JPS61127624A - Production of perovskite type oxide solid - Google Patents

Abstract

PURPOSE:To produce easily the composite perovskite type oxide solid solution less in impurities by using the raw material wherein the coprecipitated material of both a soln. contg. Zr, Ti and a precipitant is calcined in the specified temp. CONSTITUTION:The raw material of perovskite type oxide solid solution is made to the power of >=2m<2>/g specific surface area wherein the coprecipitated material of both a soln. contg. Zr, Ti and a precipitant is calcined at 400-1,200 deg.C. The mixed powder of raw material is made by mixing the above- mentioned powder with two or more kinds of powder of metal or metallic compd. selected among Pb, Mg, Nb, Mn, Y, Co, W, Ba, Sr and Ca. The perovskite type oxide solid solution is produced by calcining the mixed powder of raw material at 700-1,100 deg.C.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a raw material for producing a perovskite-type oxide solid solution containing zirconium, titanium, and at least two other metals as components, and a perovskite using the raw material. The present invention relates to a method for producing a type oxide solid solution.

A perovskite-type oxide solid solution containing zirconium, titanium, and at least two other metals as components (hereinafter referred to as composite perovskite oxide), for example,
(Ba-8r) (Zr-T4)Os, Pb['
, (“i3A NbX ) (Zr・Tt ) )
On etc. are all Pb, ferroelectric, piezoelectric 1. Since it has excellent electrical properties such as pyroelectricity, it has the advantage of being able to produce high-performance electroceramics.

[Conventional technology]

Conventionally, composite perovskite oxides are composed of zirconium oxide, titanium oxide, and Pb, My, Mn, Sr.
Although it is manufactured by mixing and firing compounds such as oxides and carbonates of zirconium and titanium, it is produced by a single oxide phase of zirconium or titanium or a solid solution with other components, such as Pbn03.

Since PbZrOs and the like are produced as intermediates, it is difficult to obtain a uniform, single-phase composite perovskite oxide.

For this reason, it is generally manufactured by repeating the crushing and firing process many times, which poses problems such as production efficiency and contamination of impurities during crushing.

[Problem that the invention seeks to solve]

As a result of various studies to solve this problem, the inventor of the present invention fired a coprecipitate of a bath liquid containing zirconium and titanium and a precipitant to the conventional raw materials of zirconium oxide and titanium oxide. Specific surface area 2 obtained by
．． Orr? The present invention was completed by discovering that it is sufficient to use a powder having a particle size of /9 or more.

[Means for solving problems]

That is, in the present invention, a coprecipitate of a solution containing zirconium and titanium and a precipitant is fired at a temperature of 400°C to 1.200°C, and the surface area of the resulting product is 2. A raw material for producing a composite perovskite oxide characterized by comprising a powder of 0-/1 or more, and a preferable method for producing a composite perovskite oxide using this powder, include the powder and Pb, A4,
Nb.

Mn, Y, Co, W, Ba, Sr and C
& A mixed raw material powder containing zirconium, titanium, and at least two other metals as components by mixing with a powder of a metal selected from or a compound of the metal,
This is a method for producing a composite perovskite oxide, which is characterized by firing the composite perovskite oxide.

The present invention will be explained in more detail below.

As the solution containing zirconium and titanium used in the present invention, an acidic aqueous solution or an alcoholic solution containing these metals as components is preferable from the viewpoint of the mixed state of the coprecipitate, reaction activity, etc. The type of acid in the acidic aqueous solution is not particularly limited and may include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, etc., and an alkoxide solution is suitable as the alcohol solution. The concentration of the solution and the ratio of zirconium to titanium can be changed freely.

There are no particular restrictions on the type of precipitant; if the solution is an acidic aqueous solution, an alkaline substance such as ammonia or sodium hydroxide or an aqueous solution thereof is suitable; if the solution is an alcoholic solution, water, an alcoholic aqueous solution, etc. are suitable. used for.

The coprecipitation method may be either a method of adding the other to either a solution containing zirconium and titanium and a precipitant, or a method of continuously supplying a predetermined amount of both to a coprecipitation tank. The latter has the advantage that it is easy to control the coprecipitation conditions at a constant level and that a highly concentrated solution can be used. As the coprecipitation tank, in order to quickly and uniformly mix both liquids, a spray type, a stirring type, a type that allows the liquid to pass through a porous plate with a wide area, etc. are adopted.

After separating the obtained coprecipitate from the liquid, it was heated at 400°C to 1.20°C.
By firing at a temperature of 0°C to form a powder with a specific surface area of 2.0 d/f, it becomes the raw material of the first invention. A filtration operation is usually employed to separate the coprecipitate from the liquid. After filtration, it is desirable to wash thoroughly with distilled water or diluted ammonia water, and in particular washing with ethanol will prevent the primary particles from agglomerating even after calcination. Raw materials with improved reaction activity can be produced without the need for further treatment.

