JPS60204667A - Thermal shock resistant ceramic sintered body and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to mullite (3A/203 ・2 S3.Op
) This article relates to a novel thermal shock-resistant ceramic sintered body that has improved strength, toughness, and thermal shock resistance as compared to porcelain, and a method for producing the same.

As is well known, mullite porcelain has Af+203 and 85-
It is synthesized using minerals containing 02 (such as kaolin), and this method allows the grains to grow large during firing, resulting in a sintered body with excellent strength and toughness.

In addition, since mullite porcelain has the characteristics of a low Young's modulus and a low coefficient of thermal expansion, it should have excellent thermal shock resistance (Theory I), but the anisotropy of the coefficient of thermal expansion of mullite itself is due to the large sintered body structure. It is known that due to the nature of the sintered material, large distortions tend to occur in the grain boundary phase, and the resulting grain boundary distortion causes the sintered body to break.

Therefore, an object of the present invention is to provide a novel thermal shock resistant ceramic sintered body that uses mullite porcelain as a matrix and has improved strength and toughness characteristics as well as thermal shock resistance Qp.

Another object of the present invention is to provide a method for producing a novel thermal shock-resistant ceramic sintered body using mullite porcelain as a matrix.

According to the present invention, there is provided a thermal shock resistant ceramic sintered body characterized in that a dispersed phase consisting of zirconia particles is formed using mullite as a matrix phase.

Furthermore, according to the present invention, the starting material is a mixture of zircon and alumina as main raw materials with a zirconia stabilizer added, the raw materials are mixed and molded into a desired shape, and the molded body is molded into a matrix of zircon and alumina. There is also provided a method for producing a thermal shock resistant ceramic sintered body, characterized in that the ceramic sintered body is sintered so as to form a dispersed phase composed of zirconia particles.

Mullite porcelain is an aggregate of mullite crystal grains with a stoichiometric ratio of 3A420g/25i09, and is mainly composed of silica (S'xf)++), with the mullite grains bound together by a lath grain boundary phase.

The thermal shock-resistant ceramic sintered body of the present invention is characterized by adding zirconia particles to mullite porcelain according to the manufacturing method described below, and this ceramic sintered body has higher strength, toughness, and heat resistance than conventional mullite porcelain. It was found that the M property was excellent.

Such improvement in properties is influenced by the particle size of the zirconia particles and the volume ratio of the dispersed phase made of the particles in the sintered body, but the inventor has repeatedly conducted experiments and found that , the average particle size of zirconia particles is 20μ
It is found that the strength, toughness properties, and thermal impact resistance of ITi' are significantly improved when it is less than m.

Further, in the present invention, it is desirable that the zirconia particles contain a partially stabilized zirconia sintered body, and for this purpose, a zirconia stabilizer (for example, +AgO, Ca,
0.0, group 111a element accumulated oxide) is preferably mixed in the zirconia grains P produced by sintering at a mixing ratio of 0.01 to 0.3 moles per mole of Zr0.1. According to this, it was found that the tetragonal ZrOe phase in the zirconia particles undergoes a phase transition to the single crystal ZrOz phase upon impact, and as a result, the toughness properties are significantly improved.

The manufacturing method of the present invention is that 2 ZrSiO4÷3AI
11103→2 ZrO2+ 3Δep03-25iO
It is characterized by producing a thermal shock-resistant ceramic sintered body by causing the reaction z.

That is, Schiff 1/:17 (Zr5iO4) and aluminum-1-(A(lpo3)) are used as the main raw materials, and at least a known zirconia stabilizer (for example, MgO, Cao, Group A element oxide) is added thereto. The starting materials were mixed uniformly and press-molded into the desired shape, and at the same time as this molded body was fired, the above reaction occurred, forming a dispersed phase consisting of zirconia particles with mullite as the matrix. Creating a heat-resistant rttI shock-resistant ceramic sintered body,
.

