JPH09157062A - Porous ceramic film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ceramic filters having various compositions, each of which is provided with one-dimensional through-pores low in pressure drop and is appropriately used for separating molecules or fine particles. SOLUTION: This ceramic film is provided with one-dimensional through-pores each of which extends from one surface of the film to the other and has a pore size of a few nanometers, and produced on a substrate made of glass, a ceramic material, plastic material or heat-resistant metal by forming a composite film consisting of a ceramic phase and a metallic phase with a vapor growth method and then, removing the metallic phase in the composite film with an etching method. Thus, the objective porous ceramic film provided with one- dimensional through-pores each having a pore size of the order of a few nanometers can be synthesized with good reproducibility. Also, by forming such ceramic films on various substrates, ceramic filters each of which shows an excellent function capable of separating molecules or fine particles each having a size of a few nanometers can be manufactured.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a porous ceramic film and a method for producing the same. More specifically, the present invention is preferably used for separating molecules and fine particles,
The present invention relates to a porous ceramic film having various compositions having one-dimensional through pores with a small pressure loss, and a method for producing the porous ceramic film with good reproducibility. The porous ceramic membrane of the present invention exhibits a separation function in the nanometer size, and is useful as a means for separating various molecules and fine particles.

[0002]

2. Description of the Related Art Ceramic filters having excellent heat resistance and corrosion resistance have been developed for the purpose of separating molecules and fine particles contained in a high temperature gas or a corrosive liquid. As a method for producing a porous ceramic body or a porous ceramic film, a ceramic raw material powder is sintered,
Many methods have been adopted in which the open pores formed in the process of densification of the ceramic body (open air holes opening on the surface of the ceramic body) are used as they are (JP-A-7-87).
No. 29). However, in the ceramic body and the ceramic film produced in this way, there are problems that it is difficult to make the pore diameters uniform in size, and it is difficult to produce nanometer-order pores with good reproducibility.

As an attempt to reproducibly produce a porous body having a uniform pore size on the order of nanometers, porous silica has been produced by a method combining a sol-gel method and spinodal decomposition (Nakanishi et al. , "Ceramic
Transactions, Porous Materials ", The American Cer
amics Society, 51-60 (1992)), in this case, a structure in which silica phases are connected in a network is formed, and the shape of pores is irregular and the direction thereof is random.

As described above, when the shape of the pores is irregular and the direction thereof is non-oriented, there are many ceramic parts that scatter molecules and particles moving in the filtering direction and hinder the movement of the pores, resulting in pressure loss. There was a problem that occurred.

In order to solve the above problems, it has been attempted to develop a ceramic film having a pore size of nanometer size and having pores penetrating one-dimensionally (hereinafter, sometimes referred to as one-dimensional penetrating pores). ing. A typical example thereof is a porous alumina film formed by anodic oxidation of aluminum (Japanese Patent Publication No. 6-37291). The film made by anodizing aluminum can control the pore diameter in the range of several nanometers to several tens of nanometers depending on the manufacturing conditions, and since the film is made of alumina, considerable heat resistance and corrosion resistance are expected. There is an advantage that you can. However, in the case of a porous alumina film by anodic oxidation, the obtained film is stable only at around room temperature due to the principle constraint of utilizing anodic oxidation of a metallic aluminum foil or a thick aluminum plate in an electrolytic solution. Limited to amorphous alumina,
Further, there is a drawback that only an aluminum plate can be selected as a substrate.

As a method of compensating for the above-mentioned defects of the porous alumina film by anodic oxidation, a method of transferring a pore pattern to a polymer membrane using a porous alumina film prepared by anodic oxidation as a template has been tried (Masuda et al. ; Ceramic Society of Japan, Spring Annual Meeting 1995, p485
3F401). However, in this case, the material that transfers the structure of the porous alumina film by anodic oxidation is limited to organic substances, and the membrane that has transferred the film structure is brought into close contact with another substrate to form a new composite film. Is difficult.

[0007]

The object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a porous ceramic membrane having one-dimensional through-holes of nanometer size which can be used for gas separation membranes and catalysts. The purpose is to provide various ceramic materials (metal oxide, metal carbide, metal boride, etc.). Furthermore, it is possible to provide a new composite film in which various porous ceramic films are formed on a dense or porous substrate made of glass, ceramics, plastics, or heat-resistant metal, and to provide such a ceramic film with good reproducibility. It is to provide a manufacturing method.

