JPH07187774A - High-strength sintered zirconia material, its production, material for crushing part and ceramic die - Google Patents

Abstract

PURPOSE:To enable the supply of a sintered ZrO2 material having remarkably high strength at a low cost and to produce a material for a crushing part having high strength, toughness, abrasion resistance, heat stability and crushing efficiency and a ceramic die made of the material. CONSTITUTION:This sintered ZrO2 material is composed mainly of ZrO2 and contains one or more kinds of rare earth metal oxide (R1) selected from La2O3, Pr2O11/3, Nd2O3, Sm2O3 and Gd2O3, one or more kinds of rare earth metal oxide (R2) selected from Y203, Yb2O3, Ho2O3, Er2O3 and Dy2O3 and 0.05-2wt.% Of B2O3. The material can be produced by mixing these oxides at the above ratios, calcining the mixture at 500-1200 deg.C and sintering at 1300-1600 deg.C. The crushing part material and ceramic die is composed of sintered ZrO2 material having an R2O3(R1+R2)/ZrO2 ratio of 2/98 to 6/94, containing the crystal particles composed mainly of tetragonal crystal or a mixed phase of tetragonal crystal and cubic crystal and having an average crystal particle diameter of <=5mum and a bulk density of >=5.8g/cm<3>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare earth metal oxide-stabilized zirconia-based sintered body containing a boron compound having high mechanical strength and excellent thermal shock resistance and thermal stability, and a method for producing the same. The present invention relates to a crushing component material and a ceramic die using the zirconia-based sintered body.

[0002]

_2. Description of the Related Art Zirconia (ZrO ₂ ) is stable as a monoclinic crystal at room temperature, and when it is heated to about 1170 ° C.
A large volume contraction occurs before and after the transition to a tetragonal system, and then to a cubic system at about 2370 ° C. On the other hand, when the cubic zirconia is cooled, it is transformed into a tetragonal system, and subsequently with a large volume expansion at about 960 ° C., it is transformed into a monoclinic system stable at room temperature.

As described above, zirconia is accompanied by a large volume contraction or volume expansion when it undergoes a reversible phase transition, and it has a drawback that cracks are generated.

In order to solve this drawback, conventionally, alkaline earth metal oxides such as magnesia and calcia, or rare earth metal oxides such as ceria and yttria are generally added as a stabilizer, and the above-mentioned substances are added. It suppresses the phase transition of zirconia.

The zirconia-based sintered body containing such a stabilizer is called as stabilized zirconia or partially stabilized zirconia depending on the phase constituting the crystal, and ceramic scissors to which its toughness is applied. In addition, it is widely used as a component material for adiabatic engine parts that utilize the properties of heat insulation and thermal expansion, oxygen sensors that apply oxygen ion conductivity, and fuel cells.

In particular, among rare earth elements as a stabilizer, a zirconia-based sintered body using oxides of Y, Dy, Ho, Er and Yb is known to be a material having high mechanical strength characteristics. Has been. On the other hand, of the rare earth elements, L
Even if these oxides of a, Pr, Nd, Sm, and Gd are used alone as a stabilizer, Y, Dy, Ho, Er, Y
Unlike a zirconia-based sintered body stabilized with an oxide such as b, it does not become a material having high mechanical strength characteristics. Therefore, the oxides of La, Pr, Nd, Sm, and Gd are stable with respect to zirconia. It is known that the effect as an agent cannot be expected.

By the way, as an apparatus currently used for mixing and crushing ceramic materials, metal powders, food-related products, etc., raw materials to be a mixture or a crushed product in a cylindrical container rotating around a horizontal axis. And a crushing medium (media), and an unbalanced weight (unbalanced sag) is fixed to a ball mill or shaft configured to mix and crush raw materials mainly by impact compression action and grinding action caused by falling due to rotation of contents However, the centrifugal effect generated by the rotation of the unbalanced weight causes the entire spring to vibrate at high speed, and the vibration energy is transmitted to the medium in the crushing cylinder, so that it is pulverized in a short time by the simultaneous action of shock and friction. Vibrating mill with various structures, jet mill that simultaneously progresses volume grinding by impact force and surface grinding by friction force,
A device such as an attritor having a structure in which a medium is placed in a fixed cylindrical container and a stirring shaft equipped with a rod-shaped arm is used to forcibly stir the processed material and the medium is widely used. Conventionally, members requiring wear resistance such as lining materials and media of these devices are often metal, porcelain, alumina, glass, rubber, plastic, agate, etc., depending on the type of substance to be mixed or crushed. Has been used.

