JPH0717772A - Production of material with gradient function - Google Patents

Abstract

PURPOSE:To efficiently produce the material with gradient function by mixing plural mixtures obtd. by mixing 2 kinds of fillers while varying the mixing ratios of them stepwise with a resin, forming a film, laminating formed films so that filler mixing ratios vary successively and sintering it. CONSTITUTION:Plural filler mixtures are prepared by varying mixing ratios stepwise using 2 kinds of fillers A and B (e.g., Al2O3 and Ni) which gives gradient function. Then respective filler mixtures are mixed and dispersed uniformly in an org. binder resin (e.g., methacrylics resin) separately to produce plural paste-like matters, then, respective paste-like matters are formed into a film-like matters by a screen printing. Then, respective films are laminated so that their filler mixing ratios vary successively, and the laminated matter is sintered to produce the material with gradient fnction. In this way, the material with gradient function as a super heat resistant material is produced efficiently in arbitrary gradient degree.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently manufacturing a functionally gradient material with an arbitrary degree of gradient.

[0002]

2. Description of the Related Art Functionally graded materials are used for transporting humans and materials between space and the ground using manned space vehicles (hereinafter referred to as space planes) under severe environmental conditions. It was born at the stage of searching for a super heat resistant material that can secure the safety of people and things stored inside the space plane even when placed.

The demands on these super-heat-resistant materials are severe. For example, when the space plane is moved back and forth between space and the ground, the outer surface temperature of the fuselage reaches nearly 1800 ° C., so the inside of the fuselage must be cooled with a coolant such as liquid nitrogen at −253 ° C. In this case, a large temperature difference and a thermal stress due to the temperature difference occur in the thickness direction of the airframe material.

Therefore, it is necessary that the exterior material of the space plane is made of a super heat-resistant material that can withstand such a remarkable temperature difference between the outer surface and the back surface and a thermal stress. One of them is the idea of a functionally graded material. Was born.

Typical methods for producing a functionally graded material include vapor deposition, particle method, thermal spraying method and combustion synthesis method.

In the vapor deposition method of (1), when the chemical vapor deposition method is performed on the substrate, the flow rate ratio of the two source gases supplied to the vapor deposition section is continuously changed with the vapor deposition time, and the inclined structure layer is formed on the substrate surface. Is a method of forming.

The particle method of (2) is one in which a mixture of two kinds of microparticles having different particle sizes is packed in a container while changing the composition ratio and sintered, or two kinds of particles having different composition ratios having different particle sizes. There is a thin film (hereinafter referred to as a green sheet) made of a mixture of the above and an organic binder resin, which is laminated and sintered to give a gradient structure to the particle size distribution.

As a thermal spraying method of 1, there is a plasma thermal spraying method, in which two types of thermal spraying agents supplied into a plasma jet generated from one plasma gun are injected while controlling the composition ratio, and an inclined structure is formed on a substrate surface. And one in which two plasma guns are used to independently control the supply amounts of two types of thermal spraying agents to form an inclined structure on the surface of the base material.

As the combustion synthesis method of (1), a mixture of two kinds of raw material powders is laminated by a self-heating reaction method (SHS method) while changing a mixing ratio thereof, and the green compact is enclosed in a combustion container and hydrostatic pressure is applied. There is one that is ignited and synthesized below.

[0010]

In the above-mentioned method of manufacturing a functionally gradient material, the vapor deposition method is difficult to manufacture a large member because a vacuum system is required to form the functionally gradient material. Further, it takes a lot of time to manufacture a thick film functionally gradient material.

The thermal spraying method (1) is used as a method for thermal spraying ceramics onto a metal surface. Among them, the plasma thermal spraying method can form a thick functionally gradient layer even on a large member having a relatively complicated shape. It has the characteristics of However, since the functionally gradient film produced by this thermal spraying method has a large number of pores therein, it has problems in physical properties such as low mechanical strength. In addition, there is a problem that a large-scale facility is required for the production thereof and the cost becomes high.

