JPH075393B2 - Method for manufacturing ceramic / metal bonded body - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a ceramic / metal bonded body that can be used in an exhaust system device of an internal combustion engine or the like.

[Problems to be Solved by Prior Art and Invention]

In order to impart heat resistance, corrosion resistance and thermal shock resistance to those that are exposed to high temperature corrosive gas such as exhaust system member of internal heat engine and are subjected to rapid thermal shock, the inner surface of ceramic is It has been proposed to apply a coating.

The biggest problem with such a ceramic-metal bonded body is that it undergoes a rapid thermal shock due to high-temperature exhaust gas, so that a large strain stress occurs at the bonded interface between the ceramic and metal due to the difference in thermal expansion between the ceramic and metal. However, the separation of the ceramic from the joint surface occurs, and the thermal conductivity of the ceramic layer is much smaller than that of metal, so the thermal shock causes a very large temperature gradient in the ceramic layer. Large strain stress occurs in
Peeling occurs in the ceramic layer.

Generally, ceramic has a high compressive strength, but a low tensile strength and a very brittle property, and has a drawback that its resistance to thermal shock is very low.

Therefore, various proposals have been made to solve such problems.

For example, Japanese Patent Laid-Open No. 58-51214 discloses that a coating layer of an amorphous refractory made of a mixture of refractory raw material particles and a heat-resistant inorganic binder is formed on the inner surface of a metal device body in contact with high-heat exhaust gas. Disclosed is a characteristic exhaust gas system device for an internal combustion engine.

In addition to this, as a method for forming a ceramic layer by applying ceramic particles after applying an inorganic binder,
In JP-A-58-99180, a heat-resistant coating layer is formed by adhering a sludge made of a mixture of refractory raw material particles, an inorganic binder and a frit to the inner surface of a metal device body in contact with high-heat exhaust gas, Subsequently, while the heat-resistant coating layer is in a wet state, fire-resistant heat-insulating material particles are attached to the surface of the heat-resistant heat-insulating layer to form a heat-resistant heat-insulating layer, and then the heat-resistant heat-insulating layer is solidified and fire-resistant on the surface of the fire-resistant heat insulating layer. Characterized in that a heat-resistant coating layer is formed by adhering a sludge made of a mixture of raw material particles, an inorganic binder and a frit, and if necessary, the fire-resistant heat-insulating layer and the same material as the heat-resistant heat-insulating layer on the surface of the heat-resistant heat-insulating layer. Disclosed is a method for manufacturing an exhaust gas system device for an internal combustion engine, in which a layer and a heat resistant coating layer made of the same material as the heat resistant coating layer are sequentially repeated to form a required layer.

However, even with these methods, the bonding strength between the ceramic layer and the metal is not always sufficient, and there is a risk of peeling at the bonding interface between the ceramic and the metal and peeling within the ceramic layer due to thermal shock, and long-term There is a problem with service life.

Recently, ceramic paints and coating agents using a metal alkoxide as a binder have been developed, but these are very expensive and it is difficult to make them thick enough to withstand long-term use.

Further, Japanese Patent Application Laid-Open No. 59-12116 discloses a composite ceramic material in which inorganic hollow particles are dispersed in a matrix made of ceramic. However, if the inorganic hollow particles are simply dispersed in the matrix, the heat insulating property is not improved. Even if it can be secured, it is not possible to obtain a coating that has good adhesion to the metal surface and is resistant to thermal shock. Moreover, since the inorganic hollow particles generally have low strength, they may be broken between the hollow particles to cause peeling or cracking.

Next, when the ceramic-metal bonded body is exposed to high temperature corrosive exhaust gas for a long time, the corrosive exhaust gas penetrates into the ceramic layer and reaches the interface with the metal, where it oxidizes the metal surface. I found that there was a problem. Due to the oxidation of the metal surface, the bonding strength between the ceramic layer and the metal layer is extremely reduced, and there arises a problem that the ceramic layer is easily peeled off by mechanical shock or thermal shock.

Therefore, an object of the present invention is to provide a method for producing a ceramic / metal bonded body which has a sufficiently large bonding strength and a good antioxidation property, and does not have a problem of peeling even when used under a high temperature condition for a long time. It is to be.

[Means for solving problems]

As a result of earnest research in view of the above-mentioned object, the present inventors formed a bonding layer in which a metal oxide film and a silicate reacted, and
To form an antioxidant layer by baking and solidifying inorganic scale-like particles, and further to provide heat insulation and fire resistance, if necessary, by forming a heat insulation and / or fire resistance layer, corrosive exhaust gas of high temperature for a long period of time, etc. The inventors have found that a ceramic-metal bonded body can be obtained which is not peeled off even when exposed to water, and conceived the present invention.

That is, the method for producing a ceramic / metal joined body according to the present invention includes: (a) applying silicate to the surface of a metal member and subjecting it to heat treatment in a steam atmosphere to oxidize the surface of the metal member;
A binding layer is formed by the reaction between the oxide film and the silicate, and (b) a mixture of inorganic scale particles, a silicate binder and a curing agent is applied to the binding layer to form an antioxidant layer. (C) Subsequently, after curing and drying, firing is performed in an atmosphere with an oxygen partial pressure of 10 mmHg or less to bond the bonding layer and the antioxidant layer.

The present invention is described in detail below.

In the method for producing a ceramic / metal joined body of the present invention, the bonding layer and the antioxidant layer are formed as indispensable constituent conditions, and if necessary, the heat insulating layer, the fireproof layer and the surface layer are formed. Each layer will be described in detail below.

