JP3530936B2 - Metal oxide structure, manufacturing method and manufacturing apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal oxide structure having whiskers with improved mechanical strength, a method for manufacturing the same, and a manufacturing apparatus for the same.

[0002]

2. Description of the Related Art Metal oxides are surface modifiers for the purpose of antibacterial and antifouling effects, etc. for electronic materials and optical materials such as ceramic capacitors, actuators, light wavelength conversion elements, laser oscillation elements and cold cathode elements. It is used in a wide range of applications such as catalysts and their supports in the gas phase, liquid phase and both phases. The gold oxide used for these purposes is required to have a large surface area per volume. The present inventors have found that a metal oxide structure having a large number of whiskers in a small area can be obtained by spraying a vaporized metal compound on a heated substrate surface together with a carrier gas under atmospheric pressure open. , I proposed earlier. (Japanese Patent Laid-Open No. 2000-58365, etc.)

[0003]

These metal oxide whisker dense structures have an extremely large surface area and are excellent in various properties such as conductivity and piezoelectricity. However, the mechanical strength of the whiskers is weak, However, there is a problem in that the whiskers are broken during processing, and the whiskers are destroyed by discharge when used as a field emission device, for example. The present invention solves these problems of the prior art, and has a metal oxide structure having whiskers with significantly improved mechanical strength and durability without deteriorating the functional characteristics of the metal oxide whisker matrix. An object is to provide a body, a manufacturing method thereof, and a manufacturing apparatus.

[0004]

In order to solve the above problems, the present invention has the following constitution. 1. In a metal oxide structure having a metal oxide whisker having a circle approximate cross-sectional diameter of 0.01 to 100 μm and a length ratio to the circle approximate cross-sectional diameter of 1 or more, the whisker is inside the whisker in the long axis direction of the whisker. metal oxide structure, characterized in that it has a reinforcing layer of different composition than the base metal composition obtained by the different elements added to the base material constituting the Huy <br/> Scar along. 2. The ratio of the different elements is 0.
The metal according to 1, which is 1 to 10 atom%.
Oxide structure. 3. Whiskers on the substrate surface 10 μm × 10 μm of
Be present at a density of 0.1 to 10,000 per area
3. The metal oxide structure according to 1 or 2, characterized in that. 4. 4. The metal oxide structure according to any one of 1 to 3, wherein the whiskers have consistent properties along the long axis direction of the whiskers. 5. 5. The metal oxide structure according to any one of 1 to 4, wherein the base material forming the whiskers and the reinforcing layer are chemically bonded. 6. 6. The metal oxide structure according to any one of 1 to 5, wherein the crystal relationship between the base material forming the whiskers and the reinforcing layer is epitaxial. 7. The base material elements and heterogeneous elements that make up the whiskers
In the periodic table, groups 1 and 2 excluding hydrogen, groups 13 excluding boron, groups 14 excluding carbon, nitrogen, phosphorus and arsenic excluding 1
Group 5 and 3,4,5,6,7,8,9,10,11,1
7. The metal oxide structure according to any one of 1 to 6, which contains at least one metal selected from Group 2. 8. Metals are Zn, Si, Al, Sn, Ti, Zr and P
8. The metal oxide structure according to 7, which is selected from b. 9. 9. The metal oxide structure according to any one of 1 to 8, wherein the space between the whiskers is filled with a material selected from organic substances, inorganic substances, and metals. 10. A gas containing a vaporized metal oxide whisker base material constituent element and a gas containing an element different from the vaporized base material are uniformly mixed with a carrier gas, and then on a substrate surface heated under atmospheric pressure release. Characterized by depositing a metal oxide structure having a metal oxide whisker having a circle approximate cross-sectional diameter of 0.01 to 100 μm and a length ratio to the circle approximate cross-sectional diameter of 1 or more by spraying. The method for producing a metal oxide structure according to any one of 1 to 9 below. 11. 11. The method for producing a metal oxide structure according to 10, further comprising filling the space between the whiskers of the obtained metal oxide structure with a material selected from organic substances, inorganic substances and metals. 12. Vaporizer of the base material that constitutes the metal oxide whiskers,
A vaporizer of an element different from the base material, a vaporized base material and a raw material mixer for uniformly mixing an element different from the base material with a carrier gas, a nozzle for ejecting the mixed raw material gas, and a base material heating table. The apparatus for producing a metal oxide structure according to any one of claims 1 to 9, wherein:

