JP2003246646A - Thin film glass structure and method for preparing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a glass composite structure having a thin film less liable to be exfoliated by a simple step comprising only heat treatment. <P>SOLUTION: In the method for preparing a thin film glass structure, a glass structure having a separated-phase texture is fired at a temperature higher than the melting point of the lower melting point one of two phases forming the separated-phase texture. Preferably the glass structure having a separated- phase texture is previously comminuted and molded. By this method, an ultrathin film of ≤10 nm can be manufactured with ease. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thin film glass structure and a method for manufacturing the same.

[0002]

2. Description of the Related Art Today, thin film coating technology for various substrates is used in a wide range of fields in order to improve the functionality of materials. When the purpose is divided according to function, there is a protective film to enhance chemical durability or mechanical strength, an optical functional film such as antireflection and coloring, and a conductive or ferroelectric electromagnetic functional coating. It is widely applied as a membrane or as a catalyst carrier membrane carrying a metal catalyst or the like, and has a wide variety of applications. Moreover, in order to obtain a more functional material, the demand for the film thickness has become thinner, and the nanometer-order thin film forming technology is regarded as important. As a method for producing such a thin film, generally, a vapor deposition method such as a physical vapor deposition method or a chemical vapor deposition method, or a sol-gel method has been widely used at present due to the demand for thinning.

[0003]

However, in the gas phase method, there are problems that expensive equipment is required and that the shape is limited and the complicated shape is dealt with. In the sol-gel method, the sol There are problems such as stricter adjustment conditions.
In this way, each method has advantages and disadvantages,
There is an urgent need to search for new methods in thin film coating technology, whose needs are diversifying. The present invention was developed in view of the above circumstances, and an object of the present invention is to obtain a glass composite structure having a thin film that is difficult to peel off by a simple process of only heat treatment.

[0004]

According to the present invention, a glass structure having a phase-separated structure is fired at a temperature higher than the melting point of one of the two phases forming the phase-separated structure having a lower melting point. A method for manufacturing a thin film glass structure is provided.

Here, the glass having a phase-separated structure is in a metastable immiscible region when a melt in a homogeneous state at a high temperature is supercooled to a temperature below the liquidus line in a specific composition region. It is a tissue that separates into two phases according to thermodynamic requirements.

In the present invention, the glass having a phase-separated structure in which the composition X is divided into the composition A and the composition B in the immiscible region is heated again. As a result, a structure having a thin film in the base material, the thin film is an amorphous body composed of the composition of the phase having a lower melting point of the phase-separated structure, the base material is the melting point of the phase-separated structure Thin-film glass structure characterized by comprising an amorphous body having a composition of a lower phase and an amorphous or crystalline mixture having a composition of a phase having a higher melting point in the phase-separated structure It was found that

The mechanism will be described below. The crystallization temperature of the composition A is Tx (A), the melting point is Tm (A), the crystallization temperature of the composition B is Tx (B), the melting point is Tm (B),
When composition A has a lower melting point than composition B, Tx is generally
The relationship is (A) <Tx (B) <Tm (A) <Tm (B). At this time, this phase-separated glass has a solid phase in both compositions A and B at temperatures below Tm (A), Tm (A) and Tm.
At a temperature between (B), the composition A is in a liquid phase, the composition B is a solid-liquid coexisting phase, and above Tm (B), both the compositions A and B are in a liquid phase. Now, when the temperature of the phase-separated glass produced in the desired shape is raised to Tm (A) or higher, the composition A changes from the solid phase to the liquid phase, while the composition B remains the solid phase. In this state, when the liquid phase has an appropriate viscosity and a sufficient time for movement, the action of reducing the surface energy of the phase-separated glass causes the liquid phase of the composition A to move and spread on the surface. A film can be formed to obtain a film structure having a film structure of the composition A on the surface. When the temperature is raised above Tm (B), the composition A and the composition B are contained in the phase-separated glass body.
Both of them are in the liquid phase, but a layer composed of the composition A can be similarly formed on the surface due to the difference in the viscosity of the melt.

The thickness of the film obtained at this time depends on the amount of the liquid phase moving to the surface, which depends on the composition of each phase-separated glass, the firing conditions (temperature, time), the phase-separated shape and size of the phase-separated glass. It can be controlled by Further, the base material of the coating structure obtained at this time is formed from a mixture of the liquid phase of the composition A that is left behind and the solid phase or the liquid phase of the composition B that does not move, and as a result, is formed on the surface. A mixture of an amorphous substance or a crystalline substance having the same composition A as the layer and an amorphous substance or a crystalline substance having the composition B.