Further, as a die material used for extrusion of metal and resin or for wire drawing, tool steel, cemented carbide, stellite and the like have been conventionally used. Usually, the die is 700 to 800 for hot extrusion of metal (brass).
C., 150 to 240.degree. C. by the inflation method of resin film (polyethylene, polypropylene, soft polyvinyl chloride, etc.), 200 to 30 by the T-die method.
Although it is used at a temperature of about 0 ° C., the conventional die materials as described above have drawbacks such that they are easily abraded, cause welding, and impair the surface gloss of the product. Therefore, in recent years, attention has been paid to dies using ceramic materials. Among them, dies made of a zirconia-based sintered body have high mechanical strength, high fracture toughness, and excellent thermal shock resistance, and have become widely used. At present, a die using ZrO ₂ stabilized with MgO (Japanese Patent Laid-Open No. 55-1219).
70) or a die using ZrO ₂ stabilized with Y ₂ O ₃ (JP-A-60-215570), or
A die using ZrO ₂ stabilized with CeO ₂ (Japanese Patent Laid-Open No. 61-48483) is known.

[0009]

Since the price of the conventionally provided zirconia-based sintered body is relatively high, the characteristics of the zirconia-based sintered body have not been sufficiently reflected in the market. Is. This may be because the rare earth metal element added and used as a stabilizer in the zirconia-based sintered body is relatively expensive, but the raw material manufacturing method of the zirconia-based sintered body itself has a large factor. As a method for producing the raw material of the zirconia-based sintered body, a chemical synthesis method such as a neutralization coprecipitation method, a hydrolysis method, an alkoxide method is well known. Among them, the neutralization coprecipitation method is industrially often used. This is the method used. The neutralization coprecipitation method is a method in which a zirconium salt and a stabilizer are mixed and dissolved, and an alkali such as aqueous ammonia is added to obtain a hydroxide coprecipitation sol, which is then calcined to form a powder. is there. This sol-forming reaction complies with the following formula (1), but it may be a costly raw material because it may require a complicated operation.

[0010]

[Chemical 1]

However, the above-mentioned neutralization coprecipitation method has an advantage in that the degree of aggregation of the sol produced by adding the solution to ammonia water can be controlled.

On the other hand, an oxide mixing method is a relatively inexpensive manufacturing method. This is a method in which zirconium oxide and a stabilizer are mixed in a solvent, and a dry powder is calcined and crushed to obtain a powder. However, compared with the above-mentioned neutralization coprecipitation method, the particle shape of the raw material powder is There is a problem that it is large and difficult to sinter, and only a sintered body having a low strength can be obtained. Therefore, in order to obtain a high-strength zirconia-based sintered body, a raw material produced by a chemical synthesis method such as the above-mentioned neutralization coprecipitation method is widely used.

The conventional zirconia-based sintered body has 20
There was a defect that the strength was remarkably reduced when left at 0 to 300 ° C for a long time. 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 the monoclinic crystal of the stable phase, and the volume expansion accompanying the phase transition causes microcracks in the fired body. by.
As a means for solving such a phenomenon, JP-A-61-2
Japanese Patent No. 6562 discloses La, Pr, Nd or Pm and Zr.
A zirconia-based sintered body containing the above double oxide and Y ₂ O ₃ has been proposed. However, according to the embodiment of the publication, La ₂
It can be seen that the strength characteristics of the sintered body deteriorate as the amount of O ₃ added increases. Therefore, with such a method, it is difficult to obtain a zirconia-based sintered body having excellent mechanical strength and heat stability.

Further, the above-mentioned conventional materials for crushing parts are generally liable to be worn, and abrasion powder made of the material for crushing parts may be mixed in the raw material during mixing or crushing.
This is a big problem when it is used as a material whose purity affects the product or as a material for electronic ceramics. Also,
In terms of crushing efficiency, these materials are still insufficient. In order to solve this problem, a crushing part material made of a zirconia-based sintered body (Japanese Patent Publication No.
No. 87) has been proposed, but some problems still remain in terms of strength and wear resistance.

