JPS63239125A - Production of perovskite ceramic powder containing zirconium - Google Patents

Abstract

PURPOSE:To obtain the ceramic powder having a prescribed structure by calcining a mixture of a coprecipitated body produced from a mixed soln. contg. water soluble Zr and Ti salts, a mixture of Ti oxide with Mg oxide, etc., and a mixture of Ti oxide with Pb monoxide, etc. CONSTITUTION:A mixed soln. contg. Z mol. water soluble Zr salt and (a) mol. water soluble Ti salt (a=0.01Z-0.6Z) is prepd. The mixed soln. is mixed with a precipitate forming soln. and a produced coprecipitated body is calcined at 700-1,300 deg.C. A mixture of (b) mol. Pb monoxide with (b-X) mol. Ti oxide, X/e mol. Mg oxide and X/3 mol. Nb oxide (b=X-Y-a) is calcined. Powders of the resulting two kinds of calcined bodies are mixed with [(X+Y)-(a+b)] mol. Ti oxide and (1-b) mol. Pb monoxide, etc., and the mixture is calcined to obtain perovskite ceramic powder represented by the formula (where X=0.875-0.01, Y=0.813-0, Z=0.95-0, X+Y+Z=1, W=0-0.2 and M is Ca, Sr or Ba).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is directed to PM, which is known to exhibit excellent piezoelectricity.
N-PT-PZ [PMN is Pb (MC1173轡b273)o3. p'r is Pb Ti 03 , PZ
is an abbreviation for PbZrO3] The present invention relates to a method for producing a ternary perovskite ceramic.

This type of ceramics is used for vibrating hands, electromagnetic wave filters,
Although it is widely used as an actuator, it is desired to further improve its various characteristics by improving the manufacturing method.

(Prior art) Such perovskite ceramic raw material powder is prepared by mixing oxides of lead, magnesium, niobium, titanium, and zirconium in a predetermined ratio and calcining the mixture.

The most common manufacturing method is known as the so-called dry method of pulverizing oxide raw materials.

This method is the easiest to operate, but the powder obtained by this method not only requires a high sintering temperature when molding and sintering, but also the density and piezoelectric properties of the resulting ceramics are insufficient. .

On the other hand, the wet method, which is another common method, involves making a mixed solution of all the constituent components, adding this to a precipitate-forming solution such as an alkali to cause coprecipitation, and then drying this coprecipitate. , a calcining method (hereinafter referred to as coprecipitation method).

When using this coprecipitation method, it is easy to obtain powder with excellent uniformity, but because of this uniformity, particles aggregate during drying or calcination to form secondary particles, making it difficult to sinter. The disadvantage is that there are many cases.

In addition, in the coprecipitation method, the precipitate forming ability of each component is not constant; for example, a certain component may form 100% precipitate, but other components may not be able to form a precipitate at all. There are things that are difficult to obtain.

In order to solve these problems with the coprecipitation method, the present inventors previously prepared a raw material powder of a solid solution having a velorskite structure represented by the general formula ABO3 by using an aqueous solution or alcohol of component A. Forming a precipitate of the A component and then forming a precipitate of the B component using a solution and a precipitate forming liquid, or forming a precipitate by changing the order of forming the precipitates of the A component and the B component. After drying, the obtained precipitate is calcined at 400 to 1200°C.
He invented a method for producing raw material powder of a solid solution having a perovskite structure using a so-called multi-stage wet process, and filed a patent application. (Japanese Patent Application No. 59-171244) According to the above method, it becomes possible to use inexpensive titanium tetrachloride as the titanium raw material used as component B, and replaces expensive titanium oxynitrate (TiO(NO3) 2 >). It is possible to produce a raw material powder of a solid solution having a perovskite structure that is easy to sinter at low cost without using the powder.

The present inventors attempted to directly apply this method to the velorskite ceramics containing zirconium according to the present invention, but they were unable to do so by dissolving magnesium, calcium, barium, and strontium (group IIA elements), which are some constituent elements of the raw materials, in an aqueous solution. A problem was encountered in that it was necessary to allow complete precipitation.

