JPS6051617A - Preparation of zirconium oxide powder containing yttrium in the state of solid solution - Google Patents

Abstract

PURPOSE:To obtain above-described powder having uniform composition without requiring mechanical crushing as required in conventional solid solution by forming solid solution of yttrium at low heating temp. by roasting semi- coprecipitate of hydrated ZrO2 with a basic salt of yttrium. CONSTITUTION:Powder of hydrated ZrO2 (for example, a material formed by adding NaOH to aq. soln. of zirconium oxychloride, aging formed gel-like product to adjust the particle size and recovering by filtration) is suspended in aq. soln. of mineral acid salt (e.g. hydrochloric acid salt) of yttrium. Alkali (e.g. NaOH) is added to the suspension to obtain semi-coprecipitate of hydrated zirconium oxide with basic salt of yttrium Y2(OH)6-mXm [where X is Cl, NO3, (SO4)0.5; 0.8<=m<=2], and the semi-coprecipitate is roasted. By this process, yttrium forms solid soln. at lower temp. than powder mixing method, and mechanical crushing after formation of solid soln. is unnecessary. Therefore, above- described powder having uniform compsn. is obtd. with a simple method inexpensively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new technology that can produce zirconium oxide powder containing yttrium as a solid solution by a simple method not previously available.

Zirconium oxide powder containing yttrium as a solid solution is used as a raw material for stabilized zirconia sintered bodies or partially stabilized zirconia sintered bodies. There are two known industrial methods for producing zirconium oxide powder containing yttrium as a solid solution: (1) powder mixing method and (2) coprecipitation method. The powder mixing method (2) is a method in which yttrium oxide powder and zirconium oxide powder are used as raw materials, each is mixed in a predetermined ratio, the mixed powder is heated to a high temperature, and yttrium oxide is dissolved in the zirconium oxide powder. Since it is a so-called reaction between solids, the reaction rate (-dissolution rate)
was largely influenced by the contact area between the two types of rice. Therefore, in order to increase the contact area, increase the reaction rate, and increase productivity, it is desired that the yttrium oxide powder and zirconium oxide powder used as raw materials have a particle size as fine as practical. . In addition, since uniformity is required for the composition of the product, the two types of raw material powders must be uniformly dispersed, and usually the two types of raw material powders are placed in a mill mill etc. at the same time and pulverized, dispersed, and mixed. After the above treatment, the general manufacturing method is to perform pressure molding if necessary to increase the degree of contact between the powders, and then heat to form a solid solution. However, even if the primary particle size of yttrium oxide powder and zirconium oxide powder produced on an industrial scale is small, the secondary or tertiary agglomerated particles that form the powder unit are large; The average particle size of the tertiary agglomerated particles is usually 0.1 to 1.0 μm even in yttrium oxide powder and zirconium oxide powder, which are said to be fine powders. Even if these fine-particle-sized yttrium oxide powders and zirconium oxide powders are used as raw materials and subjected to pulverization, dispersion, and mixing operations using an I-lumil, etc., each raw material powder becomes finer and the size of the secondary particles of each powder increases. Therefore, when producing zirconium oxide powder containing yttrium as a solid solution using the powder mixing method (2), the temperature required for the solid solution must be at least 1300°C. Moreover, the time required for solid solution is as long as 20 to 50 hours, and in order to completely achieve solid solution, a higher temperature and a longer time are required. It is still difficult to obtain a solid solution powder with a microscopically uniform composition even with this level of solid solution treatment, and since the solid solution treatment is performed at a high temperature, the obtained solid solution powder is different from solid solution. Sintering also occurs at the same time, which tends to result in strongly agglomerated lumps, and normally, the product after solid solution cannot be made into a useful raw material powder unless it is re-pulverized.

Co-precipitation method (2) was proposed to improve the drawbacks of the powder mixing method described above. In the coprecipitation method, an aqueous solution of a water-soluble yttrium salt, such as yttrium chloride or yttrium nitrate, and an aqueous solution of a water-soluble zirconium salt, such as zirconium oxychloride or zirconium nitrate, are mixed in a predetermined ratio. A common precipitant for yttrium and zirconium, such as aqueous ammonia, is added to the mixed solution to simultaneously precipitate zirconium hydroxide and yttrium hydroxide, resulting in uniform dispersion at the level of secondary particles or below. In this method, a mixed hydroxide is prepared, and the mixed hydroxide is roasted to form a mixed oxide, and at the same time, solid solution is performed.