In the present invention, the method of drying the coprecipitate is important, and the cake-like material obtained by filtration and washing is dried by spray drying, vibration fluidized drying, etc. Grind with a mill etc. If a cake-like product is dried and calcined as it is, it is difficult to obtain a fine powder, so it is pulverized using a ball mill, jet air mill, etc. In any case, it is important to prepare a fine powder with good dispersibility and a narrow particle size distribution.

In the present invention, the firing temperature is 400°C to 1,200°C,
The specific surface area is 2. Otr? The reason for limiting the value to /f or more is as follows.

If the firing temperature is lower than 400° C., the liquid in the co-washed material cannot be removed with good reproducibility, making it difficult to produce a composite perovskite oxide having a predetermined composition. Furthermore, there is no merit in raising the temperature above 1,200°C; rather, agglomeration or sintering of secondary particles occurs, the specific surface area decreases, the formation of aggregates, an increase in particle size, and a broadening of particle size distribution. etc. to reduce the reaction activity. A suitable firing temperature considering the energy aspect is 500℃~1.0℃
It is 00℃.

On the other hand, the specific surface area is 2. On? If the ratio is less than /9, it is not easy to form a composite perovskite oxide, and it is necessary to repeat firing and crushing.

Next, the second invention will be explained. This invention is a method for producing a composite perovskite oxide having favorable electrical properties using the raw material powder of the first invention.

In this invention, other raw materials used together with the raw material powder of the first invention include pb, Mg, Nb, M? l, Y.

It is at least two metal powders selected from Co, W, Ba, Sr, and Ca, or a compound containing these metals as components. Because it is necessary to further contain at least two metals in addition to zirconium and titanium, when a compound contains a single metal as a component, it is necessarily used in combination with other compounds, but when a compound contains multiple metals, 1 of the compound if it is contained as a component
Seeds are fine. However, when considering the composition of the desired composite perovskite oxide, it is rather rare that a compound with the desired metal composition exists, so it is usually difficult to find a compound that has the desired metal composition. Even if it is a compound, it is rare to use just one type of it, and it is used after adjusting the composition by using all other metals or compounds together. As the compound, oxides, carbonates, chlorides, hydroxides, oxalates, formates, etc. are used without distinction, but oxides or carbonates are usually used.

To mix the raw material powder of the first invention and the metal or compound powder, a conventional mixing method using a ball mill or the like is used. In this case, wet mixing using a volatile organic substance such as acetone or alcohol as a medium is preferred. The reason for this is that compared to dry mixing, it is more efficient and a powder with a narrower particle size distribution can be obtained. The mixing ratio of the raw material powder of the first invention and the metal or compound powder can be freely changed depending on the composition of the desired composite perovskite oxide.

The composite perovskite oxide of the present invention can be produced by preparing a mixed raw material powder containing zirconium, titanium, and at least two other metals as components as described above, and firing it. The firing temperature varies depending on the composition of the composite perovskite oxide, but is 700°C.
~1.100°C is common. When the target composite perovskite oxide contains lead, care must be taken to sinter it in a closed furnace in a lead atmosphere.

Specific examples of the composite perovskite oxide obtained by the second invention are as follows.

(Pb-8r) ”((AIg34Nb34) Z
r-Ti]Os, PbC, <434Nb%) Z
r-Tt]Os, Pb ((Y% Nb%)
Zr・7Z)Os+Pb ((,Mn3ANb%)
Zr-TL) 02, Pb[: (CoKN
b%)-〇ノZr57'j〕03. (PbmCa)
(Zr-7”j)03. (Pb-Ba)(
Zr-TL) Os, (Pb-Ca)
(Y%Nb%) Zr ClearTt )03, (Pb
-Ba) l: (Mn3ANb%) Zr-
TL) Os.

(Pb-8r) [: (Co3ANb%)zr
-n]03. (Pb・Sr) C(YMNb%)
ZroTj, :) 03, (Pb・Ca)
((Co3ANb%)Zr-Tt]OB
.

In the second invention, metal components other than zirconium and titanium include Pb, A4. Nb, -I Y j C' I
The reason for selecting at least two of W, Ba, Sr, and Ca is that composite perovskite oxides containing these metals are industrially important, and the effect of using the raw materials of the first invention is remarkable. It depends.

〔Example〕

Example 1 0.5 mol/1 titanium oxynitrate aqueous solution 0j375t
and 1.0 mol/1 zirconium oxynitrate aqueous solution 0
．． 1251 to prepare an aqueous nitric acid solution containing zirconium and titanium. This was added dropwise to a coprecipitation tank adjusted to pH 7 with aqueous ammonia while stirring to generate a coprecipitate.

After washing this with pure water and spray drying, it was milled in a ball mill for 10 minutes.
The raw material powder of the present invention was produced by wet grinding using acetone and firing at a temperature of 900° C. for 1 hour. The specific surface area of this powder was 15.6 doors/i.

Next, in order to evaluate the performance of the raw material powder as a raw material for composite perovskite oxide, the raw material powder 50.350
P, commercially available powder PbO223,200f, M
g05,878 f', Nb2O538,760?
, and Mn021.591r, Pb[(Mg%Nb%) a, asts Tio43□
s Zro425) 03+M? A mixed raw material powder having a composition of +02 (0.5% by weight) was prepared and fired at a temperature of 900° C. for 2 hours.

