JPS5826006A - Manufacture of composite metallic compound - Google Patents

Abstract

PURPOSE:To obtain a brittle-like composite decomposition product easy to pulverize in a simple stage by adding a metallic salt to an alkoxide of other metal, preparing a viscous melt of a low grade polymer, and thermally decomposing the melt. CONSTITUTION:To a single metallic alkoxide of Al or the like or a composite metallic alkoxide is added >=1 kind of salt of other metal such as ZrCl4 using a solvent or the like. By heating them, the solvent is removed, and polymn. is allowed to proceed to prepare a viscous melt of a low-grade metallic alkoxide polymer. By further heating the melt, thermal decomposition is caused to form a brittle-like decomposition product by volume increase. The product is optionally held under reduced pressure. The product is amorphous, and by pulverizing and roasting it, fine powder of a high purity crystalline composite oxide such as alumina-zirconia is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new method for producing composite metal oxide fine powder, particularly fine powder having a uniform composition and structure. For details, see Metal Al;
A salt of a different metal for the purpose of compounding is added to the oxide, the alkoxide is polymerized to form a viscous melt of a low polymer, which is then thermally decomposed, and the resulting carmela-like complex decomposition product is crushed. , relates to a method for simply and efficiently producing the composite metal oxide fine powder by roasting.

In recent years, methods for producing composite metal compound powders using metal alkoxides have been developed compared to the conventional methods of physically mixing and roasting metal oxides and metal salts, or melting and pulverizing them. (a) A product of high purity is obtained.

佽) f, FRWI Memel A product with high homogeneity can be obtained.

(C) Particles with uniformly controlled particle size and particle shape can be obtained.

(a) A product with high reactivity can be obtained.

Because of its many advantages, it is attracting attention as a powder one-component production method for various composite composition ceramics, particularly for the electronic industry.

Methods for producing composite metal oxide powder using this metal alkoxide include: (1) Hydrolysis method of composite metal alkoxide containing two or more metals; (2) dropping metal alkoxide into an aqueous solution containing hydroxides of different metals; (3) A method of flame spraying the composite metal alkoxide, and the like are known.

Of the above methods, (1) and (2) are both hydrolysis methods, but in the case of (1), the complex metal alkoxide is hydrolyzed with pure water, and in the case of method (3), the single metal alkoxide is generally The difference is that the hydroxides of dissimilar metals for the purpose of compounding are hydrolyzed in an aqueous solution, and the slurry of the obtained composite metal oxides or their hydrates is dried and roasted. It is.

However, these hydrolysis methods have the following drawbacks.

That is, the above method requires many steps and is complicated to operate, and furthermore, because the particles in the resulting slurry are minute,
When drying a slurry, the particles tend to aggregate and solidify using conventional methods. To avoid this,
A special drying method such as freeze drying or drying after washing with an organic solvent is required, which further complicates the process and requires a great deal of labor and cost.

The flame atomization method described in (3) is a method in which a solution of a composite metal alkoxide dissolved in a flammable solvent such as alcohol is atomized, heated, and burned, but it has the following drawbacks.

In other words, the above-mentioned method generally has poor reactivity because the powder obtained is tightly aggregated spherical particles, and is also uneconomical because it requires large-scale collection equipment and uses a flammable solvent. In addition, high technology and expensive equipment are required to maintain purity.

The purpose of the present invention is to provide a new production method that has the advantages of the alkoxide method described above and does not have the disadvantages of known methods. The object of the present invention is to obtain a carmela-like complex decomposition product that is easily pulverized by a simple process of thermally decomposing a viscous melt of added quince alkoxide low polymer.

The present inventors have discovered that when certain metal alkoxides are heated and polymerized, their viscosity increases, and especially immediately before decomposition, the viscosity increases significantly. Decomposition progresses with rapid foaming, and in many cases, simultaneous decomposition occurs even in temperature ranges where it would not decompose on its own if a salt of the desired dissimilar metal is added in advance. I found out. As a result, the decomposition product becomes a composite composition with a uniform composition and structure, and also swells upon arrival and becomes so-called carmela-like, which makes it very fragile, so that it can be made into a fine powder by simply pulverizing it. Since the above decomposition products are generally amorphous or have poor crystallinity, they are roasted at a predetermined temperature to form crystalline metal oxide fine powder.