Therefore, we conducted extensive research on precipitate-forming liquids and found that an organic amine aqueous solution was the most suitable solution, solving the problem.
The powder was molded and sintered to produce 1q of ceramics with extremely high piezoelectric properties, and an application was filed for this as an improved multi-stage wet process. (Patent Application No. 61-030159> (Problems to be Solved by the Invention) However, with this method, lead is present in the wastewater, albeit in minute amounts, and a considerable amount of wastewater is also generated, so measures are taken to prevent pollution. The problem is that it has to be.

On the other hand, one of the inventors of the present invention previously discovered a technique for solving the drawbacks of the conventional dry method and coprecipitation method as a method for producing velourskite ceramics containing zirconium, and published the patent application No. 60-210771 in 1986. The application was filed on September 24th. The gist of the invention is as stated in the claims: (1) A mixture (aqueous solution or alcohol solution) of a suitable amount of at least one component other than zirconium constituting a perovskite compound and a zirconium solution is prepared, and this is mixed with a precipitate. Mix with the forming liquid to form a coprecipitate, and after drying 7
(2) A step of calcining at 00 to 1300°C, (2) mixing this calcined product and the remaining constituent compounds of the target perovskie 1 to give a temperature of 500 to 1300°C;
A method for producing perovskite ceramics containing zirconium, comprising the steps of: (3) molding the obtained calcined powder and sintering it at 700 to 1700°C.

That is what it is.

Although the method of Japanese Patent Application No. 60-210771 is an excellent method for producing perovskite ceramics containing zirconium in a wide range of applications, it is considered limited to ceramics having the composition described in the claims of the present invention. However, there is still room for improvement in the solid solution reaction technology, which is the second step of the above method.

The present invention aims to further improve the method disclosed in Japanese Patent Application No. 60-210771 in order to obtain perovskite ceramics containing zirconium with a desired composition, which is the object of the present invention, and at the same time to solve the problem of wastewater. It has been done.

Generally, in order to obtain fine particles of a solid solution through an in-phase reaction, one of the requirements is that the raw material particles be fine, except for materials such as lead oxide, which have a low melting point and diffuse rapidly during the reaction.

For example, Pt) O,T! 02t Zr 02. N
b 205゜M(l) When O is mixed at once and calcined, Pb O, M(] O, Nb 20s first becomes PM
The formation of N [abbreviation for Pb(Mg173 Nb273) 03] occurs, followed by the formation of PT (Pb Ti 0
3 abbreviation).

PZ (abbreviation for PbZrO3) is generated, and these and PMN
A PMN-PT-PZ body is produced by a solid solution reaction with.

However, since MCIO is difficult to obtain as fine particles, PMN obtained using it as a raw material is PT.

The particle size is larger than that of PZ, and as a result, PMN-PT-
The particles of the PZ body also become larger. On the other hand, titanium oxide, which is the raw material for PT, is commercially available in fine and non-agglomerated form.
PT, which is a solid solution of this and PbO, can be obtained in sufficiently fine particles. In addition, PZ can be obtained in the form of sufficiently fine particles by co-precipitation with a water-soluble titanium salt (Japanese Patent Application No. 60-210771), so when PZ is also subjected to a solid solution reaction with PbO, It is possible to generate it in a fine form.

The present inventors thought that if PMN is generated in as fine a form as possible and then made into a solid solution with PT and PZ, a fine PMN-PT-PZ body in which the components are uniformly mixed may be obtained. As a result of careful consideration, P instead of PMN
It was discovered that the intended purpose could be achieved by using MN-PT, and the present invention was achieved.

(Means for Solving the Problems) In other words, the gist of the present invention is to coexist fine particle titanium oxide, which is effective in refining solid solution particles, when producing PMN in a separate process, and to form a PMN-PT type solid solution. generate,
Titania-containing zirconia obtained by coprecipitation method,
The purpose is to obtain perovskite ceramic powder containing fine zirconium by blending titanium oxide and PbO to have a desired ceramic composition, mixing, calcining, pulverizing, and drying.

As mentioned above, it is difficult to obtain PMN in fine particles, but with the PMN-PT type, if ground, the average particle size is 0.35 μm.
It is possible to do the following, and using this, P
When the MN-PT-PZ body was manufactured, ceramic raw material powder with an average particle size of 0.3 μm was finally obtained.

Embodiments of the invention are described below. That is, the production of perovskite ceramic powder represented by the general formula % consists of the following three steps.

(I> Create a mixed solution of a water-soluble salt of zirconium and a water-soluble salt of titanium, mix this with a precipitate forming solution to form a coprecipitate, and dry.