In this method, zirconium atoms and yttrium atoms are already dispersed and mixed at the level of primary particles or lower at the stage of the mixture of zirconium hydroxide and yttrium hydroxide, which are precursors, so the above-mentioned This method is more ideal than other powder mixing methods. Therefore, the temperature required for solid solution is lower (1000℃) compared to the powder mixing method.
It is considered that δ is sufficient. However, the coprecipitated mixed hydroxide produced by the coprecipitation method has the disadvantage that the mixture composition changes sequentially during the coprecipitation operation, that is, the process of adding a coprecipitant. This is because yttrium and zirconium cannot be precipitated as hydroxides at the same time and at the same rate, and subtle changes such as the PH% temperature of the solution, the addition rate of the coprecipitant, and the stirring conditions of the reaction system are important. This is because the difference affects the precipitation rate of each component independently. For this reason, on an industrial scale, it is difficult to manage the tsuchi type coprecipitation operation. For this reason, the composition of the mixed hydroxide that was coprecipitated at the beginning and the composition of the mixed hydroxide that was coprecipitated early in the morning are often quite different, which is currently causing production problems. be.

In addition, because the coprecipitated mixed hydroxide obtained by the coprecipitation method has fine particles, it is difficult to separate the water, and it is necessary to use centrifuges, filter presses, etc. for a long time. This is one of the reasons for lowering the productivity of the method.

In addition, the above co-precipitated mixed hydroxide contains a large amount of water even after filtration, for example, 85 to 95 times the weight of the filtered product, and has the disadvantage that it requires a large amount of heat for drying. are doing.

Furthermore, the product obtained by drying the coprecipitated mixed hydroxide becomes a highly agglomerated lump, and the product after heating and solid solution becomes an extremely agglomerated lump. As with the method, a practical raw material powder could not be obtained without pulverization.

In order to prevent the above-mentioned agglomeration, a method has also been proposed in which the coprecipitated mixed hydroxide is washed with an organic solvent such as acetone or methanol to remove water, followed by drying and heating to form a solid solution. However, the operation is naturally complicated.

The present inventors have developed a new yttrium-containing zirconium oxide material that has a uniform composition, the heating temperature required for solid solution is lower than that of the above-mentioned powder mixing method, and does not require mechanical pulverization after solid solution. As a result of research into powder manufacturing methods, it was discovered that the above object could be achieved by using hydrated zirconium oxide as the zirconium source and a basic salt of yttrium as the yttrium source, leading to the present invention.

That is, the present invention provides a basic salt of hydrated zirconium oxide and yttrium Yz(OH)r, - which is obtained by suspending hydrated zirconium oxide powder in an aqueous solution of a mineral salt of yttrium and reacting it with an alkali. mXm (X: C1, N
This is a method for producing zirconium oxide powder containing yttrium as a solid solution by roasting a semi-coprecipitate with O3, (SO4)o, s% 0-8≦m≦2).

The details of Honkemei are described below.

The mineral acid salts of yttrium used in the present invention are yttrium hydrochloride, nitrate, and sulfate.

The hydrated zirconium oxide used in the present invention is also called zirconyl hydroxide or zirconium hydroxide, and its structure has not been sufficiently analyzed. The X-ray diffraction chart of the powder, as shown in Figure 1, shows a pattern of ready-to-use or fine-grained powder, and the infrared absorption spectrum shows a pattern of 3.
It does not show a sharp absorption peak characteristic of hydroxyl groups around 500 crn-', but shows a broad peak that is considered to be based on water of crystallization or water of hydration.

In addition, the method for producing water-use zirconium oxide used in the present invention usually involves adding an alkali, for example ammonia, hydric soda, etc. to an aqueous solution of zirconium oxychloride, zirconium nitrate, etc., and aging the resulting gel-like material. The method used is to adjust the particle shape and then collect it by filtration. The shape of the hydrated zirconium oxide thus obtained is as shown in FIG.

The type of alkali used in the present invention is not particularly limited, and examples include caustic soda, ammonia, and caustic potash. If the use of caustic soda or caustic potash causes Na, carbon, etc. to be mixed into the product, it is desirable to use ammonia.

The basic salt of yttrium used in the present invention has a composition of Y2(OH)6-mXm + nH20(X;C4!
, K)s , (804)0.5), and C1
,, NO3, is a hydroxide containing 804 in its structure,
The range of the value of m is 0.8≦m≦2, preferably 1.0≦m≦2, when X is NOs or CA, m is phantom 1, and when X is (SO4)O9S.

