JPH0967194A - Ceramic composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a ceramic composite material having high mechanical strength and satisfactory creep resistance over the wide range from room temp. to high temp. and suitable for use as a structural material exposed to high temp. and as a functional material. SOLUTION: This ceramic composite material is a solidified body consisting of two or more kinds of oxides selected from among a metallic oxide and multiple oxides each produced from two or more kinds of oxides and the constituent phase of the solidified body consists of two or more kinds of oxides selected from among aluminum oxide (Al2 O3 ) or oxide of a rare earth element (La2 O3 , Y2 O3 , CeO2 , Pr6 O11 , Nd2 O3 , Sm2 O3 , Eu2 O3 , Gd2 O3 , Tb4 O7 , Dy2 O3 , Ho2 O3 , Er2 O3 , Tm2 O3 , Yb2 O3 or Lu2 O3 ) and multiple oxides each produced from aluminun oxide and oxide of a rare earth element.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has a large mechanical strength over a wide range from room temperature to a high temperature, has good creep resistance, and can be suitably used as a structural material or a functional material exposed to a high temperature. To a ceramic composite material capable of

[0002]

2. Description of the Related Art SiC or Si ₃ N ₄ is expected as a ceramic material to be used at high temperatures, and studies on its practical application have been made. However, these materials have insufficient high-temperature characteristics and are not suitable for practical application. It's a problem. As an alternative material, SiC / S by chemical vapor impregnation method of SEP
The iC composite material has been in the limelight and is currently considered to be the highest temperature material in the world, and its research and development is in progress, but its operating temperature range is set to 1400 ° C or lower.

At present, powder sintering is the mainstream of ceramics production methods, and is based on the improvement of powder characteristics such as finer powder and higher purity, and the production under well-controlled sintering conditions. Thus, high strength ZrO ₂ ceramics having a room temperature strength of 3.0 GPa can be manufactured. Further, it has become possible to manufacture a composite material in which different kinds of ceramic particles are nano-dispersed by the powder sintering method, and attempts have been made to improve strength, toughness, thermal characteristics and the like. However, since the sintered body obtained by the powder sintering method is a polycrystalline body and has colonies, voids, grain boundary phases and the like, there is a problem that sufficient high temperature strength cannot be obtained.

[0004] In general, oxide ceramics are easily deformed at high temperatures, and thus it has been considered that they cannot be used as high-temperature structural materials that operate under high loads. However, these oxide ceramics are superior to any type of ceramics in terms of oxidation resistance and corrosion resistance at high temperatures, and widespread use as high-temperature structural materials can be expected if mechanical properties at high temperatures are improved. From such a viewpoint, a metal oxide having a melting point exceeding 2000 ° C., for example, Al
₂ O ₃ , ZrO ₂ , MgO and rare earth element oxides such as
Y ₂ O ₃ , La ₂ O ₃ , Yb ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , N
d ₂ O ₃ and Er ₂ O ₃ are considered to be promising as high temperature ceramics.

Japanese Patent Application No. 5-85821 discloses a rare earth oxide (oxide of a rare earth element and a mixture thereof) and Al ₂
A sintered body made of O ₃ and a method for producing the same are disclosed. According to this, the rare earth oxide and Al ₂ O ₃ are mixed and molded, and the green body is sintered at an appropriate sintering temperature and an appropriate sintering time to reduce the crystal grain size of the molded body to 30 μm or less. It is said that it is possible to provide a rare earth oxide-alumina sintered body that has high strength, high toughness, and high reliability by controlling abnormal grain growth and pores that occur when a sintered body is obtained.

On the other hand, the Journal of the American Ceramics
Society Vol. 76, No. 1, pp. 29-32 (1993
(Year) discloses a composite of alumina represented by Al ₂ O ₃ —Y ₃ Al ₅ O ₁₂ eutectic and yttria-alumina garnet (hereinafter sometimes referred to as “YAG”). Further, this document discloses a method of melting the mixed powder of Al ₂ O ₃ and Y ₂ O ₃ and then unidirectionally solidifying in the crucible as a method for producing the above composite.

From the description on page 29, right column, lines 9 to 10 and FIG. 1 and FIG. 2 of the same document, it is understood that the above composite is polycrystal and has a grain boundary phase. This is because, for example, from the description in the last line in the left column of page 30 to the right column, 1 line of the above-mentioned document, "Fracture is usually along the boundary of a colony having a crack running along the Al ₂ O ₃ -YAG interface". Is also supported. Then, this colony boundary is shown by a portion where the tissue is larger than the other portions in FIG.