Among the particle methods, the method of stacking and sintering the green sheets is effective for manufacturing a large member. However, since this green sheet is produced by the doctor blade method, only a thickness of about several tens of microns has been obtained, and it is technically difficult to produce a green sheet thinner than this.

In the self-heating reaction method (SHS method) of the combustion synthesis method of (1), since solid powder is basically used as a raw material, the powder is laminated by changing the mixed composition of the raw material powder to form a functionally gradient material alone. Technology is needed. Recently, a device that can automatically produce this simple substance has been developed, and it has become possible to manufacture a large-scale functionally graded material, but there is still a problem in terms of productivity for practical use.

In view of such a situation, the present invention has an object to provide a method for efficiently producing a functionally graded material with an arbitrary degree of inclination.

[0015]

DISCLOSURE OF THE INVENTION The gist of the present invention is to provide at least two binder compositions comprising an organic binder resin and a particle mixture in which at least two fillers exhibiting a gradient function are mixed at different mixing ratios. When laminating a plurality of film-like materials prepared by screen printing, the particles are laminated so that the particle ratio in the laminated film-like materials sequentially changes from one surface to the other surface of the laminated material. There is a method of manufacturing a functionally graded material.

The particle size of the filler used for carrying out the present invention is preferably 10 μm or less. If a filler having a particle size of more than 10 μm is used, it is difficult to form a film having a film thickness of 30 μ or less by a screen printing method.
The porosity in the sintered body obtained by sintering the laminated body becomes high, which leads to deterioration of physical properties such as mechanical strength, which is not preferable.

The filler used in the present invention is S
iO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , mullite (3Al
₂ O ₃ · 2SiO ₂ ), zircon (ZrO ₂ · SiO ₂ ),
Spinel (MgO ・ Al ₂ O ₃ ), SiC, TiN, Ti
_{C, Si 3 N 4, Ni} , Al, Cu, W, and the like of stainless steel.

The organic binder resin is not particularly limited as long as it is a resin having excellent baking properties and can uniformly mix and disperse the filler. Specific examples of the organic binder resin include cellulose-based resins, vinyl alcohol-based resins, and methacrylic-based resins. Among them, methacrylic-based resins are preferable from the viewpoint of baking property.

When a paste-like material composed of an organic binder resin and a filler is formed into a film-like material by screen printing, a method of diluting the paste-like material with an organic solvent, screen-printing and then removing the organic solvent by drying is used. Is desirable. The amount of the organic binder resin is preferably 50% or less in weight ratio with respect to the filler contained in the pasty material.

When a laminate of a film-like material made of a large paste-like material having an organic binder resin content of more than 50% is sintered, the porosity in the sintered body is high and the mechanical strength is high. It is not preferable because it causes deterioration of physical properties such as.

A sintered body obtained by forming a film-like material by a screen printing method using a paste-like material having an organic binder resin of 50% or less and sintering the laminate has a small porosity and is extremely functional. It has a great feature that it can be a functionally graded structure that can be easily exhibited. That is, compared with the conventional method the filler content in the film,
It can be quite large.

In carrying out the present invention, it is also possible to use a hot pressing method in which a high pressure is applied when the film-shaped material laminate is sintered. This method can also be used. By using this method, a sintered body having a low porosity can be obtained.

The laminating order when laminating the film-like materials obtained by the above method to form a laminated body may be selected as a laminating manner necessary for satisfying the object of the present invention.

The film laminate for forming a functionally gradient material shown in FIG. 1 will be described below as an example. When the two kinds of fillers are A and B, the first layer is A / B = 10/0
It is a film-like material formed by a paste-like material in which a filler (weight ratio) is uniformly dispersed in an organic binder resin. The second layer is a film-like material formed of a paste-like material in which a filler composed of A / B = 9/1 (weight ratio) is uniformly dispersed in an organic binder resin.

Hereinafter, A / B = 8/2, 7/3, 6/4, 5
/ 5, 4/6, 3/7, 2/8, 1/9, 0/10 (all are weight ratios) by a paste-like material in which the filler is uniformly dispersed in the organic binder resin, Fourth
The fifth layer, the fifth layer, the sixth layer, the seventh layer, the eighth layer, the ninth layer
It shows the order in which the film-shaped objects of the layer, the tenth layer, and the eleventh layer were formed.