(1) Bonding layer In order to firmly bond the ceramic to the metal surface, it is important to bond the metal surface by a physical and chemical synergistic action. As a result of various studies, the present inventors have found that forming a film formed by reacting an oxide film and a silicate on a metal surface, that is, a bonding layer is effective for adhesion, but as a more effective means, When silicate is applied to the surface of metal and heat-treated in a steam atmosphere, the oxide film generated on the metal surface reacts with the silicate to form a bonding layer that is physically and chemically strongly bonded to form a bond. It was found to be effective.

The bonding layer is a dense layer for bonding the anti-oxidation layer and the metal and for preventing permeation of corrosive gas from the outside.
The thickness of the bonding layer is preferably 50 μm or less, and if it exceeds 50 μm, it may peel off from the bonding layer. Preferably 2 to 30
The thickness is μm. Here, the thickness is an average value, and there is a fluctuation of about 20 to 30% as a whole.

In the present invention, the following procedure is followed to form the bonding layer on the metal surface. First, in order to improve the wettability of the silicate solution, the surface of the metal is ground and swept by, for example, air blast or the like to form very small irregularities on the surface. Then, after washing, a silicate solution is applied and heat-treated in a steam atmosphere to generate a low-order metal oxide having a good reactivity with the silicate, thereby forming a good bonding layer. The steam atmosphere is preferably 500 ° C. or higher.

As the silicate, one kind or a mixture of two or more kinds such as sodium silicate, potassium silicate and lithium silicate is used in a liquid state. The coefficient of thermal expansion of these silicates increases in the order of lithium silicate, potassium silicate, and sodium silicate, and the coefficient of thermal expansion of the bonding layer can be matched with the coefficient of thermal expansion of the metal by appropriately selecting these.

(2) Antioxidant layer Ceramics generally have a bending strength as low as 1/3 or 1/10 of the compressive strength, are less ductile and ductile than metals, and are extremely brittle, so they are subjected to high temperature thermal shock. There is a drawback that strain stress occurs and it is easy to break.

The present inventors have conducted various studies to compensate for these drawbacks, and as a result, have found that it is effective to form an antioxidant layer having a structure in which inorganic flaky particles are laminated and crosslinked.

As the inorganic scaly particles, naturally occurring mica, artificially synthesized mica, film glass, or crushed inorganic hollow particles such as balloons are used. The shape of the inorganic scale-like particles is such that the major axis and minor axis are about 2 to 74 μm, the thickness is about 0.1 to 3 μm, and the ratio of the thickness to the major axis is 10.
The above are suitable. More preferably, the major axis is 5
30μm, thickness 0.5-2μm, ratio of thickness to major axis is 15
That is all. The fluidity as a coating agent having a major axis of more than 74 μm is poor, and the surface roughness of the coating layer is conspicuous, and if it is less than 2 μm, the particles are close to spherical and it becomes difficult to obtain scale-like characteristics.

The anti-oxidation layer can be formed by mixing inorganic scaly particles with a silicate binder and a curing agent to prepare a slurry, and applying the composition on the binder layer, followed by curing, drying and baking. The silicate binder may be the same as that used in the above bonding layer, and the curing agent may be calcined aluminum phosphate, calcium silicate or the like.

The proportion of inorganic scale-like particles in the antioxidant layer is generally
It may be about 30 to 60% by weight, preferably 40 to 50% by weight.

According to the method of the present invention, the mixture of the inorganic scaly particles, the silicate binder and the hardener is applied as a slurry onto the binder layer. After application, cure at a temperature of 18 to 30 ° C for 8 to 24 hours. Then, after removing moisture sufficiently by drying,
Baking at 50 ° C for 0.5-1.5 hours. The firing is performed in a neutral atmosphere with an oxygen partial pressure of 10 mmHg or less as in the bonding layer. In the antioxidant layer thus obtained, the inorganic scale-like particles are present in a state of being laminated due to their flat shape, and adhere as if they were cross-linked by the binder. is doing.

When the weight of the scale-like particles is the same as that of commonly used spherical or gravel-like particles, the surface area is large, and in the case of lamination, the adhesion area is large and the adhesion strength between layers is very large.

FIG. 1 schematically shows a comparison of laminated states of scaly particles and spherical particles made of the same material and having the same weight.

FIG. 1 (a) is a schematic diagram showing a laminated state of scale-like particles, and FIG. 1 (b) is a schematic diagram showing a layered state of spherical particles whose particle weight is equivalent to that of scale-like particles.

For example, the weight of a scaly particle 1 having a length of 15 μm × a width of 15 μm × a thickness of 1 μm corresponds to a sphere 2 having a diameter of 7.5 μm.
The area covering each metal surface is equivalent to four spherical particles,
The number of laminated scale-like particles is four times that of spherical particles. Therefore,
Since the contact area between the scaly particles is very large, the bonding strength between the laminated scaly particles is very large. At the same time, it can also be seen that the distance that the corrosive gas penetrates into the metal surface is lengthened and the effect of preventing metal corrosion is great.

Further, the structure in which the scale-like particles are laminated and crosslinked has better flexibility than the spherical particle layer, and cracks and peeling do not easily occur. Even if a crack occurs, it has an advantage that the crack propagation is very slow because of the laminated structure.

From the viewpoint of anticorrosion, the thicker the antioxidation layer is, the better it is. However, if it exceeds 1000 μm, the antioxidation layer may peel off due to high temperature thermal shock. Is inferior. It is preferably 300 to 700 μm.