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION With whiskers in the present invention,
It means a substance having a substantially rod-shaped structure having a circle approximate cross-sectional diameter of 0.01 to 100 μm (average value: the same applies hereinafter) and a length ratio (aspect ratio) to the circle approximate cross-sectional diameter of 1 or more. The whisker length means the length from the position where the whisker substantially protrudes from the surface (base) to the tip, and the approximate circle cross-section diameter is measured at a position half the length of the whisker. To do. The circle approximate cross-sectional diameter is represented by a value that is twice the square root of the area obtained by obtaining the cross-sectional area by a conventionally known method such as image analysis and dividing the obtained area by the pi.

If the whisker has an approximate circle cross-sectional diameter of less than 0.01, it is difficult to obtain a grown whisker, and if it exceeds 100 μm, it becomes difficult to obtain desired characteristics due to an increase in surface area. . The circle approximate cross-sectional diameter is preferably 0.05 to 50 μm, and particularly preferably 0.1 to 10 μm. The length of the whiskers is arbitrarily selected depending on the intended use, but is usually 0.1 to 1000 μm.
(Average value), preferably 1 to 500 μm. The aspect ratio is 1 or more, preferably 5 or more. If the aspect ratio is too small, the effect of increasing the surface area by whiskers does not appear.

[0007] It is preferable that the whiskers are densely present at a ratio of 0.1 to 10000, and particularly 1 to 1000, per 10 µm x 10 µm area. When this ratio is small, the effect of increasing the surface area due to whiskers is poor, and when it is too large, it becomes difficult to obtain grown whiskers. The shape of the whisker is that the diameter does not change from the root part to the tip part, the diameter does not change from the root part to a certain distance, the diameter of the base part of the whisker is small, and the diameter once increases as it goes to the tip part. The diameter gradually decreases again, the diameter decreases gradually from the root of the whisker to the tip, and the pyramid or the truncated pyramid or the cone or the truncated cone or the hemisphere is seen from a certain distance near the tip. And the like, and combinations thereof. A prismatic shape or a prismatic shape in which the diameter of the root portion of the whisker is small and the diameter is once large is preferable. In the case of a prism, the specific shape depends on the crystal structure,
For example, when the metal oxide is zinc oxide, it is often a hexagonal column, when it is aluminum oxide, it is a square column or hexagonal column, and when it is titanium oxide, it is a square column. In addition, other polygonal prisms having a cross-sectional shape may be used.
Among these, it is particularly preferable that one prism has a portion in which the surfaces facing each other are parallel to each other.
Further, in this case, the whiskers may have other shapes as long as they have mutually parallel surfaces.

The metal oxide structure having whiskers of the present invention is characterized in that the whiskers have a reinforced structure obtained by adding an element different from the base material forming the whiskers. The whiskers having such a reinforced structure can be obtained by using, for example, the apparatus shown in FIG. 1 to generate a gas containing a vaporized metal oxide whisker base material constituent element and a gas containing an element different from the vaporized base material. It can be obtained by uniformly mixing with a carrier gas and then spraying the heated substrate surface under atmospheric pressure to deposit a metal oxide structure on the substrate surface.