[0008]

In the composite material disclosed in the above-mentioned document, for example, as shown in FIG. 4, the stress when the strain rate is constant is 1,530 ° C. and 1,65 ° C.
It is almost the same as that of sapphire fiber at 0 ° C. Furthermore, according to the experiments of the present inventor, the composite described in the above-mentioned literature contains bubbles or voids inside the composite,
It was observed that the mechanical strength sharply decreased at high temperature. As is clear from this, the mechanical properties of the ceramic composite material, especially at high temperature, are greatly influenced by the structure of the grain interface of the constituent materials, the interface of the matrix and the strengthening phase, and the crystallographic properties. Precise control is considered necessary. Therefore, in view of the above-mentioned problems of the prior art, the present inventor has excellent mechanical strength and creep properties from room temperature to high temperatures, and particularly ceramic composites in which these properties are dramatically improved at high temperatures. We have conducted extensive research to obtain materials. as a result,
A composite material composed of an α-Al ₂ O ₃ phase and a YAG phase disclosed in Japanese Patent Application Laid-Open Nos. 7-149597 and 7-187893 and Japanese Patent Application No. 6-240792. We have found a novel ceramic composite material composed of crystals / polycrystals and polycrystals / polycrystals that has never existed before.

The object of the present invention is to obtain the above-mentioned α-Al ₂
Following the ceramic composite material consisting of the O ₃ phase and the YAG phase, aluminum oxide (Al ₂
O ₃ ), aluminum oxide (Al ₂ O ₃ ), and a solid oxide composed of two or more kinds of oxides selected from the group consisting of complex oxides formed from rare earth element oxides. It is an object of the present invention to provide a ceramic composite material which has excellent mechanical strength and creep properties over high temperatures, and has these properties remarkably improved especially at high temperatures. The aluminum oxide (Al ₂
O ₃ ) and rare earth element oxides (La ₂ O ₃ , Y ₂ O ₃ , Ce)
_{O 2, Pr 6 O 11,} Nd 2 O 3, Sm 2 O 3, Gd 2 O 3, Eu
₂ O ₃ , Tb ₄ O ₇ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm
Examples of the composite oxide formed from ₂ O ₃ , Yb ₂ O ₃ , and Lu ₂ O ₃ include the following. LaAl
O ₃ , CeAlO ₃ , PrAlO ₃ , NdAlO ₃ , SmA
lO ₃ , EuAlO ₃ , GdAlO ₃ , DyAlO ₃ , Yb
₄ Al ₂ O ₉ , Er ₃ Al ₅ O ₁₂ , 11 Al ₂ O ₃ La
₂ O ₃ , 11Al ₂ O ₃ · Nd ₂ O ₃ , 11Al ₂ O ₃ · Pr _{2
O 3, EuAl 11 O 18,} 2Gd 2 O 3 · Al 2 O 3, 11A
l ₂ O ₃ · Sm ₂ O ₃ , Yb ₃ Al ₅ O ₁₂ , CeAl ₁₁ O ₁₈ ,
Er ₄ Al ₂ O ₉

[0010]

The above object of the present invention is to provide aluminum oxide (Al ₂ O ₃ ) or rare earth element oxides (La ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , Pr ₆ ) shown in claim 1. O ₁₁ ,
Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₄ O ₇ ,
Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ ,
Lu ₂ O ₃ ) and a solidified body composed of two or more kinds of oxides selected from the group consisting of aluminum oxide and a composite oxide formed from rare earth element oxides. Achieved by material. However, the constituent phase of the ceramic composite material is Al ₂ O ₃
And Y ₃ Al ₅ O ₁₂ (YAG).

The ceramic composite material of the present invention will be described in detail below. The ceramic composite material of the present invention has a uniform structure free from colonies and voids by controlling the manufacturing conditions. Further, there is no grain boundary that exists in a general sintered body obtained by pressure sintering a mixed powder prepared to have predetermined components. Further, by controlling the manufacturing conditions, it is possible to obtain a ceramic composite material in which the oxide and the composite oxide constituting this composite material are composed of single crystal / single crystal, single crystal / polycrystal, and polycrystal / polycrystal, respectively. You can In the present invention, the “single crystal” means a crystal structure in which only a diffraction peak from a specific crystal plane is observed in X-ray diffraction. Furthermore, by adding an oxide other than the constituent oxides to form a solid solution or precipitate in at least one of the constituent phases of the composite material, or by allowing them to exist at the interface of the phases, the mechanical and thermal properties can be improved. It is also possible to change.