The method of the present invention is effective in producing a composite metal oxidation fine powder with a uniform composition and structure because the simultaneous decomposition of metal alkoxide and metal salt occurs uniformly. Further, in the method of the present invention, when other minor components are added to the main component, it is effective to add them homogeneously or in a dispersed manner. Most preferably, it is dissolved in an alkoxide or an organic solvent, and in this sense, hydrochlorides, nitrates, etc. are generally preferred.

Next, the present invention was developed using alumina (At203)-zirconia (
A composite system based on Zr02) will be specifically explained as an example.

First, a predetermined amount of zirconium chloride (other salts may be used, but since they are soluble in alcohol, it is convenient for uniform dispersion in the alkoxide) is added to isopropyl alcohol and completely dissolved.

Since zirconium chloride is generally used as a raw material for synthesizing zirconium alkoxide, it is clear that using it as it is is more advantageous than using a composite alkoxide of aluonium and zirconium.

Next, this alcoholic solution in which zirconium chloride was dissolved was added to a predetermined amount of aluminum isopropoxide, and fiJM in which aluminum chloride and impropoxide were dissolved was added.
Make an alcohol solution. This 1KIJtlr is discharged from the system. At this time, if nitrogen gas or the like is used as a carrier, the discharge rate becomes faster and it is more efficient. Once the alcohol has been discharged, continue heating until it reaches above the melting point (
In order to speed up the reaction, higher temperatures are preferable, and the most preferable temperature is boiling point) to advance polymerization. At this time, it is desirable to provide a cooler to reflux the aluminum isopropoxide in order to avoid loss of the aluminum isopropoxide as vapor.

After that, if the aluminum isopropoxide is kept at a predetermined temperature for a certain period of time (higher temperatures are preferred to speed up the reaction, most preferably the boiling point, but this temperature varies depending on the composition), the decomposition of aluminum isopropoxide begins rapidly, and the gas As it occurs, the viscosity increases significantly and the carmela-like decomposition product is produced within a short period of time. At this time, zirconium chloride also releases chlorine gas and decomposition progresses, so the carmela-like decomposition product has a complex composition.

Zirconium chloride has the property of sublimating at temperatures above 300°C, but at temperatures two times lower than this temperature, for example, with a composition in which zr□z is 170% in terms of oxide,
The fact that it decomposes at temperatures around 0°C is a characteristic phenomenon.

In addition, aluminum impropoxide is much less stable than when used alone, and as the decomposition temperature decreases, the time in the decomposition trench is shortened. is also a feature.

This phenomenon is more remarkable when magnesium salt is added, and this will be explained in detail in the examples below. Note that once carmela-like decomposition products are produced, it is desirable to hold them for a certain period of time in order to reduce the amount of undecomposed products and reduce the weight loss during combustion.

It is particularly efficient to carry out under reduced pressure. The decomposition product thus obtained is amorphous, and after being crushed to a predetermined particle size, it can be roasted at a predetermined temperature to obtain a crystalline alumina-zirconia complex oxide fine powder.

Therefore, the crystal structure of zirconia normally changes from monoclinic to tetragonal (at temperatures above 100°C).
tetragonal) and slowly cooled to 200°C.
When the following conditions are used, the monoclinic form is restored. However, the decomposition product obtained in the present invention is characterized in that the tetragonal crystal remains even after being roasted at a temperature of 00''S or higher and slowly cooled to room temperature.

Next, the present invention will be explained in more detail by way of examples.

Example In the noalumina-zirconia system, ■ When aiming for a ZrO2 content of 5% by weight, zirconia chloride A (ZrC24) 3. rgt-z.

