JP2911738B2 - Metal coating method on the surface of inorganic micro body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing metal-coated inorganic fine particles used as, for example, thermal spray materials, magnetic materials, conductive paints, ink materials and the like.

[0002]

2. Description of the Related Art It is known to use metal-coated inorganic fine particles, for example, as a thermal spray material. As a manufacturing method, an electroless plating method and a metallizing method are generally employed. However, in the electroless plating method, since a pretreatment is required, the operation is complicated. Further, in the metallizing method, an apparatus is large-scale. Therefore, mass production was impossible by any of the methods.

By the way, when a metal-coated inorganic fine particle is used as a thermal spraying material, the coated metal is melted and acts as a binder to form a thermal spray layer composed of the fine particle. As the thermal sprayed layer, a uniform and dense layer can be expected, and a thinner metal coating layer can provide a material having a sufficient property of a micro material. When a pigment such as metal-coated titanium oxide or iron oxide is dispersed in a paint and applied, a conductive coating film is obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating method capable of obtaining metal-coated inorganic fine particles very easily.

[0005]

According to a first aspect of the present invention, there is provided a method for coating a metal on the surface of an inorganic microparticle, wherein an anisole or diphenyl ether is added to an acetylacetonato chelate complex of one kind of a predetermined metal, a reducing agent, and an inorganic material. The microparticles are added and heated under reflux while stirring, and the inorganic microparticles are inorganic fibers or inorganic whiskers.

The inorganic fibers or whiskers have a diameter of 0.1 to 100 μm and a length of 1 to 1000 μm.
m, ceramics, cermets, diamonds, or clay minerals. Ceramics are titanium oxide, chromium oxide, aluminum oxide, silicon oxide, etc.Cermet is silicon carbide, silicon nitride, titanium nitride, aluminum nitride, tungsten carbide, chromium carbide, etc., and clay minerals , Mica, iron oxide and the like.

The predetermined metals include nickel, iron, cobalt, copper, zinc, chromium, molybdenum, titanium, vanadium, manganese, tungsten, silver, platinum, gold, palladium, beryllium, magnesium, aluminum, indium, gallium, and germanium. , Uranium, cadmium, calcium, strontium, barium, scandium, cerium, neodymium, or samarium.

The metal coating method for the surface of the inorganic fine particles according to the second invention of the present application is a method of adding one type of acetylacetonato chelate complex of a predetermined metal, a reducing agent, and inorganic fine particles to anisole or diphenyl ether, and stirring the mixture. While heating and refluxing, the inorganic fine particles are inorganic fine powder, the inorganic fine powder is ceramics, diamond, aluminum nitride, or iron oxide, the predetermined metal is titanium, vanadium, manganese, tungsten, Silver, platinum, gold, palladium, beryllium, magnesium, aluminum, indium, gallium, germanium, uranium, cadmium, calcium, strontium, barium, scandium, cerium, neodymium, or samarium. In particular, the inorganic fine powder preferably has a size of 0.01 to 100 μm.

The metal coating method on the surface of the inorganic fine particles according to the third invention of the present application is a method of adding an acetylacetonato chelate complex of two or more kinds of predetermined metals, a reducing agent, and inorganic fine particles to anisole or diphenyl ether; It is characterized by heating and refluxing while stirring.

The metal coating method on the surface of the inorganic fine particles according to the fourth invention of the present application is a method of adding one kind of acetylacetonato chelate complex of a predetermined metal, a reducing agent, and inorganic fine particles to anisole or diphenyl ether and stirring the mixture. The step of heating to reflux while heating is performed twice or more, and is characterized in that the above-mentioned predetermined metal is changed for each step.

The inorganic fine particles according to the third and fourth aspects of the present invention are inorganic fine powders having a size of 0.01 to 100 μm, such as ceramics, cermet, diamond,
Or clay minerals.

The inorganic fine particles of the third and fourth inventions are inorganic fibers or inorganic whiskers having a diameter of 0.1 to 100 μm and a length of 1 to 1000 μm.
m, ceramics, cermets, diamonds, or clay minerals.