FIG. 1 is a schematic view showing an example of an apparatus for producing the metal oxide structure of the present invention. This manufacturing device 1
Is a nitrogen gas supply source 2 or 2 serving as a carrier gas, a vaporizer 3 of a base material constituting a metal oxide whisker, a vaporizer 4 of an element different from the base material, a vaporized base material and a heterogeneous element as a carrier. Raw material mixer 5 for uniformly mixing with gas, nozzle 9 for jetting mixed raw material gas, and heating base 1 for substrate 10.
1 is provided. The base material forming the metal oxide whiskers and the element different from the base material are heated and vaporized by vaporizers 3 and 4, respectively, and sent to the raw material mixing reservoir 6 in the raw material mixer 5 together with the nitrogen gas, and then the heater 7 It is uniformly mixed with the carrier gas by the coiled heating mixer 8 provided on the outer periphery. The uniformly mixed raw material gas is sprayed from the nozzle 9 onto the surface of the base material 10 heated on the heating table 11 having the heater 12 under the atmospheric pressure, and the metal having the metal oxide whiskers on the surface of the base material. Form an oxide structure.

In the present invention, as the metal oxide constituting the whisker base material and the reinforced structure composed of an element different from the base material, the metal species is a group 1 or 2 except hydrogen in the periodic table.
Group, group 13 excluding boron, group 14 excluding carbon, group 15 excluding nitrogen, phosphorus and arsenic, and 3, 4, 5, 6, 7, 8,
Reinforcements of each element belonging to groups 9, 10, 11, and 12 can be mentioned. Examples of the metal species include Li, Na, K and R
b, Cs, Be, Mg, Ca, Sr, Ba, Al, G
a, In, Tl, Si, Ge, Sn, Pb, Sb, B
i, Po, Sc, Y, La, Th, Ce, Pr, Nd,
Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
m, Yb, Lu, Ti, Zr, Hf, V, Nb, Ta,
Cr, Mo, W, Mn, Tc, Re, Fe, Ru, O
s, Co, Rh, Ir, Ni, Pd, Pt, Cu, A
g, Au, Zn, Cd, Hg, and the like. Among these, Li, Na, K, Rb, Cs, and B are preferable.
e, Mg, Ca, Sr, Ba, Al, Ga, In, T
i, Si, Ge, Sn, Pb, Sb, Bi, Sc, Y,
La, Ce, Th, Ti, Zr, V, Nb, Ta, C
r, Mo, W, Mn, Re, Fe, Ru, Os, Co,
Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Z
n, Cd, and Hg, more preferably Li, K,
Mg, Ca, Sr, Ba, Al, In, Si, Sn, P
b, Th, Y, Ce, Ti, Zr, V, Nb, Ta, C
r, Mo, W, Mn, Fe, Co, Ni, Pd, Pt,
Cu, Ag, Zn, Cd may be mentioned. The most preferable metal species are Zn, Si, Al, Sn, Ti, Zr,
And Pb are exemplified.

Examples of metal oxides include MgO and A.
l_Two O_Three , In_Two O_Three , SiO _Two , SnO_Two , T
iO_Two , ZnO, BaTiO_Three, SrTiO_Three , Li
NiO_Three, PZT [Pb (Zr_×Ti_{1- ×} ) O
_Three ], YBCO (YBaCu_ThreeO_7-x ), YSZ
(Yttria-stabilized zirconia), YAG (Y_ThreeAl₅
O ₁₂Or 3Y_TwoO_Three・ 5Al_TwoO_Three), ITO (I
n_TwoO_Three/ SnO_Two) And the like. Also alkali
It is also possible to use a combination of a metal and another metal.
For example, by combining Ta, Nb and alkali metal, etc., K
TaO_ThreeOr NbLiO_Three Forming complex compounds like
And can be made into a metal oxide.

In the metal oxide structure of the present invention, the metal compound as a raw material for forming the whisker base material and the strengthening structure composed of a different element from the base material is a metal in the metal oxide of the target structure. It is preferable that the compound has an oxygen atom and reacts with a compound contained in the atmosphere such as oxygen and water to form an oxide. However, in the atmosphere in which the metal compound is sprayed,
Supply substances that are not normally present in the atmosphere, such as ozone
It may be present and react with these to form an oxide.

