JPH02258983A - Ceramic-metal joined body and production thereof - Google Patents

Abstract

PURPOSE:To obtain the joined body having high bonding strength and satisfactory oxidation preventing property and not causing exfoliation even after use at a high temp. over a long period of time by forming a heat insulating layer obtd. by sintering a heat insulating material based on inorg. hollow granules on a reactive binding layer consisting of a silicate and an oxide coating film formed on the surface of a metal member. CONSTITUTION:A metal member is heated to >=500 deg.C in a steam atmosphere to form an oxide coating film on the surface. This oxide coating film is coated with a sol of a silicate such as sodium silicate as a binder and the resulting binder layer is coated with a mixture of a heat insulating material based on inorg. hollow granules with a silicate binder and a hardening agent. They are held under heating at about 750-850 deg.C in a neutral atmosphere for about 0.5-1.5hr to obtain a ceramic-metal joined body having the above-mentioned characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic-metal bonded body that can be used for exhaust system equipment of internal combustion engines, and a method for manufacturing the same.

[Problems to be solved by the prior art and the invention] High-temperature corrosive gas l+ - such as exhaust system members of internal combustion engines, etc.
: It has been proposed to apply a ceramic coating to the inner surface of Jt, and to impart heat resistance, corrosion resistance, and thermal shock resistance to those subjected to sudden thermal shock.

The biggest problem with such ceramic-metal joints is that they are subject to sudden thermal shock from high-temperature exhaust gas.
The difference in thermal expansion between ceramic and metal causes large strain stress at the ceramic-metal bonding interface, which causes the ceramic to peel from the bonded surface, and the ceramic layer has a very high thermal conductivity compared to the metal. Due to the small size of the ceramic layer, the temperature gradient within the ceramic layer becomes very large due to thermal shock.
Therefore, large strain stress is generated within the ceramic layer, and peeling occurs within the ceramic layer.

In general, ceramics have a high compressive strength, but a low tensile strength and are extremely brittle, and have the disadvantage of having a very low resistance to thermal shock.

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

For example, JP-A 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 that is in contact with high-temperature exhaust gas. Discloses an exhaust gas system device for an internal combustion engine having characteristics.

In addition, Japanese Patent Laid-Open No. 58-99180 describes a method of forming a ceramic layer by attaching ceramic particles after applying an inorganic binder. A heat-resistant coating layer is formed by attaching a slurry made of a mixture of raw material particles, an inorganic binder, and a frit, and then, while the heat-resistant coating layer is in a wet state, fireproof insulation material particles are attached to the surface of the heat-resistant coating layer to make it fireproof. A heat insulating layer is formed, and then the heat resistant coating layer is solidified and a slurry made of a mixture of refractory raw material particles, an inorganic binder and a frit is attached to the surface of the fire resistant heat insulating layer to form a heat resistant coating layer. An exhaust gas for an internal combustion engine, characterized in that, if necessary, a fire-resistant heat-insulating layer made of the same material as the fire-resistant heat-insulating layer and a heat-resistant coating layer made of the same material as the heat-resistant coating layer are successively formed on the surface of the heat-resistant heat-resistant coating layer as required. A method of manufacturing gas-based equipment is disclosed.

! However, even with these methods, the bonding strength between the ceramic layer and the metal is not necessarily sufficient, and there is a risk of peeling at the bonding interface between the ceramic and the metal or within the ceramic layer due to thermal shock, resulting in long-term problems. There is a problem with time durability.

Recently, ceramic paints and coatings using metal alkoxides as binders have been developed, but these are very expensive and difficult to make thick enough to last for a long period of time.

In addition, JP-A-59-12116 discloses a composite ceramic material in which inorganic hollow particles are dispersed in a ceramic matrix, but simply dispersing the inorganic hollow particles in an IJ Fuchs However, it is not possible to obtain a coating that has good adhesion and is resistant to thermal shock on metal surfaces. Furthermore, since inorganic hollow particles generally have low strength, there is a risk that the hollow particles will break, resulting in peeling or cracking.

Next, if the ceramic-metal bonded body is exposed to high-temperature corrosive exhaust gas for a long period of time, the corrosive exhaust gas will penetrate into the ceramic layer and reach the interface with the metal, where it will oxidize the metal surface. It turns out that there is a problem. Oxidation of the metal surface causes a problem in that the bonding strength between the ceramic layer and the metal layer is extremely reduced, and the ceramic layer easily peels off due to mechanical or thermal shock.