Further, the predetermined metal of the third and fourth inventions is nickel, iron, cobalt, copper, zinc, chromium, molybdenum, titanium, vanadium, manganese, tungsten, silver, platinum, gold, palladium, beryllium. , Magnesium, aluminum, indium, gallium, germanium, uranium, cadmium, calcium, strontium, barium, scandium, cerium, neodymium, and samarium.

Further, the reducing agents of all the above inventions include:
Hydrides or hydrazines are preferably used. Examples of the hydrides include sodium borohydride, lithium hydride, potassium hydride, lithium aluminum hydride, potassium borohydride, and the like.Examples of hydrazines include hydrazinium sulfate, hydrazine, hydrazinium monochloride, and hydrazinium dichloride. And the like.

[0015]

[Action] When an acetylacetonato chelate complex of a metal such as iron, cobalt, nickel, or copper is reduced in an organic solvent,
Ultrafine particles of these metals are obtained. Therefore, when ultrafine particles of a metal are synthesized in the presence of an inorganic microparticle, the surface of the microparticle is bonded to the metal at the stage of generating a metal nucleus, and the surface of the microparticle is covered with the metal. In addition,
Since the reaction is performed in an organic solvent such as anisole or diphenyl ether, high-temperature treatment is possible, and therefore, even if the inorganic microparticles are chemically very low,
The above reaction occurs well.

When an acetylacetonato chelate complex of two or more metals is used, it is covered with an alloy having a composition composed of the metals used.

[0017]

Embodiments of the present invention will be described below. Note that the present invention is not limited to these examples. Example 1 0.01 mol of bis (acetylacetonato) diaqua nickel was dissolved in 150 ml of anisole,
20 ml of hydrazine was added thereto, and 1 g of calcium carbonate whiskers having a diameter of 1 to 2 μm and a length of 15 to 20 μm was put into the bath, and the mixture was heated and refluxed at 160 ° C. for 1 hour with stirring. The resulting whiskers were filtered, washed and dried.

1 and 2 are SEM photographs showing the obtained whiskers, and FIG. 3 is a photograph showing a characteristic X-ray image of the whiskers shown in FIG. 2, showing the distribution of the nickel component.
FIG. 4 is an X-ray diffraction diagram of the obtained whiskers. In addition,
FIG. 5 shows a whisker before coating.
FIG. 6 is an X-ray diffraction diagram of the whisker before coating. 1 and 4, it can be seen that a coating layer is formed on the whisker surface.
FIG. 3 shows that the coating layer contains a nickel component. 4 and 6, it can be seen that the coating layer is made of only metallic nickel. That is, a coating layer consisting only of metallic nickel was formed on the whisker surface by the above method.

Example 2 150 m of diphenyl ether
cerium tris (acetylacetonate) 0.03m
ol dissolved in this, sodium borohydride 0.6m
ol, and 0.5 μm in diameter and 15 μm in length were added to the bath.
5 g of α-silicon nitride whiskers of 0 to 200 μm were put therein, and the mixture was heated and refluxed at 250 ° C. for 2 hours while stirring. The resulting whiskers were filtered, washed and dried. In this example, a coating layer consisting of only cerium was formed on the whisker surface.

(Example 3) 250 m of diphenyl ether
l is tris (acetylacetonato) neodymium 0.02m
ol, and lithium aluminum hydride was added thereto.
1 mol was added, and a diameter of 10 μm and a length of 3
Add 10 g of 50 μm carbon fiber, and stir 2
The mixture was heated under reflux at 50 ° C. for 1 hour. The resulting whiskers were filtered, washed and dried. In this example, a coating layer consisting of neodymium only was formed on the whisker surface.

Example 4 0.01 mol of bis (acetylacetonato) magnesium was dissolved in 150 ml of anisole, 20 ml of hydrazine was added thereto, and 15 g of fine alumina powder having a particle size of 25 to 50 μm was added to the bath. The mixture was heated and refluxed at 160 ° C. for 1 hour with stirring. The resulting fine powder was filtered, washed and dried. In this example, a coating layer consisting of only magnesium was formed on the surface of the fine powder.

