JP2001097768A - Yag-based ceramic raw material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a YAG-based ceramic raw material from which a highly compacted YAG-based ceramic product can efficiently be produced. SOLUTION: This YAG-based ceramic raw material has the following characteristics. (1) The total content of Al2O3 and Y2O3 is >=99.6 wt.%. (2) The content ratio of Al2O3 and Y2O3 is respectively 37.4 to 47.4 wt.% and 62.6 to 52.6 wt.%. (3) The average primary particle diameter is 0.03 to 1.5 μm, and the average secondary particle diameter is 0.2 to 10 μm. (4) BET specific surface area is 0.5 to 20 m2/g. (5) The crystal phase substantially comprises YAG phase signal phase or YAG phase and at least one of YalO3 phase, Y4Al2O9 phase and Al2O3 phase. A method for producing the YAG-based ceramic raw material is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a YAG (yttrium aluminum garnet) ceramic material and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, many attempts have been made for YAG ceramics for various uses. For example, plasma-resistant materials for semiconductor manufacturing equipment, laser oscillators, photoluminescence phosphors, sapphire alternative window materials, high-frequency circuit boards, microwave dielectrics, biological implants, recording medium disks, single crystal materials, light transmission It is expected to be applied to a wide range of applications such as conductive materials, ceramic tubes for high-pressure sodium lamps, and bonding capillaries.

[0003] Among these uses, the main performance required for YAG ceramics is ionic impact resistance, corrosion resistance and thermal shock resistance. In particular, it is ideal for a plasma-resistant member for a semiconductor manufacturing apparatus to have all of these properties. In other words, if a YAG-based ceramic having all of these properties can be provided, it is possible to further expand the applications.

Conventionally, as a method for producing a YAG-based ceramic powder, for example, an aluminum hydroxide powder and a yttrium compound solution are mixed and neutralized to form a precipitate, and the obtained precipitate is calcined and pulverized. A method consisting of steps is known (JP-A-8-183613 and the like). According to this raw material, a YAG-based sintered body having excellent translucency can be obtained.

[0005]

However, a sintered body made of such a raw material is insufficient in any of ionic impact resistance, corrosion resistance and thermal shock resistance, and is used in applications where these properties are required. hard. In order to solve this problem, it is necessary to produce at least a dense sintered body, and a raw material suitable for it must be developed.

[0006] Accordingly, the present invention provides, in particular, a more precise YA
It is a main object to provide a YAG-based ceramic raw material capable of efficiently producing a G-based ceramic.

[0007]

Means for Solving the Problems The present inventor has conducted intensive studies to solve the problems of the prior art, and as a result, found that a raw material having a specific structure can achieve the above object.
The present invention has been completed.

That is, the present invention relates to the following YAG-based ceramic raw materials and a method for producing the same.

1. YAG ceramic raw material,
(1) total content of Al ₂ O ₃ and Y ₂ O ₃ is 99.6 wt% or more, (2) content ratio of Al ₂ O ₃ and Y ₂ O ₃ is from 37.4 to 47.4 wt % And 62.6 to 52.6% by weight, and (3) an average primary particle size of 0.03 to 1.5 μm.
m, average secondary particle size is 0.2 to 10 μm, and (4) BE
The T specific surface area is 0.5 to ²⁰ m ² / g, and (5) the crystal phase is a single phase of YAG phase or YAG phase and YAlO ₃ phase, Y ₄ Al
A raw material substantially composed of a mixed phase containing at least one of a ₂ O ₉ phase and an Al ₂ O ₃ phase.

