JPH0840770A - Zirconia sintered product and method for producing the same - Google Patents

Abstract

PURPOSE:To provide a rare earth metal oxide-stabilized zirconia sintered product excellent in thermal impact resistance, especially in rapid heating impact resistance up to 1800 deg.C, and having good thermal stability and high mechanical characteristics, and to provide a method for producing the same. CONSTITUTION:The zirconia sintered product is obtained by sintering a raw material composition comprising ZrO2 composing vaterite as a main component, the below-described amount of one or more rare earth metal oxides selected from Nd2O3, Sm2O3, Gd2O3, Dy2O3, Y2O3, Ho2O3, Er2O3and Yb2O3, the below- described amounts of Al2O3 and SiO2, and, if necessary, further the below- described amount of a boron compound at a prescribed temperature (1400-1700 deg.C). The molar ratio of R2O3/ZrO2:1/99 to 5/95; the content of Al2 O3:0.05-20mol.%; the content of SiO2:0.05-10mol.%; the content of the boron compound : 0.05-10mol.% converted into boron (B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly applied to dies and rolls.
La, a zirconia-based sintered body for a ceramic heat-resistant component such as a crucible and a refractory, and a manufacturing method thereof,
The present invention relates to a rare earth metal oxide-stabilized zirconia-based sintered body having excellent thermal shock resistance, particularly rapid thermal shock resistance up to 1800 ° C., and having thermal stability and high mechanical properties, and a method for producing the same.

[0002]

_2. Description of the Related Art Zirconia (ZrO ₂ ) -based sintered material is
Despite having various advantages such as excellent corrosion resistance, small thermal conductivity and excellent heat insulation,
Since it is inferior in thermal shock resistance, this has been one of the causes of hindering widespread use.

[0003]

Currently, the zirconia-based refractory material which is industrially put into practical use is generally fused zirconia obtained by electromelting a stabilizer in a predetermined amount. Even if crushed powder of zirconia is molded and fired, only porcelain having a porosity of about 20% is obtained, and mechanical properties such as bending strength are not necessarily satisfactory, and heat resistance is high. It could not be used for those requiring impact resistance. Also,
A zirconia raw material containing a stabilizer is calcined, and calcined zirconia stabilized is also known, but zirconia refractory obtained by sintering the zirconia-based refractory is unlikely to have high density and is inferior in thermal shock resistance. there were.

To give an example, in Japanese Patent Laid-Open No. 60-42274, in order to enhance the stabilizing reaction during firing, it is possible to use 32 parts of baddelite (ZrO ₂ ) having an average particle size of 0.5 to 5 μm with a particle size of 325 mesh or less.
₂ to 7% by weight of a stabilizer consisting of one or more of MgO, CaO and Y ₂ O ₃ of 5 mesh or less is blended, and this is granulated using an organic or inorganic pressure-sensitive adhesive and molded. After 1600 ~ 1850
It is described that sintering and stabilization treatment of zirconia are performed at the same time by firing at ℃, thereby producing a zirconia-based refractory having high bending strength. And, as an example, only those using MgO as a stabilizer are mentioned, but among the material composition excellent in thermal shock resistance and mechanical strength, its bending strength is the highest 15 kgf / mm ² and its porosity is 15%
High as above and minimum required as a structural ceramic material (similar to alumina sintered body with relatively low mechanical properties)
A zirconia-based sintered body that has a bending strength of 20 kgf / mm ² or more, a porosity of 15% or less that can reduce the penetration and reaction of molten metal, and has thermal shock resistance can be obtained. Absent.

In addition, a zirconia-based refractory has been proposed in which various oxides are added to zirconia so as to have a complicated microstructure, thereby improving thermal shock resistance. For example, JP-B-57-34233 and JP-A-59-1
JP-A-52266 discloses that 50 to 90% by weight of partially stabilized zirconia containing 2 to 5% by weight of CaO and 10 to 50% by weight of monoclinic zirconia are contained in the matrix portion. A zirconia-based refractory with a complex microstructure as it exists is described. However, although this zirconia-based refractory material has improved thermal shock resistance as compared with conventional zirconia-based refractory materials, it requires complicated manufacturing techniques.