Examples of such a metal compound include alkoxides in which the hydrogen atom of the alcohol hydroxyl group is replaced with a metal at the atom of the metal or metal-like element, acetylacetone, ethylenediamine at the atom of the metal or metal-like element,
Bipiperidine, bipyrazine, cyclohexanediamine,
Tetraazacyclotetradecane, ethylenediaminetetraacetic acid, ethylenebis (guanide), ethylenebis (salicylamine), tetraethyleneglycol, aminoethanol, glycine, triglycine, naphthyridine, phenanthronine, pentanediamine, pyridine, salicylaldehyde, salicylyl Various complexes having one or more kinds of ligands selected from denamine, porphyrin, thiourea, etc., Fe, Cr, Mn, Co, Ni, Mo, V, W having a carbonyl group as a ligand, Various metal carbonyls such as Ru, carbonyl groups, alkyl groups, alkenyl groups, phenyl or alkylphenyl groups, olefin groups, aryl groups, conjugated diene groups including cyclobutadiene groups, and cyclopentadienyl groups. The Group, triene group, arene group,
Various metal compounds and halogenated metal compounds having one kind or two or more kinds of ligands selected from a triel group such as a cycloheptatrienyl group can be used. Also, other metal complexes can be used. Among these, metal acetylacetonate compounds,
A metal alkoxide compound and the like are more preferably used.

As the complex in the present invention, β-
Diketones, ketoesters, hydroxycarboxylic acids or salts thereof, various Schiff bases, keto alcohols, polyvalent amines, alkanolamines, enolic active hydrogen compounds, dicarboxylic acids, glycols, ferrocenes, etc. Examples thereof include compounds in which one or more kinds of ligands are bound.

In the present invention, the ratio of the element composing the base material of the whiskers to the different element composing the reinforcing structure of the whiskers is arbitrary, but usually a small amount (0.1 A different element of about 10 atomic% is present. In the whiskers of the present invention, when the heterogeneous element is present in an amount equal to or more than the solid solution limit with respect to the metal oxide constituting the base material, it is extruded at a specific place in the whisker crystal, and the base material has high mechanical strength. It is believed to form reinforced structures of different composition. Therefore, it is preferable that the amount of the different element in the whisker is not less than the solid solution limit with respect to the metal oxide forming the whisker.

In the present invention, the reinforcing structure in the whiskers is present as a reinforcing layer formed along the long axis direction of the whiskers and having a composition different from that of the base material. FIG. 2 is a schematic view showing an example of the reinforcing structure in the whisker of the present invention,
FIG. 2A is a side sectional view of the whisker (XX in FIG. 2B).
FIG. 2B is a cross-sectional view of the whisker. The whisker 20 has a hexagonal columnar shape whose diameter gradually decreases from the root portion to the tip portion, and a reinforcing structure 22 made of aluminum oxide is provided at the center of a base material 21 made of zinc oxide. It is formed in layers along the axial direction.

FIGS. 3 and 4 are views showing other examples of the reinforcing structure in the whiskers. FIG. 3A is a side sectional view of the whiskers (a sectional view taken along line XX of each figure (B)). ) And (B) are cross-sectional views of the whiskers. These whiskers 30 and 40 have a hexagonal columnar shape similar to the whiskers of FIG. 2, and in the whiskers 30 of FIG. 3, a base material 31 made of zinc oxide has a diagonal line connecting opposite edges of the hexagonal columns. It has a layered reinforcing structure 32 made of aluminum oxide formed in a striped shape (see FIG. 3B). In addition, the whisker 40 of FIG. 4 is a reinforced structure 4 having a cavity 43 in the center of the whisker 30 of FIG.
2 is formed (see FIG. 4 (B)).