The mixture was heated and dissolved in isopropyl alcohol (d), and transferred to a glass container with an internal volume/l equipped with a reflux condenser and containing 2.0 g of aluminum isopropoxide/j in advance. While cooling the reflux condenser with water, the container is heated and maintained at 60 ° C.,
An alcohol solution was prepared in which aluminum isopropoxide and zirconium chloride were completely dissolved. Next, the reflux condenser was controlled to θ°C, and the temperature of the container was raised to the boiling point of the inpropyl alcohol solution (approximately r, 2 to 4°C > t, while nitrogen gas was flowed into the system at a rate of ioOwl/-. The isopropyl alcohol was discharged out of the system. After the isopropyl alcohol was discharged, the nitrogen gas was stopped, and the temperature was
The temperature was raised at a rate of /- and maintained at the boiling point (JY°C) to proceed with polymerization. This insect repellent gas was allowed to naturally flow out of the system. After approximately /, jt hours, decomposition started with rapid generation of gas containing chlorine gas and increase in viscosity, and a carmela-like decomposition product expanded to about three times its original volume was obtained. Next, the temperature was lowered to 200° C., and the mixture was maintained under reduced pressure for about 72 hours while being evacuated, to finally obtain 2 g of pure white carmela-like decomposition product μ, which had expanded about 6 times in volume.

This decomposition product was collected at 100% after sampling in quadrants.
Chemical analysis of the roasted material at ℃ revealed that pZr
It was confirmed that the composition was uniform and contained a large amount of 02. Next, it was lightly ground in a urethane rubber-lined bot mill, and then roasted at 100°C to produce a pure white fine powder.
Together with the sample for analysis, Jr, Og was obtained.

In this case, almost no generation of chlorine gas was observed.

The fine powder roasted at 100°C was confirmed to be amorphous by X-ray diffraction. So, i4! As a result of roasting and slow cooling at oo℃ and X-ray diffraction, crystalline α-At
2QB and tetragonal zr02 were detected.

(2) When aiming at ZrQz content IO weight%! θ
d isoglobil alcohol zirconium dichloride 7jg
and aluminum isogloboxoxide/
Using 4I4t, Og, polymerization was carried out at the boiling point (21 μC) in the same manner as in Example t-a). Decomposition started after about 1 hour, and a carmela-like decomposition product expanded to about three times its original volume was obtained. The temperature was then lowered to 0°C, and the mixture was kept under reduced pressure for about 1 hour while being evacuated, and finally the carmela-like decomposition product, which had expanded to about twice its volume and was colored very slightly yellow to brown, was produced. to/g was obtained.

As originally intended, z r O2 was
It was confirmed that the composition was uniform and contained 0% by weight. In addition, after pulverizing in the same manner as in Example/-(1),
The powder was roasted to give an almost pure white powder, and X-ray diffraction revealed that most of it was amorphous. Therefore, /4(□o
When roasted at ℃ and slowly cooled, crystalline α-A120s and tetragonal and monoclinic Zr02 (the quantitative ratio of the two was about 7:0) were detected.

(3) When aiming at Zr□g-containing t, 2jffifq6, using a solution of zirconium chloride and og dissolved in 100 ml of isopropyl alcohol, and aluminum isopropoxide saw □, og, Example No. α) and Polymerization was allowed to proceed at the boiling point (23 μC) by the same operation. Decomposition started after about aO minutes, and a carmela-like decomposition product expanded to about three times its original volume was obtained. Then, the temperature was lowered to 2□0°C and kept under reduced pressure for about 72 hours while evacuation, and finally expanded to about twice the volume and turned into a completely brown-colored carmela-like decomposition product μ. I got g.

This decomposition product was analyzed in the same manner as in Example 1-(1), and it was confirmed that it had a uniform composition containing 25% by weight of Zro2, which met the original objective. Also, Example/-(
After crushing as in 1), roo'c.

As a result of roasting it to a very slightly yellow white powder and performing X-ray diffraction, it was found that a very small amount of tetragonal Zr with poor crystallinity was found.
Only O2 was detected. Then, when the material was roasted at 7≠00°C and slowly cooled, crystalline α-At203 and tetragonal and monoclinic ZrO2 (the ratio of both amounts was about 2:l) were detected.