Further, the conventional zirconia-based sintered body is 150
It has the drawback that if it is left at about 300 ° C for a long period of time, the strength will remarkably decrease. This is because the tetragonal crystal, which is a metastable phase at room temperature among the crystal phases of the zirconia-based sintered body, transforms into a stable monoclinic crystal, and the volume expansion accompanying this phase transition causes microcracks in the sintered body. It depends. In particular, this phase transition occurs even at a temperature lower than the above-mentioned temperature (150 to 300 ° C.) under the environment of water or water vapor, and the rate thereof is also very fast. Therefore, it is a big problem that the strength is remarkably reduced in the low temperature region.

The present invention has been made in view of the above problems and drawbacks of the prior art, and the object thereof is the first aspect.
To provide a zirconia-based sintered body having excellent thermal shock resistance, particularly rapid thermal shock resistance up to 1800 ° C., and having thermal stability and high mechanical properties. Secondly, 150 to 300
A third object of the present invention is to provide a zirconia-based sintered body that is unlikely to deteriorate in the sintered body even if it is used in the air or water and steam at a temperature of ℃ for a long period of time. An object of the present invention is to provide a method for producing a bound body by simple steps, which can be easily manufactured.

[0008]

A zirconia-based sintered body according to the present invention contains ZrO ₂ composed of baddelite as a main component,
Predetermined amount of Nd ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Y ₂ O ₃ , Ho ₂ O
1 or 2 selected from the group consisting of ₃ , Er ₂ O ₃ and Yb ₂ O ₃
One or more rare earth metal oxides and a certain amount of Al ₂ O ₃ and S
characterized by comprising a raw material mixture containing iO ₂ , or a predetermined range amount of Al ₂ O ₃ , SiO ₂ and a boron compound,
In this way, the zirconia-based sintered body, which is the first and second objects, is provided.

Further, in the method for producing a zirconia-based sintered body according to the present invention, a raw material mixture is prepared by an oxide mixing method so that a predetermined raw material composition is obtained, and the mixture is molded at a predetermined temperature (1
It is characterized in that it is sintered at 400 to 1700 ° C.), thereby achieving the third object.

That is, the zirconia-based sintered body according to the present invention is characterized in that "the main component is ZrO ₂ composed of badderite, and Nd
₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Y ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Y
A zirconia-based sintered body containing one or more rare earth metal oxides selected from the group consisting of b ₂ O ₃ and Al ₂ O ₃ and SiO ₂ , or further containing a boron compound, Molar ratio of the above rare earth metal oxide (R ₂ O ₃ ) and ZrO ₂ (R ₂ O ₃ / ZrO ₂ )
Is 1/99 to 5/95, and the content of Al ₂ O ₃ is 0.05 to 2
0 mol%, the content of SiO ₂ is 0.05 to 10 mol%, or even zirconia sintered the content of the boron compound is characterized in that 0.05 to 10 mol% in terms of boron (B) Union. (Claims 1 and 2) is the gist.

Further, the method for producing a zirconia-based sintered body according to the present invention is described as follows: "ZrO ₂ composed of badderite is used as a main component, and Nd ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ as a stabilizer, Dy ₂ O ₃ , Y ₂
1 selected from the group consisting of O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Yb ₂ O ₃
Al ₂ O ₃ and SiO _{2 with one} or more rare earth metal oxides
Or a method for manufacturing a zirconia-based sintered body containing Al ₂ O ₃ , SiO ₂ and a boron compound, (1) as a raw material composition, the rare earth metal oxide (R ₂ O ₃ ) and The molar ratio with ZrO ₂ (R ₂ O ₃ / ZrO ₂ ) is 1/99 to 5/95, and the Al ₂ O ₃ is 0.05 to 20.
Mol%, the SiO ₂ content is 0.05 to 10 mol%, and the boron compound is 0.05 to 10 mol% in terms of boron (B).
Step of adjusting the raw material blend by the oxide mixing method, (2)
Step of molding the above raw material mixture, (3) 1400 the above molded body
A method for producing a zirconia-based sintered body, comprising: a step of firing at ~ 1700 ° C. (Claim 6) is the gist.