Sarakiko According to the production method of the present invention, a zirconia stabilizer is blended into the starting materials so that the zirconia particles contain partially stabilized zirconia sintered bodies during this reaction sintering. be. Therefore, the Zr02 particles grow while the zirconia stabilizer is mixed with the Zr0p generated by the reaction, and the inventor confirmed through experiment that
The zirconia stabilizer is Zr in the Zr (, 12 particles)
(It has been found that zirconia particles containing partially stabilized zirconia sintered bodies are formed when it is added at a mixing ratio of 0.01 to 0.03 moles to 1+1 mole,
It has been found that the thermal shock resistant ceramic sintered body having a dispersed phase composed of such particles has the most remarkable improvement in toughness. .

According to the present invention, the average particle size of the starting materials for zircon, alumina, and zirconia stabilizers is preferably set to 5 μm or less, preferably 1 Bm or less, and if it exceeds 511 m, the zirconia in the sintered body The average particle size of the particles tends to exceed 20 μm, and no significant improvement in strength, toughness, and thermal shock resistance is observed.

In addition, it is important to set the blending molar ratio of zircon and alumina in the starting materials in the range of L2:1 to 1:2; if it deviates from this range, the above reaction will not proceed sufficiently, and unreacted A710a remains and the thermal shock resistant ceramic sintered body of the present invention cannot be obtained.

Furthermore, in the manufacturing method of the present invention, either pressure sintering or non-pressure sintering may be used; if pressure sintering is used, a fine-grained and dense sintered body 2: is formed, so the strength and toughness properties are further improved. do. Further, it is desirable to set the firing temperature in the range of 1500 to 1650°C. If the temperature is a certain amount of 150V, the firing time will be more than 20 hours, and the above reaction will not proceed sufficiently in such a sintered body. First, the thermal shock-resistant ceramic sintered body of the present invention cannot be obtained. On the other hand, if the temperature exceeds 1,650°C, the grain growth of mullite and zirconia increases significantly, and the remarkable effect of the present invention is not found.

Thus, according to the present invention, a novel ceramic sintered body is obtained in which zircon, alumina, and a zirconia stabilizer are used as starting materials, and a reaction is caused simultaneously with firing to form a dispersed phase consisting of zirconia particles with mullite as a matrix. It will be done. This sintered body has excellent strength and toughness characteristics, and provides a thermal shock resistant ceramic sintered body that greatly improves the thermal shock resistance originally possessed by mullite porcelain. .

Next, examples of the present invention will be described.

〔Example〕

As shown in Table 1, Zircoef 1. %l constant j111 was added and this was used as the starting material 1. This raw material was thoroughly mixed so that it was homogeneous,
After press forming, 1 was pressure-free sintered under the 1° C. forming conditions shown in Table 1, except for sample No. 17, which was hot pressed. .

Thus, regarding the sintered body 111), the dispersion of the light matrix and the zirconia particles was confirmed by X-ray diffraction, and it was found that reactive sintering had been performed.

When the average particle size, strength, Mv properties and 1llit heat attack property of the zirconia particles were tested, the results shown in Table 1 were obtained. .

Measurement of strength is J+, 81/6 ('11 3 points! 110y
In the test piece method, the toughness is measured using S, E, N, R (Sing soil e m
idgeNOt;chedBea,m) method, the thermal shock resistance is measured by dipping the sample heated to a predetermined temperature in water (20
As is clear from Table 1, sample numbers 1 to 7 and sample numbers 14 to 17 of the present invention have high strength and Understand the toughness properties and have a heat impact resistance of 300 to 40.
Sample No. 1, which has a significantly dull value of 0'C, and Sample No. 17 have excellent strength because hot pressing is used. It should be noted that in all Examples falling within the scope of the present invention, it was confirmed that the zirconia particles contained partially stabilized zirconia sintered bodies. is a value of 200 to 250° C. according to the same measuring method as in this example.

However, according to Table 1, sample number 8 has no zirconia stabilizer added, sample number 9 has a low zircon content, sample number 10 has a low alumina content, and sample number 511 has a high firing temperature. , sample number 12 with a large amount of intria added and sample number 13 with a small amount of ittria added.
Since all of these samples are outside the scope of the present invention, no improvement in strength, toughness properties, or thermal shock resistance was observed.In particular, sample number 11 showed the most deteriorated strength, and sample number 8 showed the most deterioration in toughness. Ta. Note that in all of these samples outside the scope of the present invention, the partially stabilized zirconia sintered body was not included in the zirconia particles.