(4) When aiming at ZrOz containing iao weight% 10
Zirconium chloride J in 0 dl isopropyl alcohol
Using a solution in which O and Jg were dissolved, and Aluminum Impropolymer, Dotat, and Og, polymerization was proceeded at the boiling point (Kokota°C) in the same manner as in Example/-α). about 7
Decomposition started after 0 minutes, and a carmeloid-like decomposition product was obtained which expanded to about three times its original volume. Next, the temperature was lowered to 200° C., and the mixture was maintained under reduced pressure for about 10 hours while being evacuated to obtain 32.3 g of a carmela-like decomposition product that expanded to about 6 times its volume and was colored blackish brown.

This decomposition product was analyzed in the same manner as in Example/-(1). As originally intended, ZrO2 was
It was confirmed that the composition was uniform. In addition, Example/: - Similar to (1), the powder was roasted at 100°C to produce a slightly yellowed white powder, and X-ray diffraction was performed.
Only a small amount of tetragonal ZrO2 with poor crystallinity was detected. Then, after roasting at u00℃ and slow cooling, crystalline α-At203 and tetragonal and monoclinic ZrO2 were obtained.
(The ratio of both amounts was approximately J:4A) was detected.

Example In a co-alumina-zircoair system, (1) When aiming at a ZrOz content of 1, 3.7 g of zirconium oxyacetate (04H6052r) was added to isopropyl alcohol and thoroughly stirred to disperse it uniformly. Then, in advance, aluminum ξium isogloboside l
! Internal volume with reflux condenser containing 260g/l
Transferred to a glass container. After further stirring sufficiently to obtain a uniform dispersion, polymerization was carried out at the boiling point (t<<'c) by the same operation as in Example/-(1). Decomposition started after about 1 hour, and a carmela-like decomposition product expanded to about three times its original volume was obtained. Then the temperature was lowered to 200°C,
Hold it under reduced pressure for about 72 hours while evacuation, and finally about 6
Pure white carmela-like decomposition product 4to expanded to double volume
, I got a yog.

This decomposition product was analyzed in the same manner as in Example 1-α), and was found to have a uniform composition containing 27% by weight of Zl-0, which met the original objective. Also, Example/-
As in (1), the powder was crushed and roasted at 100°C to obtain a pure white powder, and as a result of X-ray diffraction, it was confirmed that it was amorphous. When the material was roasted at 00°C and slowly cooled, crystalline At2Q3 and tetragonal zrQ2 were detected.

1e2) When aiming at Zr02 content go weight% 1
Using 3 g of zirconium oxyacetate homogeneously dispersed in 00d of isobrobyl alcohol and 6.0 g of aluminum isopropoxide, Example/-(1)
Isopropyl alcohol was discharged from the system in the same manner as above. After that, the nitrogen gas stopped, and the temperature rose at a rate of J℃/m, and the stability of aluminum isopropoxide became much worse than when it was used alone, and the temperature of the melt reached approximately J℃/m.
Decomposition begins with a rapid increase in viscosity at u℃, and the initial
A carmela-like decomposition product which expanded to double the volume was obtained.

Then, raise the temperature to 200°C and 1. After being kept under reduced pressure for about 72 hours, the yellow carmel-like decomposition product finally expanded to about 6 times its volume≠2. -g was obtained.

This decomposition product was analyzed in the same manner as in Example 1-(1), and it was confirmed that it had a homogeneous composition containing 0% by weight of Zr02, which was the initial objective. Also, Examples/
- Similar to (1), after grinding, it was roasted at 100℃ to produce a slightly yellowish white powder, and as a result of X-ray diffraction, only a very small amount of tetragonal zr02 with poor crystallinity was detected. .

When the fish was roasted at 7μ00℃ and slowly cooled, crystalline α-A was obtained.
zz□s and zr02 of tetragonal and monoclinic forms (ratio of the two is approximately θ, ri=/) were detected.