The zirconia-based sintered body of the present invention and the method for producing the same will be described in detail below. First, the zirconia-based sintered body according to the present invention will be described.
Mainly composed of ZrO ₂ composed of badderite, Nd ₂ O ₃ , Sm
One or more rare earth metal oxides selected from the group consisting of ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Y ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Yb ₂ O ₃ . (R ₂ O ₃ ) is used as a stabilizer.

Regarding the compounding ratio of the stabilizer (R ₂ O ₃ ), the molar ratio with ZrO ₂ (R ₂ O ₃ / ZrO ₂ ) is 1/99 to 5/95, and the preferable range is , 1.5 / 98.5 to 4/96. R ₂ O ₃
When the / ZrO ₂ molar ratio is less than 1/99, cracks occur in the resulting zirconia-based sintered body (see composition No. 10 in Tables 1 and 2 below). On the contrary, when it exceeds 5/95, sufficient mechanical properties are obtained. A zirconia-based sintered body having the desired strength cannot be obtained (composition N in Tables 1 and 2 below).
o.18)), which is not preferable.

As a stabilizer for the zirconia-based sintered body, a rare earth metal oxide having an ionic radius smaller than Nd is used.
When using La ₂ O ₃ or Pr ₆ O ₁₁ alone or in combination thereof, microcracks were generated during firing, and a zirconia-based sintered body having sufficient mechanical properties was not obtained ( (See Composition Nos. 1 and 2 in Tables 1 and 2 below). However, the stabilizers used in the present invention (Nd ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Y ₂ O ₃ , H
O ₂ O ₃ , Er ₂ O ₃ and Yb ₂ O ₃ selected from the group consisting of 1 or 2 or more kinds of rare earth metal oxides), and 30 mol% or less of the above La ₂ O ₃ or Pr ₆ O ₁₁ No problem was found that the mechanical properties deteriorate when replaced with, for example. Therefore, this case is also included in the present invention.

Further, Eu ₂ O ₃ , Tb ₂ O ₃ , Tm ₂ O ₃ , Lu ₂ O ₃ and Sc ₂ O
Even when using a rare earth metal oxide such as ₃ as a stabilizer, the same effect as the zirconia-based sintered body of the present invention is recognized, but such a rare earth metal oxide is industrially expensive. It is not preferable because it is difficult to use.

The "baddelite" used as a zirconia raw material is the name of zirconium oxide mineral, and is produced with zircon, and one example of the analysis value is CaO; 0.06, Fe. ₂ O ₃ ; 0.82, SiO ₂ ; 0.19,
ZrO ₂ ; 98.90. When high-purity zirconia separated and refined from ores such as baddelite and zircon (for example, separated and refined by a method of forming an aqueous solution and removing impurities and the like) is used, the thermal shock resistance of the present invention is excellent. It turns out that the characteristics cannot be obtained.

In the zirconia-based sintered body according to the present invention, the addition of Al ₂ O ₃ and SiO ₂ facilitates the sintering of the raw material mixture and enables the firing at a low temperature. It greatly contributes to the improvement of the characteristics, and it is possible to reduce the amount of boron added. When the added amount (content) of Al ₂ O ₃ exceeds 20 mol%, the strength decreases (see composition No. 22 in Tables 1 and 3 below), while when it is less than 0.05 mol%.
The effect of adding Al ₂ O ₃ cannot be obtained (composition No. 1 in Tables 1 and 2 below).
9). Further, when the content of SiO ₂ exceeds 10 mol%, the strength is remarkably lowered (see composition No. 26 in Tables 1 and 3 below),
On the other hand, if it is less than 0.05 mol%, the effect of adding SiO ₂ cannot be obtained.
(See composition No. 23 in Tables 1 and 3 below).

