JPH06191957A - Ceramic sintered compact with metal as skeleton - Google Patents

Abstract

PURPOSE:To obtain a ceramic sintered compact improved in fracture strength by embedding a linear, rodlike or netty metallic material in a specified skeletal location of a specific ceramic composition, followed by monolithic molding and then sintering. CONSTITUTION:Firstly, a linear, rodlike or netty metallic material is coated with an organic pasty material prepared by a adding water to a mixture of a specified proportion of starch and charcoal powder followed by heating to form a coating film of >=0.05mm thickness. Second, mixture composed of 20-95wt.% of the main stock which become vitreous through melting at elevated temperatures and has a chemical composition of 0.6-1.5 in the molar ratio of (CaO+MgO+Al2O3)/SiO2, 3-20wt.% based on the stock, of a molding auxiliary composed of hydraulic cement and a metal salt and, where appropriate, a nonshrinkable material is calcined to continue its linear expansion with temperature rise while keeping its linear expansion coefficient at >=80X10<-7>/ deg.C, and a ceramic composition whose sintering shrinkage at >=1000 deg.C is >=0.5% is obtained. Then, this composition is molded, and the paste- coated metallic material is embedded in a specified skeletal location of the resultant form, followed by monolithic molding and then sintering at 1000-1250 deg.C, thus obtaining the objective ceramic sintered compact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic sinter having a metal skeleton. More specifically, the present invention relates to a ceramic sinter that is used in the field of materials that require high fracture strength, such as building construction materials or civil engineering materials such as sewer pipes.

[0002]

2. Description of the Related Art Ceramic materials reinforced with reinforcing bars are reinforced concrete, A. L. It is widely used in the fields of construction and civil engineering such as C, but all are limited to cementitious materials. In the field of glass materials, "net-cored glass" is known, in which a wire net is placed inside a plate glass and integrally molded, and is widely used as a glass material that is easily broken and is reinforced with metal. This plate glass has a high coefficient of thermal expansion as ceramics and is close to a metal, and uses a wire mesh with a small wire diameter, and the coefficient of thermal expansion in the cooling process from 600 to 700 ° C. which is the solidification temperature of glass. The relatively small latent stress generated inside due to the difference of the above enables such a product.

As described above, the cementitious material and the plate glass are known to be reinforced with a reinforcing bar or a metal net, but all of them are applications in a very limited material field and are "brittle and easily broken". With regard to ceramic materials having drawbacks, reinforcement with metallic materials has not yet been practically completed. In such a situation, the inventor of the present invention has proposed a “metal composite ceramics sintered body”, which is obtained by dispersing and reinforcing a fibrous or piece-shaped metal. ,
Although a partial reinforcing effect is exerted, since it does not have a skeleton as a product, its reliability as a structural material is low and its field of use is restricted.

Therefore, there has been a demand for the realization of a product in which a ceramic material is integrated with a metal material serving as a skeleton.
This was considered to be an extremely difficult task for the following reasons. (1) Metals generally have a coefficient of thermal expansion nearly twice that of ceramics, and if encapsulated inside during sintering, the structure will be destroyed by the expansion of the metal. (2) When the temperature of metal such as rebar exceeds 500 ° C, it rapidly oxidizes from the surface to form an oxide layer, which further expands the volume, and the high temperature heating for a long time causes the oxide layer to spread and the rebar gradually becomes thinner. The reinforcing effect is significantly reduced.

Therefore, a ceramic material in which metal is used as a skeleton and integrally sintered has not been realized by the conventional technique. The present invention has been made in view of the circumstances as described above, overcomes the limitations of the prior art, and uses the most reliable metal material as the product strength as the skeleton, inside the sintered body,
It is an object of the present invention to provide a ceramic sinter having a metal skeleton in which it is embedded in a stable state.

[0006]

In order to solve the above-mentioned problems, the present invention is a ceramic sinter, in which a linear, rod-shaped or wire-mesh-shaped metal material is prescribed. A ceramic sinter having a metal skeleton, which is embedded and integrated in the skeleton arrangement. In addition, more specifically, the present invention, in the process of firing, heating,
While maintaining a linear thermal expansion coefficient of 80 × 10 ⁻⁷ / ° C. or more as the temperature rises, it continues to expand almost linearly and is sintered at a temperature of 1000 ° C. or more without causing 0.5% or more of sintering shrinkage. After being cooled, the ceramic composition to be a product is embedded and integrally molded with a linear, rod-shaped or wire-mesh-shaped metal material at a predetermined skeleton position, and then sintered at a temperature of 1000 ° C. or higher and 1250 ° C. or lower. The sintered body is