This method forms a film in a general firing process without requiring a special apparatus. By controlling the size of the phase separation of the phase-separated glass and the firing conditions, a wide range of film thickness can be obtained. It is possible to obtain a coating structure having Further, since the film is formed by the spontaneous function of the material, the bondability at the interface between the film and the base material is high, and problems such as peeling of the film are extremely unlikely to occur.

Further, in the present invention, a step of pulverizing a glass structure having a phase-separated structure to prepare a phase-separated glass powder, and molding the phase-separated glass powder to prepare a phase-separated glass powder compact. A thin film glass, comprising: a step; and a step of firing the phase-separated glass powder compact at a temperature higher than a melting point of a phase having a lower melting point of the two phases forming the phase-separated structure. A method for manufacturing a structure is provided. Although the basic film forming process is the same, by using this step, a structure having a more flexible shape can be obtained,
Moreover, since there is a space between the phase-separated glass powders in the molded body, the movement of the liquid phase can be more positively controlled at a temperature of Tm (A) or higher.

According to the present invention, there is provided a structure having a thin film as a base material produced by the manufacturing method according to claim 1 or 2, wherein the thin film has a composition of a phase having a lower melting point in the phase-separated structure. The base material is composed of an amorphous body composed of a composition of a phase having a lower melting point in the phase-separated structure and a non-crystalline body composed of a composition of a phase having a higher melting point in the phase-separated structure. Provided is a thin film glass structure characterized by comprising a crystalline substance or a mixture of crystalline substances. According to this manufacturing method, the composition of the film is the composition of the phase having the lower melting point of the two phases of the phase-separating phase, for the reason described above. A structure made of phase-separated glass is Tm (A)
After forming a film at the above temperature, it is possible to control the formed film to be crystalline or amorphous by controlling the cooling rate, but a layer having a uniform thickness is formed. Since it is desirable that the surface of the antifouling member is smooth, and it is desirable that the antifouling member is expected to be used for one purpose, it is preferably made of an amorphous material. The base material is a mixture of an amorphous material having the composition of the phase having the lower melting point and an amorphous or crystalline material having the composition of the phase having the higher melting point, or It should be composed of a uniform amorphous or crystalline material having the composition of the phase having the higher melting point. As described above, the film may be composed of an amorphous material having the same composition A as that of the film or a mixture of an amorphous material and a crystalline material having a composition B, and an amorphous material having a composition B or an amorphous material having a composition B. However, by forming the base material from a structure having a structure different from that of the film in this way, it is different from the function required for the surface, for example, improvement of mechanical strength, coloring,
Functions such as giving different optical refractive indexes can be given.

[0012] In a preferred aspect of the present invention, the thin film has a thickness of 10 nm or less. By doing so, since the ratio of surface energy to the total energy of the functional layer made of this thin film is large, further improvement in functionality is expected in each application.

In a preferred aspect of the present invention, the phase having the lower melting point of the phase-separated structure has an independent droplet structure in which spherical particles are formed, and the diameter of the spherical particles is 100 nm or less. To do. In order to form a film having a thickness of 10 nanometers or less, it is necessary to make the size of the phase separation glass used into an appropriate shape and size. Generally, the shape of the phase separation has either an entangled structure (spinodal) or an independent droplet structure (binodal), but in this thin film manufacturing method, the independent droplet structure is easier to control the film thickness. In the case of an entangled structure, it is difficult to predict the amount of liquid phase that moves to the surface and spreads to form a film. Also in the case of the independent droplet structure, when the glass having a spherical shape has the higher melting point, it is difficult to predict the amount of liquid phase that moves to the surface and spreads to form a film, and the film thickness tends to increase. is there. Further, when the diameter of the spherical particles is 100 nanometers or more, the amount of liquid phase that moves to and spreads on the surface becomes too large, and the film thickness becomes 10 nanometers or more.

In a preferred embodiment of the present invention, the amorphous body having the composition of the phase having the lower melting point of the phase-separated structure contains a monovalent alkali metal such as Na, K or Li. To do. By doing so, when the thin film glass structure produced is utilized as an antifouling member, a self-cleaning action can be provided by the effect of a monovalent alkali metal such as Na, K, or Li present on the surface thereof.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment of the present invention, for example, as shown in FIG. 1, the functional material has an amorphous film of 10 nm or less on the surface of the base material. One method for manufacturing the thin film glass structure of the embodiment of FIG. 1 is to melt a mixture of raw materials of a glass having a target phase-separated structure, pour into a concave mold as shown in FIG. 2, and cool. A glass having a phase-separated structure in which the phase having a lower melting point in the phase-separated structure becomes a spherical particle by controlling the velocity, and the spherical particle has a diameter of 100 nm or less. Is manufactured in the shape of the target structure. The glass is heated in the mold again and heated at a temperature higher than the melting point of the phase having the lower melting point in the phase-separated structure.
Further, by removing the glass body poured into the concave mold from the mold and firing it on a flat mold, it is possible to obtain a structure having a film on the side surface as shown in FIG.