Example 3 Complete MgAt20 in alumina-magnesia system
4 (Spinel) For the purpose of composition (1) anhydrous magnesium chloride MgCLz (melting point 7/2°C, boiling point lμ) -
Anhydrous magnesium chloride in ethanol of jOd? ,! A solution in which g is dissolved, aluminum isopropoxide ao,
Using rg, ethanol was discharged out of the system in the same manner as in Example/-(1). After that, the nitrogen gas was stopped and the temperature was increased at a rate of j℃/m, and the temperature of the melt was approximately /
/IT:, decomposition started with rapid generation of gas containing chlorine gas and increase in viscosity, and a carmela-like decomposition product expanded to about three times its initial volume was obtained. Then the temperature is 2
The temperature was raised to 00° C. and maintained under reduced pressure for about 1 hour while evacuation, and finally 4 g of a white carmeloid decomposition product expanded to about 6 times the volume was obtained.

This decomposition product was lightly ground in a urethane rubber-lined bot mill, then roasted at 100°C and 1uoo°C, respectively.
The crystal structure was identified by 111 diffraction. As a result, MgAt204, which has poor crystallinity at too high a temperature,
At 0° C., MgAt20i with good crystallinity was detected.

(2) Magnesium nitrate Mg (NO3) 2-gHz
.

(Melting point Pju, 300℃ Chij H2Q (F) -r
Example using 100 dl of Magnesium nitrate compound).

Using the solution dissolved in tgflj and aluminum isopropoxide tAO and rg, ethanol was discharged from the system while maintaining the temperature at ti°C in the same manner as in Example 1-(1). When kept at this temperature for about 70 minutes, rapid generation of reddish-brown gas containing nitrogen dioxide and decomposition accompanied by an increase in viscosity began, and a carmela-like decomposition product expanded to about three times its original volume. was gotten. The temperature was then raised to 00°C and held under vacuum for about 10 hours with evacuation to finally obtain a slightly yellow carmeloid decomposition product which expanded to about 6 times its volume.

This decomposition product was roasted at 100°C and 7μ00°C and subjected to X-ray diffraction, and the results were the same as in Example J-(1).

(3) Magnesium acetate Mg (CH3COO)2.4
An example using tH20 (organomagnesium compound with a melting point of to°C)! Magnesium acetate comuda g dissolved and dispersed in 00d ethanol, aluminum isopropoxide ao,
Using rg, a white carmela-like decomposition product 7μ, rg was obtained through almost the same process as in Example 3-(2).

This decomposition product is roasted at too°C and i<too°C,
The results of line diffraction were the same as in Example 3-α).

(4) Magnesium oxalate MgC204・2H2
Example using magnesium oxalate/uj g homogeneously dispersed in ethanol of Owl and aluminum isopropoxide≠0. Using rg, polymerization was proceeded at the boiling point (17 s°C) by the same operation as in Example 1-ω. Decomposition started after about 20 minutes, and a carmela-like decomposition product expanded to about three times its original volume was obtained. Next, the temperature was raised to 100°C and maintained under reduced pressure while exhausting the air for about 1 hour, and finally a carmela-like decomposition product/4LJg with a very slight yellow color and expanded to about twice the volume was obtained. Ta.

This decomposition product was roasted at 100°C and subjected to X-ray diffraction, which revealed that it was mostly amorphous. Moreover, what was roasted at lμ00°C was crystalline MgAt204. In addition,
The crystallinity of spinel, detected by comparing the peak intensities of X-ray diffraction of the powder obtained by roasting Ir at 00°C, is the same as that of magnesium chloride>magnesium nitrate>magnesium acetate>magnesium sidiate (amorphous). Example 1 In the same manner as in Example 3-α), using anhydrous magnesium chloride and aluminum isopropoxide, which were precisely weighed to the milligram liter, for the purpose of stoichiometric addition of trace components. As MgO! Two types of carmela-like decomposition products were synthesized to contain 0O1iooo and 1oooP.

The above composite was then roasted at 100° C. and chemically analyzed, which showed 610, Tata 0X2030-, and Nasi, which were in very good agreement with the set values.

Claims (1)

[Claims] A single metal alkoxide or a composite metal alkoxide made of two or more metal alkoxides is added with one or more salts of metals different from the metals contained therein, and heated and polymerized to form a viscous metal alkoxide. A method for producing a composite metal compound, comprising: a low polymer melt; and a carmella-like composite decomposition product obtained by thermally decomposing the metal plucoxide low polymer melt containing the metal salt.