The ceramic composite material of the present invention has a structure in which the constituent oxide phases are homogeneously and continuously connected at a fine level. The size of each phase can be controlled by changing the solidification conditions, but generally 1
˜50 μm.

For example, in the case of a combination of Al ₂ O ₃ and Gd ₂ O ₃ , Al ₂ O ₃ : 78mol%, Gd ₂ O ₃ : 22mo.
1%, a eutectic is formed, so that the Al ₂ O ₃ phase, Al ₂ O ₃ and G
GdA having a perovskite structure which is a composite oxide of d ₂ O ₃
It is possible to obtain a ceramic composite material composed of 10 ₃ phases. Further, in the same manner as above, α-Al ₂ O ₃ is about 20-80.
The volume fraction of GdAlO ₃ can be changed within the range of about 80 to 20 volume%. In addition to this, when the oxide according to claim 1 has a perovskite structure, LaAlO ₃ , CeAlO ₃ , PrAlO ₃ , NdA
1O ₃ , SmAlO ₃ , EuAlO ₃ , DyAlO _{3 and the} like. When any of these constitutes the present composite material, it is possible to obtain a ceramic composite material having a fine structure and high mechanical strength.

In the case of a combination of Al ₂ O ₃ and Er ₂ O ₃ , Al ₂ O ₃ : 81.1 mol%, Er ₂ O ₃ : 18.
Since a eutectic is formed at 9 mol%, the Al ₂ O ₃ phase and the Al ₂ O ₃ phase
Garnet structure E which is a composite oxide of O ₃ and Er ₂ O ₃
It is possible to obtain a ceramic composite material composed of the r ₃ Al ₅ O ₁₂ phase. Further, similar to the above, α-Al ₂ O ₃ is about 20
80 volume%, Er ₃ Al ₅ O ₁₂ can be changed its fraction in the range of about 80 to 20 volume%. In addition to these, Yb ₃ Al ₅ O _{12 and the} like are included in the oxides according to claim 1 having a garnet structure. When any of these constitutes the present composite material, a ceramic composite material having high creep strength can be obtained.

The ceramic composite material of the present invention can be prepared, for example, by the following method. First, the two kinds of ceramic powders are mixed in a ratio to produce a ceramic composite material having a desired component ratio to prepare a mixed powder.
There is no particular limitation on the mixing method, and any of a dry mixing method and a wet mixing method can be employed. As a medium when using the wet mixing method, an alcohol such as methanol or ethanol is generally used. Then, this mixed powder is melted using a known melting furnace, for example, an arc melting furnace, at a temperature at which both raw materials are melted, for example, Al ₂ O ₃ and Er ₂ O ₃
In the case of, it is heated to 1,900 to 2,000 ° C. and melted.

Subsequently, the melt is charged into the crucible as it is for unidirectional solidification, or the melt is once solidified and then crushed, and the crushed product is charged into the crucible and solidified in one direction to obtain the ceramic composite of the present invention. Manufacture materials. As another method, a method in which the melt is cast into a crucible maintained at a predetermined temperature and a solidified body is obtained while controlling the cooling rate can also be adopted.

Atmospheric pressure during melting and solidification is usually 300
Torr or less, preferably 10 ^-3 Torr or less.
Further, the moving speed of the crucible during unidirectional solidification, in other words, the growth speed of the ceramic composite material is usually 500 mm.
/ Hour or less, preferably 1 to 100 mm / hour.
The adjustment conditions other than the atmospheric pressure and the moving speed are the same as those of the method known per se.

When the atmospheric pressure during melting and solidification or the moving speed of the crucible is out of the condition range, bubbles or voids are easily generated, and it is difficult to obtain a composite material excellent in mechanical strength and creep characteristics at high temperature. become.

As a device for solidifying in one direction, a crucible is movably housed in a vertically arranged cylindrical container, and an induction coil for heating is provided outside the central part of the cylindrical container. It is possible to use a device known per se, which is attached with a vacuum pump for reducing the pressure inside the container.