[0008]

The present invention has been made to solve the above problems, and a porous ceramic film of the present invention comprises a ceramic phase and a metal phase formed by a vapor phase growth method. A porous ceramic film having nanometer-sized pores penetrating from one surface of the film to the other surface, which is obtained by removing the metal phase in the composite film, wherein the porous ceramic film Is formed on a substrate made of glass, ceramics, plastics, or heat-resistant metal. In a preferred porous ceramic film according to the present invention, the substance forming the porous ceramic film is at least one compound selected from metal oxides, metal carbides and metal borides. In another preferred porous ceramic film of the present invention, the substrate supporting the porous ceramic film is a porous body. In another preferred porous ceramic film of the present invention, the pores penetrating one-dimensionally have an average pore diameter of 5 to 100 nanometers. The method for producing a porous ceramic film of the present invention is characterized in that a composite film comprising a ceramic phase and a metal phase is formed on a substrate by a vapor phase growth method, and then the metal phase in the composite film is removed by etching. To do.

[0009]

Next, the present invention will be described in more detail. That is, the porous ceramic film of the present invention is produced by a two-step process. In the first step, a film in which a metal and a ceramic material (metal oxide, metal carbide or metal boride) are mixed on a nanometer scale is prepared by using a vapor phase growth method such as a sputtering method. At this time, a fine structure in which the ceramic material surrounds the columnar grown metal phase is formed by controlling the mixing ratio of the used metal phase and the ceramic material and the film forming conditions (FIG. 1). In the present invention, the pore size can be changed depending on the particle size of the metal phase. In this case, the average particle size of the metal phase can be changed within a range of about 5 to 500 nm depending on the volume fraction of the metal phase and the ceramic phase and the film forming conditions (substrate temperature, residual gas pressure during sputtering, etc.). Further, the thickness of the grain boundary phase remaining as the ceramics filter portion can be changed by the volume fractions of the metal phase and the ceramics phase. Therefore, it is possible to independently change the film composition and film forming conditions as parameters for forming a film, and the average thickness of the grain boundary phase is about 1 to 50 n.
It can be changed by about m. In FIG. 1, dark portions are Co crystal grains, and white mesh portions are Co.
This is the portion of SiO ₂ deposited at the grain boundaries of crystal grains. The average grain size of Co crystal grains is about 12 nm, and the width of the SiO ₂ grain boundary layer is about 2 nm. A film structure similar to this is realized, for example, in a magnetic film of a hard magnetic disk by a mixed system of Co—Pt type alloy and SiO ₂ (Japanese Patent Application No. 7-51410). Subsequently, in the second step, the metal portion is removed using acid or alkali to finally obtain a porous ceramic film having one-dimensional through pores. FIG. 2 shows a schematic diagram of the procedure for forming the porous ceramic film of the present invention on the porous ceramic substrate. In the figure, (a) is a cross-sectional view of a porous ceramic substrate, (b) is a situation in which a metal film is formed on the ceramic substrate (pores on the substrate surface are filled with metal), and (c) is the ceramic substrate surface. The state where the surface is polished until appears, (d) the state in which the metal / ceramic composite film of the present invention is formed on the film obtained in (c),
(E) shows the state after the metal is eluted by etching with acid.

The vapor phase growth method used in the first stage may be a sputtering method, a vapor deposition method, a CVD method, a laser ablation method, a molecular beam epitaxy method or the like. Considering this, it is preferable to use the sputtering method.

The combination of the metal and the ceramic material may be a combination of the metal and the ceramic material that causes phase separation during film formation. In the present invention, the metal phase that grows in a columnar shape is used as the pore portion after etching, and the ceramic phase that precipitates in the grain boundary portion of the metal phase that grows in a columnar shape is used as the residual phase. A metal or an alloy which is easy to dissolve and easily dissolves in an acid / alkali, has a small binding energy with oxygen, carbon and boron and is easily reduced is preferable. Practically, considering the ease of handling during sputtering, V, Cr, Mn, Ni, F
One or more selected from 3d transition metals such as e, Co, Cu and Zn and alloys containing them as a main component, alkaline earth metals such as Mg and alloys containing them as a main component are preferable. In addition, Al, In, Sn, Pb and the like can be used. As the ceramic phase used as the residual phase, oxides such as alumina, mullite, cordierite, spinel, zeolite and forsterite, carbides such as silicon carbide, titanium carbide and zirconium carbide,
One or more selected from borides such as titanium boride, zirconium boride, and boron carbide can be preferably used.