In the reaction between an aqueous solution of yttrium salt and an aqueous alkali solution, the type of product can be changed by changing the temperature, concentration, pH, etc., and the basic salt of yttrium used in the present invention can be selectively produced. For this purpose, the yttrium concentration is high, preferably 100mM/f1. Above, more preferably 200mM/I1. It is necessary to adjust the above, keep the pH during the reaction at 8.5 or below, and keep the reaction temperature at 80°C or below. If the yttrium concentration is low and the reaction pH is high, gel-like amorphous yttrium hydroxide is likely to be produced, and if the reaction temperature is high, crystalline yttrium hydroxide is likely to be produced.

It can be easily understood that the required amount of alkali is 31 emoles per mole of KXY as shown in the reaction formula.

The basic salt of yttrium produced by the above method is as shown in the X-ray diffraction charts of Figures 4(a) and (b) when X in the composition formula is (Jl, No3). It is a crystalline substance, and after washing the basic salt with water,
When dissolved in acid and analyzed for the components of the solution, ~0.5 moles of C1 and NO3 were present relative to 71 moles, there was no alkali component as a raw material, and the basic salt had the composition formula Y2 (OH)
scJ2 + nH2O, Yt(OH)5NO3・nH
It can be seen that it is expressed as 2O.

Also, if X in the composition formula is (804)0,1. In the case of , the basic salt is an amorphous substance as shown in the X-ray diffraction chart in Figure 5, and when the basic salt is dissolved in acid after washing with water and the components of the solution are analyzed, 71 5on per mole)
o and s are present in a range of 0.4 mol to 1 mol. This is thought to be because the structure of the basic salt of yttrium containing a sulfate group is amorphous, so a wide range of abundance ratios of the sulfate group can be obtained depending on the manufacturing method, but the details are not clear.

In addition, since there is no alkali component as a raw material, the basic salt has the composition formula Yz (OK)g-m (804)J
L・nHz.

It can be seen that it is expressed as (0, 8≦m≦2).

The decomposition of a basic salt of yttrium when heated is shown in Figure 6, for example, taking Yz(OH)5Cjl -3,5H,O, which was prepared by adding aqueous ammonia to an aqueous solution of yttrium hydrochloride. Weight loss during pyrolysis as shown/e
This is thought to indicate that the basic salt decomposes with dehydration and dehydrochlorination, eventually becoming yttrium oxide. That is, Yz(OH)scj2 ・3
．． 5H20 (17 in Figure 6) A) 3.5H20Y
z(OH)scn (I in Figure 6) B) 2H20
Yzo2(OH)Cjl! (+7 in Figure 6) C) M
CI! , Y2O3 (+7)D in Figure 6). Further, the infrared absorption spectra of the products in each decomposition process are as shown in FIG. 7, and changes in the hydroxyl absorption peak due to dehydration can be seen.

Furthermore, if we take y, (OH)s No3.HzO, which was prepared by adding aqueous ammonia to an aqueous solution of yttrium nitrate, the weight loss during thermal decomposition as shown in Figure 8.
Zotar? and decomposes with dehydration and denitrification in the same way as Yz(OH)s(4・3.5H>O). That is, Yz
(OH)sNOs HzO (in Figure 8) A) -4
, OYz (OH)s NOs (+7 in Figure 6) B
) -2H20Y2O2(OH)Cj! (C in Fig. 8) -HNOs Y2O3 (D in Fig. 8) shows the thermal decomposition behavior.

On the other hand, when Y2(OH)6-m(SO4)-, which has a sulfate group in its structure, loses weight during thermal decomposition, cIl,... As seen in basic salts that have NO3 in its structure, There is no clearly defined stable region of intermediate products, and the details of the thermal decomposition process are unknown, but
It is thought that yttrium oxysulfate exhibits biodegradable behavior at 1200°C.

When creating a basic salt of yttrium by adding an alkali aqueous solution to an aqueous solution of a mineral salt of yttrium, even if hydrated zirconium oxide is present in the mineral salt aqueous solution, the basic salt is It does not affect the conditions for selective preparation or the composition of the basic salt produced. The conditions for selectively creating the basic salt mentioned above, that is, adjusting the concentration of yttrium to be high, preferably 100mM/I1 or more, more preferably 200mM/I1 or more, and adjusting the pH during the reaction to 8.5 or less. If the reaction is carried out under the conditions that the reaction temperature is maintained at 80° C. or lower, a base salt will be produced even if the hydrated zirconium oxide powder is present in the mineral salt aqueous solution.