On the other hand, as a ceramic die using a zirconia-based sintered body, ZrO ₂ stabilized with MgO (hereinafter abbreviated as MgO-based ZrO ₂ ) was promptly offered to the market. However, due to the characteristics such as low mechanical strength and not high fracture toughness characteristics, ZrO ₂ stabilized with Y ₂ O ₃ which has been widely used as a structural material (hereinafter,
Abbreviated as Y ₂ O ₃ system ZrO ₂₎ is now used as a die material. However, Y ₂ O ₃ system ZrO ₂ is
It is a material that exhibits good properties in terms of mechanical strength, but exhibits a marked decrease in strength in the low temperature range as described above. This is a big problem as a die material for resin used at around 100 to 300 ° C. Further, in recent years, CeO ₂ which exhibits high fracture toughness characteristics
Stabilized by ZrO ₂ (hereinafter CeO ₂ system ZrO ₂
Abbreviated) came to the attention. But this Ce
Since a sintered body composed only of ZrO ₂ and CeO _{2 which} are main components of O ₂ -based ZrO ₂ has low properties such as mechanical strength, thermal shock resistance and thermal stability, various additives are added. It was necessary to improve the characteristics of. However,
The materials obtained by these methods have improved mechanical strength and thermal stability, but no effect on thermal shock resistance is observed, and rather, the high fracture toughness characteristic of CeO ₂ -based ZrO ₂ is lowered. I had let it go. in this way,
The conventional zirconia-based sintered body cannot be a material having sufficient mechanical strength as a ceramic die and excellent in thermal shock resistance and thermal stability.

The present invention solves the above-mentioned conventional problems and makes it possible to obtain a high-strength zirconia-based sintered body by using inexpensive oxide powder as a raw material, a method for producing the same, and a high-strength zirconia-based sintered body. And has excellent wear resistance and thermal stability,
Aiming to provide a crushing component material using a zirconia-based sintered body with good crushing efficiency and a ceramic die using a high-strength zirconia-based sintered body having excellent wear resistance, thermal shock resistance, and thermal stability. To do.

[0017]

The high-strength zirconia-based sintered body according to claim 1 contains ZrO ₂ as a main component, La ₂ O ₃ ,
Pr ₂ O _11/3 , Nd ₂ O ₃ , Sm ₂ O ₃ and Gd ₂ O ₃
One or more rare earth metal oxides selected from the group consisting of Y ₂ O ₃ , Yb ₂ O ₃ , Ho ₂ O ₃ and Er ₂
One or two selected from the group consisting of O ₃ and Dy ₂ O ₃
A zirconia-based sintered body containing at least one rare earth metal oxide and a boron compound, characterized in that the content of boron (B) is 0.05 to 8 mol%.

The high-strength zirconia-based sintered body according to claim 2 is
ZrO ₂ as a main component, La ₂ O ₃ , Pr ₂ O _11/3 , N
Y ₂ O and one or more rare earth metal oxides selected from the group consisting of d ₂ O ₃ , Sm ₂ O ₃ and Gd ₂ O _3.
3 , Yb ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Dy ₂ O ₃
One or more rare earth metal oxides selected from the group consisting of, boron compounds, Al ₂ O ₃ and / or S
A zirconia-based sintered body containing iO ₂ , wherein the content of boron (B) is 0.05 to 8 mol%, the content of Al ₂ O ₃ is 0.1 to 5 mol%, and the content of SiO ₂ is Amount is 0.05
˜1.5 mol%.

The high-strength zirconia-based sintered body according to claim 3 is
The zirconia-based sintered body according to claim 1 or 2, wherein La ₂
O ₃ , Pr ₂ O _11/3 , Nd ₂ O ₃ , Sm ₂ O ₃ and Gd
1 or 2 or more kinds of rare earth metal oxides (R1) selected from the group consisting of ₂ O ₃ , Y ₂ O ₃ , Yb ₂ O ₃ and Ho.
The molar ratio (R1 / R2) with one or more rare earth metal oxides (R2) selected from the group consisting of ₂ O ₃ , Er ₂ O ₃ and Dy ₂ O ₃ is 5/95 to 70/30. Is characterized in that.

The high-strength zirconia-based sintered body according to claim 4 is
The zirconia-based sintered body according to any one of claims 1 to 3, wherein the boron compound is boron oxide, boron nitride, boron carbide, or a boride of the other contained components shown in claims 1 and 2. .

The high-strength zirconia-based sintered body according to claim 5 is
The zirconia-based sintered body according to claim 1, wherein ZrO _{2 is used.}
And the rare earth metal oxide (R ₂ O ₃ ) in molar ratio (R ₂ O
₃ / ZrO ₂ ) is 2/98 to 6/96, and the crystal grains are mainly composed of a tetragonal phase or a mixed phase of tetragonal and cubic.