[0020]

INDUSTRIAL APPLICABILITY The ceramic composite material of the present invention is dramatically improved in heat resistance, durability, high temperature strength and thermal stability at high temperatures, and even at high temperatures in excess of 1,500 ° C. in the atmosphere. Since it exhibits excellent characteristics, it is highly useful as a member such as a turbine blade of a jet engine or a turbine for power generation, a jig for measuring high temperature characteristics of various high temperature materials, and the like. In addition, applications where oxide-based ceramics such as Al ₂ O ₃ are specifically used,
For example, it is highly useful in a wide range of other fields such as heat exchangers for high temperature reactors, materials for nuclear fusion reactors, materials for nuclear reactors, wear resistant members, and corrosion resistant members. Further, if this ceramic composite material is made into a fibrous or powder form, for example, a Ni-base superalloy or a Co-base superalloy used for a turbine blade of a jet engine or a gas turbine for power generation, or a dispersion strengthening material of various ceramics. Can also be suitably used. Furthermore, if the obtained powder is solidified on the surface of a metal material or the like by a coating method such as a plasma spraying method, the oxidation resistance and abrasion resistance can be expected to improve.

As a method for producing a fibrous ceramic composite material, a solidified body previously produced by the unidirectional solidification method is made into a wire having a diameter of about 1 mm, and one end thereof is immersed in a heated and melted pool of the same composition and pulled up. A method of growing fibrous crystals can be adopted. Alternatively, an edge-defined film that pulls up a narrow guide that causes a capillary phenomenon in a melt pool that is heated and melted
-Fed Growth (EFG method) or a method of irradiating a rod previously produced by a sintering method with a CO ₂ laser or the like to melt the zone and solidify in one direction (Laser hair)
ted floatzone method; LHFZ
Law) can also be adopted. Further, as a method for producing a powdery ceramic composite material, a method in which a sample obtained by heating and melting is solidified by dropping a droplet from a fine hole provided in the crucible bottom into a furnace with a gentle temperature gradient is adopted. You can Furthermore, as a method of coating the surface, a method of plasma spraying or unidirectionally solidifying while the material to be coated is immersed in a melt pool heated and melted,
A method of removing the crucible holding the melt by post-processing can be adopted.

[0022]

EXAMPLES Examples and comparative examples are shown below. Example 1 78.0 α-Al ₂ O ₃ powder and Gd ₂ O ₃ powder were used as raw materials.
/22.0 mol%, and mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at 10 ^-5 Torr atmospheric pressure, and the crucible is heated to 1,850 using a high frequency coil.
Heated to ２，2,000 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 5 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 1 shows an electron micrograph of a cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In Fig. 1, the white part is GdA.
The black portion of the 10 ₃ phase is the α-Al ₂ O ₃ phase. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Furthermore, as a result of X-ray diffraction of a plane perpendicular to the solidification direction, α-Al
Only diffraction peaks from specific planes of ₂ O ₃ and GdAlO ₃ are observed, and this solidified body is a ceramic composite material composed of two phases of α-Al ₂ O ₃ single crystal and GdAlO ₃ single crystal. Do you get it. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is a value measured at 1,600 ° C. in the atmosphere. The weight gain of the composite material after being kept in the atmosphere at 1,700 ° C. for 50 hours was 0.002 g / cm ³ .

Example 2 As a raw material, α-Al ₂ O ₃ powder and Gd ₂ O ₃ powder were used for 78.0.
/22.0 mol%, and mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at 10 ^-5 Torr atmospheric pressure, and the crucible is heated to 1,850 using a high frequency coil.
Heated to ２，2,000 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 20 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 2 shows an electron micrograph of the cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In Fig. 2, the white part is Gd.
The black part of the AlO ₃ phase is the α-Al ₂ O ₃ phase. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids.
Furthermore, as a result of X-ray diffraction on a plane perpendicular to the solidification direction, α-A
Diffraction peaks from a specific plane of l ₂ O ₃ and diffraction planes from a plurality of planes of GdAlO ₃ were observed.
It was found to be a ceramic composite material composed of two phases, an Al ₂ O ₃ single crystal and a GdAlO ₃ polycrystal. The mechanical strength of this composite material is shown in Tables 1 and 2. In Table 1, the three-point bending strength is a value measured at 1,600 ° C. in the atmosphere, and in Table 2, the compression creep strength is 1 in the atmosphere.
It is a value measured at 600 ° C. and a strain rate of 10 ⁻⁴ / s. The weight gain of the composite material after being kept in the atmosphere at 1,700 ° C. for 50 hours was 0.003 g / cm ³ .