The sedimentation volume of the basic salt slurry is smaller when an alkali is added to the aqueous mineral salt solution in the presence of hydrated zirconium oxide than when no alkali is present; Since the sedimentation volume of the basic salt slurry does not change even when hydrated zirconium oxide powder is mixed, when hydrated zirconium oxide is suspended in an aqueous yttrium mineral salt solution, an alkali is added to it. Then, the basic salt is nucleated and nucleated from the water-containing zirconium oxide surface.
It is thought that the particles grow or are attached to the hydrated zirconium oxide powder immediately after generation, and are dragged by the hydrated zirconium oxide particles and settle.

The semi-coprecipitate of hydrated zirconium oxide and a basic salt of yttrium as used in the present invention refers to the semi-coprecipitate of hydrated zirconium oxide and a basic salt of yttrium, which is obtained by reacting an alkali with a yttrium mineral salt containing hydrated zirconium oxide as described above. A solid substance consisting of the basic salt of yztrium.

In carrying out the present invention, the amount of hydrated zirconium oxide to be suspended in the aqueous solution of yttrium mineral salt may be adjusted depending on the amount of yttrium to be dissolved in the hydrated zirconium oxide. That is, when applying the technology of the present invention as a raw material powder for partially stabilized zirconia sintered bodies, the amount of yttrium present in the mineral salt aqueous solution and the amount of suspended hydrated zirconium oxide are mixed with yttrium oxide. In terms of molar ratio of zirconium oxide, Y2O3/Zro2
- (1 to 7.5)/(99 to 92.5). Yes, Y
2O3/Zr02-(7,5~40)/(92,5
~60) t that has a certain ratio selected from the range
Just K.

In carrying out the present invention, the temperature at which a semi-coprecipitate of hydrated zirconium oxide and a basic salt of yttrium is roasted to dissolve yttrium in zirconium oxide is lower than that in the powder mixing method. Specifically, the temperature is 900 to 11.
A temperature of about 00°C is sufficient. Furthermore, although the roasting time depends on the roasting temperature, 1 hour is sufficient for roasting at 1100° C., which is extremely short compared to the powder mixing method.

A possible reason for this is that in the semicoprecipitate of the basic salt of hydrated zirconium oxide and yttrium used in the present invention, the basic salt of yttrium nucleates and grows from the surface of the hydrated zirconium oxide. Alternatively, by adhering to the surface of water-conserving zirconium oxide powder immediately after generation,
Since it exists in a form that encloses the water-conserving zirconium oxide powder, it is used in the conventional powder mixing method.
Compared to the contact area between aluminum and zirconium oxide powder,
It has an extremely large contact area and the rate of solid solution is extremely high.
It is thought to be a proboscis.

However, unlike the conventional powder mixing method and coprecipitation method, the zirconium oxide powder containing yttrium as a solid solution produced by the method of the present invention shows little agglomeration after the roasting for solid solution. It can be used as a raw material powder for molding materials without any pulverization operation.

In addition, the particle size distribution of the zirconium oxide powder containing yttrium as a solid solution obtained by the method of the present invention is almost the same as the particle size distribution of the zirconium oxide powder used as a raw material as shown in the examples, and it is suitable for the purpose of use of the present invention. The particle size distribution of the zirconium oxide powder used as the raw material may be selected accordingly.

In the present invention, the zirconium oxide powder containing IJium as a solid solution has an elemental composition of zirconium, oxygen, and yttrium, and the X-ray diffraction chart of the powder shows the following: This is a substance in which the independent diffraction peaks of yttrium oxide hardly appear.

Examples of the present invention will be described below.

Example 1 0.2 M/j each of yttrium chloride, yttrium nitrate, and yttrium sulfate! Hydrated zirconium oxide powder (average particle size 0.5μ+n, Ig.

1oss 64 wt%, GP zirconyl hydroxide manufactured by Kigenso Kagaku Kogyo Co., Ltd.) 4.6 M (1,56 Kf
) was added and stirred for 10 minutes to suspend.

While stirring each suspension, 1.6 fi of a 0.6 M/fi aqueous solution of sodium hydroxide was added dropwise over 3 hours. The pH of the reaction solution was 8.5 or less. Stirring was stopped after 20 minutes and the mixture was left to stand for 2 hours. Solid matter settled at the bottom of the container with the can liquid, and the top was clear liquid. The sedimentation volume of the solids at the bottom was ~0.5 L for both the tank liquid and the bottom.

