JPH02184524A - Production of piezoelectric perovskite-type compound - Google Patents

Abstract

PURPOSE:To improve uniformity and sintering properties of the title compound by adding precipitation forming liquid to a mixed aqueous solution of each component of Ti, Zr, Ni and Nb to form precipitation of each component, blending the resultant precipitation with a compound of Zn and Pb and burning the blend. CONSTITUTION:A mixed aqueous solution of hydroxide, chloride, etc., of Ti, Zr and Ni is blended with a solution of Nb acidified with hydrochloric acid and containing >=2 times (mol) H2O. Ni component precipitation-forming liquid of aqueous solution of ammonia containing oxime having >=2 times (mol) Ni is added to the blend solution. pH after precipitation formation is kept to >=7 and then impurities of Cl<->, NO ion, etc., are removed and precipitation product containing Ti, Zr, Hi and Nb is filtered and dried. Zn compound and Pb com pound such as hydroxide or oxide are blended with the precipitation product and calcined at 600-1000 deg.C for 1-2hr to provide the piezoelectric perovskite-type compound expressed by the formula (a+b+c+d=1).

Description

[Detailed description of the invention] [Industrial use! I'f1 The present invention relates to a method for producing a piezoelectric perovskite structure compound (hereinafter referred to as a perovskite compound).

[Prior Art] Conventionally, the method for producing perovskite compound powder is as follows:
Solid phase reaction methods, coprecipitation methods, etc. are known.

Among these, the solid phase reaction method is a method in which the components constituting the herovskite compound are mixed in a dry or wet manner and calcined. Further, the coprecipitation method is a method in which a mixed solution of all the constituent components is prepared, a precipitate is formed by adding a precipitate forming liquid such as an alkali, and the coprecipitate is dried and calcined.

[Problems to be Solved by the Invention] In the solid-phase reaction method described above, the composition of the obtained compound is poor in uniformity, and in the case of perovskite compounds containing Nb components, a pyrochlore phase is generated during the reaction process, resulting in poor quality. A high calcination temperature is required during calcination of the compound, and the residual pyrochlore phase causes a decrease in the pressure gamma arsenic property of the compound.

In particular, Pb as shown in the general formula in the present invention,
When producing a multi-component perovskite type compound consisting of Ti, 2', Nl5Nb, and Zn components, Ti, Zr, Ni, Nb, which occupy the same position in the crystal structure,
Large fluctuations tend to occur in the composition ratio of Zn and Zn components, and this fluctuation in composition also leads to a decrease in the piezoelectricity.

On the other hand, although it is easy to obtain fine powder with excellent uniformity in the coprecipitation method, particles may aggregate during precipitate formation, drying, or calcination, making sintering difficult. Furthermore, in the coprecipitation method, the precipitate formation conditions for each component often differ as the number of components increases, resulting in variations in precipitate formation depending on the component.
It becomes difficult to obtain the desired composition. Further, even if the precipitate is completely formed, there are many cases in which not all components are precipitated at the same time, so that the formed precipitate has a compositional variation, and even when a coprecipitation method is used, it lacks uniformity.

Regarding the constituent components of the compound of the above general formula in the present invention, in the case of precipitate formation with aqueous ammonia used in a normal coprecipitation method, T1, Zrs, and Nb components can be coprecipitated as their respective hydroxides. However, Nl
, and Zn components do not form a precipitate and it is difficult to obtain a precipitate having a 11-dimensional composition.

In addition, an aqueous solution of the Nb component is very easily hydrolyzed even when using an acidic solution of hydrochloric acid, so it may form a precipitate before other components.
Care was required in handling, including storage, of component solutions.

[Object of the Invention] The object of the present invention is to solve problems such as the heterogeneity of the product in the solid phase reaction method and the conventional coprecipitation method, and to
Another object of the present invention is to provide a method for producing a piezoelectric perovskite compound with less aggregation and excellent uniformity.

[Means for Solving the Problems] That is, the present invention provides Perovsky! expressed by the general formula % (where a+b+c+d-1).・Tl5Zr in the production of the type compound.

A solution of each component of Nb and Nl is mixed with a precipitate forming solution to form a precipitate of each component, and a Zn compound and P are added to the product.
The present invention relates to a method for producing a piezoelectric perovskite compound by mixing B compounds and firing the mixture.

The details will be explained below.

In all the components in the general formula in the present invention, T1, Zr
, Nb, and Ni component solutions in predetermined amounts,
Prepare a mixed solution of these. At this time, the Nb component solution is preferably an acidic hydrochloric acid solution containing H20□ from the viewpoint of precipitation formation. This mixed solution is mixed with a precipitate forming solution containing a precipitant forming agent of Ni component to form a precipitate. Precipitation is generated by adjusting the pH of the mixed solution to 4 (8 to 10). Next, Zn is added to the precipitate.
A perovskite compound is obtained by adding a compound and a Pb compound, mixing and firing. That is, the present invention is a production method characterized by synthesis by a combination of a coprecipitation method and a solid phase reaction method.