In order to prevent peeling of the antioxidant layer, it is desirable that its coefficient of thermal expansion be as close as possible to that of the metal to be joined. Specifically, the difference in the coefficient of thermal expansion between the two may be about 0 to 0.3%, preferably 0 to 0.1%. For this purpose, it is necessary to adjust the composition of the ceramic component in the antioxidant layer.

Generally, the coefficient of thermal expansion of ceramics is much smaller than that of metals, so the matrix in the ceramic layer contains K ₂ O and Na ₂ O.
The coefficient of thermal expansion of the ceramic can be approximated to that of a metal by increasing the amount of glass and vitrifying it.

The matrix of the ceramic layer in the present invention is formed of silicate, and as the silicate, one kind or a mixture of two or more kinds of sodium silicate, potassium silicate and lithium silicate is used and used in a liquid state. The thermal expansion coefficient of these silicates increases sequentially with lithium silicate, potassium silicate, and sodium silicate, and the thermal expansion coefficient increases with an increase in the amount of alkali. Therefore, by selecting these appropriately, the thermal expansion coefficient of the bonding layer can be increased. It can match the coefficient of thermal expansion of metals.

(3) Heat insulation layer This layer is for imparting heat insulation properties, and is composed of a heat insulation material composed mainly of inorganic hollow particles, and is a mixture of a heat insulation material, a silicate binder and a curing agent. Is applied to the dried surface of the antioxidant layer, and the oxygen partial pressure is reduced to 10 after curing and drying.
It can be formed by firing in a neutral atmosphere of mmHg or less.

As the heat insulating material, it is preferable to use inorganic hollow particles such as shirasu balloon, expanded silica, and ceramic balloon. The average particle size of the powder is generally in the range of 10 to 500 μm. If it is less than 10 μm, cracking and peeling due to shrinkage occur, and if it is more than 500 μm, it is difficult to form a smooth coating layer. The preferred particle size range is 40 to 200 μm.

The silicate binder and the curing agent may be the same as those used for the antioxidant layer. The curing, drying and firing conditions may be the same as those for the antioxidant layer. In addition, in the heat insulation layer,
As shown in FIG. 11, inorganic scale-like particles may be mixed. When the structure in which the inorganic scale-like particles 1 are mixed is used, the heat insulating layer also has sufficient strength and flexibility, and peeling and cracking do not easily occur even when subjected to high temperature thermal shock, and also has an antioxidant function. improves.

As for the thickness of the heat insulation layer, the thicker it is, the better from the aspect of heat insulation, but 20
If it exceeds 00 μm, it may be peeled off by high temperature thermal shock, and if it is less than 200 μm, the heat insulating effect cannot be obtained. It is preferably 300 to 800 μm.

(4) Refractory layer This layer is a layer formed to impart fire resistance, and has a structure in which a refractory material mainly composed of inorganic particles is solidified.

The refractory layer is formed by applying a slurry of a mixture of a refractory material, a silicate binder and a curing agent to the surface of the antioxidant layer or the heat insulating layer after drying,
After curing and drying, it can be formed by firing in a neutral atmosphere with an oxygen partial pressure of 10 mmHg or less.

As the refractory material, generally used materials such as chamotte, alumina, zircon, and zirconia may be used, but zirconia is particularly preferable because of its low thermal conductivity. The average particle size of the refractory powder is generally in the range of 10 to 500 μm. If it is less than 10 μm, agglomeration between particles is likely to occur, it is difficult to form a smooth coating layer, and it tends to shrink due to the influence of high heat. If it is larger than 500 μm, it is difficult to form a smooth film. A preferable average particle size is 20 to 200 μm.

The silicate binder and the curing agent may be the same as those used for the antioxidant layer.

The curing, drying and firing conditions for forming the refractory layer may be basically the same as the conditions for forming the antioxidant layer.

The thickness of this layer is better from the viewpoint of fire resistance, but 2000
If it exceeds 100 μm, it may peel off due to thermal shock at high temperature, and if it is less than 100 μm, a sufficient fire resistance effect cannot be obtained. It is preferably 200 to 800 μm.

(5) Surface layer This layer is a layer that forms a dense ceramic thin film on the final surface of the antioxidant layer, the heat insulating layer or the refractory layer to prevent intrusion of corrosive gas from the surface.

The surface layer has a constitution comprising an inorganic binder and / or an organometallic binder, and the inorganic binder and / or the organometallic binder is applied to the final surface of the antioxidant layer, the heat insulating layer or the fireproof layer after drying. Then, it can be formed by firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less.

Further, when the inorganic binder and / or the organometallic binder is stabilized only by drying, the inorganic binder and / or the organometallic binder may be formed on the final surface of the antioxidant layer, the heat insulating layer or the refractory layer after firing. The surface layer can be formed by applying a binder and drying.

Suitable inorganic binders are solutions of alkali silicates such as sodium silicate, potassium silicate and lithium silicate, silcasol, alumina sol and aluminum phosphate solution.

Further, as the organometallic binder, a binder containing silicon alkoxide, zirconium alkoxide or the like as a main component is suitable.

With respect to this layer, it is difficult to match the coefficient of thermal expansion with the metal in terms of material, and the layer thickness must be 15 μm or less. If the layer thickness exceeds 15 μm, the strain stress due to the difference in the coefficient of thermal expansion increases, which may cause peeling or cracking. It is preferably 3 to 10 μm.