Therefore, in the present invention, Al ₂ O ₃ : 0.05-2
0 mol%, SiO ₂ : 0.05 to 10 mol% are preferable, more preferably Al ₂ O ₃ : 0.1 to 10 mol%, SiO ₂ : 0.05 to 5 mol%
Is. These additives have similar effects even when added in the form of nitrides, carbides, hydroxides, etc. in addition to oxides of additive components (Al, Si). It is included in the invention.

Further, the zirconia-based sintered body according to the present invention preferably contains a boron compound in its raw material composition. Explaining this boron compound, 200
As a result of observing the bending strength and surface structure of the sample that was subjected to a water test at 250 ° C for 250 hours, a large decrease in strength was observed in the zirconia-based sintered body that did not contain a boron compound, and many microcracks were also observed on the sample surface. Was observed. On the other hand, in the zirconia-based sintered body to which the boron compound is added,
The above-mentioned cracking phenomenon was not observed, and the strength of the sample before the test was different depending on whether or not the boron compound was added, and it was clearly recognized that the strength of the added one was improved.

From these test results, it was found that the thermal stability of the zirconia-based sintered body can be improved by adding the boron compound. Therefore, in the zirconia-based sintered body according to the present invention, it is preferable to add a boron compound especially when heat stability is required.

However, even when a boron compound is contained, if the content thereof is less than 0.05 mol% in terms of boron (B), the effect of the addition of the boron compound is not observed, and conversely 10 mol%. If it is added over the range, the initial bending strength tends to be lowered (see composition No. 30 in Tables 1 and 3 below). From this, in the zirconia-based sintered body according to the present invention, the addition amount of the boron compound is preferably 0.05 to 10 mol% in terms of boron (B), and more preferably 0.05.
~ 5 mol%.

As the above-mentioned boron compound, boron oxide,
Boron nitride, boron carbide, or Nd, Sm, Gd, Dy,
A metal boride other than Y, Ho, Er and Yb (for example, a metal boride composed of Zr as a main component or Al as an additional component) can be used. In the zirconia-based sintered body according to the present invention, such a boron compound is not an essential additive component. The reason is that even if it does not contain a boron compound, the zirconia-based sintered body defined by the present invention is excellent in thermal shock resistance and mechanical properties, except that it has poor thermal stability, and has an industrial value of This is because it can be a high product (composition No. 27 in Tables 1 and 3 below).
reference).

In the zirconia-based sintered body according to the present invention, the crystal grains of the sintered body are mainly composed of a mixed phase of monoclinic crystal and tetragonal crystal or a mixed phase of monoclinic crystal, tetragonal crystal and cubic crystal. A sintered body with a diameter of 5 μm or less and a porosity of 15% or less, and deterioration of the sintered body occurs during long-term use in air, water or steam at a temperature of 150 to 300 ° C. It has difficult characteristics. Further, the zirconia-based sintered body according to the present invention, Al ₂ O ₃ and SiO ₂ (or Al ₂ O ₃ , SiO ₂ and boron compound) source Al and Si (or Al, Si and B)
Is a sintered body mainly concentrated and precipitated at the grain boundary between ZrO ₂ particles.

Next, a method of manufacturing a zirconia-based sintered body according to the present invention will be described. Zr composed of baddelite
O ₂ , rare earth metal oxide (Nd ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Y
1 selected from the group consisting of ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Yb ₂ O _3.
One or two or more rare earth metal oxides), Al ₂ O ₃ , SiO ₂ and, if necessary, a boron compound so as to have a composition within the above-mentioned predetermined range by using an oxide mixing method to prepare a raw material mixture. Prepare. The obtained raw material mixture is molded, and the molded body is molded at 1400 to 17
Sintering is performed within a temperature range of 00 ° C. (preferably within a temperature range of 1450 to 1580 ° C.) to produce a target zirconia-based sintered body. If the sintering temperature is less than 1400 ° C, the densification does not proceed (see the firing temperature of composition No. 14 in Table 2 below: 1350 ° C), while 17
If the temperature exceeds 00 ° C, a high-strength sintered body cannot be obtained due to abnormal grain growth of crystal grains, etc. (Table 2
O.14 firing temperature: 1750 ° C).