Component compounds for preparing a solution of Ti, Zrs and N1 components, which are the constituent components of the perovskite compound represented by the general formula of the present invention, are not particularly limited, but include their hydroxides, chlorides, and carbonates. , inorganic salts such as nitrates, and organic salts such as oxalates, which are water-soluble. Further, as a component compound for preparing a solution of the Nb component, Nb chloride, oxalate, etc. are used, and an aqueous solution is prepared by dissolving this in a hydrochloric acid acidic solution containing H20□. In the preparation of this Nb component aqueous solution, the hydrochloric acid concentration of the hydrochloric acid solution is preferably 6N or more, and the amount of H2O2 added is
It is preferable to add at least twice the number of moles of .

As Pb1 and Zn components, respective hydroxides,
The compound is appropriately selected from inorganic salts such as carbonates, organic salts such as oxalates, and oxides, but preferably compounds that do not dissolve in the solvent during subsequent mixing using a ball mill, etc., and decompose on heating to become oxides. selected from. As the precipitate-forming liquid, an aqueous solution of ammonia, ammonium carbonate, etc. is used, and at this time, it is preferable that a precipitate-forming agent of the N1 component is present.

Examples of precipitating agents for the Nl component include organic substances such as oxine and dimethylglyoxime.In order to completely precipitate the Nl component, the number of moles of N1 must be twice or more to form a precipitate. It is preferable to add an agent.

When a mixed solution of Ti, Zr, NI, and Nb components is mixed with a precipitate-forming solution to produce a coprecipitate of each component, it is necessary to precipitate each component at once instead of precipitating each component in stages. Since this is preferable in terms of the properties of the product, it is preferable to add the mixed solution to the precipitate forming solution and mix to form a precipitate. Further, in order to remove CI- and NO3- ions, which are undesirable impurities at this time, it is preferable to adjust the pH after the precipitation to 7 or higher.

71% Zrs Nb produced in this way, and N
The precipitated product containing the l component is separated by filtration or centrifugation and dried. Organic substances such as a precipitate forming agent in the obtained precipitate are removed, for example by calcining the precipitated product. The firing temperature at this time is preferably in the range of 300 to 800[deg.] C., since if it is too high, the particles will become coarse and the size of the final raw material powder will be affected.

In the present invention, the ZnSPb component is mixed with the precipitated product, but the timing of mixing the Zn and Pb compounds with the precipitated product is different from when the Zn compound is mixed with the dried precipitate before calcination. , or may be mixed after firing, and either of these may be used. In addition, in Pb compounds, Z
There are cases where the Zn compound is mixed at the same time as the Zn compound, and there are cases where the Zn compound is mixed and then mixed after firing, but either method may be used. In the present invention, a method in which a Zn compound is mixed with the precipitated product and calcined, and then compound l)b is mixed is preferred in terms of the physical properties and yield of the resulting compound. moreover,
As for the mixing method at this time, a mixing device such as a ball mill, a vibration mill, an atrider, etc. is used.

In the method of the present invention, a and b of the above general formula.

There are no particular limitations on the values of c and d, and a perovskite compound having the desired composition can be obtained by using raw materials in proportions that match the composition of the desired perovskite compound.

PbSTl, Zr5Nl, Nb obtained in this way
.

The mixture containing all the components of Zn and Zn is fired to form a compound having a perovskite structure. If the firing temperature is too low, a single set of perovskites cannot be obtained, and if it is too high, the particles will become coarse.
Preferably, the temperature is 0°C for about 1 to 2 hours.

The perovskite compound obtained as above is pulverized using a ball mill, vibration mill, atrider, etc.
Used as raw material powder.

[Effects of the Invention] According to the present invention described above, (3) In a perovskite compound containing an Ntt component, a pyrochlore phase is not formed during the production process, so a perovskite compound can be produced without leaving a pyrochlore phase. be able to. (2) Even if it is a multi-component compound as shown by the general formula in the present invention,
Uniform raw material powder can be produced with little variation in composition.

(3) In the present invention, fine particles with a particle size of l#I11 or less can be obtained, and these particles are easily sinterable piezoelectric perovsky! with little agglomeration.・Can be used as a raw material powder.

[Example] Example 1 Titanium tetrachloride (TfCI4) 9.280 g1 A solution in which zirconium oxychloride (ZrOCh ) 8.107 g and nickel chloride (NtCh ) 2.002 g were dissolved in water, and niobium pentachloride (NbCI, )
6 containing 10.728g and 18g of 31% hydrogen peroxide solution
A solution was prepared by dissolving each in 200 g of N hydrochloric acid.

These were mixed and 17.5g of oxine was dissolved in 28
% ammonia water to form a precipitate. This precipitate was filtered, washed and dried, and the dried precipitate was heated to 550°C.
After decomposing and removing organic substances such as precipitants,
174 g of ZnC011 was added, mixed using a ball mill, and then fired at 600°C to obtain a composite oxide other than Pb.