In the above, the bonding layer, the antioxidant layer, the heat insulating layer, the refractory layer, and the surface layer have been described, but these layers do not have to be all except the bonding layer and the antioxidant layer, and may be omitted according to the application. You can Therefore, the preferable combination of the present invention is as follows.

(A) Bonding layer + antioxidant layer (b) Bonding layer + antioxidant layer + surface layer (c) Bonding layer + antioxidant layer + heat insulating layer (d) Bonding layer + antioxidant layer + heat insulating layer + surface layer (e) ) Bonding layer + Antioxidant layer + Fireproof layer (f) Bonding layer + Antioxidant layer + Fireproof layer + Surface layer (g) Bonding layer + Antioxidant layer + Thermal insulation layer + Fireproof layer (h) Bonding layer + Antioxidant layer + Heat insulating layer + Fireproof layer + Surface layer [Example] The present invention will be described in more detail by the following examples.

Example 1 L-shaped tubular member 3 made of vermicular cast iron having the shape shown in FIG. 2 (long axis a: 200 mm, short axis b: 120 mm, inner diameter c: 40 mm, pipe thickness d:
3 mm) to form the bonding layer 4 on the inner and outer surfaces, the inner and outer surfaces of the tubular member 3 are ground and blasted,
After washing with dilute potassium silicate solution (concentration 5% by weight),
For application of the silicate, it was immersed in a potassium silicate solution (SiO ₂ / K ₂ O molar ratio 3.0, concentration 10% by weight), held for 3 minutes and then pulled up to remove excess potassium silicate. Then, after holding at room temperature for 1 hour, by holding it in a furnace adjusted to a heated steam atmosphere at 550 ° C. for 90 minutes, an oxide film is formed and reacted with potassium oxide, and cooled to room temperature to form a bonding layer 4. did.

Next, in order to form an antioxidant layer, inorganic scaly particles made of a crushed product of Shirasu balloon, a silicate binder, and a curing agent were mixed in the following proportions to prepare a slurry.

Sodium silicate (SiO ₂ / Na ₂ O molar ratio 3.0, concentration 30% by weight) 100 parts by weight Scale-like fine particles (<74 μm) 30 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight It was applied to the inner surface and the outer surface, cured for 2 hours, and then applied again to form the antioxidant layer 5 as a laminate of two layers.

In this state, curing was carried out at room temperature for 15 hours to carry out a curing reaction between sodium silicate and calcined aluminum phosphate.

Next, this tubular member 3 was heated in a dryer from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute, held for 1 hour, and then cooled to room temperature to dehydrate excess water.

Next, the tubular member 3 was heated in an N ₂ atmosphere (oxygen partial pressure 5 mmHg) to 800 ° C. at a temperature rising rate of 200 ° C./hour, held for 1 hour, and then cooled to room temperature in the furnace, and the bonding layer 4 and The antioxidant layer 5 was baked.

Further, silica sol is applied to the inner surface and the outer surface of the tubular member 3 obtained by baking and solidifying the antioxidant layer 5, and the temperature is raised at 110 ° C./min.
The temperature is raised to 8 hours, held for 1 hour, cooled to room temperature, and
A surface layer 8 having a thickness of μm was formed.

FIG. 4 is a cross-sectional view schematically showing a cross section of one side of the coating layer formed by the bonding layer 4, the antioxidant layer 5, and the surface layer 8 thus formed.

A bonding layer 4 having a thickness of about 10 μm is formed on the surface of the ceramic-coated tubular member 3 thus obtained, and the bonding layer 4 has a thickness of 0.5 to 2 μm and a length of 5 to 20 μm.
The scale-like particles 1 are laminated so as to form a cross-linked structure to form an antioxidant layer 5 having a thickness of about 300 μm, and the surface of the antioxidant layer 5 has a dense and thin surface layer 8 having a thickness of about 8 μm. Had been formed.

The following evaluation test was carried out to confirm the characteristics of the coating layer.

1) Oxidation increase test The above-mentioned tubular member 3 was attached to an inner surface heating evaluation device that burns propane gas to generate a high temperature gas, and a test was conducted under the following conditions.

Gas temperature 980 ℃ Primary air flow rate 50Nm ³ / hour Propane gas flow rate 2Nm ³ / hour Secondary air flow rate 36Nm ³ / hour Oxygen concentration 11% Tubular member inner surface temperature 620 ℃ (with coating) Tubular member inner surface temperature 580 ℃ ( Uncoated) Weight before test 1385.26g (with coating) Weight before test 1362.91g (without coating) Table 1 shows the oxidation weight gain. Table 1 also shows, for comparison, the oxidation gain without the ceramic coating.

2) Durability test The tubular member 3 was repeatedly subjected to 100 cycles of heating / cooling test with a heating evaluation device.

The conditions of the heating / cooling cycle were as follows.

Gas temperature 1050 ℃ Primary air flow rate 300Nm ³ / hour Propane gas flow rate 12Nm ³ / hour Secondary air flow rate 200Nm ³ / hour Oxygen concentration 15% Tubular member surface temperature 780 ℃ (with coating) Temperature rising rate 1000 ℃ / min Hold time 30 minutes Cooling in air 30 minutes As a result of the above test, it was confirmed that the coating layer had no cracks or peeling at all, and the durability was sufficiently satisfactory.

Although the coating layer is formed on the inner surface and the outer surface of the tubular member in the above-described embodiment, it is of course possible to form the coating layer only on the inner surface.

Example 2 FIG. 3 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a cross-sectional view schematically showing a coating layer composed of an anti-oxidation layer 5 and an anti-oxidation layer 5.