Example 5 150 m of diphenyl ether
cerium tris (acetylacetonate) 0.03m
ol dissolved in this, sodium borohydride 0.6m
Then, 10 g of tungsten carbide fine powder having a particle size of 30 to 50 μm was put into the bath, and the mixture was heated and refluxed at 250 ° C. for 2 hours while stirring. The resulting fine powder was filtered, washed and dried. In this example, a coating layer made of only cerium was formed on the surface of the fine powder.

(Example 6) 250 m of diphenyl ether
l is tris (acetylacetonato) neodymium 0.02m
ol, and lithium aluminum hydride was added thereto.
1 mol is added and the size is 20-50 μm in this bath.
10 g of fine powder of mica (precisely, a plate-like body) was added, and the mixture was heated and refluxed at 250 ° C. for 1 hour with stirring. The resulting fine powder was filtered, washed and dried. In this embodiment,
A coating layer consisting only of neodymium was formed on the surface of the fine powder.

(Example 7) 300 m of diphenyl ether
1 to 0.02 mol of tris (acetylacetonato) iron
And bis (acetylacetonato) nickel 0.02mol
And sodium borohydride 0.24m
Then, 2 g of alumina fine powder having a particle size of 20 μm was put into the bath, and the mixture was heated and refluxed at 210 ° C. for 8 hours while stirring. The resulting fine powder was filtered, washed and dried. FIG. 7 is an X-ray diffraction diagram of the obtained fine powder. Apparently, a peak of the iron-nickel alloy is observed. That is, in this example, a coating layer made of an iron-nickel alloy was formed on the surface of the fine powder. The alloy composition of this coating layer was iron: nickel = 1: 1.

Fine powders were obtained in the same manner as described above while varying the mixing ratios of tris (acetylacetonato) iron and bis (acetylacetonato) nickel to be used. When the relationship with the above mixing ratio was examined, the results shown in FIG. 8 were obtained. From FIG. 8, it can be seen that the content ratio and the compounding ratio substantially match. That is, by changing the mixing ratio, the alloy composition of the coating layer is arbitrarily set.

(Example 8) 300 m of diphenyl ether
l, tris (acetylacetonato) cobalt 0.03
mol and bis (acetylacetonato) nickel 0.07
mol of sodium borohydride.
24 g was added, and 2 g of alumina fine powder having a particle size of 20 μm was put into the bath, and the mixture was heated and refluxed at 210 ° C. for 8 hours while stirring. The resulting fine powder was filtered, washed and dried. In this example, a coating layer having an alloy composition of cobalt: nickel = 3: 7 was formed on the surface of the fine powder.

(Example 9) 300 m of diphenyl ether
l, tris (acetylacetonato) cobalt 0.02
mol and bis (acetylacetonato) nickel 0.04
mol and tris (acetylacetonato) iron 0.04mo
and sodium borohydride 0.24
mol was added to the bath, and the diameter was 10 μm and the length was 35 μm.
10 g of carbon fiber of 0 μm is added, and 21 g is stirred.
The mixture was refluxed at 0 ° C. for 8 hours. The resulting whiskers were filtered, washed and dried. In this example, a coating layer having an alloy composition of cobalt: nickel: iron = 1: 2: 2 was formed on the whisker surface.

Example 10 0.31 mol of bis (acetylacetonato) nickel and 10 mol of anhydrous hydrazine were mixed with 1.5 l of anisole, and fine powder of α-alumina having a particle size of 2.5 μm was placed in the bath. 30 g was added, and the mixture was heated and refluxed at 110 ° C. for 1 hour with stirring. The obtained fine powder was filtered, washed with acetone, and dried. This fine powder was further placed in a bath in which 1.6 l of diphenyl ether was mixed with 0.16 mol of tris (acetylacetonato) cobalt and 1.5 mol of sodium borohydride, and the mixture was heated and refluxed at 230 ° C. for 4 hours with stirring. . The resulting fine powder was filtered, washed and dried. When the obtained fine powder was subjected to X-ray diffraction measurement, a peak of a nickel-cobalt alloy was recognized. That is, a coating layer made of a nickel-cobalt alloy was formed on the surface of the fine powder. Further, the alloy composition of the coating layer was nickel: cobalt = 2: 1, which was consistent with the mixing ratio.