The zirconia-based sintered body according to the present invention obtained by the above composition and manufacturing method has an average crystal grain size of
Less than 5 μm and porosity less than 15%, 150-300
It has a characteristic that deterioration of the sintered body is unlikely to occur during long-term use in the atmosphere, water or steam at a temperature of ° C.

With a sintered body having an average particle size of more than 5 μm, good characteristics in terms of wear resistance and thermal stability cannot be obtained, and the sintered body is heated to 150 ° to 300 ° C. in the air or in water or water. When used in steam for a long time, the sintered body is deteriorated. Further, if the porosity exceeds 15%, not only the penetration and reaction of molten metal and the like increase, but also the bending strength decreases.

Further, the zirconia-based sintered body according to the present invention was analyzed by electron probe microanalysis, and as a result, Al ₂ O ₃ and SiO ₂ (or Al ₂ O ₃ , SiO ₂ and boron compound) were obtained.
It was confirmed that Al and Si (or Al, Si and B), which are the sources, were concentrated and precipitated mainly in the grain boundary part between the ZrO ₂ particles, and the precipitation of Al was particularly remarkable.

[0028]

[Function] The zirconia-based sintered body "Al ₂ O ₃ and S according to the present invention"
A rare earth metal oxide-stabilized zirconia-based sintered body containing badelite, which contains iO ₂ (or Al ₂ O ₃ , SiO ₂ and a boron compound), has the composition defined by the present invention, and also the present invention The zirconia-based sintered body that satisfies the crystal constitution phase, the average crystal grain size, and the composition of the grain boundary portion defined in 1. is not found in the conventional zirconia-based sintered body, is excellent in thermal shock resistance and thermal stability, and A zirconia-based sintered body having mechanical properties can be provided.

[0029]

Next, examples of the present invention will be described together with comparative examples.
The present invention will be described more specifically, but the present invention is not limited to the following examples unless it exceeds the gist.

Examples and Comparative Examples Compositions shown in Table 1 (composition N
o.1 to 30), the baddelite (ZrO ₂ ) having a purity of 98% or more, various rare earth metal oxides (R ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), silicon dioxide (SiO ₂₎ ), Boron oxide (B ₂
O ₃ ) is weighed (Al ₂ O ₃ and SiO ₂ in the baddelite are also included in the composition values in Table 1), ion-exchanged water is used as a solvent, and 3% by weight of an acrylic copolymer resin is further added to the rubber lining. After kneading with ZrO ₂ quality media in a ball mill,
Spray granulation was performed.

[0031]

[Table 1]

This granulated powder was CIP-molded at a pressure of 1000 kgf / cm ^{2 and} was subjected to main firing at the temperatures shown in Tables 2 and 3. "Porosity""Average crystal grain size""Crystalphase""3-point bending strength (bending strength test method for fine ceramics: value measured based on JIS R1601)" for each of the obtained zirconia-based sintered bodies Vickers hardness (JIS R1610) "" Thermal stability "
Tables 2 and 3 show the “thermal shock resistance”.

The "porosity" of the sintered body was measured using a three-point bending strength measurement sample with reference to JIS R2205. In addition, the "thermal stability" of the sintered body is the deterioration of the sintered body after the sintered body was placed in an autoclave and subjected to an aging test for 200 hours in hot water at 200 ° C. It was judged by observing the condition. The "heat shock resistance" of the sintered body is that the sintered body is directly placed in an acetylene burner flame maintained at 1800 ° C from room temperature for 30 seconds and then the cracked state of the sintered body is observed. I judged it.