In order to form the bonding layer 4 on the inner surface and the outer surface of the cast iron metal tubular member 3, the inner and outer surfaces of the tubular member 3 were cleaned by air blasting and washed with a dilute potassium silicate solution (concentration 5% by weight). Thereafter, for application of the silicate, it was immersed in a potassium silicate solution (SiO ₂ / K ₂ O molar ratio 3.0, concentration 23 wt%), held for 3 minutes and then pulled up to remove excess potassium silicate. Then, after holding at room temperature for 1 hour, by holding it in a furnace adjusted to a heated steam atmosphere at 550 ° C. for 90 minutes, an oxide film is formed and reacted with potassium oxide, and cooled to room temperature to form a bonding layer 4. did.

Next, in order to form the antioxidant layer 5, the inorganic scale-like particles 1 (SiO ₂ : 77 wt%, Al ₂ O ₃ : 14 wt%, Na ₂ O: 3.3 wt%, K ₂ O: 3.5 wt% A crushed piece of film-shaped glass containing as a main component, sodium silicate (silicate binder), and calcined aluminum phosphate (curing agent) were mixed in the following proportions to prepare a mixed slurry.

Sodium silicate (SiO ₂ / Na ₂ O molar ratio 3.0, concentration 30% by weight)
100 parts by weight Shattered pieces of film glass (<74 μm) 30 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight The above mixed slurry is applied to the inner surface of the metallic tubular member 3,
After curing for 1 hour, the coating was applied again to form an antioxidant layer 5 having a thickness of 300 μm.

In this state, curing was carried out at room temperature for 15 hours to carry out a curing reaction between sodium silicate in the antioxidant layer and calcined aluminum phosphate.

Next, this metallic tubular member 3 was heated from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute in a dryer, held for 1 hour, cooled to room temperature, dehydrated with excess water, and then calcined.

Example 3 FIG. 4 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a diagram schematically showing a coating layer including an antioxidant layer 5 and a surface layer 8.

The bonding layer 4 and the antioxidant layer 5 were formed by the same method as in Example 2, dried and then coated with silica sol (concentration 40% by weight) on the surface of the antioxidant layer 5 in an N ₂ atmosphere (oxygen partial pressure). 5mmHg)
Then, the temperature was raised to 800 ° C. at a heating rate of 200 ° C./hour, heat treatment was performed for 1 hour, and then cooled to room temperature to form a surface layer 8 having a thickness of 8 μm.

Example 4 FIG. 5 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a diagram schematically showing a coating layer including an antioxidant layer 5 and a heat insulating layer 6.

In order to form the bonding layer 4 on the inner surface and the outer surface of the cast iron metal tubular member 3, the inner and outer surfaces of the tubular member 3 were cleaned by air blasting and washed with a dilute potassium silicate solution (concentration 5% by weight). Thereafter, for application of the silicate, it was immersed in a potassium silicate solution (SiO ₂ / K ₂ O molar ratio 3.0, concentration 23 wt%), held for 3 minutes and then pulled up to remove excess potassium silicate. Then, after holding at room temperature for 1 hour, by holding it in a furnace adjusted to a heated steam atmosphere at 550 ° C. for 90 minutes, an oxide film is formed and reacted with potassium oxide, and cooled to room temperature to form a bonding layer 4. did.

Next, inorganic flake particles 1 (SiO ₂ : 77% by weight, Al ₂ O ₃ : 14% by weight, Na ₂ O: 3.3% by weight, K ₂ O: 3.5% by weight as a main component crushed pieces of glassy glass ), Sodium silicate (silicate binder), and calcined aluminum phosphate (curing agent) were mixed in the following proportions to prepare a mixed slurry.

Sodium silicate (SiO ₂ / Na ₂ O molar ratio 3.0, concentration 30% by weight)
100 parts by weight Shattered pieces of film glass (<74 μm) 30 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight The above mixed slurry is applied to the inner surface of the metallic tubular member 3,
After curing for 1 hour, it was applied again to form an antioxidant layer 5 having a thickness of 300 μm.

In this state, curing was carried out at room temperature for 15 hours to carry out a curing reaction between sodium silicate in the antioxidant layer and calcined aluminum phosphate.

Next, the metallic tubular member 3 was heated in a dryer from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute, held for 1 hour, and then cooled to room temperature to dehydrate excess water.

Next, heat-insulating material powder (Shirasu balloon having a bulk specific gravity of 0.2 and a particle size of 44 to 150 μm), sodium silicate (silicate binder),
Calcined aluminum phosphate (curing agent) was blended in the following proportions to prepare a mixed slurry.

Sodium silicate (SiO ₂ / Na ₂ O molar ratio 3.0, concentration 30% by weight)
100 parts by weight Shirasu balloon (<74 μm) 10 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight The above-mentioned mixed slurry is applied to the surface of the antioxidant layer 5 formed on the inner surface of the metallic tubular member 3 and cured for 2 hours. The above operation was repeated to form the heat insulating layer 6.

In this state, curing was carried out at room temperature for 15 hours to carry out a curing reaction between sodium silicate in the heat insulating layer and calcined aluminum phosphate.

Next, this metallic tubular member 3 was put into a drier, heated from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute, and held for 1 hour, and then cooled to room temperature to dehydrate excess water.

Next, the metal tubular member 3 was placed in an N ₂ atmosphere (oxygen partial pressure 5 mmH
In (g), the temperature was raised to 800 ° C. at a temperature rising rate of 200 ° C./hour and held for 1 hour, then cooled to room temperature, and the heat insulating layer 6 having a thickness of 1500 μm was solidified.

