, and 5 As compared with the sintered body of Comparative Example No. 9, erosion by slag was remarkably suppressed, and it was confirmed that the sintered body was excellent in corrosion resistance. This is because the sintered body of the comparative example is inferior in relative density and has many voids at grain boundaries and the existence of a liquid phase between particles promotes erosion by slag. It is considered that the sintered body of the example has a high relative density, and such a cause is suppressed.

Further, No. As for the characteristics of the eight types of sintered bodies of Examples 1 to 8, the relationship between the characteristics and the firing conditions was examined in detail, and the following was found. First, No. 1 was obtained by changing the firing temperature while keeping the pressure constant. From the sintered bodies 1 to 5, as shown in Table 1, the relative density
In all cases, high values were obtained, but it was found that as the firing temperature was increased, the grain growth tended to proceed, and the bending strength tended to decrease. Therefore, it was found that firing at the lowest firing temperature was effective if the pressure was the same.

On the other hand, as a result of the above examination, a better chromia sintered body was obtained. 6 to 8 sintered bodies were obtained.
As shown in Table 1, the obtained No. The relative densities of the sintered bodies Nos. 6 to 8 depended on the pressing force, and there was a tendency that densification became difficult as the pressing force became lower. Therefore, it is preferable to bake with as high a pressing force as possible, but from the viewpoint of economy, the pressing force should be 30 MPa.
It turned out that the degree was enough.

[0039]

[Table 1]

<Example 2> As a raw material of chromia powder, a commercial product (Nippon Kagaku Kogyo Co., Ltd., G5) having an average particle diameter of 1 μm similar to that used in Example 1 was used. The filling portion of the powder is formed by upper and lower punches and a die as shown in FIG.
The die had an outer diameter of 140 mm, an inner diameter of 100.8 mm, and a height of 70 mm. These materials are all graphite. First, after inserting the lower punch into the die, the above-mentioned raw material powder is uniformly filled in the die, and the upper punch is inserted. At this time, in order to prevent the die from being damaged due to the reaction between the die and the punch and the powdery raw material, 0.2 mm as in the case of the first embodiment.
One thick carbon sheet was placed between the upper and lower punches and the filled powder material, and two were placed on the inner wall of the die filled with the powder material.

In this embodiment, a graphite powder having an average particle size of 100 μm is interposed between the upper and lower punches and the green compact forming surface to be formed in an amount of 1.5 to 3 μm.
Two types each of which were arranged with a thickness of mm were prepared.

As described above, two types of dies each having a raw material powder and two types of dies filled with graphite in addition to the raw material powder were respectively used in a discharge plasma sintering machine (manufactured by Izumi Tech Co., Ltd., SPS-7. It was set in the chamber of 40) and baked under pressure. The firing conditions were as follows. First, the inside of the chamber was evacuated to 5 Pa or less, and the temperature was raised to 1350 ° C. in 19 minutes while applying a pressure of 30 MPa to the powder. Then, after maintaining at this temperature for 5 minutes, the pressure was completely released and the sample was naturally cooled. When the temperature reached 400 ° C., the sample was released to the atmosphere. 10 and 11 chromia sintered bodies were obtained. No. in which graphite was placed In the chromia sintered body of No. 10, after firing, the solidified graphite was removed together with the carbon sheet.

The two types of sintered bodies obtained above were cut and processed in the same manner as in Example 1 to measure the relative density, observe the microstructure by SEM, measure the three-point bending strength, Erosion tests with slag were performed respectively. as a result,
No. The chromia sintered bodies of Nos. 10 and 11 are the same as in Example 1.
No. 5 and No. 5 7 had the same sintering characteristics as the chromia sintered body of No. 7.

Further, in order to confirm the effect of the provision of the graphite powder, when measuring the three-point bending strength at room temperature, no. Two samples for bending strength measurement were taken from five places of each of the sintered bodies 10 and 11 in accordance with JIS-R1601, and the three-point bending strength was measured for each. Then, while confirming the variation of the bending strength from the measured values, the standard deviation of the bending strength is obtained from these values, and it is determined that the smaller the standard deviation, the better the homogeneity. A homogeneity evaluation was performed.