Example 3 Example 2 except that the moving speed of the crucible was 50 mm / hour.
Was repeated to obtain a solidified body. Electron micrographs of the cross-sectional structure of the thus obtained solidified body perpendicular to the solidification direction are shown in FIGS. 3 and 4. 3 and 4, the white part is the GdAlO ₃ phase and the black part is the α-Al ₂ O ₃ phase. This solidified body has a unique structure in which a structure finer than that of Example 2 and a structure in which the fibrous GdAlO ₃ phase is uniformly dispersed in the Al ₂ O ₃ phase are mixed. I understood. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is 1,600 in the atmosphere.
It is a value measured at ° C.

Comparative Example 1 α-Al ₂ O ₃ powder and Gd ₂ O ₃ powder were used as raw materials in Example 1.
The mixture was mixed at the same mixing ratio as above with a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder was filled in a graphite die, and 10 ^-2 Tor
Under the atmospheric pressure of r, temperature 1,680 ° C, pressure 500kg
/ Mm ² for 2 hours under pressure to obtain a sintered body. As a result of X-ray diffraction of the sintered body thus obtained, α-Al ₂
Diffraction peaks from a plurality of planes were observed for both O ₃ and GdAlO ₃ . Further, an electron micrograph of the cross-sectional structure of the surface of this sintered body which is perpendicular to the pressing direction is shown in FIG. In FIG. 5, the white part is GdAlO ₃ particles and the black part is α-Al ₂
O ₃ particles. This composite material consists of Al ₂ O ₃ grains and GdAl.
It was found to be a ceramic composite material composed of O ₃ grains. The mechanical strength of this composite material is shown in Tables 1 and 2. In Tables 1 and 2, the three-point bending strength and the compression creep strength are both values measured at 1,600 ° C. in air and a strain rate of 10 ⁻⁴ / s.

Example 4 81.1 of α-Al ₂ O ₃ powder and Er ₂ O ₃ powder were used as raw materials.
/18.9 mol%, and mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at an atmospheric pressure of 10 ^-5 Torr, and the crucible is heated to 1,900 using a high-frequency coil.
Heated to ２，2,000 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 5 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 6 shows an optical micrograph of the cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 6, the white part is Er ₃
The black portion of the Al ₅ O ₁₂ phase is the α-Al ₂ O ₃ phase. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Further, as a result of X-ray diffraction of a plane perpendicular to the solidification direction, α
-Diffraction peak from a specific surface of Al ₂ O ₃ and Er ₃ Al ₅ O
Diffraction peaks from ₁₂ specific planes were observed, and it was found that the solidified body was a ceramic composite material composed of two phases of α-Al ₂ O ₃ single crystal and Er ₃ Al ₅ O ₁₂ single crystal.
The mechanical strength of this composite material is shown in Tables 1 and 2. Table 1
In Table 3, the three-point bending strength is a value measured at 1,800 ° C. in the atmosphere, and in Table 2, the compression creep strength is a value measured at 1,600 ° C. in the atmosphere at a strain rate of 10 ⁻⁴ / s. In addition, this composite material was exposed to 1,700 ° C in the atmosphere at 50
The weight gain after holding for a period of time was 0.002 g / cm ³ .

Example 5 81.1 of α-Al ₂ O ₃ powder and Er ₂ O ₃ powder were used as raw materials.
/18.9 mol%, and mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at an atmospheric pressure of 10 ^-5 Torr, and the crucible is heated to 1,900 using a high-frequency coil.
Heated to ２，2,000 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 50 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 7 shows an optical micrograph of a cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 7, the white part is Er.
_The black portion of the ₃ Al ₅ O ₁₂ phase is the α-Al ₂ O ₃ phase. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Further, as a result of X-ray diffraction of a plane perpendicular to the solidification direction, α
-Diffraction peak from a specific surface of Al ₂ O ₃ and Er ₃ Al ₅ O
Diffraction peaks from ₁₂ planes were observed, and it was found that the solidified body was a ceramic composite material composed of two phases of α-Al ₂ O ₃ single crystal and Er ₃ Al ₅ O ₁₂ polycrystal.
The mechanical strength of this composite material is shown in Tables 1 and 2. Table 1
In Table 3, the three-point bending strength is a value measured at 1,800 ° C. in the atmosphere, and in Table 2, the compression creep strength is a value measured at 1,600 ° C. in the atmosphere at a strain rate of 10 ⁻⁴ / s. In addition, this composite material was exposed to 1,700 ° C in the atmosphere at 50
The weight gain after holding for a period of time was 0.002 g / cm ³ .