Example 5 FIG. 6 is a cross-sectional view schematically showing a coating layer composed of a bonding layer 4, an antioxidant layer 5, a heat insulating layer 6 and a surface layer 8 formed on the inner surface of a metallic tubular member 3. Is.

The bonding layer 4, the antioxidant layer 5, and the heat insulating layer 6 were formed by the same method as in Example 4, and after firing, an aluminum phosphate solution (concentration 40% by weight) was applied to the surface of the heat insulating layer 6, The temperature was raised to 110 ° C. at a temperature rising rate of 10 ° C./minute, heat treatment was performed for 1 hour, and then cooled to room temperature to form a surface layer 8 having a thickness of 8 μm.

Example 6 FIG. 7 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a cross-sectional view schematically showing a coating layer including an antioxidant layer 5, a heat insulating layer 6, and a fireproof layer 7.

After forming the bonding layer 4, the antioxidant layer 5, and the heat insulating layer 6 in the same manner as in Example 4, the refractory powder (particle size 44 to 150 μm) is formed.
Stabilized zirconia of m FSD # 35 manufactured by Daiichi Rare Element Co., Ltd.
0), sodium silicate (silicate binder), and calcined aluminum phosphate (curing agent) were mixed in the following proportions to apply a mixed slurry.

Sodium silicate (SiO ₂ / Na ₂ O molar ratio 3.0, concentration 30% by weight)
100 parts by weight Stabilized zirconia (<74 μm) 170 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight The above-mentioned mixed slurry is applied to the surface of the heat insulating layer 6 formed on the inner surface of the metallic tubular member 3 and cured for 2 hours. Repeat the operation,
The refractory layer 7 was formed.

In this state, curing was carried out at room temperature for 15 hours to carry out a curing reaction between sodium silicate in the refractory layer and calcined aluminum phosphate.

Next, the metal tubular member 3 is put in a drier and heated from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute and held for 1 hour.
The excess water was dehydrated by cooling to room temperature.

Next, the metal tubular member 3 was placed in an N ₂ atmosphere (oxygen partial pressure 5 mmH
In g), raise the temperature to 800 ° C at a heating rate of 200 ° C / hour, and
After holding for a period of time, it was cooled to room temperature, and the refractory layer 7 and the heat insulating layer 6 having a thickness of 1000 μm were fired and solidified.

Example 7 FIG. 8 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a cross-sectional view schematically showing a coating layer including an antioxidant layer 5, a heat insulating layer 6, a refractory layer 7, and a surface layer 8.

The bonding layer 4, the antioxidant layer 5, the heat insulating layer 6, and the refractory layer 7 were formed by the same method as in Example 6, and after firing, an aluminum phosphate solution (concentration 40% by weight) was added to the refractory layer 7. It was coated on the surface, heated to 110 ° C. at a heating rate of 10 ° C./minute, heat-treated for 1 hour, and then cooled to room temperature to form a surface layer 8 having a thickness of 8 μm.

Example 8 FIG. 9 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a cross-sectional view schematically showing a coating layer composed of an antioxidant layer 5 and a fireproof layer 7.

After forming the bonding layer 4 and the antioxidant layer 5 by the same method as in Example 2, the refractory material powder (alumina having a particle size of 44 to 150 μm), sodium silicate (silicate binder), and calcined phosphoric acid. A mixed slurry prepared by mixing aluminum (curing agent) in the following ratio was applied.

Sodium silicate (SiO ₂ / Na ₂ O molar ratio 3.0, concentration 30% by weight) 100 parts by weight Alumina (<74 μm) 100 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight Formed on the inner surface of the metallic tubular member 3 The operation of applying the mixed slurry to the surface of the antioxidant layer 5 and curing it for 2 hours was repeated to form the refractory layer 7.

In this state, curing was carried out at room temperature for 15 hours to carry out a curing reaction between sodium silicate in the refractory layer and calcined aluminum phosphate.

Next, this metallic tubular member 3 was put into a drier, heated from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute, and held for 1 hour, and then cooled to room temperature to dehydrate excess water.

Next, the metal tubular member 3 was placed in an N ₂ atmosphere (oxygen partial pressure 5 mmH
In g), raise the temperature to 800 ° C at a heating rate of 200 ° C / hour, and
After holding for a period of time, it was cooled to room temperature, and the refractory layer 7 having a thickness of 1000 μm was solidified.

Example 9 FIG. 10 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a diagram schematically showing a coating layer formed by an antioxidant layer 5, a fireproof layer 7, and a surface layer 8.

After forming the bonding layer 4, the antioxidant layer 5, and the refractory layer 7 by the same method as in Example 8, alumina sol (concentration 10% by weight) is applied to the surface of the refractory layer 7 to raise the temperature rise rate to 10%. The temperature was raised to 110 ° C. at a rate of ° C./min, heat treatment was performed for 1 hour, and then cooled to room temperature to form a surface layer 8 having a thickness of 8 μm.

Example 10 FIG. 11 shows a bonding layer 4 formed on the inner surface of a metallic tubular member 3.
FIG. 3 is a cross-sectional view schematically showing a coating layer including an antioxidant layer 5 and a heat insulating layer 6.

The bonding layer 4 and the antioxidant layer 5 were formed by the same method as in Example 4. Next, this metallic tubular member 3 was heated from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute in a dryer and held for 1 hour, after which excess water was dehydrated.