The reinforcing structure formed in the whisker may be formed so as to completely traverse the whisker as seen in the above examples, or may be partially formed in the cross section of the whisker. . The whisker of the present invention is strong against lateral strain by having the reinforcing layer along the major axis direction as described above, and also has conductivity, strength, piezoelectricity, etc. along the major axis direction of the whisker. The whisker has consistent physical properties. It is preferable that the base material forming the whiskers and the reinforcing structure are chemically bonded to each other by an ionic bond, a covalent bond, or the like. Further, when the crystal relationship between the base material and the reinforced structure is epitaxial, a metal oxide structure having excellent characteristics such as conductivity and piezoelectricity can be obtained, which is preferable.

The base material for producing the metal oxide structure having whiskers of the present invention is, for example, a metal oxide single crystal such as aluminum oxide, a semiconductor single crystal, a ceramic, silicon, Fe, Ni or the like. Examples include metal, glass, and plastic. The metal oxide structure having whiskers of the present invention more preferably has the whiskers epitaxially grown on the substrate. Whether the metal oxide is epitaxially grown on the substrate depends on
It can be confirmed by a usual X-ray diffraction method. In particular,
A method of confirming by observing the in-plane orientation relationship between the substrate and the metal oxide by the φ scan method is preferably used.

Those which are particularly preferably used as the substrate of the present invention are specifically silicon, aluminum oxide,
It is a metal oxide single crystal such as magnesium oxide or SrTiO ₃ . In this case, the crystal may be one or more single crystals, a polycrystal, one or more semi-crystalline substances having an amorphous part and a crystal part at the same time, or a mixture thereof. May be. Most preferably, it is a single crystal. In this case, the surface of the substrate is preferably a specific surface of the single crystal.

In the present invention, the raw material compound constituting the whisker base material and the raw material compound constituting the whisker strengthening structure of a different element from the base material are heated and vaporized, respectively, and then uniformly mixed with the carrier gas. A metal oxide structure having a target whisker is manufactured by spraying the surface of a base material heated under atmospheric pressure. The carrier gas is not particularly limited as long as it does not react with the metal compound used. Specific examples thereof include nitrogen gas, an inert gas such as helium, neon, and argon, carbon dioxide gas, organic fluorine gas, and organic substances such as heptane and hexane. Of these, inert gas is preferable from the viewpoint of safety and economy. In particular, nitrogen gas is the most preferable in terms of economy.

The temperature of the base material on which the metal oxide structure is formed is not particularly limited as long as it is the temperature at which the metal oxide is formed near and on the surface of the base material. It is preferable to set the temperature higher than the temperature, and usually it is set to 100 to 700 ° C. In the present invention, the reaction time required to form the metal oxide structure having whiskers is appropriately selected depending on the type of raw material, reaction conditions, intended use of the structure, and the like.

In the present invention, a metal oxide structure in which whiskers are usually formed in a dense state is obtained, but voids exist between the whiskers. Therefore, the structure may be deformed at the time of use depending on the form used. In other words, physical stress may cause many whiskers to be knocked down. To prevent this, for example, thermoplastic resin, thermosetting resin,
The whiskers can be filled and fixed with an organic substance such as an elastomer or an instant adhesive such as cyanoacrylate, an inorganic substance such as glass or ceramic, or a metal.

The thermoplastic resin used for filling and fixing between the whiskers includes low, medium and high density polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polystyrene, acrylonitrile-styrene copolymer (hereinafter referred to as "SAN"). Abbreviated as "resin"), acrylonitrile-butadiene-styrene copolymer (abbreviated as "ABS resin" hereinafter), polyamide, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, polymethylmethacrylate, polyetherimide. , Polysulfones, polyesterimides, polyarylates, polyphenylene sulphite, styrene-butadiene copolymers and hydrogenated compositions thereof, and polymers of combinations of two or more thereof. Rend and copolymers, for example, polycarbonate and acrylonitrile-butadiene-styrene copolymer, polyphenylene ether and polystyrene, and the like.