[0010] 2. When the content ratio of Al ₂ O ₃ and Y ₂ O ₃ is 3
7.4-47.4% by weight and 62.6-52.6% by weight
The aluminum hydroxide powder and the aqueous solution containing the yttrium compound are mixed so as to obtain a mixture, and then the mixture is brought into contact with an alkali.
A method for producing a YAG-based ceramics raw material, wherein the method is sintering at ℃.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The YAG ceramic raw material of the present invention has the following features: (1) the total content of Al ₂ O ₃ and Y ₂ O ₃ is 99.
6 is a% by weight or more, ₍₂₎ Al 2 O ₃ and Y ₂ O ₃ containing ratio from 37.4 to 47.4 wt% and 62.6 to 52.
(3) average primary particle size of 0.03 to 1.
5 μm, average secondary particle size 0.2 to 10 μm, (4)
(5) a BET specific surface area of 0.5 to ²⁰ m ² / g;
Crystal phase is YAG single phase or YAG phase and YAlO ₃ phase, Y ₄
It is characterized by being substantially composed of a mixed phase containing at least one of an Al ₂ O ₉ phase and an Al ₂ O ₃ phase.

The total content of Al ₂ O ₃ and Y ₂ O ₃ (hereinafter also referred to as “purity”) is usually at least 99.6% by weight, preferably at least 99.8% by weight. Therefore, other components may be contained as long as the purity is within the above range.

The raw material of the present invention may contain, in addition to Al ₂ O ₃ and Y ₂ O ₃ , other components such as unavoidable impurities as long as the effects of the present invention are not impaired.

In particular, in the present invention, it is preferable to contain a certain amount of SiO ₂ . The content of SiO ₂ may be usually 3000 ppm by weight or less, particularly 100 to 3000 ppm by weight, and most preferably 300 to 2900 ppm by weight.
The presence of SiO ₂ in such a range can promote high density and the like, and can improve the plasma resistance of the sintered body.

The raw material of the present invention is SiO_TwoIs the predetermined amount (3
000 ppm by weight or less)
It does not need to be quantitatively included. The predetermined amount of S in the raw material
iO _TwoIf not included, prior to forming and sintering
T SiO_TwoAnd the like can be added.
The addition time of the silicon compound may be determined during the preparation of the raw material or during the preparation.
It may be any one after production. Silicon compounds that can be added
As, for example, SiO _TwoPowder, colloidal silica, etc.
Others, such as tetraethylorthosilicate (TEOS)
Like SiO_TwoAlso use a silicon compound that can supply
Can be.

The content ratio of Al ₂ O ₃ and Y ₂ O ₃ is usually 3
7.4-47.4% by weight (Al ₂ O ₃ ) and 62.6-5
2.6 wt% and (Y ₂ O _3), preferably 39.4 to 4
5.4 wt% and (Al ₂ O ₃₎ and from 60.6 to 54.6 wt% (Y ₂ O _3). Within this range, a dense sintered body can be obtained more reliably.

The average primary particle size of the raw material is usually from 0.03 to 1.
About 5 μm (preferably 0.03 to 0.3 μm), and the average secondary particle size is usually about 0.2 to 10 μm (preferably 0.1 to 0.3 μm).
2-3 μm). The BET specific surface area is usually 1 to
20m ² / g approximately (preferably, 5~20m ² / g) a. By adjusting the particle size and the like, a dense Y
An AG-based sintered body can be manufactured efficiently.

The method for preparing the raw material of the present invention is not particularly limited. For example, known powder synthesis methods such as a solution method (coprecipitation method), an oxide mixing method and a sol-gel method (liquid phase method, solid phase method, gas phase method) Act).

In the present invention, in particular, the content ratio of Al ₂ O ₃ and Y ₂ O ₃ is 37.4-47.4% by weight and 62.6-5%.
An aluminum hydroxide powder and an aqueous solution containing a yttrium compound were mixed at a concentration of 2.6% by weight, and then an alkali was added to the mixed solution.
A method of firing (calcining) at １1300 ° C. is preferred.

As the aluminum hydroxide powder, a powder obtained by a known production method or a commercially available product can be used as it is. The purity of aluminum hydroxide is not particularly limited,
Usually, it is preferably at least 99% by weight, particularly preferably at least 99.5% by weight.

The aluminum hydroxide preferably has an Na ₂ O impurity content of usually 7000 ppm by weight or less, especially 3000 ppm by weight or less. Na ₂
By using aluminum hydroxide having an O content of 7000 ppm by weight or less, a sintered body having more excellent plasma resistance can be obtained.