Another method for producing the thin film glass structure of the embodiment shown in FIG. 1 is, for example, to melt a mixture of raw materials of a glass having a target phase-separated structure and control the cooling rate. Then, a glass having a phase-separated structure in which the phase having a lower melting point of the phase-separated structure becomes a spherical particle and the diameter of the spherical particle is 100 nm or less is prepared. The glass is crushed and molded by a pressing method or the like in a concave mold as shown in FIG. 2 to obtain a glass powder molded body. The glass powder compact is heated again in the mold and fired at a temperature higher than the melting point of the phase having the lower melting point in the phase-separated structure. Further, by removing the molded glass powder compact from the mold and firing it on a flat mold, it is possible to obtain a structure having a film on the side surface as shown in FIG.

As another method of forming the phase separation, a step of melting and homogenizing the glass raw material, quenching it in the shape of the target structure, and then heat treating it again at a temperature below the liquidus line is used. May be. Further, it can be obtained by changing the size of the target phase separation, the cooling rate in the immiscible region, or controlling the heat treatment time below the liquidus.

As another embodiment, when the phase-separated glass powder is molded in the shape of the target structure, it is preferable to increase the filling rate of the molded body. This is because, when the filling rate is low, it is necessary to consider the control for making the base material part dense, which hinders the control of the layer thickness and the like.

【Example】

[0019]

[Table 1] 100 g of a glass raw material having the composition shown in Table 1 was weighed, a sample well mixed in a mortar was placed in a platinum crucible, which was melted in an electric furnace at 1650 ° C. for 1 hour, then poured into a mold and rapidly cooled in water to 20 A phase-separated glass body of × 10 × 5 mm was produced. The phase-divided glass body is heated in an electric furnace for about 20 hours per hour.
A sample was obtained by heating to 1200 ° C. at 0 ° C., heat-treating at 1200 ° C. for 1 hour, and cooling by air cooling. The cross section of the sample thus obtained was observed in the vicinity of its surface with a scanning transmission electron microscope (HD2000, Hitachi, Ltd.). The result is shown in FIG. It was observed that there was a glass layer of about 2 nanometers on the surface, and the base material had a mixed structure of two kinds of amorphous materials.

[0020]

According to the present invention, it is possible to obtain a glass composite structure having a thin film which is difficult to peel off by a simple process of only heat treatment.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing one manufacturing process in one embodiment of the present invention.

FIG. 3 is a diagram showing one manufacturing process in another embodiment of the present invention.

FIG. 4 is an S of a sample manufactured in an example of the present invention.
It is a TEM photograph.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shin Hayakawa             2-1-1 Nakajima, Kokurakita-ku, Kitakyushu City, Fukuoka Prefecture             No. Totoki Equipment Co., Ltd. F-term (reference) 4G059 AA17 AC30 CA01 CB04

Claims (6)

[Claims] 1. A thin film glass structure, comprising: firing a glass structure having a phase-separated structure at a temperature higher than a melting point of a phase having a lower melting point of the two phases forming the phase-separated structure. Body manufacturing method. 2. A step of crushing a glass structure having a phase-separated structure to produce a phase-separated glass powder, and a step of forming the phase-separated glass powder to produce a phase-separated glass powder compact. Baking the phase-separated glass powder compact at a temperature higher than the melting point of the phase having the lower melting point of the two phases forming the phase-separated structure. Production method. 3. The phase-separated structure having a lower melting point has an independent droplet structure in which spherical phases are spherical particles, and the spherical particles have a diameter of 100 nanometers or less. Or the manufacturing method according to 2. 4. A structure having a thin film as a base material, which is produced by the manufacturing method according to any one of claims 1 to 3, wherein the thin film is composed of a phase having a lower melting point in the phase-separated structure. The base material is an amorphous material, and the base material is an amorphous material having a composition of a phase having a lower melting point in the phase-separated structure and an amorphous material having a composition of a phase having a higher melting point in the phase-separated structure. Alternatively, a thin film glass structure comprising a crystalline mixture. 5. The thin film glass structure according to claim 4, wherein the thin film has a thickness of 10 nanometers or less. 6. The amorphous body having a composition of a phase having a lower melting point in the phase-separated structure contains a monovalent alkali metal such as Na, K, or Li. The thin film glass structure according to claim 4.