A process of calcining and crushing to create fine particles of a solid solution of zirconia and titanium oxide.

(n) A step in which Pb O, MgO, and Nb 205 are made to coexist with titanium oxide and calcined to generate a PMN-PT solid solution, and then fine particles of PMN-PT are created.

(III) The calcined powder obtained in (I) and (If> above, titanium oxide and PbO (a part of PbO may be at least one of oxides of 3r, 3a, and Ca). The process of mixing, calcining, and pulverizing to create the desired perovskite ceramics.

As the water-soluble salt of zirconium used in step (I>,
Zirconium oxychloride.

Examples include zirconium oxynitrate, zirconium chloride, and zirconium nitrate.

Further, water-soluble salts of titanium include titanium tetrachloride and titanium nitrate.

Ammonia is usually sufficient as the precipitating agent, but ammonium carbonate, caustic alkali, oxalic acid, ammonium oxalate, amines, oxine, etc. can also be used.

In addition, in step (I>), when the molar ratio of the water-soluble titanium salt is a, it can be set to 0.01 2 < a < 0.6 2, but the mixed oxide (modified 0.05 to make the particles of zirconia fine and non-agglomerated.
A range of Y<a<0.25Y is roughly preferred. Also, the ratio of titanium oxide used in step (III) (Ya
It is also preferable to consider so that the value of -b) does not become too small. (b is the molar ratio of PbO) In addition, during drying in this step, water adhering to the particles is replaced in advance with an organic solvent such as alcohol, as is commonly used for ceramic raw powder. This is effective in preventing agglomeration.

In step (II>), It can be taken that x<b<　(Ya).

The larger b is, the more effective it is in refining PMN-PT particles, but the ratio of PbO and titanium oxide used in step (III) (1-b) and (x0y)-(a00) Since the value of b) becomes small, it is not preferable to make it too large from that point of view.

Therefore, it is appropriate to take a range of 1.1 x<b<1.5 x.

In step (III), it is necessary to ensure that the solid solution reaction is almost completed and grain growth hardly occurs.

Therefore, it is preferable to select a calcination temperature in the range of 800 to 1100°C.

In addition, this family of piezoelectric ceramics uses manganese oxide and nickel oxide, to improve sinterability and mechanical and electrical properties.

It is customary to add trace amounts of auxiliaries such as silicon oxide, and these auxiliaries or their precursors are used in steps (I>, (I
It may be appropriately added to either I) or (DI) in solid or solution form.

Further, in this application, the term "metal oxide" can be replaced with a precursor of an oxide such as a carbonate.

The present invention will be explained in more detail in the following examples.

(Example) Group 11 Pb("'1/3 Nb2/3) 0.125"
0.447' 0.43503 Production of ceramics.

Step (I > 1.120 mol#l zirconium oxychloride aqueous solution 3887d (0,435 mol = Z mol equivalent) and 1.322 mol/ρ titanium tetrachloride aqueous solution 6
5.8 d (equivalent to 0,087 mol=a mol). On the other hand, 2.5 g of 6N ammonia water used as a precipitate forming liquid was stirred, and the mixed liquid was gradually added thereto to form a hydroxide coprecipitate of Ti''&Zr'+.

This was washed with water, washed with ethanol, dried, and calcined at 1100'C (T
io, 2Zro4) 02 powder was obtained. The average particle size of this powder was 0.32 μm.

Step (II> Pb O33,51 with a purity of 99.9%
g (0,15+-/L, = b mo/L, equivalent), 1,70 g of MgO with a purity of 99.0% (0,0417 mole
/3 mole equivalent) and purity 99.9% (7) Nb 20
522.179 (equivalent to 0,0417-E/1z=X/3 moles) and 2.02 g of titanium oxide with a purity of 98.8%
. Next, Pb()fo 1/3 N1) 2/3 ) 03 ・0 with an average particle size of 0635 μm was pulverized in a ball mill in acetone, day and night, and then dried.
．． A fine powder of 2Pb Ti O3 was obtained.

Step (III) Step (I) Calcined powder obtained in Onibi step (II>) and 190.17 g of PbO with a purity of 99.9% (equivalent to 0.85 mol-: (1-b) mol) and Titanium oxide 27.339 with purity 98.8%
(0,338 mol = [(x+Y)-(a+b)] mole equivalent) was mixed in a ball mill for a day and night, then press-molded into a cylindrical shape, calcined at 850°C for 2 hours, and ground again in a ball mill to form a piezoelectric 237 g of ceramic raw material powder was obtained. Its average particle size was 0.30 μm.