In addition, if necessary, these film materials may include sintering aids, deflocculants, wetting agents, plasticizers, protective colloid agents, antistatic agents, antifoaming agents, bactericides, chelates and Additives such as a hidden pay agent and a surfactant may be added.

The film thickness can be arbitrarily controlled by changing the screen plate and printing conditions. Therefore, by using this method, a functionally graded material having an arbitrary degree of gradient can be obtained.

As a method for investigating the thermal shock resistance of the obtained functionally graded material, there is a method by laser irradiation.

[0029]

EXAMPLES The present invention will be described below with reference to examples. In the examples, “part” means “part by weight”.

Viscosity: 25 ° C., adjusted with an E-type viscometer (Tokyo Keiki Co., Ltd.). Thermal shock resistance: A spot diameter of about 2 mm was obtained by irradiation with YAG laser.

[Example 1] <First layer> 99 parts of isobutyl methacrylate, 1 part of methacrylic acid, and 1.3 parts of azoisobutyronitrile were reacted in butyl cellosolve at 80 ° C for 10 hours. 15 parts (solid content) of the obtained acrylic resin was mixed with Al ₂ O ₃ 10
0 part was dispersed and kneaded, and the viscosity was adjusted to 10 with butyl cellosolve.
The paste was obtained by adjusting the pressure to 000 cps. Then, the obtained paste-like material was solid-printed on a glass plate with a # 200 mesh screen plate to a film thickness of 15 μm.
It dried at 50 degreeC for 40 minutes, and created the film-form.

<Second Layer> A paste-like product was obtained in the same manner as in the first layer, except that 90 parts of Al ₂ O _{3 and} 10 parts of Ni were dispersed and kneaded in 15 parts (solid content) of the acrylic resin. . Next, the obtained paste-like material was overprinted and dried on the first-layer film-like material in the same manner as in the first layer to form a film-like material.

<Third Layer> A paste-like material was obtained in the same manner as in the first layer except that 80 parts of Al ₂ O _{3 and} 20 parts of Ni were dispersed and kneaded in 15 parts (solid content) of the acrylic resin. . Then, the obtained paste-like material was overprinted and dried on the second-layer film-like material in the same manner as in the first layer to form a film-like material.

<Fourth layer> A paste-like material was obtained in the same manner as in the first layer except that 15 parts (solid content) of acrylic resin were dispersed and kneaded with 70 parts of Al ₂ O _{3 and} 30 parts of Ni. . Next, the obtained paste-like material was overprinted and dried on the film-like material of the third layer in the same manner as the first layer to form a film-like material.

<Fifth Layer> A paste-like material was obtained in the same manner as in the first layer except that 60 parts of Al ₂ O _{3 and} 40 parts of Ni were dispersed and kneaded in 15 parts (solid content) of the acrylic resin. . Then, the obtained paste-like material was overprinted and dried on the film-like material of the fourth layer in the same manner as in the first layer to form a film-like material.

<Sixth Layer> A paste-like material was obtained in the same manner as in the first layer except that 50 parts of Al ₂ O _{3 and} 50 parts of Ni were dispersed and kneaded in 15 parts (solid content) of the acrylic resin. . Next, the obtained paste-like material was overprinted and dried on the film-like material of the fifth layer in the same manner as in the first layer to form a film-like material.

<Seventh Layer> A paste-like material was obtained in the same manner as in the first layer except that 40 parts of Al ₂ O _{3 and} 60 parts of Ni were dispersed and kneaded in 15 parts (solid content) of the acrylic resin. . Next, the obtained paste-like material was overprinted and dried on the sixth-layer film-like material in the same manner as in the first layer to form a film-like material.