Comparative Example 2 α-Al ₂ O ₃ powder and Er ₂ O ₃ powder were used as raw materials in Example 4.
The mixture was mixed at the same mixing ratio as above with a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder was filled in a graphite die, and 10 ^-2 Tor
Temperature of 1,780 ℃, pressure of 500kg under r atmosphere pressure
/ Mm ² for 2 hours under pressure to obtain a sintered body. As a result of X-ray diffraction of the sintered body thus obtained, α-Al ₂
Diffraction peaks from a plurality of planes were observed for both O ₃ and Er ₃ Al ₅ O ₁₂ . An electron micrograph of the cross-sectional structure of the surface of this sintered body perpendicular to the pressing direction is shown in FIG. In FIG. 8, the white portion is Er ₃ Al ₅ O ₁₂ particles, and the black portion is α-.
These are Al ₂ O ₃ particles. This composite material contains Al ₂ O ₃ grains and Er
It was found to be a ceramic composite material composed of ₃ Al ₅ O ₁₂ grains. The mechanical strength of this composite material is shown in Tables 1 and 2. In Tables 1 and 2, the three-point bending strength is a value measured at 1,800 ° C. in the air, and the compression creep strength is a value measured at 1,600 ° C. in the air at a strain rate of 10 ⁻⁴ / s.

Example 6 69.0 of α-Al ₂ O ₃ powder and Sm ₂ O ₃ powder were used as raw materials.
/31.0 mol% and were mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at 10 ^-5 Torr atmospheric pressure, and the crucible is heated to 1,850 using a high frequency coil.
To 950 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 50 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 9 shows an electron micrograph of the cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 9, the white part is Sm.
The black part of the AlO ₃ phase is the α-Al ₂ O ₃ phase. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids.
Furthermore, as a result of X-ray diffraction on a plane perpendicular to the solidification direction, α-A
Diffraction peaks from plural planes of l ₂ O ₃ and plural diffraction peaks of SmAlO ₃ were observed, and this solidified body was α-Al ₂ O ₃
It consists of two phases, polycrystal and SmAlO ₃ polycrystal, and α-
It was found to be a ceramic composite material in which the fibrous SmAlO ₃ phase was uniformly dispersed in the Al ₂ O ₃ phase. The mechanical strength of this composite material is shown in Tables 1 and 2. In Table 1,
The three-point bending strength is a value measured at 1,700 ° C. in air, and in Table 2, the compression creep strength is 1,60 in air.
It is a value measured at 0 ° C. In addition, this composite material
Weight increase after holding in the atmosphere of 00 ℃ for 50 hours is 0.0
It was 02 g / cm ³ .

Example 7 As raw materials, α-Al ₂ O ₃ powder and Yb ₂ O ₃ powder were used at 83.7.
The mixture was mixed at a ratio of /16.3 mol% and mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at 10 ^-5 Torr atmospheric pressure, and the crucible is heated to 1,850 using a high frequency coil.
To 950 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 5 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 10 shows an electron micrograph of a cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 10, the white part is 3
The black portion in the Yb ₂ O ₃ .5Al ₂ O ₃ phase is the α-Al ₂ O ₃ phase. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Furthermore, as a result of X-ray diffraction on a plane perpendicular to the solidification direction, a diffraction peak from a specific plane of α-Al ₂ O ₃ and 3Y
Only diffraction peaks from a specific plane of b ₂ O ₃ .5Al ₂ O ₃ were observed, and this solidified body was α-Al ₂ O ₃ single crystal and 3Yb ₂
O ₃ · 5Al ₂ O ₃ was found to be ceramic composites consisting of two phases of single crystal. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is a value measured at 1,600 ° C. in the atmosphere. The weight gain of the composite material after being kept in the atmosphere at 1,700 ° C. for 50 hours was 0.002 g / cm ³ .