When the obtained powder was subjected to X-ray diffraction, it was found that the powder had a single phase of composite perovskite oxide, as shown in the diffraction pattern of the first layer.

Comparative Example] Spray drying and wet crushing in a ball mill are omitted t 11
) A powder containing zirconium and titanium was produced in the same manner as in Example 1 except that the precipitate was dried as it was. Is the specific surface area of this powder 1.2rr? /7.

Using this powder, a composite perovskite oxide was produced in the same manner as in Example 1 and subjected to X-ray diffraction.
In addition to the perovskite phase shown in Figure 2, 3PbO
2Nb205, Pb7t03.

Many peaks such as PbZrOs were observed.

Comparative Example 2 The coprecipitate obtained in Example 1 was fired under firing conditions of 350°C for 1 hour to obtain a raw material powder. This raw material powder 10.00Or
When it was further baked at 900℃ for 1 hour, its weight was 9.
．． It decreased to 786f. This reduction rate was about 2.1%. This means that at a firing temperature of 350°C, as mentioned above, the removal of water in the coprecipitate is incomplete, and when an attempt is made to manufacture a composite perovskite oxide using this powder as a raw material, the composition of zirconium and titanium is This results in a composite perovskite oxide with a composition less than the desired composition by about 2%, indicating that the composition cannot be controlled.

Example 2 In Example 1, when producing a coprecipitate, p114
A powder containing zirconium and titanium was produced in the same manner as in Example 1 except for the following. The specific surface area of this powder is 7.
3n? /f. When a composite perovskite oxide was produced using this powder in the same manner as in Example 1, a good result of a single phase composite perovskite oxide was obtained.

Example 3 0.5 mol/l titanium tetrachloride aqueous solution 0.875A and 1
．． 0 mol/l zirconyl oxychloride aqueous solution 0.125
Raw materials were produced in the same manner as in Example 1, except that an aqueous hydrochloric acid solution of t was used, and a composite perovskite oxide was produced and subjected to X-ray diffraction. As a result, similar good results as in Example 1 were obtained.

Example 4 An isopropoxide solution containing zirconium and titanium was prepared by dissolving 0.4375 mol of titanium isopropoxide and 0.125 mol of zirconium isopropoxide in Impro (12 Tupanol). 500 moles of distilled water per mole was added with stirring to form a coprecipitate.

Thereafter, the same operations as in Example 1 were performed to produce powder containing zirconium and titanium. The specific surface area of this powder is 2
It was 3.2 m'/r. When a composite perovskite oxide was produced using this powder in the same manner as in Example 1, a good result of a single phase composite perovskite oxide was obtained.

Example 5 According to Example 1, the atomic ratio of titanium:zirconium was 0.
．． 460: A raw material powder of the present invention having a ratio of 0.490 was produced. The specific surface area of this powder is 16.4 tr? /f. 96.750t of this raw powder was added to P of commercially available powder.
bO223,200t, Coo 1.249t
, and Nb2054.425f were mixed and fired at a temperature of 900° C. for 2 hours, resulting in a single phase composite perovskite oxide.

Comparative Example 3 Instead of using the raw material powder of the present invention, commercially available 几02 and Zr were used.
Using O2 powder, a composite perovskite oxide was produced in the same manner as in Example 1 and subjected to X) IJJ diffraction.
Pb0.2Nb2 o5. Pb7'40B,
Many peaks such as PbZrO3 were observed.

〔Effect of the invention〕

By using the raw material of the first invention, it is possible to easily produce a composite perovskite oxide with few impurities without repeating the crushing and re-firing of the fired product as in the conventional method, and
According to the second invention, it is possible to easily produce an industrially useful composite perovskite oxide having excellent electrical properties.

[Brief explanation of the drawing]

1 and 2 are X-ray diffraction images of the composite perovskite oxide. FIG. 1 shows the results of Example 1, and FIG. 2 shows the results of Comparative Example 1. Patent applicant Denki Kagaku Kogyo Co., Ltd. Ca-~2θ

Claims (2)

[Claims] (1) A powder with a specific surface area of 2.0 m^2/g or more obtained by firing a coprecipitate of a solution containing zirconium and titanium and a precipitant at a temperature of 400°C to 1,200°C. A raw material for producing a perovskite-type oxide solid solution containing zirconium, titanium, and at least two other metals as components. (2) A powder with a specific surface area of 2.0 m^2/g or more obtained by firing a coprecipitate of a solution containing zirconium and titanium and a precipitant at a temperature of 400°C to 1,200°C, and Pb, Mg, N
b, a mixture containing zirconium, titanium, and at least two other metals as components by mixing powder of a metal selected from Mn, Y, Co, W, Ba, Sr, and Ca or a compound of the metal; A method for producing a perovskite-type oxide solid solution, which comprises preparing a raw material powder and firing it.