<Eighth Layer> A paste-like product was obtained in the same manner as in the first layer, except that 30 parts of Al ₂ O ₃ and 70 parts of Ni were dispersed and kneaded in 15 parts (solid content) of the acrylic resin. . Next, the obtained paste-like material was overprinted and dried on the film-like material of the seventh layer in the same manner as in the first layer to form a film-like material.

<Ninth Layer> A paste-like product was obtained in the same manner as in the first layer, except that 20 parts of Al ₂ O ₃ and 80 parts of Ni were dispersed and kneaded in 15 parts (solid content) of the acrylic resin. . Then, the obtained paste-like material was overprinted and dried on the film-like material of the eighth layer in the same manner as in the first layer to form a film-like material.

<10th layer> A paste-like product was obtained in the same manner as in the 1st layer except that 15 parts (solid content) of acrylic resin were dispersed and kneaded with 10 parts of Al ₂ O ₃ and 90 parts of Ni. . Next, the obtained paste-like material was overprinted and dried on the film-like material of the ninth layer in the same manner as in the first layer to form a film-like material.

<Eleventh Layer> A paste-like material was obtained in the same manner as in the first layer except that 100 parts of Ni was dispersed and kneaded in 15 parts (solid content) of the acrylic resin. Next, the obtained paste-like material was overprinted on the 10th layer film-like material and dried to form a film-like material. The thus obtained 11-layer laminate was sintered at 1400 ° C. for 5 hours to obtain a functionally graded material.

The result of examining the thermal shock resistance of the resulting FGM, cracks in the power density 2.87w / mm ² did not occur, cracks occurred in power density 3.87w / mm ^2.

Example 2 A laminated body was obtained by the screen printing method in the same manner as in Example 1, and then sintered at 1400 ° C. for 5 hours while applying a pressure of 1 ton / cm ² , to obtain a functionally graded material. It was

As a result of examining the thermal shock resistance of the obtained functionally graded material, the power density was 2.87 w / mm ² and 3.87.
In w / mm ² cracking did not occur, cracking occurs in the power density 4.87w / mm ^2.

[Comparative Example 1] Isobutyl methacrylate 9
9 parts, methacrylic acid 1 part, and azoisobutyronitrile 1.3 parts were made to react in butyl cellosolve at 80 degreeC for 10 hours. To 15 parts (solid content) of the obtained acrylic resin,
100 parts of Al ₂ O ₃ was dispersed and kneaded, and the viscosity was adjusted to 10,000 cps with butyl cellosolve to obtain a paste.

Then, the paste-like material thus obtained was coated on a glass plate with a # 200 mesh screen plate to a film thickness of 15 μm.
m was solid-printed and dried at 150 ° C. for 40 minutes to prepare a film-like material. The same paste-like material was used to repeat the printing and drying operations 10 times to obtain a laminated body having a thickness of 165 μm.

The obtained laminated body was sintered at 1400 ° C. for 5 hours to obtain an Al ₂ O ₃ sintered body. The obtained Al
_When the thermal shock resistance of the ₂ O ₃ sintered body was performed with a spot diameter of about 2 mm, cracking occurred at a power density of 2.87 w / mm ² .

As described in detail above, the method of the present invention is
It is possible to efficiently produce a functionally graded material that is a super heat resistant material with an arbitrary degree of gradient, and its industrial significance is remarkable.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the concept of a functionally graded material.

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[Procedure amendment]

[Submission date] September 3, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

In carrying out the present invention, it is also possible to use a hot pressing method in which a high pressure is applied when the film-shaped material laminate is sintered. By using this method, a sintered body having a low porosity can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B32B 27/20 Z 8413-4F 31/04 7148-4F C08K 3/22 KAE

Claims (2)

[Claims] 1. A filler comprising two or more kinds of films prepared by a screen printing method from a paste mixture consisting of a filler mixture having different mixing ratios of at least two kinds of fillers exhibiting a gradient function and an organic binder resin. A method of manufacturing a functionally gradient material, comprising: laminating a laminated material so that a mixing ratio is sequentially changed to obtain a functionally gradient structure. 2. The method for producing a functionally gradient structure according to claim 1, wherein the organic binder resin content of the film-like material is 50% or less.