A method for producing the high-strength zirconia-based sintered body according to claim 6 is a method for producing the zirconia-based sintered body according to any one of claims 1 to 5, which comprises a chemical synthesis method (neutralization coprecipitation method, hydrolysis). Method, alkoxide method, etc.) or a method obtained by mixing oxide powders is calcined at 500 to 1200 ° C. and then sintered at 1300 to 1600 ° C.

The crushing component material according to claim 7 is a crushing component material formed by using the high-strength zirconia-based sintered body according to claim 5, wherein the average particle diameter of the sintered body is 5 μm or less. In addition, the bulk density is 5.8 g / cm ³ or more.

A ceramic die according to claim 8 is a ceramic die formed by using the high-strength zirconia-based sintered body according to claim 5, wherein the average crystal particle diameter of the sintered body is 5 μm or less and the pores are The rate is 0.3% or less, 20
It is characterized in that the sintered body is less likely to deteriorate even if it is used for a long time in the air or water and steam at a temperature of 0 to 300 ° C.

The present invention will be described in detail below.

In the zirconia-based sintered body of the present invention, Z
The rare earth metal oxide used as a stabilizer for rO ₂ is L
a ₂ O ₃ , Pr ₂ O _11/3 , Nd ₂ O ₃ , Sm ₂ O _3, and one or more rare earth metal oxides selected from the group consisting of Gd ₂ O ₃ (hereinafter abbreviated as “R1”). .) And Y
₂ O ₃ , Yb ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Dy
_It is one or more rare earth metal oxides (hereinafter abbreviated as “R2”) selected from the group consisting of ₂ O ₃ .

Of these rare earth metal oxides, R2
Has the effect of stabilizing ZrO ₂ , as described above, and makes it possible to obtain a good zirconia-based sintered body. On the other hand, as described above, R1 has no effect as a stabilizer even when used alone. However, the inventors of the present invention, by mixing R1 and R2 in a fixed ratio to form a stabilizer, have excellent characteristics as compared with the conventionally known zirconia-based sintered body stabilized with R2. It was found that it is possible to obtain a zirconia-based sintered body having This constant ratio is the ratio specified in the present invention,
The molar ratio of R1 and R2 (R1 / R2) is 5/95 to 70 /
Thirty. When the molar ratio is less than 5/95 and the amount of R1 is small, it is no different from the conventional zirconia-based sintered body stabilized by R2. Also, the molar ratio is 70
When R1 is more than / 30 and the number of R1 is large, the influence of R1 becomes large and it becomes difficult to stabilize ZrO ₂ . From this, when the molar ratio R1 / R2 of R1 and R2 is out of the range of 5/95 to 70/30, a zirconia-based sintered body having excellent properties aimed at by the present invention is obtained. May not be possible.

Further, in the present invention, these R1 and R
The total rare earth metal oxide (R ₂ O ₂ ) and ZrO ₂ molar ratio (R ₂ O ₃ / ZrO ₂ ) is 2/98 to 6/9.
4, particularly preferably within the range of 2/98 to 4/96. When the molar ratio of R ₂ O ₃ / ZrO ₂ is less than 2/98, it is difficult to stabilize ZrO ₂ , and
If it exceeds 6/94, a high-strength zirconia-based sintered body having sufficient mechanical strength cannot be obtained.

The zirconia-based sintered body of the present invention contains a compound consisting of boron in its raw material composition. This is for the following reason. That is, as a result of observing the bending strength and the surface structure of the sample which was subjected to the underwater test at 200 ° C. for 250 hours, the zirconia sintered body containing no boron compound showed a large decrease in strength, and many fine particles were observed on the surface of the sample. A crack was observed. However, on the other hand, the above phenomenon was not observed in the zirconia sintered body to which the boron compound was added, and the strength of the sample before the test was different depending on whether the boron compound was added or not. It was clearly recognized that the strength was improved. From these facts, it was proved that the boron compound is an additive capable of further increasing the strength of the zirconia-based sintered body and improving the thermal stability. That is, in the zirconia-based sintered body of the present invention, a high-strength zirconia-based sintered body cannot be obtained if the boron compound is not contained, and the content is 0.05 mol% even when the boron compound is contained. When the amount is less than the above, the effect of adding the boron compound is not observed.
Further, when the boron compound is added in an amount of more than 8 mol%, the strength tends to be rather lowered. From this, the amount of boron (B) added is 0.05 to 8 mol%, preferably 0.05 to 5 mol%.

