JPS60176920A - Sol dispersed with ultra-fine particle of zirconia single crystal, and its production - Google Patents

Abstract

PURPOSE:To peoduce the titled sol, by adding a base to an aqueous solution of a zirconium salt, washing the resultant precipitate with water, adding an alkaline earth metal hydroxide to the precipitate to obtain a suspension, and aging the suspension by heating at a specific temperature. CONSTITUTION:A base (e.g. ammonia water) is added to an aqueous solution of a zirconium salt (e.g. an aqueous solution of ZrOCl2, etc.) to produce the precipitate of zirconium hydroxide. The precipitate is washed with water to remove the major part of the soluble components, and is added with an alkaline earth metal (e.g. calcium hydroxide) or its aqueous solution to obtain a suspension or paste of the mixture. The produce is aged by heating at 90-200 deg.C. The obtained sol contains dispersed separate ultra-fine primary particles of the single crystal of ZrO2-CaO solid solution having a tetragonal or cubic crystal lattice and almost uniform particle diameter of <=200Angstrom .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an additional invention of Patent Application No. 215208 filed in 1982 (hereinafter referred to as the original patent application) already filed by the present inventor. The present invention relates to a sol in which single-crystal ultrafine particles are dispersed and a method for producing the same.

ZrO2, Y2O3, CaO, MgO, CeO2,
Others, Sc.

Solid solutions containing one or more of oxides such as Yl), La, Nd, and Gd have various applications such as high-temperature materials, ion conductive materials, and piezoelectric materials, and these solid solutions are used as starting materials. It has already been described in detail in the original patent application that a sol in which ultrafine particles are dispersed is extremely useful.

However, at the time of the original patent application, Zr02-CaO
A sol in which single-crystal ultrafine particles of a solid solution of ZrO2 and divalent metal ions are dispersed cannot necessarily be obtained by the method described in the patent application. This was briefly mentioned in Example 2 of the original patent application, but as a result of subsequent research, by slightly improving the method, ZrO2CaO
As for systems, etc., it has become possible to produce a sol in which similar solid solution 11 crystalline ultrafine particles are dispersed, so this will be explained below as an additional application.

In other words, at the time of the original patent application, there was a defect in that no consideration was given to the dissolution and separation of the coprecipitate of Zr(OH)4 and divalent metal hydroxide and the interfering effect of ammonium chloride. . As a result of subsequent detailed research, we found that hydroxide or co-precipitated hydroxide was washed away as much as possible in 1-min, and unnecessary products during precipitation formation.

In other words, ammonium chloride, common salt, potassium chloride, nitric acid sorter, potassium nitrate, etc. should be removed by washing with water as much as possible.
It was found that rO2 is necessary for the production of a solid solution of divalent metal ions, and that success can only be achieved by washing with a saturated aqueous solution of rO2 to prevent the divalent metal ions from dissolving and disappearing due to oxidation. 8 The formation temperature is 90° (1), the formation rate is too slow and is not practical, and at 200° (1), the formed particles become wavy and begin to aggregate and connect to rIH.
oxidation becomes worse, and elution of calcium content increases. Finally, the product is ultrafine particles of about 50A, which dissolve and disappear when a strong acid is added and separated as in the patent application, so depending on the target amount of solid solution such as CaO,
It is necessary to wash with dilute acetic acid or aqueous ammonia.

In addition, the inventors washed the zirconium hydroxide precipitate in a water-containing state with water, added an aqueous calcium hydroxide solution, and heat-aged only the mixed suspension or paste-like material to produce a gravity type or cubic type with a low CaO content. We have newly discovered that zirconia single crystal ultrafine particles can be produced. This method without co-precipitation is not successful with yttrium hydroxide, and is increasing in cases where yttrium hydroxide is a strong base such as calcium hydroxide. Although this is a slight improvement, the effect is enormous, and it enables the production of a sol in which crystalline fine particles are dispersed in a ZrO2-CaO solid solution, which has not been previously possible.

Other cars J+'; Strong divalent metal ion of H, for example B
, 1°Sr, etc. As a result, Zr(') is a divalent metal oxide that is cheaper than rare class 1 phosphorus.
The zirconia thread used as a stabilizer or a stabilizing agent in No. 2 can now be used as a raw material for ceramics, and its fine particles make it highly valuable as a raw material for ceramics to which 2611i metal ions are added. It is.