Table 2 shows that No. 1 prepared by arranging graphite powder. No. 10 and a sintered body of No. 10 prepared without disposition.
With respect to the 11 sintered bodies, the bending strengths of the samples obtained at different points and obtained by the above method, and the standard deviations thereof, are shown. As a result, N without graphite powder
o. In the case of the sintered body of No. 11, the width of the variation in bending strength was about 200 MPa at the maximum, whereas when graphite powder was arranged, it was about half of that, and the standard deviation was also the same. From the small size, it was confirmed that uniform firing was performed as a whole.

[0046]

[Table 2]

Example 3 As a raw material chromia powder,
A commercially available product having a purity of 99.9% (manufactured by Nippon Chemical Industry Co., Ltd., G
The material having an average particle size of 3 μm in 5) was used. The filling portion of the powder is formed by upper and lower punches and a die as shown in FIG.
mm, and the shape of the die is outer diameter φ170 mm, inner diameter φ
Those having a size of 60 mm and a height of 120 mm were used. These materials are all graphite. First, after inserting the lower punch into the die, the above-mentioned raw material powder is uniformly filled in the die, and the upper punch is inserted. At this time, in order to prevent damage to the die caused by the reaction between the die and the punch and the powder raw material, a carbon sheet having a thickness of 0.2 mm was placed between the upper and lower punches and the filled powder raw material in the same manner as in Example 1. And one on each die inner wall filled with the powder material.

The die filled with the chromia powder raw material as described above is set in a chamber of a hot press sintering machine (FVPHP-R-15, FRET-30, manufactured by Fuji Denpa Kogyo KK) and fired. Was done. First, after the chamber is evacuated to 5 Pa or less, the firing conditions are as follows:
While applying a pressure of 30 MPa to the powder at 1350 ° C., the temperature was increased to the ultimate temperature of 1350 ° C. in 270 minutes, and the pressure was maintained at the predetermined temperature for 180 minutes to perform pressure firing. After firing in this manner, the pressure was completely released and the product was naturally cooled. When the temperature reached 400 ° C., the product was released to the atmosphere to obtain a sintered body. As a result, a sintered body having a relative density of 99.6% was obtained. Observation of the microstructure of the obtained sintered body by SEM showed that the sintered body had a dense structure composed of fine particles of about 3 μm. Further, similarly to Example 1, slag erosion was significantly suppressed, and it was confirmed that the sintered body was excellent in corrosion resistance.

[0049]

As described above, according to the present invention, a dense and homogeneous chromia sintered body having high purity can be easily provided by a simple manufacturing method. According to the present invention, a chromia sintered body that has excellent corrosion resistance and can economically provide a chromia sintered body useful as a high-temperature corrosion-resistant material that can be used for a long time in a glass melting furnace, a waste treatment melting furnace, or the like on an industrial scale. A manufacturing method is provided.

[Brief description of the drawings]

FIG. 1 is a view showing the results of microscopic observation of a chromia sintered body of the present invention by SEM.

FIG. 2 is a schematic view showing a container for filling a powder sample for obtaining a chromia sintered body of the present invention.

FIG. 3 is a view showing the results of microscopic observation of the structure of a chromia sintered body obtained by a conventional firing method using a SEM.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Okawa 1-46 Kamezaki-Kitaura-cho, Handa-shi, Aichi Prefecture Inside the Technical Research Institute, Mino Ceramics Co., Ltd. No. Mino Ceramic Industry Co., Ltd. F-term (reference) 4G030 AA22 BA25 GA11 GA23 GA24 GA27 GA29 GA31

Claims (6)

[Claims] 1. A chromia sinter having a dense form having a relative density of 97% or more and obtained by sintering a chromia powder under pressure in a vacuum or an inert atmosphere. Union. 2. A method for producing a chromia sintered body for producing the chromia sintered body according to claim 1, wherein the chromia powder is heated and baked while being pressed in a vacuum or in an inert atmosphere. A method for producing a chromia sintered body, comprising: 3. The method for producing a chromia sintered body according to claim 2, wherein the heating is performed by pulse current heating. 4. The chromia powder has an average particle size of 1 to 3 μm.
The method for producing a chromia sintered body according to claim 2 or 3, wherein 5. The calcining method according to claim 2, wherein graphite powder is arranged between the chromia powder filled in the sintering mold and upper and lower punches for applying at least pressure to the chromia powder. 3. The method for producing a chromia sintered body according to 1.). 6. A firing temperature of 1200 to 1600 ° C. and a load of 1
The pressure baking is performed in the range of 0 to 60 MPa.
The method for producing a chromia sintered body according to any one of the above.