When the above-mentioned metal-ceramic composite film is formed by a sputtering method or the like, a small piece of a ceramic material such as a metal oxide, a metal carbide or a metal boride is placed on the metal target and used as a composite target. it can. More preferably, in order to reduce the variation in composition within the film after film formation, a composite material is prepared that is uniformly mixed by a powder metallurgical method at the time of producing the target.

The substrate used for producing the above-mentioned porous ceramic film can be selected from glass, ceramics, plastics and heat-resistant metals, and it is also possible to use a porous substrate instead of a dense substrate. Is.
As the heat-resistant metal used for the substrate, Fe, Ni, Cr, V
Oxidation-resistant alloys such as stainless steel and Hastelloy are suitable. FIG. 2 shows, as an example, a method for forming a film using a porous ceramic substrate.
That is, the surface of a ceramic porous body having an average pore diameter of several nanometers to several tens of micrometers is impregnated with a metal or a resin, and the surface is polished to form a smooth surface. Next, this surface is washed with water, a surfactant, an organic solvent or the like, and this is used as a substrate to form a sputtered film thereon. At this time, as the metal or resin to be impregnated, it is preferable to use one that can be removed under the same etching conditions as the material of the metal target.

Next, the metal component in the obtained composite film is removed by etching with an acid or alkali solution. Acids used in this etching treatment include sulfuric acid, hydrochloric acid, nitric acid,
Oxalic acid, acetic acid, or the like can be used, and it is preferable to select appropriately depending on the kind of metal to be eluted. Since the ceramic portion formed by the first film forming process is often amorphous or has a low degree of crystallization, it is preferable to perform etching under a weak etching condition using a sufficiently diluted solution. For example, C as a metal component
When o is used and SiO ₂ is used as the ceramic component, it is preferable to use a 0.003N nitric acid aqueous solution and perform the treatment at an etching rate of 0.3 nanometer per second.

As described above, according to the method for producing a porous ceramics film of the present invention, when forming the porous ceramics film, a composite film of metal and ceramics is produced by a vapor phase growth method, and then a metal phase is formed by etching. It is characterized in that it is used in combination with a method of removing the above, and it can provide various porous ceramic films having a novel structure and composition. INDUSTRIAL APPLICABILITY The porous ceramic membrane of the present invention can exhibit a separation function in a nanometer size, and is useful as a filter for separating molecules and fine particles. The porous ceramic film of the present invention can control the pore size and the width of the grain boundary phase independently (in particular, thicken the width of the grain boundary phase). It is essentially different from a membrane or the like.

[0016]

In the present invention, by the film forming method such as the sputtering method,
Ceramics by forming a composite film in which two phases consisting of metal and ceramics (metal oxide, metal boride, metal carbide) with different chemical durability are mixed in nanometer order, and then removing only the metal part by acid etching etc. By allowing the portion to remain, it becomes possible to synthesize a porous ceramic film having one-dimensional through pores with a small pressure loss. That is, by appropriately controlling the film formation conditions, a metal phase, which is one of the main film components, grows in a columnar shape, a ceramic material is precipitated at the grain boundaries, and the metal phase is removed by etching to obtain nanometers. It is possible to obtain a porous ceramics film having one-dimensional through pores with a pore size of the order.

Further, since the composite film before acid etching is formed by the sputtering method or the like, a wide variety of materials and forms such as metal, glass, ceramics and plastics can be used for the substrate supporting the film. Become.

[0018]

The present invention will be specifically described below with reference to examples. Example 1 Metallic Co was deposited on a 1.2 mm thick soda lime glass substrate.
And a composite thin film consisting of two phases of SiO ₂ was formed. For sputtering, 1 cm on a metal Co target with a diameter of 6 inches
A composite target with square SiO ₂ glass chips was used. At this time, 2 out of the total surface area of one side of the target
The amount of SiO ₂ glass chips was adjusted to occupy 0%. After evacuating the vacuum chamber to 5 × 10 ^-6 Torr, A
The gas pressure inside the vacuum chamber was 2 × 10 ^-2 To when r gas was introduced.
The flow rate of Ar gas was adjusted to rr and a high frequency of 600 W was input to generate plasma. The film formation rate at this time was about 1 nm / sec, and the substrate was not heated and the bias voltage was not applied during the film formation.