Therefore, an object of the present invention is to provide a ceramic-metal bonded body that has sufficiently high bonding strength and good antioxidation properties, and does not cause peeling problems even when used under high temperature conditions for a long period of time. .

Another object of the present invention is to provide a method for manufacturing such a ceramic-metal joint.

[Means for solving problems]

As a result of intensive research in view of the above objectives, the present inventors formed a bonding layer in which a metal oxide film and a silicate reacted, and
Insulation and/or fire resistance to provide insulation and/or fire resistance.
Alternatively, the inventors discovered that by forming a refractory layer, it is possible to obtain a ceramic-metal bonded body that is free from peeling even when exposed to high-temperature corrosive exhaust gas or the like for a long period of time, and came up with the present invention.

That is, the ceramic-metal bonded body of the present invention has a bonding layer in which an oxide film and a silicate have reacted on the surface of a metal member, and a heat insulating material mainly composed of inorganic hollow particles is baked on the surface of the bonding layer. It is characterized by having a solid heat insulating layer.

Another ceramic-metal bonded body of the present invention is
It is characterized by having a bonding layer in which an oxide film and a silicate have reacted on the surface of the metal member, and having a refractory layer on the surface of the bonding layer made by sintering a refractory material mainly composed of inorganic particles. do.

In addition, the method for manufacturing a ceramic-metal bonded body of the present invention includes: (a) heat-treating a metal member in a steam atmosphere to form an oxide film on its surface; and (b) forming a silicate film on the oxide film. Apply bonding agent, (c
) A mixture of a heat insulating material mainly composed of inorganic hollow particles, a silicate binder, and a hardening agent, or a mixture of a fireproof material, a silicate binder, and a hardening agent is applied to the surface of the bonding layer to form a heat insulating layer or a fireproof layer. A layer is formed, (6) followed by curing and drying, and (e) firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less, whereby a bonding layer is formed by the reaction between the oxide film and the silicate, and a heat insulating layer is formed. Or, it is characterized by hardening the refractory layer.

Another method of manufacturing a ceramic-metal bonded body according to the present invention is as follows: (a) A silicate is applied to the surface of a metal member, and the surface of the metal member is oxidized by heat treatment in a steam atmosphere, and the silicate is (b) A mixture of a heat insulating material mainly composed of inorganic hollow particles, a silicate binder, and a hardening agent, or a mixture of a fireproof material, a silicate binder, and a hardening agent. A heat insulating layer or a fireproof layer is formed by coating on the surface of the bonding layer, (c) followed by curing and drying, and (6) baking in an atmosphere with an oxygen partial pressure of 10 mmHg or less to form a heat insulating layer or a fireproof layer. It is characterized by hardening the heat insulating layer or the fireproof layer.

The invention will be explained in detail below.

The ceramic-metal bonded body of the present invention has a bonding layer, a heat insulating layer and/or a refractory layer, and further has a surface layer if necessary. Each layer will be explained in detail below.

(1) Bonding Layer In order to firmly bond the ceramic to the metal surface, it is important to bond the ceramic to the metal surface by physical and chemical synergy. As a result of various studies, the present inventors have discovered that forming an oxide film on the metal surface in advance is effective for adhesion.

By forming an oxide film on the surface of the metal in advance, very small irregularities are generated on the surface layer, which improves the wettability of the silicate as a binder, and the oxide film and silicate react with each other during the final heat treatment. Forms a good bonding layer that is also strongly bonded.

The bonding layer is a dense layer that joins the heat insulating layer or the fireproof layer and the metal and prevents corrosive gases from penetrating from the outside. The thickness of the bonding layer is suitably 50 μm or less;
If it exceeds μm, there is a risk of peeling from the bonding layer. Preferably the thickness is 2 to 30 μm. The thickness here is an average value, and there is an overall variation of about 20 to 30%.

In contrast, in the enamel technology, ceramic is formed on a metal surface without an oxide film and then oxidized and fired to bond the ceramic while forming an oxide on the metal surface. In the method of forming a bonding layer, an oxide film is formed on the surface of the metal in advance to a predetermined thickness.1 After applying a silicate binder, baking is performed in a neutral atmosphere to cause the oxide film and silicate to react. and form a stable bonding layer. In the present invention, as long as the bonding layer is sufficiently formed, even if some oxide film remains, the effects of the present invention will not be affected.

In the bonding layer forming method of the present invention, the formation of an oxide film on the metal surface can be performed, for example, by placing the metal member in a heated atmosphere. The heating atmosphere is preferably 500° C. or higher in steam.