In the zirconia-based sintered body of the present invention,
Furthermore, the addition of Al ₂ O ₃ and SiO ₂ facilitates the sintering of the sample and enables the sample to be fired at a low temperature. It is also possible to reduce the amount of boron added. Al ₂ O
_{When 3} and / or SiO ₂ is contained, the strength decreases when the content of Al ₂ O ₃ exceeds 5 mol%, and 0.1 mol%
If it is less than the above, the effect of adding Al ₂ O ₃ cannot be obtained. SiO
_If the content of ₂ exceeds 1.5 mol%, the strength is remarkably reduced, and if it is less than 0.05 mol%, the effect of adding SiO ₂ cannot be obtained. Therefore, Al ₂ O ₃ is 0.1 to 5 mol%, and SiO ₂ is 0.05 to 1.5 mol%. Similar effects can be obtained from these additives even if the additive components (Al, Si) are added in the form of nitride, carbide, hydroxide or the like in addition to the oxide. Further, boron may be added in addition to an oxide made of boron by a nitride, a carbide, or a compound made of Zr as a main component or Al as an additional component.

In order to produce a high-strength zirconia-based sintered body according to the method of the present invention, first, a chemical synthesis method such as an oxide mixing method or a neutralization coprecipitation method is used, and R ₂ O _{3 is} added to ZrO _2.
And a boron compound, and if necessary, Al ₂ O ₃ and / or
Alternatively, a raw material having the above-mentioned predetermined composition containing SiO ₂ is prepared. Next, the obtained raw material powder is calcined within a temperature range of 500 to 1200 ° C., and the calcined powder is crushed and then molded 13
Sintering is performed within a temperature range of 00 to 1600 ° C.

In the method of the present invention, calcination is for making the mixed raw material as uniform as possible and for promoting the sintering in the firing process by causing a part of ZrO ₂ to undergo phase transition. And is an important requirement in the manufacturing method of the present invention. Even under the calcination conditions here, the lower limit value is 500.
C is the lowest temperature at which part of the monoclinic ZrO ₂ crystal can be transformed into a tetragonal phase by calcination. Generally, Z
The transition of rO ₂ from monoclinic to tetragonal is said to be around 1170 ° C. However, by adding a stabilizer to ZrO ₂ , the temperature shifts to a low temperature, and for example Y ₂ O ₃ is stabilized. When used as an agent, a phase transition is observed at a temperature of about 800 ° C. This temperature varies depending on the type or amount of stabilizer. On the other hand, the upper limit of the calcination temperature is 120
0 ° C. is the maximum temperature at which the agglomerated powder found in the raw material after calcination can be sufficiently crushed in the crushing step. It remains and becomes a major breaking point, leading to a decrease in strength of the zirconia-based sintered body. Therefore, the calcination temperature is 500 to 12
Set to 00 ° C.

The sintering temperature for the main firing is 1300 ° C.
In the case of less than, the crystal grains of the sintered body become a mixed phase of monoclinic and tetragonal crystals, which cannot be mainly a tetragonal phase or a mixed phase of tetragonal and cubic crystals, and sufficient sintering should be performed. I can't. On the other hand, when the temperature exceeds 1600 ° C., a high-performance sintered body cannot be obtained due to an increase in the amount of tetragonal crystals and abnormal grain growth of crystal grains. The term "phase mainly composed of tetragonal crystals" as used herein means that tetragonal crystals occupy 95% or more of the crystal phase, and suggests that less than 5% of monoclinic crystals are contained. It is a thing.

The crushing component material of the present invention must have the above-described composition and manufacturing method, and have an average crystal grain size of 5 μm or less and a bulk density of 5.8 g / cm ³ or more. With a sintered body having an average particle diameter of more than 5 μm, good properties in terms of wear resistance and thermal stability cannot be obtained. Further, in the case of a sintered body having a bulk density of less than 5.8 g / cm ^3, there is a problem that the pulverization efficiency that appears when used as a medium becomes small and the strength characteristic becomes a low value.