As the thermosetting resin used for filling and fixing the space between the whiskers, epoxy resin, DF
K resin, xylene resin, guanamine resin, diallyl phthalate resin, vinyl ester resin, phenol resin, unsaturated polyester resin, furan resin, polyimide, poly (p-hydroxybenzoic acid), polyurethane, maleic acid resin, melamine resin, urea resin And so on.
Elastomers used to fix whiskers include natural rubber, butadiene rubber, silicone rubber, polyisoprene rubber, chloroprene rubber, ethylene propylene rubber, butyl rubber, isobutylene rubber, styrene.
Butadiene rubber, styrene / isoprene / styrene block copolymer rubber, acrylic rubber, acrylonitrile /
Examples thereof include butadiene rubber, hydrochloric acid rubber, chlorosulfonated polyethylene rubber, synthetic rubber such as polysulfide rubber, and the like.
In addition, polytetrafluoroethylene, petroleum resin, alkyd resin and the like can also be used.

The metal oxide structure having whiskers obtained in the present invention is an insulator, a conductor, a fixed electrolyte, a fluorescent display tube, an EL device, a ceramic capacitor, an actuator, a laser oscillator, a cold cathode device, a ferroelectric. Electronic materials such as memory, piezoelectric material, thermistor, ballis, superconductor, printed circuit board, electromagnetic wave shield material, photodielectric material,
Optical switch, optical sensor, solar cell, optical wavelength conversion element,
It can be used as an optical element such as a light absorption filter, a sensor material such as a temperature sensor or a gas sensor, a catalyst or a carrier in a gas phase, a liquid phase or both phases.

[0027]

EXAMPLES Next, the present invention will be further described with reference to examples, but the following specific examples do not limit the present invention. Example 1 An Al: ZnO whisker dense structure was produced on a sapphire single crystal substrate (0001) surface by the following procedure using the atmosphere open type CVD apparatus of FIG. Acetylacetonato Zn was charged in the vaporizer 3 of the base material forming the metal oxide whiskers, and acetylacetonato Al was charged in the vaporizer 4 of different elements. Base material vaporizer 3 1
At 15 ° C, the vaporizer 4 for different elements is set to 100 to 125 ° C.
At a flow rate of 1.5 l / min and a flow rate of 0.
It was transported to the raw material mixer 5 by nitrogen gas of 5 to 1.5 l / min. The raw material gas heated to 125 ° C. by the coiled heating mixer 8 in the raw material mixer 5 is heated from the nozzle 9 to 550 ° C. on the heating table 11 to form a 0.5 mm thick sapphire single crystal (0001) plane. Then, it was sprayed under atmospheric pressure. The distance between the slit 9 and the substrate 10 was 2 cm.
The source gas was thermally decomposed in the atmosphere and deposited as Al: ZnO whiskers on the sapphire single crystal substrate. In this example, the length of the whiskers was 25 μm, the circle approximate cross-sectional diameter of the whiskers was 1.5 μm, and the Al content in the whiskers was 1.8 atom%. Since the solid solution limit of Al to ZnO that is generally known is 1 atom%, Al exceeding the solid solution limit is precipitated along the long axis direction inside the whiskers and strengthened by an aluminum oxide layer with high mechanical strength. The structure formed. The preferred orientation direction of the generated Al: ZnO whiskers was the (0001) orientation.

Comparative Example 1 Example 1 was repeated except that acetylacetonato Al was not charged in the vaporizer 4 for different elements.
ZnO whiskers having the same dimensions as in Example 1 were deposited on the sapphire single crystal substrate in the same manner as in.

(Indentation Buckling Test) Example 1 and Comparative Example 1
The indentation buckling test was performed on the metal oxide structure having the whiskers obtained in 1. using a nano indenter equipped with a 200 × 200 mm ² flat diamond indenter. The fracture strength of the metal structure having whiskers of Example 1 was 450 mN, while the fracture strength of the structure of Comparative Example 1 was 350 mN.