Further, the reaction between the oxide film and the silicate can be carried out by final heat treatment, that is, by holding the film under heating conditions of about 750 to 850° C. for about 0.5 to 1.5 hours in a neutral atmosphere. As a neutral atmosphere, the oxygen partial pressure is 10 mmHg.
Use the atmosphere below.

Note that the silicate is one or a mixture of two or more of sodium silicate, potassium silicate, lithium silicate, etc., and is used in the form of a sol. These silicates are lithium silicate,
The coefficient of thermal expansion increases in the order of potassium silicate and sodium silicate, and by appropriately selecting these, the coefficient of thermal expansion of the bonding layer can be matched to the coefficient of thermal expansion of the metal.

Next, another method of forming a bonding layer according to the present invention will be explained. The present inventors have discovered that in order to firmly adhere ceramic to a metal surface, it is more effective to form a film formed by reacting an oxide film and a silicate on the metal surface. When silicate is applied to the surface of a metal and heat treated in a steam atmosphere, the oxide film generated on the metal surface reacts with the silicate, creating a denser bonding layer that is even more strongly bonded physically and chemically. is formed.

The thickness of the bonding layer can be similar to the thickness of the bonding layer described above.

In this method for forming a bonding layer, the following steps are followed to form a bonding layer on a metal surface. First, the surface of the metal is polished by, for example, air blasting to form very small irregularities on the surface to improve the wettability of the silicate solution. After cleaning, a silicate solution is then applied and heat treated in a steam atmosphere to form a bonding layer. The water vapor atmosphere is preferably 500°C or higher.

As the silicate, the same silicates as those mentioned above can be used.

(2) Heat insulating layer This layer is intended to provide heat insulating properties, and is composed of a heat insulating material mainly composed of inorganic hollow particles, which is hardened with a heat insulating material, an IJx material, a silicate binder, and a hardened material. The mixture with the agent is applied onto the bonding layer, and after curing and drying, the oxygen partial pressure becomes 10
It can be formed by firing in a neutral atmosphere of mtnHg or less.

As the heat insulating material, it is preferable to use inorganic hollow particles such as glass balloons, foamed silica balloons, and ceramic balloons. The average particle size of the powder generally ranges from 10 to 500 μm. If it is smaller than 10 μm, cracks and peeling will occur due to shrinkage, and if it is larger than 50 (1 μm), it will be difficult to form a smooth film layer. The preferred particle size range is 40 to 200 μm.

The silicate binder can be selected from among the potassium silicate, sodium silicate, lithium silicate, etc. mentioned in the section on the bonding layer above. As a hardening agent, calcined aluminum phosphate,
Calcium silicate, etc. can be used.

According to the method of the invention, a mixed slurry of insulation, silicate binder and hardener is applied onto the bonding layer. After coating, it is cured for 8 to 24 hours at a temperature of about 18 to 30°C. Then, after sufficiently removing moisture by drying,
Firing is performed at 850°C for 0.5 to 1°5 hours. The firing is performed in a neutral atmosphere with an oxygen partial pressure of 10 mmHg or less, similarly to the bonding layer.

In addition, the 8th [! As shown in f, inorganic scale-like particles may be mixed. As inorganic scaly particles,
Naturally occurring mica, artificially synthesized mica, membrane glass, or crushed inorganic hollow particles such as balloons are used.

The shape of the inorganic scale-like particles has a major axis and a minor axis of 2 to 74μ.
It is suitable that the thickness is about 0.1 to 3 μm, and the ratio of the thickness to the major axis is 10 or more. More preferably, the major axis is 5 to 30 μm, the thickness is 0.5 to 2 μm, and the ratio of the thickness to the major axis is 15 or more. When the inorganic scaly particles 1 are mixed in the structure, the heat insulating layer has sufficient strength and flexibility, and does not easily peel or crack even under high-temperature thermal shock, and also has an anti-oxidation effect. improves.

The thicker the insulation layer is, the better it is from the standpoint of insulation, but 2
If it exceeds 000 μm, there is a risk of peeling due to high-temperature thermal shock, and if it is less than 200 μm, no heat insulating effect can be obtained. Preferably, 300 to 800 μm is appropriate.

(3) Large resistant layer This layer is formed to impart fire resistance, and has a structure obtained by baking and hardening a fire resistant material mainly composed of inorganic particles.