Solid matter was separated from the above-mentioned canned liquid using a G-4 glass filter. A small amount of each of the obtained water-containing cakes was taken and subjected to X-ray diffraction.
The X-ray diffraction patterns shown in b) and (e) were observed, and the diffraction pattern of the basic salt of yttrium was observed along with the amorphous diffraction pattern of the raw material hydrated zirconium oxide. Also, after washing the cake with water, dissolve it in acid and use fluorescent X.
Y and Zr in each solution were determined by linear and ion chromatography methods.
, C4! When the concentrations of NO3 and SO4 were measured, the ratio of Y and Zr was calculated as Y2O3/Zr02== (0,080±0.
005 )/(0,92±o,oos)-r for those starting from yttrium chloride, yttrium nitrate, the ratio of C2 or NOx to Y is 0.5:1 and using yttrium sulfate. Regarding things, Y and (SO
4) The molar ratios of 0.5 were equal.

From these facts, each water-containing cake is a mixture of zirconium oxide and Yx (OH)s C1l ・nHzo, zirconium oxide and Y2 (OH)6 NO3 ・nHzO, zirconium oxide and Y2 (OH) SO4 ・nH2O, and the It was found that the mixing ratio was 92 molar ratio, which is the used composition, to 8 molar ratio.

Each of the above water-containing cakes was dried in a hot air dryer whose temperature was adjusted to 10 (Ic).

Each dry powder was divided into six equal parts and roasted under the following conditions.

B) 600℃ x 2 hours In) 900℃ When the composition ratio of Yz was measured by the fluorescence X <4 method, each
03 / Z r02 molar ratio (0,080
±o, ool)/(0,920±0.002).

Furthermore, when each roasted product was subjected to X-ray diffraction, no single peak of yttrium oxide, which was not solidly dissolved in the zirconium oxide, was observed, and it was found that yttrium was solidly dissolved in the zirconium oxide.

Example 2 o, sM/J of yttrium chloride! Aqueous solution with a concentration of 1.6
Add 4.6M (1,5
6Ky) was added and stirred for 10 minutes to suspend. While stirring this solution, add 1 ml of ammonia water at a concentration of 0.6 M/4.
．． 61 was added all at once. Stirring was stopped after 20 minutes, and solid matter was separated from the slurry using a G-4 glass filter. When the obtained water-containing cake was subjected to Xa diffraction, it showed the same X-ray diffraction pattern as in Example 1, and was found to be a mixture of the water-containing cake rl:Y2 (OH)s C1l .nHzo and hydrated zirconium oxide. .

After drying this water-containing cake in a hot air dryer at 100°C, it was roasted at 1100°C for lhr. Product X
Linear diffraction revealed a barbaric type of stabilized zirconium.
The peak of residual yttrium oxide was not observed.

Example 3 In a solution of 200rnM/Jl of yttrium rI4ate,
The same hydrated zirconium oxide powder used in Example 1 was
It was suspended to have the following composition.

(a) Yz Os / Z r 02 (molar ratio) =
3/9? (b) = l 6 / 84 (c) = 32/68) = 40/60 Without stirring these solutions, 6M/n@degree ammonia water was added dropwise at the same addition rate as in Example 1. Then, the obtained slurry was subjected to solid matter separation using a G4 glass filter,
After drying at 100°C, it was roasted at 1100°C for 1 hour.

The resulting products were powders with little agglomeration, each with an average particle size between 0.4 and 0.6 μm.

When X-ray diffraction was performed on each powder obtained, (a).

There was no undissolved yttrium oxide in both (b) and ri, and (a) had a tetragonal phase, and all had a cubic phase crystal structure. As an example, FIG. 11 shows an X-ray diffraction chart of a product prepared under the conditions (f).

Furthermore, in the case of (2), a single peak of yttrium oxide, which was not dissolved in solid solution, was observed. A certain amount of the roasted product of ) was taken, and a certain amount of bismuth oxide was added as an internal standard and mixed. This method involves making a diffraction chart and measuring the ratio of the height of the diffraction peak of the (222) plane of yttrium oxide to the height of the diffraction peak of the (121) plane of bismuth oxide. A rough measurement of the amount of undissolved yttrium oxide J
There was a wt person in charge.