Next, a ceramic balloon with a bulk specific gravity of 0.47 and a particle size of 44 to 150 μm (insulator powder), crushed silica balloon particles (inorganic scaly particles), and sodium silicate (silicate binder)
And calcined aluminum phosphate (curing agent) were mixed in the following proportions to prepare a mixed slurry.

Sodium silicate (SiO ₂ / Na ₂ O molar ratio 3.0, concentration 30% by weight)
100 parts by weight Ceramic balloon (<100 μm) 20 parts by weight Silica balloon crushed particles (<74 μm) 25 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight Surface of antioxidant layer 5 formed on inner surface of metal tubular member 3 The heat-insulating layer 6 was formed by repeating the procedure of applying the above-mentioned mixed slurry to and then curing it for 2 hours.

In this state, curing was carried out at room temperature for 15 hours to carry out a curing reaction between sodium silicate in the heat insulating layer and calcined aluminum phosphate.

Next, this metallic tubular member 3 was placed in a dryer to dehydrate excess water.

The mixture was heated from room temperature to 300 ° C. at a temperature rising rate of 1 ° C./minute, held for 1 hour, and then cooled to room temperature.

Next, the metal tubular member 3 was placed in an N ₂ atmosphere (oxygen partial pressure 5 mmH
In (g), the temperature was raised to 800 ° C. at a temperature rising rate of 200 ° C./hour and held for 1 hour, then cooled to room temperature, and the heat insulating layer 6 having a thickness of 1500 μm was solidified.

The constitution and thickness of each coating layer in Examples 2 to 10 are as shown in Table 2 below.

The following heating test was carried out in order to evaluate the properties of the coating layers obtained in Examples 2 to 10 above.

1) Test conditions Each tubular member was attached to a heating evaluation device that burns propane gas to generate a high temperature gas, and an inner surface heating test was performed under the conditions shown in Table 3.

2) Anticorrosion test Under the conditions shown in Table 3, the thickness of the oxide layer on the adhesion surface by the combustion gas after each test time was measured by a scanning electron microscope (SEM).

The results are shown in Table 4 together with Comparative Example 1 having no coating layer.

The antioxidant effect of Examples 2 and 3 is about 4 times that of the case without coating, and that of Examples 4 and 5 is about 30 times.

3) Adiabatic test The surface temperature of the metallic tubular member was measured under the conditions shown in Table 3 to examine the adiabatic property. The results are shown in Table 5 together with Comparative Example 1 having no coating layer.

4) Durability test As a result of 100 cycles of repeated heating / cooling test of heating and holding for 30 minutes under the conditions shown in Table 3 and then cooling to room temperature, cracks and peeling are not observed in the coating layer and the durability is sufficiently satisfied. Things were confirmed.

The operation and effect of each layer in the above embodiment will be described.

A bonding layer 4 having a thickness of about 30 μm is formed on the inner surface of the metallic tubular member 3. The bonding layer 4 is a dense glass and adheres well to the casting, and contributes to the bonding between the antioxidant layer 5 and the casting.

The thickness of the antioxidant layer 5 formed on the surface of the bonding layer 4 is about
It was 300 μm. The antioxidant layer 5 is firmly bonded to the tubular member 3 by the bonding layer 4, and has a thickness of 0.5 to 2 μm and a major axis of 5 to 2
The evaluation test demonstrates that it has flexibility because it has a layered and cross-linked structure of 0 μm scale-like particles and that it can maintain a healthy coating layer without cracking or peeling even when it expands and shrinks due to repeated heating and cooling. It was

The heat insulating layer 6 had a thickness of 1500 μm. Since the heat insulating layer of Example 10 was formed by using the mixture of the hollow ceramic particles as the matrix consisting of the inorganic scaly particles, the binder and the curing agent, the heat insulating layer firmly bonds to the antioxidant layer 5 and is resistant to a sudden thermal shock. It also has sufficient flexibility and has excellent heat insulating properties.

The refractory layer 7 is a refractory material that sufficiently withstands exhaust gas at a temperature higher than 1000 ° C., and is a layer that is firmly bonded to the heat insulating layer 6.

The surface layer 8 had a thickness of 8 μm. Since the surface layer 8 is a dense and thin layer and fills the open pores of the heat insulating layer 6 or the refractory layer 7, it has an extremely excellent effect of preventing invasion of harmful gas into the antioxidant layer 5. Although this embodiment describes the manifold, it can be similarly applied to a port liner, a front tube, a turbocharger and the like.