The fireproof layer is made by applying a mixture of a fireproof material, a silicate binder, and a hardening agent to the dried surface of the bonding layer or heat insulating layer, curing, and drying it in a neutral atmosphere with an oxygen partial pressure of 1 g (10 mm) or less. It can be formed by firing inside.

As the refractory material, commonly used materials such as chamotte, alumina, zircon, and zirconia may be used, but zirconia is particularly preferred because of its low thermal conductivity. The average particle size of the refractory powder generally ranges from 10 to 500 μm. 10μ
If it is smaller than 500 μm, agglomeration between particles tends to occur (it is difficult to form a smooth film layer, and it tends to shrink under the influence of high heat. If it is larger than 500 μm, it is difficult to form a smooth film. Preferred average The particle size is 20-200 μm.

Note that the silicate binder and curing agent may be the same as those used for the heat insulating layer.

Furthermore, the curing, drying and firing conditions for forming the refractory layer may be basically the same as those for forming the heat insulating layer.

The thickness of this layer is 20%, although the thicker the better in terms of fire resistance.
If it exceeds 00 μm, there is a risk of peeling due to high temperature thermal shock, and if it is less than 100 μm, sufficient fireproofing effect cannot be obtained. Preferably, 200 to 800 μm is appropriate.

(4) Surface layer This layer forms a dense ceramic thin film on the surface of the heat insulating layer or fireproof layer to prevent corrosive gases from entering from the surface. The surface layer has a structure consisting of an inorganic binder and/or an organometallic binder, and after applying the inorganic binder and/or organometallic binder to the dried surface of the heat insulating layer or fireproof layer, the oxygen partial pressure is It can be formed by firing in an atmosphere of 10+++e Hg or less.

In addition, if the inorganic binder and/or organometallic binder can be stabilized simply by drying, the inorganic binder and/or organometallic binder may be applied to the fired surface of the heat insulating layer or fireproof layer. , a surface layer can be formed by drying.

Suitable inorganic binders include sols of alkali silicate salts such as sodium silicate, potassium silicate, and lithium silicate, silka sol, alumina sol, and aluminum phosphate solutions.

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

Regarding this layer, it is difficult to match the thermal expansion coefficient with that of the metal because of the material, so the layer thickness needs to be 15 μm or less. When the layer thickness exceeds 15 μm, the strain stress due to the difference in thermal expansion coefficient becomes large, and there is a risk of peeling or cracking. A suitable thickness is preferably 3 to 10 μm.

The bonding layer, heat insulating layer, fireproof layer, and surface layer have been explained above, but these layers do not need to be complete, except for the bonding layer, heat insulating layer, or fireproof layer, and may be omitted depending on the application. be able to. Therefore, the preferred combinations of the present invention are as follows.

(a) Bonding layer + heat insulation layer (b) Bonding layer + heat insulation layer + surface layer (c) Bonding layer + fireproof layer Co., Ltd. Bonding layer + Large-resistant layer 10 surface layers (e) Bonding layer + heat insulation layer + fireproof layer (f) Bonding layer + heat insulation layer + fireproof layer 10 surface layers [Example] The present invention will be explained in further detail by the following examples.

Example 1 The present invention was carried out using an L-shaped tubular member 2 made of vermilion iron having the shape shown in FIG. did.

FIG. 2 shows a bonding layer 3 formed on the inner surface of a metal tubular member 2.
FIG. 4 is a diagram schematically showing a covering layer consisting of a heat insulating layer 4 and a heat insulating layer 4. FIG.

A metal tubular member 2 made of cast iron was heated to 550° C. to form an oxide film of 3 μm.

This metal tubular member 2 was soaked in a sodium silicate solution (S+Oi).
/ NaaO molar ratio 3.0, concentration 23% by weight), held for 3 minutes, pulled up to remove excess sodium silicate, and heated from room temperature to 150°C in a dryer for 2 minutes.
The temperature was raised over 5 minutes, maintained for 1 hour, and then cooled to room temperature to form a bonding layer 3.

Next, insulation powder (bulk specific gravity 0.16, particle size 44-150
A mixed slurry was prepared by blending a μm-sized shirasu balloon), sodium silicate (silicate binder), and calcined aluminum phosphate (hardening agent) in the following proportions.

Sodium silicate (Sins/Na2D molar ratio 3.0, concentration 30% by weight
) 100 parts by weight Shirasu balloon crushed particles (<74 μm) 20 parts by weight Shirasu balloon (44 to 150 μm) 10 parts by weight Calcined aluminum phosphate (<74 μm) 10 parts by weight Bonding layer 3 formed on the inner surface of the metal tubular member 2 The above-mentioned mixed slurry was applied to the surface and the operation of curing for 2 hours was repeated to form a heat insulating layer 4.