The ceramic die of the present invention is obtained by the above-described composition and manufacturing method, has an average crystal grain size of 5 μm or less and a porosity of 0.3% or less,
When used for a long time in the air or water and water vapor at a temperature of 200 to 300 ° C., deterioration of the sintered body is unlikely to occur, and the ceramic die of the present invention does not meet such conditions. Cannot be. As described above, in a sintered body having an average particle diameter of more than 5 μm, good properties in terms of wear resistance and thermal stability cannot be obtained. Therefore, when used in the air or water and water vapor at a temperature of 200 to 300 ° C. for a long time, the sintered body is deteriorated. Further, those having a porosity of more than 0.3% cannot similarly improve the thermal stability. In addition, the surface precision required as a die material cannot be obtained, and problems such as welding with the material used may occur.

The content of the monoclinic crystal in the crystal phase of the sintered body was determined by grinding the surface of the sintered body with a # 600 diamond grindstone and then finishing it into a mirror surface with diamond grains of 1 to 5 μm. It was calculated from the intensity ratio by line diffraction using the following formula.

[0037]

[Equation 1]

Further, the average particle diameter is measured by etching the surface of the above-mentioned mirror-finished sintered body with hydrofluoric acid, and using an electron micrograph, a constant area S containing 50 or more particles. The diameter d of a circle equal to
It is calculated by (4S / π) ^1/2 . Then, d is obtained for three or more visual fields of the same sample, and the average value is taken as the average particle size. The number of particles n is 1 / the number of particles completely contained in the constant area S and the number of particles cut at the boundary line of the constant area.
2 and the sum of the values (for the measuring method, Japanese Patent Publication No. 61-21)
184).

In the present invention, in particular, the zirconia-based sintered body having a higher strength can be manufactured by manufacturing the zirconia-based sintered body by the pressure sintering treatment. For example, in the examples described later, those having a strength of 100 kgf / mm ² or more produced by firing after CIP molding can be made into a high-strength sintered body of 140 Kgf / mm ² or more by HIP treatment.

The crushing component material and the ceramic die of the present invention can also be manufactured according to the above-mentioned method.

[0041]

With the zirconia-based sintered body of the specific composition of the present invention, a high-strength zirconia-based sintered body can be obtained by using not only the chemical synthesis method but also a relatively inexpensive oxide mixing method. be able to.

An R ₂ O ₃ -stabilized zirconia-based sintered body containing the boron compound of the present invention and a sintering aid, that is, having the composition defined in the present invention, having a crystal constitution phase, an average crystal grain size, According to the crushing component material using the zirconia-based sintered body satisfying the bulk density, the crushing component material and the ceramic having high strength, excellent abrasion resistance and thermal stability, and excellent crushing efficiency, which have never existed before. Die material is provided.

The crushing component material of the present invention is particularly effective as a lining material, a medium or the like used in a crushing device for finely crushing particles of ceramics, metals, organic polymers or the like in a dry or wet manner. Further, the ceramic die of the present invention,
It is effective as a die material used for metal or resin extrusion or wire drawing.

[0044]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Example 1 Zirconium oxide (Z
rO ₂ ), R1 and R2 rare earth metal oxides (R ₂ O
_3), aluminum oxide (Al ₂ O _3), silicon dioxide (SiO _2), were weighed boron oxide (B ₂ O _3), with ion-exchanged water as a solvent, ZrO ₂ quality cobbles in the rubber lining ball mill After kneading using, it was dried.

Then, calcination is carried out at the temperatures shown in Tables 3 to 5 (however, in Tables 3 to 5, those with a calcination temperature of 0 ° C. are not calcined), and the obtained calcined powder is subjected to the above-mentioned treatment. The mixture was crushed by the same ball mill as at the time of kneading, 3% by weight of an acrylic copolymer resin was added, and spray granulation was performed. 1000 kgf / c of the obtained granulated powder
CIP molding was performed at a pressure of m ² and main firing was performed at the temperatures shown in Tables 3 to 5.

The main crystal phase of the obtained zirconia-based sintered body, the bending strength test method for fine ceramics (JIS
R1601) three-point bending strength, hot water resistance, Vickers hardness (JIS R1610), and fracture toughness value (JIS R1607) determined by the IF method are shown in Table 3 to.
5 shows.

The evaluation of the thermal stability was carried out as a hot water resistance test by setting the sample in hot water (200
(° C) and heat-treated for 250 hours, the state of the sample surface and the bending strength were measured, and it was judged whether there was deterioration (x) or not (◯).

In Tables 3 to 5, M is a monoclinic crystal and T is a monoclinic crystal.
Indicates a tetragonal crystal, and C indicates a cubic crystal.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

[0053]

[Table 4]

[0054]

[Table 5]

From the above results, the following is clear.

