JPS62105927A - Production of ceramic powder having electro-optical properties - Google Patents

Abstract

PURPOSE:To obtain ceramic powder having electro-optical characteristics, by blending a mixed solution of lead nitrate, lanthanum nitrate and zirconium nitrate with a precipitate-forming solution, coprecipitating metallic components, adding a solution of titanium alkoxide to the precipitate to blend and to coprecipitate them. CONSTITUTION:A mixed solution of lead nitrate, lanthanum nitrate and zirconium nitrate is prepared, the mixed solution is blended with a precipitate-forming solution and metallic components are coprecipitated. Further the precipitate is mixed with a solution of titanium alkoxide and coprecipitated. The precipitate is dried and calcined at 400-1,200 deg.C to produce ceramic powder containing Pb, La, Zr and Ti as active ingredients.

Description

[Detailed description of the invention] Production 1L and 4 interest - batch M.

The present invention is directed to the production of ceramic powders having electro-optic properties, particularly powders for P LZ T ceramics having high transmittance, which are used as materials for piezoelectric bodies, optoelectronic materials, dielectrics, f-conductors, sensors, etc. Regarding the law.

1 store.

In recent years, lead (Pb), lanthanum (La), zirconium (
A polycrystalline material (referred to as PLZT) obtained by densely sintering oxide powders of Zr) and titanium (Ti) has a larger electro-optic coefficient than a single crystal, and a relatively large substrate can be produced. Due to its easy properties, it has been widely used as a ceramic material for piezoelectric materials, electronic materials, dielectric materials, electrical conductors, sensors, etc.

Recently, with the advancement of functionality in each of the above fields, it has become possible to meet the demands for easy sintering, preferably sintering under normal pressure. There is an increasing demand for powder for ceramics as a material that exhibits high density and high transmittance and can be prepared at low cost.

Conventionally, as described above, the method for producing the polycrystalline body called PLZT includes Pb, La, Zr and T.
A method is used in which compounds such as oxides of each component (i) are mixed in a dry manner and the mixture is calcined.

However, with this method, it is difficult to obtain powder with a uniform composition, and its sinterability is also insufficient, so it is practically impossible to produce powdered gold powder for PLZT ceramics that can meet the above-mentioned requirements.

On the other hand, in recent years, a wet method has been attracting attention as a powder gold powder method for PLZT ceramics, and this method can be applied to pb, La,
A mixed solution of various compound forms of each component of Zr and Ti is prepared, and a precipitate forming liquid such as an alkali is added to this mixed solution to cause co-precipitation (hereinafter referred to as coprecipitation). This method (hereinafter referred to as coprecipitation method) consists of drying the material and then calcining it.

However, although this coprecipitation method makes it easy to obtain powder with excellent uniformity, on the other hand, because of the uniformity, particles coagulate during precipitate formation, drying, or calcination to form secondary particles. As a result, there is a drawback that it is difficult to obtain a material that is easily sinterable. Furthermore, in this coprecipitation method, since the concentration of the precipitate-forming solution at the time of addition is constant, the precipitate-forming ability of each component in the mixed solution is not constant; for example, some components precipitate 100%, but other components do not. There are cases where it is not possible to generate all the precipitate, and therefore, there is also the problem that it is difficult to obtain powder with the desired composition.

In addition, in preparing the mixed solution in the above coprecipitation method,
Pb, La, Zr and Ti are mainly used in the form of oxides, but in recent years it has been proposed to use them in the form of alkoxides.

In view of the above-mentioned circumstances, the present inventor has developed a method for producing PLZT ceramic powder, which is easy to sinter, has high density, and has excellent transmittance, by a coprecipitation method. As a result of our investigation, we found that the method is made by mixing Pb, La, and Zr in a nitrate solution, adding a precipitate forming solution to this mixed solution to form a precipitate, and then adding Ti as an alkoxide F6 solution. The present inventors have discovered that it is possible to obtain a powder for ceramics having the above-mentioned characteristics by coprecipitating the desired powder from a mixed solution, drying the resulting coprecipitate, and then calcining it, which led to the present invention. Ta.

That is, the present invention has succeeded in solving the conventional problems associated with powdered gold powder for PLZT ceramics, and provides a PLZT powder for ceramics that is easily sinterable, has high density, and high transmittance. The purpose is to provide a method for manufacturing.

The present invention will be explained in detail below.