The average particle size of the aluminum hydroxide powder used in the present invention is not particularly limited, but is usually 0.5 to
It is preferably about 10 μm, particularly preferably 1 to 5 μm.
By using aluminum hydroxide having such a particle size range, a raw material can be more efficiently and reliably produced.

The yttrium compound is not particularly limited as long as it is water-soluble. For example, yttrium chloride,
Chloride such as yttrium iodide and yttrium bromide, inorganic acid salts such as yttrium nitrate and yttrium sulfate, and organic acid salts such as yttrium acetate can be used. The purity of the yttrium compound is not particularly limited, but is usually 98% by weight.
It is preferably at least 99.5% by weight.
The concentration of the aqueous solution may be appropriately set according to the type of the yttrium compound to be used and the like, but may be usually about 0.1 to 2 mol / l.

Next, aluminum hydroxide powder and an aqueous solution of an yttrium compound are mixed so as to have the above-mentioned composition (Y ₂ O ₃ / Al ₂ O ₃ ) of the ceramic of the present invention. At the time of mixing, for example, the aluminum hydroxide powder is mixed with an aqueous solution containing a yttrium compound, and then the mixture is usually stirred for about 20 to 60 minutes.

Next, an alkali is added to the obtained mixture. The alkali used here is not particularly limited as long as the mixture can be neutralized. For example, sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate,
Potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia, ammonium bicarbonate and the like can be mentioned. Particularly, in the present invention, it is preferable to use an ammonium salt or ammonia containing no metal component such as ammonium hydroxide and ammonium hydrogen carbonate.

The conditions for the addition of the alkali are not particularly limited as long as a predetermined precipitate is obtained.
At about 35 ° C, pH 6.5 to around 9 (preferably 7 to 8)
What should be done is as follows. By adding under such conditions, a raw material having particularly excellent sinterability can be obtained.

The precipitate formed is separated into solid and liquid by a known method such as a filter press, and if necessary, washed and filtered for 1 hour.
Perform one or more times. After that, the temperature is generally about 700 to 1300 ° C., preferably 950 to 1300 ° C. in the air or in an oxidizing atmosphere.
Baking (calcination) at 1250 ° C. The calcined body obtained is
If necessary, it may be pulverized by a known pulverizer such as a ball mill and a vibration mill.

The YAG-based sintered body can be obtained by subjecting the raw material of the present invention to molding, firing and the like according to known molding methods and firing methods. For example, a raw material may be formed, and the obtained formed body may be generally sintered at about 1500 to 1850 ° C.

The molded body may be formed by molding the raw material as it is, or by mixing additives such as a binder, a dispersant, and a sintering aid with a pot mill or the like, if necessary, using a known molding method (press molding method, press molding method). HIP method, CIP method, cast molding method,
Doctor blade method). For example, a compact can be obtained by mixing a binder or the like with the above-mentioned raw materials to form a slurry, spray-drying the slurry with a spray drier to obtain granules, and then molding the granules by the CIP method.

The obtained compact may be degreased if necessary, and then sintered at the above temperature. The molding and sintering may be performed simultaneously by a hot press method. The sintering atmosphere is not particularly limited, and may be, for example, any of air, oxygen, hydrogen, and vacuum. The sintering time may be appropriately set according to the sintering temperature and other conditions.

YAG-based sintered body obtained from the raw material of the present invention
Is preferably (1) Al_TwoO_ThreeAnd Y _TwoO_ThreeTotal content of
Is not less than 99.6% by weight, and (2) SiO_Two30
(3) Al_TwoO_ThreeAnd Y_TwoO_Three
Is 37.4-47.4% by weight and 62.6-
52.6% by weight, and (4) the porosity is 2% or less.
You.

The total content of Al ₂ O ₃ and Y ₂ O ₃ (hereinafter also referred to as “purity”) in the sintered body is usually at least 99.6% by weight, preferably at least 99.8% by weight. Therefore, other components may be contained as long as the purity is within the above range. Other components include unavoidable impurities and the like contained in the raw material, in addition to the above-mentioned SiO ₂ .