The zirconia-based sintered body of the present invention is different from
Contains rare earth metal oxides R1 and R2 selected from the group of types, and further contains a boron compound with a boron content of 0.05 to
8 mol% so that the boron compound is out of this addition range, or R1 and R
If 2 is not contained at the same time, the high-strength zirconia-based sintered body of the present invention cannot be obtained.

Further, even if the composition of the present invention is satisfied, if the calcination conditions and the main calcination conditions are outside the preferred range of the present invention, a zirconia-based sintered body having excellent properties is obtained. You may not get it.

Example 2 The respective raw materials were weighed so as to have the composition No. 7 and the composition No. 10 shown in Table 1, and then the raw materials were prepared by the method as shown in Example 1. Using the obtained raw material powder, 1
Molded into a ball shape with a diameter of 1/2 inch by CIP at a pressure of 000 kgf / cm ² , and the composition No. 7 is 150
The composition No. 10 was fired at 0 ° C. and 1600 ° C., respectively.

Table 6 shows the physical properties and characteristics of the obtained zirconia-based sintered body. The amount of wear was measured with a 2 liter alumina ball mill pot using a test ball (φ1
/ 2 ") 3.6 kg, 800 cc of water, and fused alumina powder (# 325) were put in, and the rotation speed was 100 rpm and 48
It was determined by rotating for a time and measuring the weight loss before and after the test.

Further, FIG. 1 shows a grinding ball (composition No. 7) using a zirconia-based sintered body obtained by the present invention,
Also, the pulverizing ability based on the particle size distribution of the fused alumina powder in the abrasion test conducted using the pulverizing balls (composition No. 10) using the zirconia-based sintered body obtained by the conventional technique is shown. In addition to showing the results, Table 6 shows the average particle size of the ground alumina powder.

[0061]

[Table 6]

As is clear from these results, the zirconia-based sintered body according to the present invention exhibits higher wear resistance than the zirconia-based sintered body of the conventional composition. Therefore, it is recognized that the pulverizing member using the zirconia-based sintered body described in the present invention has good pulverizing efficiency and excellent characteristics as shown in FIG.

Example 3 The respective raw materials were weighed so as to have the composition No. 7 and the composition No. 10 shown in Table 1, and the raw materials were prepared by the method as shown in Example 1. Using the obtained raw material powder, as the final processed shape after firing, outer diameter φ40 mm, inner diameter φ1
3.8 mm, 10 mm thick metal (copper) hot extrusion die and outer diameter φ25 mm, inner diameter φ7.6 mm, thickness 1
Molded by CIP so as to be a 0 mm resin die,
The composition No. 7 was fired at 1500 ° C, and the composition No. 10 was fired at 1600 ° C. After processing the obtained sintered body into the above-mentioned shape, a metal case made of SKD61 was attached to the metal die and SUS304 was attached to the resin die by shrinkage fitting to obtain each die.

Using these dies, for metal, as an extruded material, Cu: Zn: Pb = 60: 37: 3 (wt)
%) Was used, the billet temperature was set to 700 ° C., and the number of extrusions until the die cracked was measured. For resin, vinyl chloride was used as the extruding material, the resin temperature was set to 150 ° C., and the number of times of extrusion until the resin deposit (meyer) was attached to the die was measured.

Table 7 shows the measurement results.

[0066]

[Table 7]

The zirconia-based sintered body according to the present invention has higher flexural strength characteristics than the conventional zirconia-based sintered body having the composition, and exhibits excellent wear resistance and thermal stability. is there. Therefore, as is clear from the results in Table 7, when used as a ceramic die for metal and resin, it can be used for a long period of time, and it is recognized that it has excellent properties that have never been obtained.

[0068]

As described above in detail, according to the high-strength zirconia-based sintered body of the present invention and the method for producing the same, not only the production by the chemical synthesis method but also the oxide mixing method which is a relatively inexpensive production method. Even if is used, a high-strength zirconia-based sintered body which has never been obtained is provided.

Therefore, according to the present invention, various characteristics such as toughness, lubricity, heat insulation, thermal expansion characteristics, and oxygen ion conductivity are provided, and by utilizing each characteristic, a wide range of industrial fields can be applied. It is possible to provide a zirconia-based sintered body that is a desired zirconia-based sintered body having extremely high strength at low cost, and its industrial utility is extremely large.