Example 1 Reagent zirconyl chloride (ZrOCl2.8H20) 87y
was dissolved in about 500 ml of water, and 1:1 ammonia water was added thereto for 1 minute to form a white sludge of zirconium hydroxide. 1. This was repeatedly decanted with a saturated aqueous solution of calcium hydroxide. I washed it. A mixed suspension of the zirconium hydroxide precipitate obtained in this way and an aqueous calcium hydroxide solution was prepared to a volume of about 500 ml,
When this was aged in a sealed Teflon container at 120°C for 30 hours, a suspension with low viscosity was obtained. This is 1N
The separation was carefully repeated with dilute hydrochloric acid for <6 IC, and finally, after decantation twice with alcohol, a solid mass was obtained after drying at 60°C. This solid mass can be easily dispersed in water to form any desired concentration. According to an electron microscope, this vine is a single crystal with a shape close to a 9-sided solid with approximately 10 OA on each side, which is almost the same as that of the example of the original patent (Z ro2- Y203 solid solution), and there is an isolated t' in Ll: /: L minute 1PIb
It was confirmed that the particles were ultrafine particles.

Example 2 Reagent Zirconyl chloride (ZrOCl 2' 8 H2O
)8711 as calcium chloride (CaC12) 8.49
(Equivalent to about 10 mo1% of CaO with respect to ZrO2)
was dissolved in about 500 ml of water, and this was added dropwise to a 6N caustic soda solution to obtain a co-precipitated hydroxide of zirconium and calcium. This was washed by repeated decantation with a saturated aqueous solution of calcium hydroxide. Approximately 500 ml of a mixed suspension of the coprecipitated hydroxide thus obtained and a saturated aqueous calcium hydroxide solution was prepared, and this was heated at 97"C for 1 hour.
After aging for a week, a suspension with low viscosity was obtained. This was carefully washed and separated repeatedly with IN acetic acid, finally decanted twice with alcohol, and dried at 60°C to obtain a solid mass. This solid mass can be easily dissolved in water to give a sol of any concentration. By electron microscopy, it was confirmed that the crystal was a single crystal with a shape almost identical to that of Example 1 except that the cube-shaped apex was rounded, and that it was an ultrafine particle with an arc ratio of 1 to 5.

Example 3 An equimolar mixed aqueous solution of test mulberry zirconyl nitrate and barium nitrate was dropped into a 3N caustic potassium aqueous solution to obtain a coprecipitate of zirconium hydroxide and barium hydroxide. This was thoroughly washed with a saturated aqueous solution of barium hydroxide to obtain a milky mixed suspension of 97%
After aging at °C for one week, a suspension with low viscosity P1 was obtained. After carefully washing with IN/ammonia water, the ammonia was removed by heating. According to an electron microscope, it was an ultrafine sol of about 300 A, and X-ray diffraction of the dry product showed a crystal lattice of BaZrO3.

Claims (3)

[Claims] (1) It has an iF or Sy crystal lattice, and 2
Isolated Zr02-Ca with almost uniform particle size of less than 00λ
A sol in which fine particles of an O-based solid solution are dispersed. (2) After adding a base to an aqueous zirconium salt solution to form a precipitate and removing most of the soluble portion by washing with water. Add alkaline earth metal hydroxide or its aqueous solution, t
;1 Mixed suspension or paste-like material is heated to 90°C to 200°C.
It is characterized by heating and aging at a temperature of °C. 11 A method for producing a sol in which one-sided or X7-gonal ZrO, single-crystal ultrafine particles are dispersed. (3) Co-precipitated hydroxide of divalent metal ions such as zirconium and calcium. Divalent metal hydroxide is dissolved from the coprecipitate 11
π'J)"i', jc Wash with a divalent metal hydroxide aqueous solution to the extent that it does not cause damage, and a mixed suspension or paste-like substance of the obtained coprecipitated hydroxide and a divalent metal hydroxide saturated aqueous solution 90
A method for producing a sol in which zirconia-based single crystal ultrafine particles containing divalent metal ions are dispersed, the method comprising heating and aging at a temperature of 200°C.