909 g of Pb02B was added to this composite oxide, and after mixing in a ball mill, it was fired at 700°C for 2 hours.
35(PbT10i)-0,19(PbZrO3)J
JO(Pb(Nl+/i Nbz/3)031-0.1
A perovskite compound represented by 6{Pb(Zn1/i Nb273)031 was obtained.

This powder was pulverized for 24 hours using a ball mill.

A portion of this powder was measured using a BET measuring device to measure the specific surface area/l.
When 1 lJ was determined, it was 5.98 rf/g, and the average particle diameter calculated from this was 0.1211 m.

Further, when the crystal phase of this product was examined by X-ray diffraction, the content of the perovskite compound was 98% based on its intensity ratio, and the rest was unreacted PbO and composite oxides other than the Pb component. The content at this time is Ip (%) - 1p / (Ip + lPb + 1°).

MP) ■, - Intensity of (110) plane of perovskite phase IPb - Intensity of (111) plane of PbO I coMp
It was determined based on the strength specific gravity (%) of the perovskite phase expressed by the strength of the (131) plane of the composite oxide other than -Pb, and a previously determined calibration curve.

After molding this powder with a mold at 300 kg/d, 20
Isostatically formed with 00kg # and 1100℃- under lead atmosphere.
Firing was performed for 2 hours. The density of the obtained sintered body was determined by the Archimedes method and was 7.9 g/cm'.

The sintered body was approximately 1001% perovskite compound.

Example 2 The same procedure as in Example 1 was carried out using 9.751 g of titanium tetrachloride, 6.087 g of zirconium oxychloride, 1.914 g of nickel chloride, 054 g of niobium pentachloride, 0.571 g of zinc carbonate, and 31.884 g of oxidized carbonate. A perovskite compound of the following formula was obtained by the method.

0.36(PbTIOi)-0,24(PbZrOi
)-OJO+Pb(N1□/3Nbzzi)031
-0.10{Pb(Zn17i Nb2/3)031
The specific surface area of this powder was 5.12 rrr/g, and the average particle size calculated from this was 0.15 μm. Further, the content of the perovskite compound was 98.5%, and the rest was a composite oxide other than PbO and Pb components.

When this powder was molded and fired in the same manner as in Example 1,
The density of the sintered body was 8.0 g/ar+'.

Example 3 Tl5Zr, N! , and a precipitate of Nb component, filtered and dried, and the dried precipitate and ZnC0g
2.93 (after mixing ig by ball mill, 7
A composite oxide was obtained by firing at 00°C. Pb0137.837g was added to the obtained composite oxide, mixed in a ball mill, and fired at 800°C for 2 hours to form 0.28(PbT103)-0,22(PbZrOi).
)-0,25iPb(Nl+/3Nb2/i)031
A perovskite compound represented by -0.251Pb(Zn+/iNb2z3)031 was obtained.

The specific surface area of this powder was 2.88 r#/g, and the average particle size calculated from this was 0.27 μm. Further, the content of the perovskite compound was 97%, and the rest was a composite oxide other than the O and Pb components.

When this powder was molded and fired in the same manner as in Example 1,
The density of the sintered body was 8.0 g/cm'.

Comparative Example 1 Lead oxide (PbO) 7o, 2g, titanium oxide (T10
2) 7.8g, zirconium oxide (ZrO2) 8.
Weighed 2 g, 3.0 g of niobium oxide (NIO), 11.0 g of niobium pentoxide (NbzOs), and 18 g of zinc oxide (ZnO), wet-mixed them using ethanol in a ball mill, and then dried them. . This was baked at 800°C for 4 hours. The composition of the obtained powder was the same as in Example 1.

The specific surface area of this powder is 1. Q3rrr/g, and the average particle diameter calculated from this was 0.46 μm, but SE
According to M observation, the particle size was non-uniform.

Furthermore, according to X-ray diffraction, the perovskite phase is 909
6, but also contained several percent of pyrochlore phase.

When this powder was fired in the same manner as in Example 1,
The density of the obtained sintered body was 7.4 g/am'. In addition, the pyrochlore phase contained in the powder remained in the sintered body.

Claims (3)

[Claims] (1) General formula, a(PbTiO_3)-b(PbZrO_3)-c{P
b(Ni_1_/_3Nb_2_/_3)O_3}-d
{Pb(Zn_1_/_3Nb_2_/_3)O_3}
(However, a + b + c + d = 1) When producing a perovskite-type structure compound represented by 1. A method for producing a piezoelectric perovskite structure compound, which comprises: mixing a Zn compound and a Pb compound with the product; and firing the mixture. (2) The manufacturing method according to claim 1, wherein the aqueous solution of the Nb component is an acidic hydrochloric acid solution containing H_2O_2. (3) The manufacturing method according to claim 1 or 2, wherein the precipitate forming liquid is an aqueous solution of ammonia or ammonium carbonate containing oxine or dimethylglyoxime.