Further, the present inventor confirmed through experiments that 0.3 mol of a second mixed powder consisting of magnesia (MgO) and alumina was added to the first mixed powder in which the molar ratio of zircon and alumina was 40% and 60%, respectively. % and sintered without pressure at a firing temperature of 1500°C for 2 hours using this starting material.
When the particles were analyzed, the presence of zirconia and mullite was confirmed, but alumina and glass phases were also significantly present, and no partially stabilized zirconia sintered bodies were observed in the zirconia particles.

Therefore, the present inventor found that even if the M/JO zirconia stabilizer was used in the same way as in Sample No. 15,
As is clear from 3, it was found that the partially stabilized zirconia sintered body could not be produced depending on various factors such as the type of zirconia stabilizer, its additive amount, and firing conditions.

As shown in the above examples, the ceramic sintered body formed from the mullite +-+' phase and the zirconia particle dispersed phase produced by the manufacturing method of the present invention not only has excellent strength and toughness properties, but also has superior strength and toughness. It was found that the inherent thermal shock resistance was significantly improved.

Furthermore, the thermal shock ceramic sintered body of the present invention (1) contains partially stabilized zirconia sintered bodies in the zirconia particles, and therefore has excellent toughness characteristics. .

Patent No. 1 Kyocera Co., Ltd. Before procedural amendment (voluntary) Yuzuki 1, 1980 Mr. Kazuo Wakasugi, Commissioner of the Brass Patent Office■, Small case indication 1988 Patent Application No. 62 SO Ushi No. 2,
Name of the invention Thermal shock-resistant ceramic sintered body and its manufacturing method 3, Relationship with the case of the person making the amendment Patent applicant address 224, 5-5 Higashino Kitainoue-cho, Yamashina-ku, Kyoto City Date of amendment order Spontaneous 5, subject of amendment -・ , ' +1 6. Contents of the amendment (1) "Single crystal ZrO2 phase" in the first line of page 6 of the specification is read as "monoclinic Zro 2 phase" ii, iF.

. that's all

Claims (9)

[Claims] (1) A thermal shock-resistant ceramic sintered body characterized in that a dispersed phase consisting of zirconia (ZrO2) particles is formed using mullite (3A#p03.25iO2) as a parent phase. (2) The heat-resistant cross-shaped ceramic sintered body according to claim 1, wherein the average particle diameter of the zirconia particles is 20 μm or less. (3) The thermal shock resistant ceramic sintered body according to claim 1, wherein the zirconia particles include a partially stabilized zirconia sintered body. (4) A 1m starting material is prepared by adding a zirconia stabilizer to the main raw materials zircon (ZrOg・5102) and A/L/Mif (AIHI03), and the raw materials are mixed and molded into the desired shape. The molded body is made of mullite (3Al0a・
2Sj-0+) as the matrix, and zirconia (Zr
1. A method for producing a +1itt heat-attackable ceramic sintered body, characterized in that the sintering is performed so that a dispersed phase consisting of O+) particles is formed. (5) Thermal shock-resistant ceramic sintered according to claim 4, characterized in that the molar ratio of zircon and alumina in the starting materials is set in the range of 1.2:1 to 1:2. How the body is made. (6) The zirconia stabilizer has MR:O, Ca, 0
5. The method for producing a thermal shock-resistant ceramic sintered body according to claim 4, characterized in that the ceramic sintered body is made of at least one type of oxide of a group ff1a element. (7) The zirconia stabilizer is added to the starting material so that the zirconia particles or partially stabilized zirconia sintered body produced by sintering are included. 1. Manufacturing method of thermal shock-resistant ceramic sintered body. (8) The sintering temperature is 1500 to 1.650'C.
Claim 4 is characterized in that it is set within the scope of
A method for producing a thermal shock-resistant ceramic sintered body as described in . (9) The average particle size of the zirconia particles is 2o11 mJ)
J, F, the method for producing a thermal shock resistant ceramic sintered body according to claim 4. α1 1# heat W'J according to claim 4, characterized in that the average particle diameter of the starting material is 5 μm or less
3' Manufacturing method of W ceramic sintered body 4.