Example 11 In 150 ml of anisole,
0.05 mol of bis (acetylacetonato) nickel and 0.15 mol of anhydrous hydrazine are mixed, and 5 g of carbon fibers having a diameter of 10 μm and a length of 350 μm are placed in the bath.
And heated to reflux at 110 ° C. for 1 hour with stirring.
The obtained carbon fiber was filtered, washed with acetone, and dried. The carbon fiber was further added to 170 ml of diphenyl ether and 0.1 m of tris (acetylacetonato) iron.
ol and 1 mol of sodium borohydride were placed in a mixed bath, and the mixture was heated and refluxed at 230 ° C. for 4 hours with stirring. The obtained carbon fiber was filtered, washed, and dried. The obtained carbon fiber was subjected to X-ray diffraction measurement. As in Example 1, a peak of an iron-nickel alloy was observed. That is, a coating layer made of an iron-nickel alloy was formed on the carbon fiber surface. The alloy composition of the coating layer was iron: nickel = 2: 1, which was consistent with the compounding ratio.

[0030]

Another Embodiment The inorganic fine powder used in the present invention is 0.0
It is not limited to the above embodiment as long as the size is 1 to 100 μm. Also, inorganic fibers or inorganic whiskers,
The present invention is not limited to the above embodiment as long as the diameter is 0.1 to 100 μm and the length is 1 to 1000 μm. Further, as the type of the inorganic fine powder, the inorganic fiber, or the inorganic whisker, ceramics, cermets, diamonds, clay minerals, and the like other than those used in the above embodiment may be used.

The metal to be coated in the present invention is
Not limited to the above embodiments, nickel, iron, cobalt, copper, zinc, chromium, molybdenum, titanium, vanadium, manganese, tungsten, silver, platinum, gold, palladium, beryllium, magnesium, aluminum, indium, gallium, germanium , Uranium, cadmium,
Any of calcium, strontium, barium, scandium, cerium, neodymium, and samarium can be used.

Further, the reducing agent used in the present invention is not limited to those of the above-mentioned embodiments, as long as they are hydrides or hydrazines.

[0033]

As described above, according to the method for coating a surface of an inorganic fine body with a metal according to the present invention, the following effects can be obtained. (1) According to the method of the first invention of the present application, a metal coating layer can be formed on the surface of inorganic fibers or inorganic whiskers.

In addition, since it is only necessary to add a metal acetylacetonate chelate complex, a reducing agent, inorganic fibers, and the like to an organic solvent and heat and reflux while stirring, the process can be performed very easily.

Further, since the reaction is carried out with stirring, the complex, the reducing agent, the inorganic fibers and the like are uniformly dispersed in the organic solvent, and the surface of the inorganic fibers or the inorganic whiskers uniformly encounters the metal. Therefore, a metal coating layer having a uniform thickness can be formed.

In addition, since the quantitative ratio of the substance to be added can be easily changed, the thickness of the metal coating layer can be easily adjusted, for example, it can be very thin.

(2) According to the method of the second invention of the present application,
A coating layer made of a predetermined metal can be formed on the surface of the inorganic fine powder. The other effects are the same as those of the above (1).

(3) According to the method of the third invention of the present application,
A coating layer made of an alloy can be formed on the surface of the inorganic fine body in a single reaction step.

Further, by changing the kind and the mixing ratio of the metal to be added, an alloy coating layer having an arbitrary composition and content can be formed. The other effects are the same as those of the above (1).

(4) According to the method of the fourth invention of the present application,
A coating layer made of an alloy can be formed on the surface of the inorganic fine particles. The other effects are the same as those of the above (3).

[Brief description of the drawings]

FIG. 1 is a photograph replacing a drawing showing a particle structure,
3 is an SEM photograph showing a whisker obtained in Example 1.

FIG. 2 is a photograph replacing a drawing showing a particle structure,
3 is an SEM photograph showing a whisker obtained in Example 1.