Three features of the present invention: In a method for producing ceramic powder containing lead (Pb), lanthanum (La), zirconium (Zr) and titanium (Ti) as active ingredients, lead nitrate, lanthanum nitrate and A mixed solution of zirconium nitrate is prepared, the resulting mixed solution and a precipitate forming solution are mixed to form a co-precipitate of each of the above components, and a titanium alkoxide solution is added to this to form a co-precipitate of each of the above metal components. Co-precipitation is performed, and the resulting precipitate is dried and then calcined at 400 to 1200°C.

□ In the present invention for fortune-telling, solutions of lead nitrate [Pb(NO)2], lanthanum nitrate (La(NOyo)2) and zirconium nitrate (Zr(NOa)2), e.g. By mixing each aqueous solution or alcohol/8 solution, and mixing this mixed aqueous solution with a solution of alkali such as ammonia, ammonium carbonate, or caustic alkali as a precipitate-forming liquid, and in some cases, a solution of oxalic acid, etc., with stirring. The above metal components are coprecipitated. A titanium alkoxide solution is added to and mixed with the coprecipitate solution while stirring to form a coprecipitate of the metal components. In this coprecipitation, After the precipitate of two or a mixture of the above metal components was formed, the type and concentration of the precipitate-forming solution was appropriately selected and adjusted to allow the remaining components to precipitate. You can operate it as follows.

Separate the coprecipitate obtained by coprecipitation as described above,
After washing to remove NO ions, drying and then
Calcinate at a temperature of 00 to 1200°C. When calcining the rice,
If the temperature is less than 400°C, the dehydration and thermal decomposition of the compact precipitate will be insufficient, while if it exceeds 1200°C, the resulting powder will become coarse, which is not preferred.

By calcining the dried coprecipitate in two series and pulverizing it, a uniform polycrystalline raw material powder that is easy to sinter (can be sintered under normal pressure) is obtained.

Mitsuhiro/Kanichi: The r'LZT ceramic powder obtained by the present invention has the above-mentioned features of easy sinterability, and f). ;1. Re, a) 4
．． knee! The mix is high-density and high-transmission, suitable for bursting high-quality ceramics (C'), which is 41 years old and has high-density and high-transmission characteristics, and is suitable for Tojo (electro-optical). Obtoelectronic I/ronics materials, piezoelectric materials,
Ceramic materials are useful for body parts, sensors, etc.

In addition, in the present invention, dozens of materials, Pb, La and Z
Since R is used in the form of a water-soluble nitrate, there is also the advantage that the process of preparing a coprecipitate of these metal components can be done simply and easily.

In addition, although Ti is used in the form of flukoxide in the present invention, titanium aluminum, :r :4'-cyto is i! Even if it remains in the Lamix powder, there is no adverse effect 9 due to the contamination of CI- as in the case of using it in the form of TiCl4,
Rather, there is no problem since it acts as a binder.

The present invention will be explained below with reference to Examples.

Example PbO81, 21g, 1. , a20i, 5.86 g was dissolved in nitric acid, and then Zr (NOq>21.1 mol/l aqueous solution 2
3k I! 7fi was combined into this to make 600mE.

4N NH,Ol (water 6201) 1! While stirring,
E water distribution solution is added and coprecipitation is performed, followed by Ti-Buto
46.65 g of xide diluted with isopropanol was added to the slurry that was being continuously stirred, and coprecipitation was performed to obtain hydroxide.

After washing, the precipitate was dried and calcined at 700°C for 2 hours.

The obtained powder was subjected to M-type pulverization with acetone in a ball mill and then calcined at 700° C. for 2 hours. As a result, PI and Zr powders were obtained. This powder had a uniform particle size of about 0.3 to .064 microns. This powder was molded at i, st/C-, sintered in a closed MgO crucible at 1'200°C for 2 hours in an oxygen atmosphere at normal pressure, and then annealed in MgO at 1)00'C for 10 hours. Upstream translucent PLZT (transmittance 6
4%, thickness 0.5 mm) was obtained. The high density during molding was 4.93, reaching 63% of the theoretical value.

Applicant: Science and Technology Agency, Inorganic Materials Research Institute L f & Yu Fuji

Claims (2)

[Claims] (1) Lead (Pb), lanthanum (La), zirconium (
In a method for producing a powder for ceramics containing Zr) and titanium (Ti) as active ingredients, a mixed solution of lead nitrate, lanthanum nitrate, and zirconium nitrate is prepared, and the obtained mixed solution and a precipitate forming solution are mixed. By co-precipitating each of the metal components, a titanium alkoxide solution is added thereto, mixed with the precipitate, and the resulting precipitate is dried and then calcined at 400 to 1200°C. A method for producing ceramic powder with optical properties. (2) The production method according to claim (1), wherein the precipitate forming liquid is an alkaline liquid.