The content of SiO _{2 in} the sintered body is usually 3000 ppm by weight or less, preferably 100 to 300 ppm.
0 weight ppm, most preferably 300-2900 weight p
pm. If the SiO ₂ content exceeds 3000% by weight, a remarkable grain boundary phase is formed between the YAG particles constituting the sintered body, which may adversely affect corrosion resistance, ion impact resistance, and the like.

The above Al_TwoO_ThreeAnd Y_TwoO_ThreeContent ratio
37.4-47.4% by weight (Al _TwoO_Three) And 62.6.
~ 52.6% by weight (Y_TwoO_Three), Preferably 39.4
~ 45.4% by weight (Al_TwoO_Three) And 60.6-54.6.
% By weight (Y_TwoO_Three). If it is out of this range,
Not only cannot achieve excellent corrosion resistance and ion impact resistance.
In some cases, excellent thermal shock resistance cannot be obtained.

The porosity of the sintered body is usually 2% or less, preferably 1.5% or less. If the porosity exceeds 2%, desired corrosion resistance and ion impact resistance may not be obtained. Note that the upper limit may be set to be the theoretical density.

The average crystal grain size of the sintered body may be appropriately set according to the composition, the use of the final product, and the like.
Usually, it is preferably at least 5 μm, particularly preferably at least 10 μm. By controlling to such an average crystal grain size,
More excellent ion impact resistance can be imparted. Note that the upper limit of the average crystal grain size is not particularly limited, but may be generally about 40 μm.

The crystal phase of the sintered body is generally
Is the garnet mineral phase (YAG phase = Y _ThreeAl_FiveO₁₂Phase)
Single phase or YAG phase and YAlO_ThreePhase, Y_FourAl_TwoO₉Phase and A
l_TwoO_ThreeSubstantially from a mixed phase comprising at least one of the phases
Be composed. That is, in the present invention, only the YAG phase is used.
The intermediate phase generated during the formation of the YAG phase,
Corresponding phases may also be included. The proportion of these crystalline phases is
There is no particular limitation, and it is appropriately determined according to the use of the final product, etc.
Can be

[0038]

FIGS. 1 to 5 show the difference between the microstructure and the erosion pattern when the structure of the YAG-based sintered body is controlled and when the structure is not controlled.

First, in the case where impurities (especially SiO ₂ ) are not regulated by ceramics whose structure is not controlled (FIG. 1), an impurity phase mainly composed of SiO ₂ is formed at the grain boundaries between YAG particles constituting the sintered body. It is formed as an interphase (SiO ₂ -based grain boundary phase). SiO _{2 has} a ΔG (cast free energy) of about −190 kcal / mol and is a relatively stable oxide. However, ΔG when SiF ₄ is generated is also about −1.
90 kcal / mol, which is about the same as that of SiO ₂ ,
SiF ₄ is relatively easily generated even by direct reaction with fluorine gas, and SiF ₄ generation is promoted particularly in plasma.
SiF ₄ generated by this reaction is a gas component,
The SiO ₂ -based grain boundary phase precipitated at the grain boundaries of the sintered body is preferentially and violently attacked. At this time, since the fluoride film formed on the surface of the YAG-based sintered body is formed discontinuously (that is, formed by being divided at the grain boundary portion), it does not function sufficiently as a protective film. For this reason, the grain boundary portion of the YAG-based sintered body is significantly eroded, and the bonding force between the YAG particles near the reaction interface with the plasma is weakened. The etching rate becomes extremely high. Thus, the corrosion resistance and the ion impact resistance of the sintered body are reduced, and the semiconductor performance is also reduced due to dust generation.

FIG. 2 shows a wet synthetic powder having a poor sintering property, Y
It shows a microstructure and erosion pattern with many pores as in the case of producing an AG-based sintered body. In this case, significant corrosion starts from the remaining pores, and the protective film on the surface of the sintered body is separated from the pores. As a result, the erosion rate becomes extremely high as in the case shown in FIG. . In addition, since the remaining pores exist along the grain boundaries, even if a slight impurity phase is present, grain boundary corrosion occurs as a secondary effect, loosening the bonding of the microstructure, and thus particle generation due to the dropped YAG particles. Also cause problems.