The structure of the formed composite thin film is shown in the transmission electron micrograph of FIG. FIG. 1 is an enlarged photograph of the glass substrate ground and removed, and further, the composite film is ion-polished to be thinned and viewed from a direction perpendicular to the film surface. In this photograph, Co crystal particles having an average particle diameter of 12 nm grow in a columnar shape, and SiO ₂ is amorphously precipitated at the grain boundaries.

Next, a film thickness of 50 nm produced by the above method
The composite film of was immersed in a 0.003N aqueous nitric acid solution for 5 minutes to dissolve and remove the Co phase. FIG. 3 is an enlarged photograph of the film after dissolution and removal of the Co phase observed by a scanning electron microscope. The Co phase was almost completely eluted, and SiO ₂ at the grain boundaries remained in a mesh form. FIG. 4 shows an example of an enlarged and perspective view of the ceramic film thus obtained.

Example 2 By the same procedure as in Example 1, a composite thin film composed of two phases of metal Co and SiO ₂ was formed on a 1.2 mm thick soda lime glass substrate. For the sputtering, a composite target in which a 1 cm square SiO ₂ glass chip was placed on a metal Co target having a diameter of 6 inches was used. At this time, SiO ₂ should be contained so as to occupy 10% of the total surface area of one side of the target.
The amount of glass chips was adjusted. Vacuum chamber 5 × 10 ^-6 To
After exhausting to rr, Ar gas was introduced, the flow rate of Ar gas was adjusted so that the gas pressure inside the vacuum chamber was 2 × 10 ⁻² Torr, and a high frequency of 600 W was input to generate plasma. The film forming rate at this time is about 1 nm / se
c, and the substrate was not heated and the bias voltage was not applied during film formation.

The structure of the formed composite thin film is very similar to that shown in FIG. 1, in which Co crystal grains grow in columns and amorphous SiO ₂ is deposited at the grain boundaries. The average particle size of Co crystals was about 20 nm, which was slightly large. This composite film with a thickness of 50 nm is 0.003
The Co phase was dissolved and removed by immersing in a specified aqueous nitric acid solution for 5 minutes. Similar to the case of Example 1, the Co phase was almost completely eluted, and the SiO ₂ at the grain boundaries remained in a mesh form.

Example 3 By the same procedure as in Example 1, a composite thin film composed of two phases of metal Co and SiO ₂ was formed on a 1.2 mm thick soda lime glass substrate. For sputtering, a composite target in which a 1 cm square SiO ₂ glass chip was placed on a metal Co target having a diameter of 6 inches was used. At this time, the SiO 2 is made to occupy 10% of the total surface area of one side of the target.
₂ The amount of glass chips was adjusted. Vacuum chamber 5 × 10 ^-6 T
After evacuating to orr, Ar gas was introduced, the flow rate of Ar gas was adjusted so that the gas pressure inside the vacuum chamber was 2 × 10 ⁻² Torr, and a high frequency of 600 W was input to generate plasma. The film forming rate at this time is about 1 nm / s.
ec, and the substrate was heated to about 200 ° C. during film formation.

The structure of the formed composite thin film is very similar to that shown in FIG. 1. Co crystal grains grow in columns and amorphous SiO ₂ is deposited at the grain boundaries. In this case, It was found that the average particle size of the Co crystal was as large as about 35 nm.

The composite film having a thickness of 50 nm was immersed in a 0.003N nitric acid aqueous solution for 5 minutes to dissolve and remove the Co phase. Similar to the case of Example 1, the Co phase was almost completely eluted, and the SiO ₂ at the grain boundaries remained in a mesh form.