Monoclinic crystal, tetragonal crystal of the crystal phase in the sintered body,
The cubic crystal content is calculated by the following formula from the intensity ratio of the surface by X-ray diffraction after grinding the surface of the sintered body with a # 600 diamond grindstone and finishing it to a mirror surface with diamond grains of 1 to 5 μm.
It was determined using (1) to (3).

[0035]

[Equation 1]

Further, the average particle diameter is measured by etching the surface of the sintered body, which has been mirror-finished as described above, with hydrofluoric acid, and the number of particles (n) is 50 in an electron micrograph.
Diameter of a circle (d) that is equal within a certain area (S) that contains more than one
Was calculated by the equation: d = (4S / π) ^1/2 , and d was determined for three or more visual fields of the same sample, and the obtained average particle size was obtained. The number of particles (n) is the number of particles completely contained in a certain area (S) and the number of particles cut by the boundary line of a certain area.
The sum is 1/2. (For the method for measuring the average particle diameter, see JP-B-61-21184).

[0037]

[Table 2]

[0038]

[Table 3]

From Tables 2 and 3, the stabilizer (R ₂ O ₃ ) and ZrO ₂
Within a predetermined range of the present invention, and within a predetermined range
In the examples containing Al ₂ O ₃ , SiO ₂ , and the boron compound (B ₂ O ₃ ),
It can be understood that a zirconia-based sintered body having high mechanical properties and good thermal stability can be obtained.

On the other hand, even if one of the above-mentioned predetermined ranges defined by the present invention is out of the range, the zirconia-based sintered body intended by the present invention cannot be obtained. For example, in a comparative example of composition No. 10 (Y ₂ O ₃ / ZrO ₂ : 0.5 / 99.5) which is outside the range of “R ₂ O ₃ / ZrO ₂ : 1/99 to 5/95” specified in the present invention, In addition, since the stabilizer Y ₂ O ₃ is present in a small amount, cracks are generated, and in the comparative example of the composition No. 18 (Y ₂ O ₃ / ZrO ₂ : 6/94), the bending strength is 15 kgf / mm ² or less. It is too low to obtain the desired zirconia-based sintered body.

Even within the range of the R ₂ O ₃ / ZrO ₂ molar ratio specified in the present invention, compositions No. 19, No. 22 and No. _{2 in} which Al ₂ O ₃ and SiO ₂ were out of the predetermined ranges were used. Bending strength of 20 kg for .23 and No. 26
Since it is as low as f / mm ² or less, a desired zirconia-based sintered body cannot be obtained. Further, in the composition No. 30 (B ₂ O ₃ content: 15 mol%) in which the boron compound (B ₂ O ₃ ) is out of the predetermined range, not only the thermal stability is poor, but also the bending strength is 8.2 kgf / mm. It was extremely low at ² . The composition No. 27 did not contain B ₂ O ₃ , and therefore had high thermal strength and good thermal shock resistance although it had poor thermal stability.

Further, the molar ratio of the stabilizer (R ₂ O ₃ ) and ZrO ₂ is within the predetermined range of the present invention and within the predetermined range of Al ₂ O ₃ , SiO ₂ and boron compound (B ₂ O ₃ ). Even if the raw material composition adjusted to be used is used, the desired zirconia-based sintered body cannot be obtained under the firing conditions outside the range of 1400 to 1700 ° C. That is, 1350 ° C or 17 outside the range specified in the present invention.
In the comparative example fired at 50 ° C (see the composition No. 14 in Table 2), the bending strength was as low as 20 kgf / mm ² or less, and the thermal stability was poor, so that the desired zirconia-based sintered body was obtained. I couldn't.

[0043]

As described in detail above, the present invention comprises ZrO ₂ composed of baddelite as a main component, Al ₂ O ₃ and SiO ₂ (or
Al ₂ O ₃ , SiO ₂ and a boron compound) is a rare earth metal oxide-stabilized zirconia-based sintered body, having a composition defined by the present invention, and a crystal constituent phase also defined by the present invention,
Average crystal particle diameter, porosity, a zirconia-based sintered body that satisfies the grain boundary composition, this sintered body is not found in conventional zirconia-based sintered bodies, excellent thermal shock resistance and thermal stability,
A zirconia-based sintered body having high mechanical properties can be provided. In particular, it has excellent thermal shock resistance up to 1800 ° C. and has excellent thermal shock resistance, and since it can be provided at a low price, its industrial utility is extremely large.