On the other hand, the ceramics of the raw material of the present invention can exhibit excellent corrosion resistance, ion impact resistance, etc. by exhibiting at least one of the functions shown in FIGS. As shown in FIG. 3, in the ceramics of the raw material of the present invention, when the amount of SiO ₂ is regulated, a fine structure having a particularly high density and a small grain boundary phase can be obtained. In general,
Although it is difficult to increase the density of a high-purity YAG-based sintered body, the presence of a predetermined amount of SiO ₂ is very effective in further improving the sinterability of the raw materials used in the present invention. A predetermined amount of SiO ₂ is present as a liquid phase component at the grain boundary when the raw material is sintered, and promotes mass transfer or grain growth, which is important as a parameter for densification. In addition, Si which was present as a liquid phase at the grain boundaries of the YAG-based
Most of O ₂ forms a solid solution in the YAG particles at the final stage of sintering, and even if it precipitates as a grain boundary phase, only a part of the precipitation occurs. Therefore, due to the effect of SiO ₂ ,
As shown in FIG. 3, a YAG-based sintered body having few residual pores, relatively large particle size and uniform particle size can be obtained.
In a YAG-based sintered body having such a microstructure, there are few places where preferential corrosion occurs, so that the surface of the sintered body causes a uniform fluorination reaction, and uniform and continuous fluoride protection over the entire surface of the sintered body. A film is formed, whereby the progress of the fluorination reaction inside the sintered body is suppressed. By such a mechanism, the corrosion resistance, ion impact resistance, and the like of the YAG-based sintered body are dramatically improved.

FIG. 4 shows the composition of the YAG-based sintered body as Y
The histological diagram and the erosion pattern in the case of the AG-YAlO ₃ system (namely, Y ₂ O ₃ richer than the stoichiometric composition of YAG (Y ₃ Al ₅ O ₁₂ )) are shown. Especially from the stoichiometric composition Y ₂
When the composition is changed to the O ₃ side, YAlO ₃ (YAP, perovskite phase), which is a Y ₂ O ₃ rich phase, precipitates in the sintered body in spots in addition to YAG. Also, YAlO
₃ has a structure interspersed between YAG particles, that is, along the grain boundaries of the YAG-based sintered body. As described above, SiO ₂ is effective as a sintering aid for a YAG-based sintered body, but if its amount exceeds 3,000 ppm by weight, it will be extremely remarkable as a grain boundary phase. The YAG-based sintered body having such a microstructure is significantly affected by intergranular corrosion as shown in FIG. 1, and the corrosion resistance is rapidly reduced. However, since the interspersed YAlO ₃ phase has a larger amount of SiO ₂ dissolved in the crystal than YAG, it absorbs SiO ₂ (grain boundary part) added for finishing into a high-density YAG-based sintered body. And has the function of preventing or suppressing the precipitation of the impurity component as a grain boundary phase. For this reason, grain boundary erosion by the fluorine-based gas can be prevented by positively depositing YAlO ₃ in the YAG-based sintered body. YAlO
No. ₃ is effective for the precipitation of a local grain boundary phase accompanying the non-uniformity of SiO ₂ even in a region where SiO ₂ is 1500 ppm by weight or less. The corrosion resistance of YAlO ₃ containing a large amount of SiO ₂ as a solid solution in a YAG-based sintered body is pure YAlO ₃ , YA
Although it is considered to be inferior to G, unlike the case where it precipitates as a grain boundary phase, it exists only in a discontinuous (spot-like) manner, so that even if the erosion rate increases, the reaction rate of the entire sintered body is reduced. I can't rule. In an actual erosion test, the erosion rate of a YAG-based sintered body in which a relatively large amount of SiO ₂ was added and YAlO ₃ was precipitated was overwhelmingly higher than that of a YAG-based sintered body in which YAlO ₃ was not precipitated. It has been confirmed that it is small. However, YAlO ₃
Has a lower thermal conductivity than YAG, so the Y ₂ O ₃ content is lower than that of YAG.
If the stoichiometric composition is not set within the range of 5% by weight before and after, the sintered body may be thermally broken.