The powder thus obtained was mixed with 0.24 g of silicon oxide with an average particle size of 2 μm as an auxiliary agent, and press-molded at 500 pieces/d.
Sintering was carried out at 1220° C. for 2 hours in an atmosphere containing lead vapor and oxygen gas to obtain a piezoelectric ceramic disk having a diameter of about 10 and a thickness of about 11 Ivr1.

Le School Feng Yu Commercially available Pb O, Ti 02. Zrα, MgO.

Nb2O5 powder was blended to have the same composition as the target powder in Example 1, mixed overnight in a ball mill, press-molded into a cylindrical shape, calcined at 900°C for 2 hours, and ground again in a ball mill to form a piezoelectric A ceramic raw material powder was obtained.

The average particle size was 0.36 μm. To this, 0.24'j of silicon oxide with an average particle size of 2 μm was added as an auxiliary agent.
00 K'J/ci and sintered at 1260° C. for 2 hours in an atmosphere coexisting with lead vapor and oxygen gas to produce a piezoelectric ceramic disc having the same dimensions as Example 1 and weighing 1 q.

Example 1
Synthesize the powder of (Ding! 02 Zr O, 8>α by the method of step (I), and combine this with commercially available (7) Pb O, T! Ch, M(] O,
Nb 20s, oxidized (P) powder was blended to have the same composition as the target powder in Example 1, mixed in a ball mill for a day and night, then press-molded into a cylinder shape, calcined at 850°C for 2 hours, and then heated again. A piezoelectric ceramic raw material powder was obtained by pulverizing with a ball mill.The average particle size was 0.36 μm.

The powder thus obtained was added with an auxiliary agent having an average particle size of 2 μm.
0.249 m of silicon oxide was blended, press molded and sintered under the same conditions as Example 1, and the diameter was about 10 m and the thickness was about 11 r.
A piezoelectric ceramic disk of IIrI was obtained.

Table 1 shows a comparison of the characteristics of the ceramics obtained in Example 1 and Comparative Example 1.2. The ceramic obtained in Example 1 had Kl) (radial electromechanical coupling coefficient), O3
1 (lateral equivalent piezoelectric coefficient).

g31 (lateral voltage output coefficient) is obtained by firing the constituent components at once, or the patent application No. 60-21077
．． It exhibited piezoelectric properties superior to those obtained by method 1.

Loss of fire ■2 PbO,94" 0.038aO,03 (Hg1/3
Nb2/3) 0.375"0.375" 0
．． 2503 Manufacture of ceramics.

Step (I > 1.120 mol/, the amount of the zirconium oxychloride aqueous solution of 11 was 223d (0,250
50 moles = equivalent to b), 1.322 m01/, 11
(7) The amount of titanium tetrachloride aqueous solution was 47.3d (0,
0625 mol = equivalent to a mol), and 6 for precipitate formation.
Example 1 except that the amount of N-ammonia water was 1.5 g
A powder of (T zr )02 having an average particle size of 0.32 μm was obtained by operating in the same manner as above.

0.2 0.8 Step (II> 99.9% purity Pb 0 83.7
89 (equivalent to 0.45 moles = b moles), 5.09 g of MgO with a purity of 99.0% (equivalent to 0.125 moles = X/3 moles)
and Nb 20s 33.2 (5
'J (equivalent to 0,125 moles = X/3 moles) with a purity of 98
．． 2.02 g of 8% titanium oxide (0,0,25 mol (b
-x) molar equivalent) were allowed to coexist and mixed in a ball mill for a day and night, and then calcined at 850°C for 1 hour. Thereafter, the same operation as in Example 1 was performed to obtain Pb(Hg1/3 Nb2/3)03.0.2Pb with an average particle size of 0.35 μm.
A fine powder of Ti 03 was obtained.