Example 4 By the same procedure as in Example 1, a composite thin film composed of two phases of metal Co and SiO ₂ was formed on a Hastelloy substrate having a thickness of 2 mm. For sputtering, a composite target in which a 1 cm square SiO ₂ glass chip was placed on a metal Co target having a diameter of 6 inches was used. At this time, the amount of SiO ₂ glass chips was adjusted so that 10% of the total surface area of one side of the target was occupied. After evacuating the vacuum chamber to 5 × 10 ^-6 Torr, introducing Ar gas, adjusting the Ar gas flow rate so that the gas pressure inside the vacuum chamber is 2 × 10 ^-2 Torr, and inputting a high frequency of 600 W Then, plasma was generated. The film formation rate at this time was about 1 nm / sec, and the substrate was not heated or the bias voltage was not applied during the film formation.

The structure of the formed composite thin film is very similar to that shown in FIG. 1, in which Co crystal grains grow in columns and amorphous SiO ₂ is deposited at the grain boundaries. The average particle size of the crystal was about 25 nm.

The composite film having a thickness of 50 nm was immersed in a 0.003N nitric acid aqueous solution for 5 minutes to dissolve and remove the Co phase. Similar to the case of Example 1, the Co phase was almost completely eluted and the SiO ₂ at the grain boundaries remained in a mesh shape, and almost no peeling of the film from the Hastelloy substrate was observed.

Example 5 By the same procedure as in Example 1, a composite thin film composed of two phases of metal Co and SiO ₂ was formed on an alumina substrate having a thickness of 5 mm. For sputtering, a composite target in which a 1 cm square SiO ₂ glass chip was placed on a metal Co target having a diameter of 6 inches was used. At this time, the amount of SiO ₂ glass chips was adjusted so that 10% of the total surface area of one side of the target was occupied. After evacuating the vacuum chamber to 5 × 10 ⁻⁶ Torr, Ar gas was introduced, and the gas pressure inside the vacuum chamber was set to 2
The flow rate of Ar gas was adjusted so as to be × 10 ^-2 Torr, and a high frequency of 600 W was input to generate plasma. The film formation rate at this time was about 1 nm / sec, and the substrate was not heated or the bias voltage was not applied during the film formation.

The structure of the formed composite thin film is very similar to that shown in FIG. 1. Co crystal grains grow in columns and amorphous SiO ₂ is deposited at the grain boundaries. The particle size was about 19 nm.

This composite film having a thickness of 50 nm was immersed in a 0.003N nitric acid aqueous solution for 5 minutes to dissolve and remove the Co phase. Similar to the case of Example 1, the Co phase was almost completely eluted, SiO ₂ at the grain boundaries remained in a mesh form, and almost no peeling of the film from the alumina substrate was observed.

Example 6 By the same procedure as in Example 1, a composite thin film composed of two phases of metal Co and SiO ₂ was formed on a polyethylene film substrate having a thickness of 0.8 mm. For sputtering, a composite target in which a 1 cm square SiO ₂ glass chip was placed on a metal Co target having a diameter of 6 inches was used. At this time, the Si should be 10% of the total surface area of one side of the target.
The amount of O ₂ glass chips was adjusted. Vacuum chamber 5 × 10 ^-6
After evacuating to Torr, Ar gas was introduced, the flow rate of Ar gas was adjusted so that the gas pressure inside the vacuum chamber was 2 × 10 ⁻² Torr, and a high frequency of 600 W was input to generate plasma. The film forming rate at this time is about 0.8 n
m / sec, the substrate was not heated and a bias voltage was not applied during film formation.

The structure of the formed composite thin film is very similar to that shown in FIG. 1, in which Co crystal grains grow in columns and amorphous SiO ₂ is deposited at the grain boundaries. The particle size was about 26 nm.

A Co film having a film thickness of 50 nm was immersed in a 0.003N aqueous nitric acid solution for 5 minutes to dissolve and remove the Co phase. As in the case of Example 1, the Co phase was almost completely eluted and SiO ₂ at the grain boundaries remained in a mesh form. When a polyethylene film was used as the substrate, the film peeling occurred significantly during the acid etching process. However, it was found that if the surface of the polyethylene film was treated with a corona discharge treatment or a silane coupling agent before forming the composite film by the sputtering method, the peeling was considerably suppressed.