FIG. 5 shows the composition of the YAG-based sintered body as YAG-
Al ₂ O ₃ -based (ie, more A than the stoichiometric composition of YAG)
1 shows a histological diagram and an erosion pattern in the case of (L ₂ O ₃ rich). When the composition is changed from the stoichiometric composition to the Al ₂ O ₃ side, Al ₂ O ₃ other than YAG precipitates in the sintered body. As for the mode of precipitation, for example, precipitation occurs in YAG particles or in the form of a film in gaps between YAG particles. The Al ₂ O ₃ phase precipitated in the form of particles or a film has a higher solid solution amount of SiO _{2 in} the crystal than YAG, so
It has an effect of adsorbing SiO ₂ (grain boundary phase component) added for producing an AG-based sintered body and preventing or suppressing the precipitation of impurity components as a grain boundary phase. Therefore, intergranular corrosion due to the fluorine-based gas can be prevented by positively depositing Al ₂ O ₃ in the YAG-based sintered body. Al ₂ O containing a large amount of SiO ₂ in YAG-based sintered body
_Although the corrosion resistance of No. ₃ is considered to be inferior to that of pure Al ₂ O ₃ or YAG, even if the erosion rate of the above-mentioned portion increases, it does not control the reaction rate of the whole sintered body. Even in actual erosion tests, relatively large amounts of Si
It has been confirmed that the erosion rate of a YAG-based sintered body in which O ₂ is added and Al ₂ O ₃ is precipitated is overwhelmingly smaller than that of a YAG-based sintered body in which Al ₂ O ₃ is not precipitated. . Also, since the thermal conductivity of Al ₂ O ₃ is higher than that of YAG, it should increase with the addition amount.
When the amount of l ₂ O ₃ exceeds the predetermined range, the densification of the YAG-based sintered body is hindered, which leads to a decrease in the thermal conductivity.
l ₂ O ₃ causes a decrease in resistance to ion bombardment or thermal shock resistance due to enrichment.

[0044]

The raw material of the present invention is particularly excellent in its sinterability, and can provide a high-density YAG-based sintered body without performing high-pressure sintering, which is economically advantageous. Suitable for industrial scale production.

Since the YAG-based sintered body obtained from the raw material of the present invention is dense, it can be expected to be widely used for applications requiring plasma resistance, thermal shock resistance, corrosion resistance, and the like.

That is, since the YAG-based sintered body has a specific structure, excellent corrosion resistance and ion impact resistance can be achieved at the same time. At the same time, it has excellent thermal shock resistance and is not easily damaged by heat even if a sudden temperature change occurs. Therefore, such a sintered body can be suitably used as a material for plasma resistance (particularly for fluorine-based plasma etching). Therefore, it can be suitably used for each component such as an inner wall material and a transmission window material of a semiconductor manufacturing apparatus.

[0047]

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention. In each table, YAP is YAlO
₃ , A represents Al ₂ O ₃ .

Examples 1 to 10 and Comparative Examples 1 to 12 Raw materials were prepared, and the relative densities of the obtained sintered bodies were examined.

An aluminum hydroxide powder (average particle size: 3 μm) having a purity of 99.8% by weight was mixed with a 0.3 mol / liter yttrium nitrate aqueous solution. At this time, Y ₂ O ₃ : A
_They were mixed so that l ₂ O ₃ = 57.6: 42.4 (weight ratio). Next, ammonium bicarbonate was added to the mixed solution (30 ° C.) until the pH reached 7.2 to prepare a precipitate. This was filtered with a centrifugal dehydrator, washed three times with ion-exchanged water, and suction-filtered to take out a solid content. Next, the solid content was taken out, dried at 100 ° C. to remove adhering moisture, and calcined at the temperature shown in Table 1 to obtain a powder.
The calcined powder was pulverized in a vibration mill, and adjusted so that the average primary particles, average secondary particles, and BET specific surface area were within the ranges shown in Table 1, to obtain raw materials, respectively.