Step (III) The calcined powder obtained in step (I> and step (II), 109.48 g (0.49 mol) of PbO with a purity of 99.9%, and S with a purity of 99.9%
r CO34,43 g (0,03 mol) and purity 99
．． 83% 13a CO35.93g (0.03 mol) (total of the above three is 0.55 mol, equivalent to (1-b) mol) and titanium oxide 19.219 (0.2375 mol) with a purity of 98.8% −E le = [(x 10 Y)
- (equivalent to a and b) J moles) were added and mixed in a ball mill for a day and night, then press-molded into a cylinder and calcined at 850°C for 2 hours. Afterwards, it is ground again in a ball mill to produce ceramic raw material powder 2 with an average particle size of 0.31 μm.
19g was obtained.

0.24 g of nickel oxide was added as an auxiliary agent to the powder thus prepared, and 500 kg
/cr/l press molding and lead vapor.

Sintered at 1220'C for 2 hours in an atmosphere coexisting with oxygen gas,
Diameter approximately 10IM1. A piezoelectric ceramic disk with a thickness of about 1# was obtained.

Commercially available PI) 0.3r CO3,Ba CO3,T!
02゜Zr O2, VI'J O, Nb 20s,
Wi-forming (P) powder was blended to have the same composition as the target powder in Example 2, mixed in a ball mill for a day and night, then press-molded into a cylindrical shape, calcined at 900°C for 2 hours, and again ball-milled. A raw material powder for piezoelectric ceramics was obtained by pulverization.The average particle size was 0,837 μm.This powder was mixed with 0.24 t of nickel oxide as an auxiliary agent, and press-molded and baked under the same conditions as Comparative Example 2. A piezoelectric ceramic disk having a diameter of about 10 m and a thickness of about 1 m was obtained.

Example 2 (T!o, 2Zr04) O7 powder was synthesized by the method of the first step, and this and commercially available (7) Pb 0.3r CO3, Ba CO3
,T! 02. MgO.

Nb 205 powder was blended to have the same composition as the target powder in Example 2, mixed overnight in a ball mill, press-molded into a cylinder, calcined at 850°C for 2 hours, and ground again in a ball mill. A piezoelectric ceramic powder was obtained.

This powder was mixed with 0.249 nickel oxide as an auxiliary agent, press-molded and fired under the same conditions as in Example 2, and was made into a powder with a diameter of about 1 mm.
A piezoelectric ceramic disk having a thickness of about 1# and a thickness of about 1# was obtained.

Table 2 shows a comparison of the characteristics of the ceramics obtained in Example 2 and Comparative Examples 3 and 4. The ceramics prepared by 1q in Example 2 had Kp, d31. g3. Those obtained by firing all the constituent components at once, or
It exhibited piezoelectric properties superior to those obtained by the method of No. 0771.

(Effect of the invention) As a result of mixing Pb O, MFO, and Nb 205 in advance and coexisting titanium oxide, firing and pulverizing, PMN-P
Fine particles of T solid solution were obtained. By mixing this with sufficiently fine particles of PT and PZ, calcining and pulverizing, it was possible to finally obtain a perovskite ceramic raw material powder containing fine zirconium with an average particle size of about 0.3 μm. As a result of molding and sintering this powder, we were able to obtain ceramics that exhibit piezoelectric properties superior to those obtained by dry methods or coprecipitation methods.

Claims (1)

[Claims] General formula Pb_1_-_WM_w(Mg_1_/_3Nb_2_
/_3)_XTi_YZr_ZO_3 [However, in molar ratio X = 0.875 to 0.01, Y = 0.813 to 0 (0
Does not include. ), Z=0.950-0 (not including 0) X+Y+Z=1, W=0-0.20 M represents at least one of Ca, Sr, and Ba. ] A method for producing perovskite ceramic powder containing zirconium, which comprises the following three steps. (I) Create a mixed solution of 0.01Z≦a≦0.60Z from water-soluble salt Z of zirconium (molar ratio) and water-soluble salt a of titanium (molar ratio), and mix this with the precipitate-forming solution. A process of forming a coprecipitate, drying, calcining at 700 to 1300°C, and pulverizing. (II) Lead monoxide b (molar ratio), titanium oxide (b-x)
(molar ratio), magnesium oxide X/3 (molar ratio), and niobium oxide The process of doing. (III) The calcined powder obtained in steps (I) and (II) and at least one of the group consisting of titanium oxide [(x+Y)-(a+b)] (molar ratio) and lead monoxide or Sr, Ba, and Ca. A process of mixing lead monoxide (1-b) (molar ratio) containing a type of metal oxide, calcining at 500 to 1300°C, and pulverizing.