That is, the above-mentioned composition of the present invention exhibits a coefficient of thermal expansion of 80 × 10 ⁻⁷ / ° C. or more almost linearly, and the shrinkage due to sintering does not occur even at a sintering temperature of 1000 ° C. or more. A preferable requirement is that the composition has a small shrinkage not exceeding 0.5%. In a general ceramic composition, quartz shows a large expansion due to its transformation in the temperature rising process of firing, and when it exceeds 570 to 600 ° C., the temperature rising expansion becomes 80 × 10 ⁻⁷ / ° C. or more. ,
At a temperature of 600 ° C. or lower, the temperature rise expansion remains at a low level of about 50 to 60 × 10 ⁻⁷ / ° C. due to the shrinkage of the clay component, etc.
% Shows a large sinter shrinkage.

Therefore, in the case of the conventional general ceramic composition, for example, as shown in FIG. 1 (A), a large inflection point for expansion and contraction is exhibited, for example, 120 to 150.
Since it cannot have expansion similarity with a metal material that linearly expands due to thermal expansion of × 10 ^-7 / ° C (Fig. 1 (B)), it escapes from destruction due to expansion of this metal material during sintering. Absent.

However, in the present invention, as shown in FIG. 1C, the linear expansion is performed while maintaining the similarity with the metal material. Therefore, the composition and the metal material can be integrated as a sintered body. A porcelain composition suitable for realizing a porcelain sinter having a metal skeleton of the present invention is preferably a chemical composition having a (CaO + MgO + Al ₂ O ₃ ) / SiO ₂ ratio of 0.6 to 1.5. A molding aid which has a composition and is produced as a glassy material by melting at a high temperature within a range of 20 to 95% by weight as a main raw material, and which comprises a metal salt and a hydraulic cement. A composition is shown in which one or more kinds are blended in an amount of 3 to 20% by weight of the raw material, and a non-shrinkable raw material is further blended as necessary, and the shrinkage is sintered within 0.5%. The raw material produced in a glass state is typically a blast furnace slag, and the glassy slag crystallizes in the temperature range of 850 ° C to 950 ° C in the heating process while causing an exothermic reaction, and slightly. It has the property of reacting and sintering while exhibiting expansion. The composition containing 20% or more of this glassy material as a main raw material is 1
At a sintering temperature of 000 ° C or higher, the sintering shrinkage is 0.5
It is adjusted to the range below%. The greater the blending ratio, the more the sintered body shows expansiveness. From the viewpoint of dimensional stability of the sintered body product,
The blending ratio is preferably 20 to 95%.

When a metal salt such as sodium silicate or potassium silicate is used as a molding aid, the range of 3% to 10% is appropriate, and when it is 3% or less, sufficient molding strength cannot be obtained.
If it exceeds 10%, there is a problem in terms of economy. When using hydraulic cements such as Portland cement and blast furnace cement, the range is 10% to 20%. These molding aids are used alone or as a mixture. Further, the composition is a chamotte crushed ceramics or bricks, etc., which is preliminarily fired at a high temperature so as not to shrink depending on the required physical properties of the intended product or the size of the product,
For the purpose of fly ash or weight reduction, perlite or the like may be added.

Further, in the present invention, as the metal material to be embedded inside the sintered body, an iron wire as a reinforcing bar, other round bar or square bar, wire mesh and the like are used. In this case, needless to say, not only iron materials but also various metal materials whose thermal expansion is close to that of iron materials are preferably used. These metal materials generally have a higher degree of thermal expansion than the above composition, but in order to absorb this difference, starch, polyvinyl alcohol,
C. M. It is also effective to apply a coating film of an organic paste material such as C. This organic paste material does not easily disappear when the composition contains little oxygen.
Carbonization begins at 0 ° C and remains at the surface layer of the reinforcing bar as carbon even at 1200 ° C. Then, as long as this carbon remains, the oxidation of the reinforcing bar does not easily proceed, and when the state of the reinforcing bar surface is observed by cutting after completion of firing, the reinforcing bar surface shows a glossy state like a carburized layer. From the experimental results, the thickness of the organic glue layer may be 0.5% of the diameter of the reinforcing bar, but considering the amount of residual carbon remaining in the surface layer and the absorption of stress due to the expansion and contraction of the reinforcing bar in the longitudinal direction, the diameter of 1.0 It is desirable to set it to be at least%. When the thickness of the coating film is required to be 0.05 mm or more, it is also effective to mix charcoal powder, paper powder and the like.