In this state, it was cured at room temperature for 15 hours to effect a hardening reaction between the sodium silicate and calcined aluminum phosphate in the heat insulating layer.

Next, this metal tubular member 2 was placed in a dryer, heated from room temperature to 300 t' in 7 minutes at a heating rate of 1, held for 1 hour, and then cooled to room temperature to remove excess water.

Next, this metal tubular member 2 is placed in a N2 atmosphere (oxygen partial pressure 5
mmHg)1. : Te, heating rate 200t/hour-ct
ao.

The temperature was raised to .degree. C. and maintained for 1 hour, then cooled to room temperature, and the heat insulating layer 4 having a thickness of 1500 .mu.m was baked and hardened.

Example 2 FIG. 2 shows a bonding layer 3 formed on the inner surface of a metal tubular member 2.
FIG. 2 is a cross-sectional view schematically showing a covering layer consisting of a heat insulating layer 4 and a heat insulating layer 4. FIG.

After cleaning the inner and outer surfaces of the metal tubular member 2 by air blasting and cleaning with a dilute potassium silicate solution (concentration 5% by weight), potassium silicate solution (Si0
2/N20-r: JL/Ratio 3. o1 concentration 10% by weight
), held for 3 minutes, and then pulled out to remove excess potassium silicate. Then, after keeping it at room temperature for 1 hour,
90 t: in a furnace adjusted to a heated steam atmosphere of 550 t.
By holding for a minute, an oxide film was formed and a reaction with potassium oxide was caused, and the bonding layer 3 was formed by cooling to room temperature.

Next, a heat insulating layer 4 was formed on the bonding layer 3 thus obtained in the same manner as in Example 1.

Example 3 FIG. 3 is a cross-sectional view schematically showing a coating layer formed on the inner surface of a metal tubular member 2 and consisting of a bonding layer 3, a heat insulating layer 4, and a surface layer 5.

The bonding layer 3 and the heat insulating layer 4 are formed by the same method as in Example 1, and after firing, aluminum phosphate solution <A degree 40% by weight)
was applied to the surface of the heat insulating layer 30, heated to 110° C. at a heating rate of 10° C./min, heat treated for one hour, and then cooled to room temperature to form a surface layer 5 with a thickness of 8 μm.

Example 4 FIG. 4 shows a bonding layer 3 formed on the inner surface of a metal tubular member 2.
FIG. 2 is a cross-sectional view schematically showing a covering layer consisting of a heat insulating layer 4 and a fireproof layer 6.

After forming the bonding layer 3 and the heat insulating layer 4 in the same manner as in Example 1, refractory material powder (stabilized zirconia with a particle size of 44 to 150 μm), sodium silicate (silicate binder), and calcined aluminum phosphate ( A mixed slurry containing the following components (cured side) was applied.

Sodium silicate (Sins/Na, 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 mixed slurry is applied to the surface of the heat insulating layer 4 formed on the inner surface of the metal tubular member 2 and cured for 2 hours. The operation was repeated to form a fireproof layer 6.

In this state, it was cured at room temperature for 15 hours to effect a hardening reaction between the sodium silicate and calcined aluminum phosphate in the fireproof layer.

Next, this metal tubular member 2 was placed in a dryer and heated from room temperature to 300° C. at a temperature increase rate It/min, held for 1 hour, and then cooled to room temperature to remove excess water.

Next, this metal tubular member 2 is placed in a N2 atmosphere (oxygen partial pressure 5
The temperature was raised to 800°C at a temperature increase rate of 200°C/hour at a temperature of 1g), held for 1 hour, cooled to room temperature, and a thickness of 10
The refractory layer 6 and the heat insulating layer 4 having a thickness of 00 μm were baked and hardened.

Example 5 FIG. 5 shows a bonding layer 3 formed on the inner surface of a metal tubular member 2.
FIG. 2 is a cross-sectional view schematically showing a covering layer consisting of a heat insulating layer 4, a fireproof layer 6, and a surface layer 5.

A bonding layer 3, a heat insulating layer 4, and a fireproof layer 6 are formed by the same method as in Example 4, and after firing, an aluminum phosphate solution (a degree 4
0% by weight) on the surface of the fireproof layer 6, and the heating rate was 1.
After heat treatment, the temperature was raised to 110° C. at a rate of 0° C./min and maintained for 1 hour, and then cooled to room temperature to form a surface layer 5 with a thickness of 8 μm.