Further, according to the crushing part material using the zirconia-based sintered body having the composition according to the present invention, high strength,
Provided is a crushing component material having high toughness, excellent wear resistance and thermal stability and high crushing efficiency. Such a crushing component material of the present invention is a dry or wet ceramics, metal,
It is industrially very useful as a material for crushing parts such as lining materials and media used in various crushing devices for finely crushing particles such as organic polymers.

Further, according to the ceramic die using the zirconia-based sintered body having the composition according to the present invention, there is provided a ceramic die having high strength, high toughness, excellent wear resistance and thermal stability and good surface properties. To be done. Such a ceramic die of the present invention has excellent properties as a die material used for extrusion of metal or resin, wire drawing and the like, and is industrially extremely useful.

[Brief description of drawings]

FIG. 1 is a graph showing the results of a wear test in Example 2.

Claims (8)

[Claims] 1. A main component of ZrO ₂ , La ₂ O ₃ , P
one or more rare earth metal oxides selected from the group consisting of r ₂ O _11/3 , Nd ₂ O ₃ , Sm ₂ O ₃ and Gd ₂ O ₃ , and Y ₂ O ₃ , Yb ₂ O ₃ , Ho ₂ O ₃ and Er ₂ O
A zirconia-based sintered body containing one or more rare earth metal oxides selected from the group consisting of ₃ and Dy ₂ O ₃ and a boron compound, and having a boron (B) content of 0.
The high-strength zirconia-based sintered body is characterized in that the content is 05 to 8 mol%. 2. ZrO ₂ as a main component, La ₂ O ₃ , P
one or more rare earth metal oxides selected from the group consisting of r ₂ O _11/3 , Nd ₂ O ₃ , Sm ₂ O ₃ and Gd ₂ O ₃ , and Y ₂ O ₃ , Yb ₂ O ₃ , Ho ₂ O ₃ and Er ₂ O
1 or 2 or more rare earth metal oxides selected from the group consisting of ₃ and Dy ₂ O ₃ , a boron compound, and Al ₂ O
A zirconia-based sintered body containing ₃ and / or SiO ₂ , wherein the content of boron (B) is 0.05 to 8 mol%, A
l ₂ content of O ₃ is 0.1-5 mol%, high strength zirconia sintered body in which the content of SiO ₂ is characterized in that 0.05 to 1.5 mol%. 3. La ₂ O ₃ , Pr ₂ O _11/3 , Nd ₂ O
One or more rare earth metal oxides (R1) selected from the group consisting of ₃ , Sm ₂ O ₃ and Gd ₂ O ₃ , and Y ₂
O ₃ , Yb ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ and Dy ₂
The molar ratio (R1 / R2) with one or more rare earth metal oxides (R2) selected from the group consisting of O ₃ is 5/9.
It is 5-70 / 30, It is characterized by the above-mentioned.
The high-strength zirconia-based sintered body according to 1. 4. The boron compound according to claim 1, wherein the boron compound is boron oxide, boron nitride, boron carbide, or a boride of the other contained components shown in claims 1 and 2. The high-strength zirconia-based sintered body according to item 1. 5. ZrO ₂ and a rare earth metal oxide (R ₂ O
₃ ) and the molar ratio (R ₂ O ₃ / ZrO ₂ ) is 2/98 to 6
/ 96, and the crystal grains mainly consist of a tetragonal phase or a mixed phase of tetragonal and cubic crystals. body. 6. A chemical synthesis method (neutralization coprecipitation method, hydrolysis method,
Alkoxide method or the like) or a method obtained by mixing oxide powders is calcined at 500 to 1200 ° C and then sintered at 1300 to 1600 ° C. 5. The method for producing a high-strength zirconia-based sintered body according to any one of 5 above. 7. A crushing part material constituted by using the zirconia-based sintered body according to claim 5, wherein the sintered body has an average particle diameter of 5 μm or less and a bulk density of 5.8 g. / C
A crushing part material using a high-strength zirconia-based sintered body characterized by having a size of m ³ or more. 8. A ceramic die formed by using the zirconia-based sintered body according to claim 5, wherein the sintered body has an average crystal grain diameter of 5 μm or less and a porosity of 0.
Uses a high-strength zirconia-based sintered body, which is 3% or less, and is resistant to deterioration of the sintered body even when used in the air or water and steam at a temperature of 200 to 300 ° C. for a long time. It was a ceramic die.