The difference in the coefficient of thermal expansion between the reinforcing bar and the composition up to about 350 ° C. at which the organic paste material starts to be heated and carbonizes to decrease the volume is only 0.1% or less. It has been confirmed that the rebar expansion stress exerted can be sufficiently elastically absorbed. Hereinafter, the present invention will be described in more detail with reference to examples.

[0013]

[Example] Size 300 mm x 600 mm under the following conditions
A reinforcing bar having a diameter of 5 mm was embedded and molded inside a ceramic body of 20 mm in diameter, and the roller hearth kiln was used to raise the temperature to 1200 ° C. at a heating rate of 20 ° C./min, and after holding for about 20 minutes, 30 ° C. A sintered product was obtained by cooling at a rate of / min. (1) Reinforcing bar surface treatment After mixing starch and charcoal powder in a weight ratio of 1: 1 and adding 10 to 12 times water to heat and adjust the paste, the thickness of the reinforcing bar surface is about 0.2 mm. It was applied to a certain degree and dried. (2) Arrangement and Binding of Reinforcing Bars As shown in FIG. 2, reinforcing bars (2) were embedded in the center of the molded composition (1). The crossing part of the rebar (2) is 1.0m
Loosely bound with a wire of m diameter. (3) Blending of ceramic composition The blending ratio (weight ratio) is shown in Table 1 below.

[0014]

[Table 1]

(4) Molding method NO. 1, NO. 2 is powder pressure molding method 150kg / cm
Molded at a pressure of ² , press NO. In the case of No. 3, 30 to 50% of water was added and kneaded as cement mortar, and vibration filling molding was performed between molds, followed by curing and curing for 24 hours in a steam atmosphere at 60 ° C. (5) Appearance of the product after sintering and observation of cracks around the reinforcing bars that become internal incisions The following results were observed.

NO.1 Appearance and no internal cracks at all NO.2 Appearance and no internal cracks at all NO.3 Appearance and internal cracks at all (6) Physical properties of sintered products The physical property values were confirmed.

[0017]

[Table 2]

In Table 2, "+" indicates expansion and "-" indicates contraction in the sintering shrinkage column. The bending strength indicates the strength value at the time when a crack was found in the composition by observing the surface while applying a load to the center with a span of 200 mm. In addition, NO. 1, NO. 2, NO. 1000kg for all 3
Even under a load of / cm ^2, the reinforcing bar and the composition were not separated.

[0019]

EFFECT OF THE INVENTION A ceramic sinter is provided in which a metal skeleton such as a reinforcing bar, which has been conventionally impossible, is embedded and integrated. Provided is a new material as a structural material for construction that takes advantage of the characteristics of metal materials such as steel frames having high strength and reliability and ceramics having high weather resistance.

[Brief description of drawings]

FIG. 1 is a temperature correlation diagram showing the thermal expansion properties of a reinforcing bar and a composition according to the present invention in comparison with a conventional ceramic composition.

2A and 2B are a plan sectional view and a front sectional view showing a sintered body of the present invention as an example.

[Explanation of symbols]

 1 molded body 2 rebar

Claims (4)

[Claims] 1. A ceramic skeletal body, wherein a linear, rod-shaped, or wire mesh-shaped metallic material is embedded and integrated in a predetermined skeleton arrangement in the sintered body. And ceramic sinter. 2. In the process of firing and heating, while maintaining a linear thermal expansion coefficient of 80 × 10 ⁻⁷ / ° C. or more as the temperature rises, expansion continues almost linearly and a temperature of 1000 ° C. or more is applied to 0.5. %, The ceramic composition to be a product after being sintered without causing a sintering shrinkage of not less than 100% is embedded and integrally molded with a linear, rod-shaped or wire mesh-shaped metal material at a predetermined skeleton position. The ceramic sinter having a metal skeleton according to claim 1, which is obtained by sintering at a temperature of not less than 1 ° C and not more than 1250 ° C. 3. A ceramic sinter is (CaO + MgO +).
Al ₂ O ₃ ) / SiO ₂ ratio has a chemical composition in the range of 0.6 to 1.5, and it is melted at high temperature and produced as vitreous material as main raw material 20 to 95 weight % Composition, one or more molding aids consisting of metal salts and hydraulic cements are blended in an amount of 3 to 20% by weight of the raw material, and a non-shrinkable raw material is further blended as necessary. A ceramic sinter having the metal skeleton according to claim 1 or 2, which is the sinter. 4. The metal skeleton according to claim 2 or 3, wherein a coating film is formed on the surface layer of the metal material to be integrally molded by embedding to a thickness of 1% or more of the diameter of the metal material with organic glue. And ceramic sinter.