[0050] In each of the raw materials, the content of SiO ₂ was adjusted to 350 ppm by weight by adding colloidal silica.
As other impurity components, Na ₂ O = 0.04 wt%, K ₂ O = 0.02 wt%, and Fe ₂ O ₃ = 0.03 wt% except for Comparative Example 11. In Comparative Example 11, the purity was 98.0% by weight (the Na ₂ O content was 750%).
Raw materials were prepared in the same manner as in Example except that aluminum hydroxide powder (0 ppm by weight) was used.

Using each raw material at a pressure of 196 MPa, CI
P molded and tablet (diameter 30mm x height 10mm)
Was prepared. Then, the molded body is heated at 1600 ° C.
For 3 hours. The relative density of this sintered body was measured.
The results are shown in Tables 1 and 2.

[0052]

[Table 1]

[0053]

[Table 2]

The physical properties shown in Tables 1 and 2 were measured as follows. (1) The composition ratio of Y ₂ O ₃ and Al ₂ O _{3 in} the raw material was measured by X-ray fluorescence analysis. (2) Raw material purity is determined by plasma emission spectroscopy (ICP)
And by atomic absorption analysis. (3) The crystal phase in the raw material was confirmed by X-ray diffraction analysis. (4) The average primary particle size of the raw material was measured by X-ray diffraction analysis (particularly the half width of the diffraction peak) and a scanning electron microscope. The average secondary particle size of the raw material was measured by a centrifugal sedimentation method and a laser scattering method. (5) The specific surface area of the raw material was measured by the BET method.

As is clear from the results shown in Tables 1 and 2, according to the raw material of the present invention, a sintered body having a high relative density of 99% or more can be obtained.

Reference Example A raw material of the present invention was prepared, and a YAG-based sintered body was manufactured by controlling the composition, the content of SiO ₂ , the density, etc., and the plasma resistance and thermal shock resistance were examined.

Aluminum hydroxide powder (average particle size: 3 μm) having a purity of 99.8% by weight was mixed with a 0.3 mol / liter yttrium chloride aqueous solution. At this time, the components were mixed so as to have the compositions shown in Tables 3 to 5. Next, ammonia was added to the mixed solution (30 ° C.) until the pH reached 7.2 to prepare a precipitate. This is filtered with a centrifugal dehydrator,
The solid was washed three times with ion-exchanged water and filtered by suction to remove a solid content. Next, the solid content was taken out, dried at 100 ° C. to remove adhering moisture, and calcined at 1000 ° C. to obtain a powder. This calcined powder was prepared by adding a primary particle diameter of 0.08 μm, a secondary particle diameter of 0.7 μm and a BET specific surface area of 11.2 m ² /
The raw material was obtained by pulverizing in a vibration mill until the weight of the raw material became g.

An appropriate amount of colloidal silica (SiO ₂ ), a commercially available acrylic binder, a commercially available amine dispersant and a solvent (pure water) are added to the raw materials, mixed in a pot mill to form a slurry, and spray-dried with a spray drier. Thereby, granules of about 70 μm were obtained. Next, the obtained granules were molded into a disk shape (diameter 50 mm × height 15 mm) and CIP-molded at a pressure of 196 MPa. After calcining the molded body at 600 ° C.,
Sintered at 0 to 1700 ° C for 5 hours. Tables 3 to 5 show the characteristics of the obtained sintered body.

In the table, “Test 1” for plasma resistance is CF
₆ + O ₂ mixed gas atmosphere at 190 ° C and microwave output 65
The etching rate (unit: nm / h) when the sintered body is irradiated with plasma under the condition of 0 W is shown. "Test 2"
Indicates an etching rate (unit: nm / h) when the sintered body is irradiated with plasma at 200 ° C. and a microwave output of 700 W in an SF ₆ + Ar mixed gas atmosphere.