Example 7 Metal Co having a thickness of 100 nm was formed to a thickness of 2 mm by a sputtering method.
Was formed on the porous silica substrate of. The surface of the substrate after the film formation was polished by a diamond polishing apparatus to remove the Co phase on the substrate while leaving Co clogged in the pores of silica to obtain a smooth polished surface. A composite thin film composed of two phases of metal Co and SiO ₂ was formed on this substrate. For sputtering, a composite target in which a 1 cm square SiO ₂ glass chip was placed on a metal Co target having a diameter of 6 inches was used. At this time, the amount of SiO ₂ glass chips was adjusted so that 10% of the total surface area of one side of the target was occupied. 5 x 1 vacuum chamber
After evacuating to 0 ^-6 Torr, Ar gas was introduced to adjust the gas pressure inside the vacuum chamber to 2 × 10 ^-2 Torr.
The flow rate of r gas was adjusted, and a high frequency of 600 W was input to generate plasma. Deposition rate is about 0.8 nm / s
ec, the substrate was not heated and the bias voltage was not applied during film formation.

The structure of the formed thin film is very similar to that shown in FIG. 1, in which Co crystal grains grow in columns and amorphous SiO ₂ is deposited at the grain boundaries. The diameter was about 26 nm.

This 50 nm-thick composite film was immersed in a 0.003 N aqueous nitric acid solution for 5 minutes to remove the Co phase clogged in the pores of silica and the Co phase in the Co—SiO ₂ composite film formed thereon. It was dissolved and removed. As in the case of Example 1, Co
The phases were almost completely eluted, and the SiO ₂ at the grain boundaries remained in the form of a mesh.
It was found that the phases were almost completely removed. Further, almost no peeling of the composite film from the porous silica substrate was observed.

Example 8 By the same procedure as in Example 1, a composite thin film composed of two phases of metallic Co and SiC was formed on a soda lime glass substrate having a thickness of 1.2 mm. For spatter, metal C with a diameter of 6 inches
o A composite target in which a 1 cm square SiC sintered chip chip was placed on the target was used. At this time, the amount of the SiC sintered body chips was adjusted so as to occupy 20% of the total surface area of one surface of the target. Vacuum chamber 5 × 10 ^-6 Torr
After evacuation to the above, Ar gas was introduced, the flow rate of Ar gas was adjusted so that the gas pressure inside the vacuum chamber was 2 × 10 ⁻² Torr, and a high frequency of 600 W was input to generate plasma. The film forming speed is about 0.9 nm / sec,
The substrate was not heated and the bias voltage was not applied during the film formation.

The structure of the formed composite thin film was very similar to that shown in FIG. 1. Co crystal grains grew in a columnar shape, and a phase considered to be amorphous SiC was precipitated at the grain boundary. The average particle size of the Co crystal particles was about 35 nm.

The composite film having a thickness of 50 nm was immersed in a 0.003N aqueous nitric acid solution for 5 minutes to dissolve and remove the Co phase. Similar to the case of Example 1, the Co phase was almost completely eluted, and the SiC at the grain boundary remained in a mesh shape.

Example 9 By the same procedure as in Example 1, a composite thin film composed of two phases of metal Co and ZrB ₂ was formed on a 1.2 mm thick soda lime glass substrate. For the sputtering, a composite target in which a 1 cm square ZrB ₂ ceramic chip was placed on a metal Co target having a diameter of 6 inches was used. At this time, the amount of ZrB ₂ ceramic chips was adjusted so as to occupy 20% of the total surface area of one side of the target. After evacuating the vacuum chamber to 5 × 10 ^-6 Torr, introducing Ar gas, adjusting the Ar gas flow rate so that the gas pressure inside the vacuum chamber is 2 × 10 ^-2 Torr, and inputting a high frequency of 600 W Then, plasma was generated. Deposition rate is about 0.9n
m / sec, the substrate was not heated and a bias voltage was not applied during film formation.

The structure of the formed composite thin film is very similar to that shown in FIG. 1, in which Co crystal grains grow in columns and amorphous ZrB ₂ is deposited at the grain boundaries.
The average particle size of the o crystal particles was about 21 nm.

The composite film having a thickness of 50 nm was immersed in a 0.003N aqueous nitric acid solution for 5 minutes to dissolve and remove the Co phase. Similar to the case of Example 1, the Co phase was almost completely eluted and ZrB ₂ at the grain boundaries remained in a mesh shape, and almost no peeling of the film from the soda lime glass substrate was observed.