Example 8 77.5 as raw materials were α-Al ₂ O ₃ powder and La ₂ O ₃ powder.
/22.5 mol% and were mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder was charged into a molybdenum crucible installed in the chamber, the atmospheric pressure was maintained at 10 ⁻⁵ Torr, and the crucible was heated to 1,800 using a high frequency coil.
The mixed powder was melted by heating to ˜1,900 ° C. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 50 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 11 shows an electron micrograph of a cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 11, the white portion is the LaAlO ₃ phase and the black portion is the α-Al ₂ O ₃ phase. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Further, as a result of X-ray diffraction of a plane perpendicular to the solidification direction, α
A plurality of diffraction peaks of both -Al ₂ O ₃ and LaAlO ₃ were observed, and this solidified body showed α-Al ₂ O ₃ polycrystal and La
It has been found that the ceramic composite material is composed of two phases of AlO ₃ polycrystal, and the fibrous LaAlO ₃ phase is uniformly dispersed in the α-Al ₂ O ₃ phase. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is a value measured at 1,600 ° C. in the atmosphere. The weight gain of the composite material after being kept in the atmosphere at 1,600 ° C. for 50 hours was 0.002 g / cm ³ .

Example 9 80.3 of α-Al ₂ O ₃ powder and Nd ₂ O ₃ powder were used as raw materials.
/19.7 mol% and were mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at 10 ^-5 Torr atmospheric pressure, and the crucible is heated to 1,850 using a high frequency coil.
To 950 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 20 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 12 shows an optical micrograph of a cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 12, the white part is the NdAl ₁₁ O ₁₈ phase and the black part is the AlNdO ₃ phase, both of which are complex oxides. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Further, as a result of X-ray diffraction of a plane perpendicular to the solidification direction, diffraction peaks from a specific plane of NdAl ₁₁ O ₁₈ and plural diffraction peaks of AlNdO ₃ were observed, and this solidified body was identified as NdAl ₁₁ O ₁₈ single crystal. AlNdO ₃
It was found to be a ceramic composite composed of two polycrystalline phases. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is 1,700 in the atmosphere.
It is a value measured at ° C.

Example 10 80.3 of α-Al ₂ O ₃ powder and Nd ₂ O ₃ powder were used as raw materials.
/19.7 mol% and were mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder is charged into a molybdenum crucible placed in a chamber, and the crucible is maintained at 10 ^-5 Torr atmospheric pressure, and the crucible is heated to 1,850 using a high frequency coil.
To 950 ° C. to dissolve the mixed powder. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 50 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 13 shows an optical micrograph of the cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 13, the white portion is the NdAl ₁₁ O ₁₈ phase and the black portion is the AlNdO ₃ phase, both of which are complex oxides. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Further, as a result of X-ray diffraction of a plane perpendicular to the solidification direction, diffraction peaks from a plurality of planes of NdAl ₁₁ O _{18 and} a plurality of diffraction peaks of AlNdO ₃ were observed, and this solidified body was identified as NdAl ₁₁ O ₁₈ polycrystal. AlNdO ₃
It was found to be a ceramic composite material composed of two polycrystalline phases, in which the fibrous NdAl ₁₁ O ₁₈ phase was uniformly dispersed in the AlNdO ₃ phase. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is a value measured at 1,700 ° C. in the atmosphere.

Example 11 71.7 α-Al ₂ O ₃ powder and Eu ₂ O ₃ powder were used as raw materials.
/28.3 mol% and were mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder was charged into a molybdenum crucible installed in the chamber, the atmospheric pressure was maintained at 10 ⁻⁵ Torr, and the crucible was heated to 1,750 using a high frequency coil.
The mixed powder was melted by heating to ˜1,850 ° C. next,
Under the same atmospheric pressure, the crucible was lowered at a speed of 20 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 14 shows an electron micrograph of a cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 14, the white portion is the AlEuO ₃ phase and the black portion is the EuAl ₁₁ O ₁₈ phase, both of which are complex oxides. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Further, as a result of X-ray diffraction on a plane perpendicular to the solidification direction, diffraction peaks from a specific plane of AlEuO ₃ and multiple diffraction peaks of EuAl ₁₁ O ₁₈ were observed, and this solidified body was formed of AlEuO ₃ single crystal and EuAl ₁₁ O ₁₈
It was found to be a ceramic composite composed of two polycrystalline phases. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is 1,600 in the atmosphere.
It is a value measured at ° C.