(Resin embedding test) An epoxy resin having a thickness of 25 μm was injected by injecting an epoxy resin into the voids between the whiskers of the metal oxide structure having whiskers obtained in Example 1 and Comparative Example 1 A membrane was prepared. When the compressive strength in the vertical direction of the obtained whisker-reinforced epoxy resin film was measured by a conventional method, the compressive ratio at 50 mN of that obtained from Example 1 was 3%.
Met. On the other hand, 5 of those obtained from Comparative Example 1
The compressibility at 0 mN was 7%, and it was found that the present invention can provide a material useful as a thin film circuit board or the like having a small dimensional change.

(Example 2) The thickness was the same as in Example 1 except that the heating temperature of the vaporizer 4 for different elements was 130 ° C and the flow rate of nitrogen gas supplied to the vaporizer 4 was 1.0 l / min. Al: ZnO whiskers were deposited on a sapphire single crystal (0001) surface having a thickness of 0.5 mm. In this example, the length is 20 μm, the circle approximate cross-sectional area diameter is 1.5 μm, by adjusting the charging amount of the raw material and the spraying time.
Whiskers having an Al content of 2.8 atomic% in the whiskers were obtained. Similar to Example 1, this whisker had a reinforced structure composed of an aluminum oxide layer having high mechanical strength.

Comparative Example 2 Example 2 was repeated except that acetylacetonato Al was not charged in the vaporizer 4 for different elements.
ZnO whiskers having the same dimensions as in Example 2 were deposited on the sapphire single crystal substrate in the same manner as in.

(Piezoelectric element test) An epoxy resin having a thickness of 20 μm, which was reinforced by injecting an epoxy resin into the voids between the whiskers of the metal oxide structure having whiskers obtained in Example 2 and Comparative Example 2. A membrane was prepared. When the piezoelectric characteristics of the obtained whisker reinforced epoxy resin film in the vertical direction were evaluated by a conventional method, the one obtained from Example 2 had a limit of compression at 650 mN and the maximum voltage at that time was 65V. On the other hand, the material obtained from Comparative Example 2 has a limit of compression at 450 mN and the maximum voltage at that time is 45 V, and a sensor material capable of sensing a larger strain can be obtained by the present invention.

(Embodiment 3) The heating temperature of the vaporizer 4 for different elements is 118 ° C., the flow rate of the nitrogen gas supplied to the vaporizer 4 is 1.2 l / min, and the substrate is S having a thickness of 0.5 mm.
Al: ZnO whiskers were deposited on the substrate as in Example 1 except that a US316 substrate was used. In this example, the length is 10 μm, the approximate circle cross section is 1.0 μm,
Whiskers having an Al content of 1.3 atomic% in the whiskers were obtained. Similar to Example 1, this whisker had a reinforced structure composed of an aluminum oxide layer having high mechanical strength.

Comparative Example 3 Example 3 was repeated except that acetylacetonato Al was not charged in the vaporizer 4 for different elements.
ZnO whiskers having the same dimensions as in Example 3 were deposited on the sapphire single crystal substrate in the same manner as in.

(Electron Emission Test) An electron emitting device was formed from the whisker dense structure having a length of 10 μm obtained in Example 3 and Comparative Example 3, and the electron emission current was measured. Distance from whisker tip to anode is 200μm
Then, when a positive voltage of 5 kV was applied to the anode, the electron-emitting device obtained from Example 3 had an emission current of 0.1 m.
The current was continuously emitted at A / cm ² for 300 hours. On the other hand, the electron-emitting device obtained from Comparative Example 3 has an emission current of 0.1.
The current was discharged at mA / cm ² for 3 hours. According to the present invention, the Al reinforced structure in the whiskers keeps the shape of the whiskers unchanged during discharge, so that an electron-emitting device capable of operating for a longer period of time can be obtained.

[Brief description of drawings]

FIG. 1 is an apparatus 1 for producing a metal oxide structure of the present invention.
It is a schematic diagram which shows an example.