〔The invention's effect〕

As described above in detail, the ceramic-metal bonded body of the present invention has a bonding layer having an action of strengthening the bonding between the metal and the ceramic layer, and has a structure in which the inorganic scale-like particles are laminated thereon. Since it has an anti-oxidation layer having, there is no risk of peeling or cracking of the ceramic layer even under high temperature heating conditions, and the corrosion resistance is remarkably good. Therefore, when the ceramic-metal bonded body of the present invention is used, for example, in an exhaust system device of an internal combustion engine or the like, it can sufficiently withstand a rapid repeated thermal shock caused by a high temperature exhaust gas exceeding 800 ° C. It has anti-corrosion properties, heat insulating properties and fire resistance, and has a significant effect on increasing the service life of the member. The ceramic-metal bonded body of the present invention having such effects is particularly suitable for use in an engine exhaust gas manifold, an exhaust pipe, and the like.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing the action of the scale-like particles in the antioxidant layer of the present invention, FIG. 2 is a sectional view showing an example of a metal member to which the present invention can be applied, and FIGS. FIG. 11 is a sectional view schematically showing a ceramic / metal bonded body according to each embodiment of the present invention. 1: Inorganic scale-like particles 2: Hollow spherical particles 3: Metal tubular member 4: Bonding layer 5: Antioxidant layer 6: Thermal insulation layer 7: Fireproof layer 8: Surface layer 9: Fireproof particle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masatoshi Nakamizo, 35 Nagahama-cho, Kanda-cho, Kyoto-gun, Fukuoka Prefecture Kyushu Factory, Hitachi Metals, Ltd. (72) Kensuke Kido 1-1, Higashihama-cho, Hachimansai-ku, Kitakyushu, Fukuoka Kurosaki Ceramics Co., Ltd. (72) Inventor Katsumi Morikawa 1-1, Higashihama-cho, Hachimansai-ku, Kitakyushu, Fukuoka Prefecture Kurosaki Ceramics Co., Ltd. (56) Reference JP-A-61-70119 (JP, A) JP-A-62 -107083 (JP, A) JP 62-107080 (JP, A) JP 62-107085 (JP, A) JP 62-107086 (JP, A) JP 1-145383 (JP, A) ) JP-A-2-258983 (JP, A)

Claims (12)

[Claims] 1. A method for producing a ceramic / metal joined body, comprising: (a) applying a silicate to the surface of a metal member and heat-treating in a steam atmosphere to oxidize the surface of the metal member;
A binding layer is formed by the reaction between the oxide film and the silicate, and (b) a mixture of inorganic scaly particles, a silicate binder and a curing agent is applied to the binding layer to form an antioxidant layer. (C) Subsequently, after curing and drying, the bonding layer and the antioxidant layer are bonded by firing in an atmosphere having an oxygen partial pressure of 10 mmHg or less, to bond the ceramic / metal member bonded body. Manufacturing method. 2. The method for manufacturing a ceramic / metal joined body according to claim 1, wherein (a) after drying the antioxidant layer, an inorganic binder and / or an organometallic binder is applied to the surface thereof. To form a surface layer, and (b) firing is then performed in an atmosphere with an oxygen partial pressure of 10 mmHg or less. 3. The method for manufacturing a ceramic / metal joined body according to claim 1, wherein (a) after firing the antioxidant layer, an inorganic binder and / or an organometallic binder is applied to the surface thereof. To form a surface layer by (b) followed by drying at 110 ° C to 500 ° C, which is a method for producing a ceramic / metal bonded body. 4. The method for producing a ceramic / metal joined body according to claim 1, wherein (a) after drying the antioxidant layer, a heat insulating material mainly composed of inorganic hollow particles, a silicate binder and a hardening agent. A ceramics characterized by applying a mixture of the above to the surface of the antioxidant layer to form a heat insulating layer, and (b) subsequently curing and drying, and then firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less. Manufacturing method of metal bonded body. 5. The method for manufacturing a ceramic / metal joined body according to claim 4, wherein (a) after drying the heat insulating layer, an inorganic binder and / or an organometallic binder is applied to the surface thereof. A method for producing a ceramic / metal joined body, comprising forming a surface layer, and then (b) firing in an atmosphere having an oxygen partial pressure of 10 mmHg or less. 6. The method for manufacturing a ceramic / metal joined body according to claim 4, wherein (a) after firing the heat insulating layer, an inorganic binder and / or an organometallic binder is applied to the surface thereof. A method for producing a ceramic / metal joined body, which comprises forming a surface layer, and then (b) drying at 110 ° C to 500 ° C. 7. The method for manufacturing a ceramic / metal joined body according to claim 4, wherein (a) after drying the heat insulating layer, a mixture of a refractory material, a silicate binder and a curing agent is added to the heat insulating layer. A method for producing a ceramic / metal bonded body, which comprises coating the surface to form a refractory layer, (b) subsequently curing and drying, and then firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less. 8. The method for manufacturing a ceramic / metal joined body according to claim 7, wherein (a) the refractory layer is dried and then an inorganic binder and / or an organometallic binder is applied to the surface thereof. A method for producing a ceramic / metal joined body, comprising forming a surface layer, and then (b) firing in an atmosphere having an oxygen partial pressure of 10 mmHg or less. 9. The method for manufacturing a ceramic / metal joined body according to claim 7, wherein (a) after firing the refractory layer, an inorganic binder and / or an organometallic binder is applied to the surface thereof. A method for producing a ceramic / metal joined body, which comprises forming a surface layer, and then (b) drying at 110 ° C to 500 ° C. 10. The method for producing a ceramic / metal joined body according to claim 1, wherein (a) after drying the antioxidant layer, a mixture of a refractory material, a silicate binder and a curing agent is added to the antioxidant. A method for producing a ceramic / metal bonded body, which comprises coating the surface of a layer to form a refractory layer, (b) subsequently curing and drying, and then firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less. 11. The method for manufacturing a ceramic / metal joined body according to claim 10, wherein (a) the refractory layer is dried and then an inorganic binder and / or an organometallic binder is applied to the surface thereof. A method for producing a ceramic / metal joined body, comprising forming a surface layer, and then (b) firing in an atmosphere having an oxygen partial pressure of 10 mmHg or less. 12. The method for manufacturing a ceramic / metal joined body according to claim 10, wherein (a) after firing the refractory layer, an inorganic binder and / or an organometallic binder is applied to the surface thereof. A method for producing a ceramic / metal joined body, which comprises forming a surface layer, and then (b) drying at 110 ° C to 500 ° C.