3 is a photograph replacing the drawing, and is a photograph showing a characteristic X-ray image of a nickel component of the whisker shown in FIG. 2;

FIG. 4 is an X-ray diffraction diagram of the whiskers obtained in Example 1.

FIG. 5 is a photograph replacing a drawing showing a particle structure,
5 is an SEM photograph showing whiskers before metal coating is performed in Example 1.

FIG. 6 is an X-ray diffraction diagram of a whisker before metal coating is performed in Example 1.

FIG. 7 is an X-ray diffraction diagram of the fine powder obtained in Example 7.

FIG. 8 is a view showing the relationship between the mixing ratio of metals and the content ratio in the method of Example 7.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C23C 18/31

Claims (11)

(57) [Claims] 1. Anisole or diphenyl ether,
An inorganic acetylacetonate chelate complex of one kind of a predetermined metal, a reducing agent, and an inorganic microparticle, which are heated and refluxed with stirring, wherein the inorganic microparticle is an inorganic fiber or an inorganic whisker; Metal coating method on the surface of the micro body. 2. The inorganic fine particles have a diameter of 0.1 to 1
00 μm, ceramics having a length of 1 to 1000 μm,
The method for coating a metal on the surface of an inorganic microparticle according to claim 1, which is a cermet, a diamond, or a clay mineral. 3. The predetermined metal is nickel, iron, cobalt, copper, zinc, chromium, molybdenum, titanium, vanadium, manganese, tungsten, silver, platinum, gold, palladium, beryllium, magnesium, aluminum, indium, gallium. 2. The method according to claim 1, wherein the metal is selected from the group consisting of germanium, uranium, cadmium, calcium, strontium, barium, scandium, cerium, neodymium and samarium. 4. Anisole or diphenyl ether,
One kind of acetylacetonato chelate complex of a predetermined metal, a reducing agent, and an inorganic microparticle are added and heated and refluxed with stirring. The inorganic microparticle is an inorganic fine powder, and the inorganic fine powder is a ceramic, diamond,
Aluminum nitride or iron oxide, the predetermined metal,
Titanium, vanadium, manganese, tungsten, silver, platinum, gold, palladium, beryllium, magnesium, aluminum, indium, gallium, germanium, uranium, cadmium, calcium, strontium, barium, scandium, cerium, neodymium, or samarium Characteristic metal coating method on the surface of inorganic microparticles. 5. The method according to claim 1, wherein the inorganic fine powder is 0.01 to 100.
The method for coating a metal on the surface of an inorganic microparticle according to claim 4, which has a size of μm. 6. Anisole or diphenyl ether,
A method for coating a metal surface on an inorganic microparticle, comprising adding an acetylacetonatochelate complex of two or more kinds of predetermined metals, a reducing agent, and an inorganic microparticle, and heating and refluxing while stirring. 7. Anisole or diphenyl ether,
The step of adding one kind of acetylacetonato chelate complex of a predetermined metal, a reducing agent, and inorganic microparticles and heating and refluxing with stirring is performed twice or more. A method of coating a metal on the surface of an inorganic microscopic body, characterized in that the metal coating is performed. 8. The inorganic fine body is a fine inorganic powder, having a size of 0.01 to 100 μm, ceramics,
The method for coating a metal surface on an inorganic microparticle according to claim 6, which is a cermet, a diamond, or a clay mineral. 9. The inorganic fine body is an inorganic fiber or an inorganic whisker, having a diameter of 0.1 to 100 μm and a length of 1 to 1000 μm, ceramics, cermet,
The method for coating a metal on an inorganic microparticle surface according to claim 6 or 7, which is a diamond or a clay mineral. 10. The predetermined metal is nickel, iron, cobalt, copper, zinc, chromium, molybdenum, titanium, vanadium, manganese, tungsten, silver, platinum, gold, palladium, beryllium, magnesium, aluminum, indium, gallium. 8. The method for coating a metal surface on an inorganic microparticle according to claim 6, wherein the metal is arbitrarily selected from the group consisting of, germanium, uranium, cadmium, calcium, strontium, barium, scandium, cerium, neodymium, and samarium. 11. The method according to claim 1, wherein the reducing agent is a hydride or a hydrazine.