FIG. 2 is a schematic view showing an example of a reinforcing structure in a whisker of the present invention.

FIG. 3 is a schematic view showing another example of the reinforcing structure in the whisker of the present invention.

FIG. 4 is a schematic view showing another example of the reinforced structure in the whisker of the present invention.

[Explanation of symbols]

1 Manufacturing equipment 2 Nitrogen gas supply source 3 Base material vaporizer 4 Vaporizer of different elements 5 Raw material mixer 6 Raw material mixing reservoir 7, 12 heater 8 coiled heating mixer 9 nozzles 10 Base material 11 heating table 20, 30, 40 whiskers 21, 31, 41 Base material 22, 32, 42 Reinforced structure 43 cavity

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 2000-58365 (JP, A) JP 2-60988 (JP, A) JP 2001-114600 (JP, A) JP 2002-167300 (JP , A) International publication 99/057345 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C30B 1/00-35/00 D01F 9/08 CAplus (STN) JSTPlus (JOIS) WPI (DIALOG)

Claims (12)

(57) [Claims] 1. A circle approximate cross-sectional diameter of 0.01 to 100 μm,
In a metal oxide structure having metal oxide whiskers in which the ratio of the length to the approximate circular cross-section diameter is 1 or more, the whiskers are arranged inside the whiskers along the long axis direction of the whiskers.
Metal oxide structure characterized <br/> have a reinforcing layer of different composition than the base metal composition obtained by the different elements added to the base material constituting the whiskers I. 2. The ratio of different elements to the elements constituting the base material
0.1 to 10 atomic%
1. The metal oxide structure according to 1. 3. Whiskers are 10 μm × 10 on the surface of the substrate.
μm Exists at a density of 0.1 to 10,000 per area
The metal oxide according to claim 1 or 2, characterized in that
Object structure. 4. The whiskers have consistent properties along the long axis of the whiskers.
The metal oxide structure according to any one of 1. 5. The metal oxide structure according to claim 1, wherein the base material forming the whiskers and the reinforcing layer are chemically bonded. 6. The crystal relationship between the base material forming the whiskers and the reinforcing layer is epitaxial.
The metal oxide structure according to any one of 1 to 5. 7. A matrix element and a heterogeneous element constituting a whisker are groups 1 and 2 excluding hydrogen, group 13 excluding boron, group 14 excluding carbon, group 14 excluding carbon, and excluding nitrogen, phosphorus and arsenic 15 in the periodic table. Tribe and 3,4,5,6,7,8,9,10,
The metal oxide structure according to any one of claims 1 to 6, which contains at least one metal selected from Groups 11 and 12. 8. The metal is Zn, Si, Al, Sn, Ti, Z.
The metal oxide structure according to claim 7, which is selected from r and Pb. 9. The metal oxide structure according to claim 1, wherein the space between the whiskers is filled with a material selected from organic substances, inorganic substances and metals. 10. A gas containing a vaporized metal oxide whisker base material constituent element and a gas containing an element different from the vaporized base material are uniformly mixed with a carrier gas,
A metal oxide whisker having a circular approximate cross-sectional diameter of 0.01 to 100 μm and a length ratio to the approximate circular cross-sectional diameter of 1 or more is sprayed onto the surface of the base material heated under atmospheric pressure release. The method for producing a metal oxide structure according to claim 1, wherein the metal oxide structure having the metal oxide structure is deposited. 11. The metal oxide structure according to claim 10, wherein the whiskers of the obtained metal oxide structure are filled with a material selected from organic substances, inorganic substances and metals. Manufacturing method. 12. A vaporizer of a base material forming a metal oxide whisker, a vaporizer of an element different from the base material, a vaporized base material, and a raw material for uniformly mixing an element different from the base material with a carrier gas. 10. A mixer, a nozzle for ejecting a mixed raw material gas, and a base material heating base are provided.
An apparatus for producing a metal oxide structure according to any one of 1.