[0060]

[Table 3]

[0061]

[Table 4]

[0062]

[Table 5]

The physical properties of the sintered bodies in Tables 3 to 5 were measured as follows. (1) The composition ratio of Y ₂ O ₃ and Al ₂ O _{3 in} the sintered body
Measured by line analysis. (2) The purity of the sintered body was determined by plasma emission spectroscopy (IC
P) and plasma emission spectroscopy and mass spectrometry (ICP-MAS)
S). (3) The crystal phase of the sintered body was confirmed by X-ray diffraction analysis. (4) The presence or absence of SiO _{2 in} YAlO ₃ present in the sintered body was determined by scanning electron microscope / energy dispersive X-ray analysis (S
(EM-EDX) and scanning electron microscope / wavelength dispersive X-ray analysis (SEM-WDX). (5) The average crystal grain size was observed with a reflection microscope and a scanning electron microscope. The arithmetic average value of the 100 crystal grains arbitrarily selected is shown as the average crystal grain size. (6) The presence or absence of the grain boundary phase in the sintered body is determined by SEM-EDX, transmission electron microscope / energy dispersive X-ray analysis (TEM-
EDX) and secondary ion mass spectrometry (SIMS). (7) The porosity (density) of the sintered body was measured by the Archimedes method. (8) The thermal shock resistance of the sintered body was measured by repeating the thermal cycle test (cooling is air-cooled) 50 times between room temperature and 300 ° C. before and after the test. The thermal shock resistance was determined by the following equation using the bending strength (JIS R1601).

Thermal shock resistance% = (Bending strength after test / Bending strength before test) × 100 The above bending strength is obtained by excluding the minimum value and the maximum value from the data of n (number of data) = 20. It was determined using the average value of the data.

As is apparent from the results of Tables 1 to 3, Reference Examples 1 to 7 (YAG sintered bodies) and Reference Examples 8 to 11 (YAG-
YAP sintered body) and Reference Examples 12 to 16 (YAG-Al ₂
O ₃ sintered body) has a plasma erosion rate of 15 nm.
/ H or less, which indicates that the sintered body exhibits superior performance to other sintered bodies (Reference Examples 17 to 31). Further, the thermal shock resistances in these Reference Examples 1 to 16 all exceed 80%, and it can be seen that excellent effects are exhibited as plasma resistant materials.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a microstructure and an erosion pattern of a YAG-based ceramic when the structure is not controlled.

FIG. 2 is a schematic diagram showing a microstructure and an erosion pattern of a YAG-based ceramic when the structure is not controlled.

FIG. 3 is a schematic view showing a microstructure of a YAG-based ceramic when the structure is controlled.

FIG. 4 is a schematic diagram showing a microstructure of a YAG-based ceramic (mainly in the case of Y ₂ O ₃ rich) when the structure is controlled.

FIG. 5 is a schematic view showing a microstructure of a YAG ceramic (mainly Al ₂ O ₃ rich) when the structure is controlled.

Claims (4)

[Claims] 1. A YAG-based ceramic raw material,
(1) total content of Al ₂ O ₃ and Y ₂ O ₃ is 99.6 wt% or more, (2) content ratio of Al ₂ O ₃ and Y ₂ O ₃ is from 37.4 to 47.4 wt % And 62.6 to 52.6% by weight, and (3) an average primary particle size of 0.03 to 1.5 μm.
m, average secondary particle size is 0.2 to 10 μm, and (4) BE
The T specific surface area is 0.5 to ²⁰ m ² / g, and (5) the crystal phase is a single phase of YAG phase or YAG phase and YAlO ₃ phase, Y ₄ Al
A raw material substantially composed of a mixed phase containing at least one of a ₂ O ₉ phase and an Al ₂ O ₃ phase. 2. The YAG-based ceramic raw material according to claim 1, which contains 3000 ppm by weight or less of SiO ₂ . 3. A granulated product comprising the raw material according to claim 1 and an organic binder and having an average particle size of 20 to 100 μm. 4. The content ratio of Al ₂ O ₃ and Y ₂ O ₃ is 37.4.
４７47.4% by weight and 62.6-52.6% by weight of aluminum hydroxide powder and an aqueous solution containing a yttrium compound, and then the alkali was brought into contact with the mixed solution. A method for producing a YAG-based ceramics raw material, comprising firing the precipitate at 700 to 1300 ° C.