[0044]

As described in detail above, the present invention provides a porous ceramic membrane having nanometer-sized pores penetrating from one surface of the membrane to the other surface in a one-dimensional manner. The present invention relates to a porous ceramic film, characterized in that the ceramic film is formed on a substrate made of glass, ceramics, plastics or heat-resistant metal, and a method for producing the same. It is possible to provide a porous ceramic film having original through holes. Further, the porous ceramic film of the present invention can be used as a ceramic filter when combined with a porous ceramic substrate. Moreover,
Since the material of this ceramics filter can be widely selected from metal oxides, metal carbides, metal borides, etc., 2000
Select a high melting point material such as metal carbide or metal boride when high heat resistance around ℃ is required, and select metal oxide when used in a high temperature oxidizing atmosphere. You can Further, if the porous ceramic film of the present invention is produced by the sputtering method and etching, the porous ceramic film is formed on the substrate of almost all materials such as organic materials such as metal, glass, ceramics and plastics as the substrate material. can do. Further, when the composite film is formed by the sputtering method, the film can be formed even if the surface shape of the substrate is not flat, and it can be evenly formed on a substrate having a large area of several square meters. is there.

The ceramic filter of the present invention in which the porous ceramic membrane and the porous ceramic membrane are combined with the porous ceramic substrate is not only a gas separation membrane, but is also a general factory exhaust gas if the pore diameter is controlled according to the purpose. It can be used to remove harmful fine particles contained in exhaust gas from thermal power plants and exhaust gas from automobiles. It can also be used for separating fine particulate matter in a liquid, for example, microscopic microorganisms such as viruses, separating colloidal molecule populations dispersed in a solvent, and sieving specific molecules.

Furthermore, by modifying the surface of the through pores of the membrane with an inorganic or organic catalyst, it is possible to obtain a catalyst membrane with higher activity.

[Brief description of the drawings]

FIG. 1 is an enlarged photograph of a Co—SiO ₂ system prototype sample observed by a transmission electron microscope from a direction perpendicular to a film surface.

FIG. 2 is a schematic view of a procedure for forming a porous ceramic film of the present invention on a porous ceramic substrate.

FIG. 3 is a graph showing the composition of a Co-SiO ₂ composite film formed on a soda-lime glass substrate by sputtering according to the present invention.
A scanning electron micrograph of a film etched with 03 normal nitric acid as viewed from the cross-sectional direction of the film.

FIG. 4 is a perspective view showing an outline of a porous ceramic film according to the present invention.

[Explanation of symbols]

(A) Cross-sectional view of porous ceramic substrate (b) Situation where metal film is formed on ceramic substrate (pores on substrate surface are filled with metal) (c) State where surface is polished until ceramic substrate surface appears (D) A state in which the metal / ceramic composite film of the present invention is formed on the film obtained in (c). (E) A state after the metal is eluted by etching with an acid.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area C23F 1/00 103 C23F 1/00 103 // C23C 14/06 C23C 14/06 L 14/34 14/34 A (72) Inventor Shinji Kondo 2-27 Kamenoi, Meito-ku, Nagoya, Aichi Prefecture Harvest Hills, Ltd. 302 (72) Inventor Shinichi Hirano, Maruikedai, Ogawa, Higashiura-cho, Chita-gun, Aichi Prefecture.

Claims (5)

[Claims] 1. One-dimensionally penetrating from one surface of the film to the other surface obtained by removing a metal phase in a composite film composed of a ceramic phase and a metal phase formed by a vapor phase growth method. A porous ceramic film having nanometer-sized pores, characterized in that the porous ceramic film is formed on a substrate of glass, ceramics, plastics, or heat-resistant metal. 2. The porous ceramic film according to claim 1, wherein the porous ceramic film is one or more compounds selected from metal oxides, metal carbides and metal borides. 3. The porous ceramic film according to claim 1, wherein the substrate supporting the porous ceramic film is a porous body. 4. The porous ceramic film according to claim 1, wherein the pores penetrating one-dimensionally have an average pore diameter of 5 to 100 nanometers. 5. A composite film comprising a ceramic phase and a metal phase is formed on a substrate by a vapor phase growth method, and then the metal phase in the composite film is removed by etching. A method for producing a porous ceramics film having nanometer-sized pores penetrating one surface in one dimension.