Example 12 78% of α-Al ₂ O ₃ powder and Pr ₆ O ₁₁ powder were used as raw materials.
The mixture was mixed at a ratio of 8 / 21.2 mol%, mixed by a wet ball mill using an ethanol solvent, and ethanol was removed from the obtained slurry using a rotary evaporator. The obtained mixed powder was charged into a molybdenum crucible installed in the chamber, the atmospheric pressure was maintained at 10 ⁻⁵ Torr, and the crucible was heated to 1,90 by using a high frequency coil.
It heated at 0-1950 degreeC and melt | dissolved the mixed powder. Next, under the same atmospheric pressure, the crucible was lowered at a speed of 20 mm / hour to unidirectionally solidify to obtain a solidified body. FIG. 15 shows an electron micrograph of a cross-sectional structure perpendicular to the solidification direction of the solidified body thus obtained. In FIG. 15, the white portion is the PrAlO ₃ phase and the black portion is the PrAl ₁₁ O ₁₈ phase, both of which are complex oxides. It was found that this coagulated body had no colony or grain boundary phase and had a uniform structure free of bubbles and voids. Further, as a result of X-ray diffraction of a plane perpendicular to the solidification direction, diffraction peaks from a specific plane of PrAl ₁₁ O ₁₈ and plural diffraction peaks of PrAlO ₃ were observed, and this solidified body was identified as a PrAl ₁₁ O ₁₈ single crystal. PrAl
It was found to be a ceramic composite material composed of two phases of O ₃ polycrystal. The mechanical strength of this composite material is shown in Table 1. In Table 1, the three-point bending strength is 1,60 in the atmosphere.
It is a value measured at 0 ° C.

[0036]

[Table 1]

[0037]

[Table 2]

[Brief description of drawings]

FIG. 1 is an electron micrograph showing a particle structure of a composite material obtained in Example 1 in place of a drawing.

FIG. 2 is an electron micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 2.

FIG. 3 is an electron micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 3.

FIG. 4 is an electron micrograph, which is a drawing and shows the particle structure of the composite material obtained in Example 3.

FIG. 5 is an electron micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Comparative Example 1.

FIG. 6 is an optical micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 4.

FIG. 7 is an optical micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 5.

FIG. 8 is an electron micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Comparative Example 2.

FIG. 9 is an electron micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 6.

FIG. 10 is an electron micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 7.

FIG. 11 is an electron micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 8.

FIG. 12 is an optical micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 9.

FIG. 13 is an optical micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 10.

FIG. 14 is an optical micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 11.

FIG. 15 is an optical micrograph as a substitute for a drawing, which shows the particle structure of the composite material obtained in Example 12.

 ─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 7-177985 (32) Priority date Hei 7 (1995) June 22 (33) Priority claim country Japan (JP) (72) Inventor Otsubo Hideki 5 1978, Kobe, Oji, Ube, Yamaguchi Prefecture, Ube Research Co., Ltd., Ube Laboratory (72) Inventor, Kazutoshi Shimizu 5 1978, Kogeshi, Ube, Yamaguchi Prefecture, Ube Laboratory, Ube Research Co., Ltd. (72) Inventor Shintoku Yasuhiko 5 Ube City, Ube, Yamaguchi Prefecture 5 1978, Kobugushi 5 Ube Kosan Co., Ltd. Ube Laboratory

Claims (7)

[Claims] 1. A compound selected from the group consisting of metal oxides and complex oxides formed from two or more metal oxides.
A solidified body composed of one or more kinds of oxides, the constituent phase of which is aluminum oxide (Al ₂ O ₃ ) or rare earth element oxides (La ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , Pr ₆ O ₁₁ , Nd ₂
O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₄ O ₇ , Dy _{2
O 3, Ho 2 O 3,} Er 2 O 3, Tm 2 O 3, Yb 2 O 3, Lu 2
O ₃ ) and two or more kinds of oxides selected from the group consisting of aluminum oxides and composite oxides formed from rare earth element oxides (however, constituent phases) But Al ₂ O ₃ and Y ₃ Al ₅
Except when it is O ₁₂ (YAG). ). 2. The ceramic composite material according to claim 1, wherein the solidified body has no colonies or pores. 3. The ceramic composite material according to claim 1, wherein the oxide composing the ceramic composite material is composed of a single crystal. 4. The ceramic composite material according to claim 1, wherein at least one of the oxides composing the ceramic composite material is composed of a single crystal. 5. The ceramic composite material according to claim 1, wherein the oxide composing the ceramic composite material is composed of polycrystal. 6. The ceramic composite material according to claim 1, wherein at least one of the oxides constituting the ceramic composite material is an oxide having a perovskite structure. 7. The ceramic composite material according to claim 1, wherein at least one of the oxides constituting the ceramic composite material is an oxide having a garnet structure.