Comparative Example 1 Yttrium oxide powder with a purity of 99.9 wt% and an average particle size of 0.5 μm and zirconium oxide powder with a purity of 99.6 wtf% and an average particle size of 1 μm were used, and the molar ratio was YzO.
They were measured and mixed so that s/Zr0z=4/96 and 8/92, and each was placed in a Lumil and dispersed and mixed for 24 hours to make a mixed powder.

Each mixed powder was roasted under the following conditions.

B) No roasting) 1100°C x 4 hours C) 1300°C x 21 2) # It was a thing.

Further, each roasted product was subjected to X-ray diffraction, and the degree of solid solution of yttrium was measured using the same internal standard method using bismuth oxide as in Example 3, and the results were as shown in Table 1.

Also, as an example, Y2O5/Z r (h = 8 / 92
The X-ray diffraction charts of the mixed powder treated under the conditions of (a) and (b) are shown in Figures 12-(a) and (b).

Table 1 As can be seen from the Examples and Comparative Examples, the method of the present invention:
The solid solution rate of yttrium is fast, and the product obtained after roasting for solid solution has little agglomeration, and almost maintains the particle size of the zirconium oxide powder used as a raw material.

Furthermore, as can be seen from Example 5, in the method of the present invention,
Y2 Q3/ yttrium oxide in zirconium oxide
This means that ZrO2 (mole ratio) can be dissolved in solid solution very easily up to about 30/70.

[Brief explanation of the drawing]

Figure 1 is an X-ray diffraction chart of the hydrated zirconium oxide powder, Figure 2 is the infrared absorption spectrum of the hydrated zirconium oxide powder, and Figure 3 is the SE of the hydrated zirconium oxide powder.
M observation photograph, Figure 4 (,) is the basic salt of yttrium Y
z (OR)lIClt-nH2O X-ray diffraction chart, Figure 4(b) is the basic salt of yttrium Y2 (OH
) X-ray diffraction chart of SNO3/nHto, Figure 5 is the basic salt of yttrium Yx (OH)6-m(SO4)
, Figure 6 shows the weight loss and turn during thermal decomposition of the basic salt of yttrium Y2 (OH) scjL ・3.5 HzO, and Figure 7 shows the A in Figure 6.
, B, C, D point product infrared absorption spectrum, Figure 8 shows the basic salt of yttrium Yz(OH)sNO3.H2O.
Figure 9 is an X-ray diffraction chart of the semi-co-precipitated hydrous cake of the basic salt of zirconium oxide and yttrium obtained in Example 1.
) is ZrO2Y2(OH), Cf1-nf (20, 9th
Figure (b) shows Zr02-Y2(OH)5NO3・nH2O
, FIG. 9(C) shows Zr02Y2(OH)804 ・n[
20, and FIG. 10(,) is an X-ray diffraction chart of the product roasted under the conditions (b) in Example 1, and FIG. 10(b) is the X-ray diffraction chart of the product roasted under the conditions (e) in Example 1. The X-ray diffraction chart of the roasted product, FIG. 11, is the X-ray diffraction chart of the zirconium oxide in which 3 mol of e-cent yttrium oxide was dissolved in solid solution prepared under the conditions (a) in Example 3, and FIG. 12 is the X-ray diffraction chart of the roasted product. is an X-ray diffraction pattern of Comparative Example 1 treated under conditions (b) and (b). Patent applicant Asahi Kasei Industries, Ltd. Figure 1 □ +0 20 30 40 50 e Figure 2 Height (cm”) Figure 3 Figure 4 (0) 1 Figure 4 (b) □ 10 4u (2e) 5 Figure (2e) Figure 6 Temperature (xlOOoC) Figure 7 1 3835 30 25 20 Old 16 14 12
10 8 6 42-1 Thickness & (xlOcm) Fig. 8 511L degrees (0C) Fig. 9 (Q) No. +0 20 30 2θ Fig. 9 (b) 10 20 30 Fig. 9 (C) IQ 20 30 40 2θ e Fig. 11 0 Fig. 12 (0) 27 29 31 33 35 Fig. 12 (b) 26 28 30 32 34 36

Claims (1)

[Claims] The basic sound Y2 (O
H) 6-yHXm (XsC1l, NOs,
(SO4) o, s. 0.8≦m≦2) A method for producing zirconium oxide powder containing yttrium as a solid solution, characterized by roasting a semicoprecipitate with yttrium (0.8≦m≦2)