Claims (6)

[Claims] 1. A main component is ZrO ₂ composed of badderite, and Nd ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Y ₂ O ₃ , Ho ₂ O ₃ and Er ₂ O _{3 are} contained.
And a zirconia-based sintered body containing one or more rare earth metal oxides selected from the group consisting of Yb ₂ O ₃ and Al ₂ O ₃ and SiO ₂ , wherein the rare earth metal oxide (R ₂ O ₃ ) and Zr
The molar ratio with O ₂ (R ₂ O ₃ / ZrO ₂ ) is 1/99 to 5/95, the content of Al ₂ O ₃ is 0.05 to 20 mol%, and the content of SiO ₂ is
A zirconia-based sintered body characterized by being 0.05 to 10 mol%. _{2. A} main component is ZrO ₂ composed of badderite, and Nd ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Y ₂ O ₃ , Ho ₂ O ₃ and Er ₂ O _{3 are} contained.
And a zirconia-based sintered body containing one or more rare earth metal oxides selected from the group consisting of Yb ₂ O ₃ , Al ₂ O ₃ and SiO _2, and a boron compound, the rare earth metal being The molar ratio of oxide (R ₂ O ₃ ) and ZrO ₂ (R ₂ O ₃ / ZrO ₂ ) is 1/99 to 5
/ 95 and the content of Al ₂ O ₃ is 0.05 to 20 mol%, S
The content of iO ₂ is 0.05 to 10 mol%, the content of boron component is 0.05 to 10 mol% in terms of boron (B), and further 15
A zirconia-based sintered body, which has a characteristic that deterioration of the sintered body does not easily occur even when used for a long time in the air or water and steam at a temperature of 0 to 300 ° C. 3. The boron compound is boron oxide, boron nitride, boron carbide, or Nd, Sm, Gd, Dy, Y, H.
The zirconia-based sintered body according to claim 2, which is a metal boride other than o, Er and Yb. 4. Crystal particles of the sintered body are mainly composed of a mixed phase of monoclinic and tetragonal or a mixed phase of monoclinic, tetragonal and cubic, and have an average crystal particle diameter of 5 μm or less and a porosity. Is 15
% Or less, The zirconia-based sintered body according to claim 1 or 2, wherein 5. The Al ₂ O ₃ and SiO ₂ , or the Al ₂ O ₃ ,
SiO ₂ and boron compound as the source Al and Si, or Al,
The zirconia-based sintered body according to claim 1, wherein Si and B are concentrated and deposited mainly at grain boundaries between ZrO ₂ particles. 6. A stabilizer containing Nd ₂ O ₃ , Sm ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ and Y ₂ as a main component and ZrO ₂ composed of badderite.
1 selected from the group consisting of O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Yb ₂ O ₃
Al ₂ O ₃ and SiO _{2 with one} or more rare earth metal oxides
Or a method for producing a zirconia-based sintered body containing Al ₂ O ₃ , SiO ₂ and a boron compound, (1) as a raw material composition, the rare earth metal oxide (R ₂ O ₃ ) and The molar ratio with ZrO ₂ (R ₂ O ₃ / ZrO ₂ ) is 1/99 to 5/95, and the Al ₂ O ₃ is 0.05 to 20.
Mol%, the SiO ₂ content is 0.05 to 10 mol%, and the boron compound is 0.05 to 10 mol% in terms of boron (B).
Step of adjusting the raw material blend by the oxide mixing method, (2)
Step of molding the above raw material mixture, (3) 1400 the above molded body
A method for producing a zirconia-based sintered body, comprising: a step of firing at ~ 1700 ° C.