Example 6 FIG. 6 shows a bonding layer 3 formed on the inner surface of a metal tubular member 2.
FIG. 2 is a cross-sectional view schematically showing a coating layer consisting of a fireproof layer 6 and a fireproof layer 6. FIG.

A cast iron metal tubular member 2 is heated to 550°C to have a thickness of 3
An oxide film of μm was formed.

In order to form a bonding layer, this metal tubular member 2 was immersed in a potassium silicate solution (Stew/KJ molar ratio 3.0, concentration 23% by weight), held for 3 minutes, and then pulled up to remove excess potassium silicate. After that, place it in a dryer at room temperature 1
The temperature was raised to 50° C. over 25 minutes, maintained for 1 hour, and then cooled to room temperature to form a bonding layer 3.

Thereafter, a mixed slurry containing refractory material powder (alumina with a particle size of 44 to 150 μm), silicic acid (silicate binder), and calcined aluminum phosphate (hardening agent) in the following proportions was applied.

Sodium silicate (SiO, / Na2O 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 metal tubular member 2 The above mixed slurry was applied to the surface of the bonding layer 3 and the operation of curing for 2 hours was repeated to form the fireproof layer 6.

In this state, it was cured at room temperature for 15 hours to effect a hardening reaction between the sodium silicate and calcined aluminum phosphate in the fireproof layer.

Next, this metal tubular member 2 was placed in a dryer, heated from room temperature to 300° C. at a temperature increase rate of 1° C./min, held for 1 hour, and then cooled to room temperature to remove excess water.

Next, this metal tubular member 2 was placed in a nitrogen atmosphere (oxygen partial pressure 5
mmt1g) at a heating rate of 200°C/hour to 810°C.
After heating up to 1 hour and cooling to room temperature, a thickness of 1
The refractory layer 6 with a thickness of 000 μm was baked and hardened.

Example 7 FIG. 7 shows a bonding layer 3 formed on the inner surface of a metal tubular member 2.
FIG. 2 is a diagram schematically showing a fireproof layer 6 and a covering layer formed by a surface layer 5.

After forming the bonding layer 3 and the refractory layer 6 by the same method as in Example 6, alumina sol (S degree 10% by weight) was applied to the refractory layer 5.
The temperature was raised to 110° C. at a heating rate of 10° C./min, heat treated for 1 hour, and then cooled to room temperature to form a surface layer 5 with a thickness of 8 μm.

Example 8 FIG. 8 shows a bonding layer 3 formed on the inner surface of a metal tubular member 2.
FIG. 4 is a cross-sectional view schematically showing a covering layer consisting of a heat insulating layer 4 and a heat insulating layer 4. FIG.

A bonding layer 3 was formed by the same method as in Example 1.

Next, this metal tubular member 2 was heated from room temperature to 300° C. in a dryer at a heating rate of 1° C./min and held for 1 hour, after which excess water was dehydrated.

Next, ceramic balloons (insulating material powder) with a bulk specific gravity of 0.47 and a particle size of 44 to 150 μm, crushed silica balloon particles (inorganic scale-like particles), IJium (silicate binder), and calcined aluminum phosphate ( curing agent) in the following proportions to prepare a mixed slurry.

Sodium silicate (SiOa/Na, 0 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 bonding layer 3 formed on the inner surface of metal tubular member 2 The heat insulating layer 4 was formed by repeatedly applying the mixed slurry and curing for 2 hours.

In this state, it was cured at room temperature for 15 hours to effect a hardening reaction between the sodium silicate and calcined aluminum phosphate in the heat insulating layer.

Next, this metal tubular member 2 was placed in a dryer to remove excess water.

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

Next, this metal tubular member 2 was placed in a nitrogen atmosphere (oxygen partial pressure 5
mmHg) at a heating rate of 200°C/hour to 810°C.
After raising the temperature to 1 hour and holding it for 1 hour, cool it to room temperature and form
The heat insulating layer 4 having a thickness of 500 μm was baked and hardened.

The structure and thickness of each coating layer in Examples 1 to 8 above are as shown in Table 1 below.

Nafu, each coating layer in Example 1 and Example 2 has the same structure.

Note that in Examples 3 to 8, the bonding layer was formed using the same method as in Example 1, but the bonding layer may be formed using the method in Example 2.

In order to evaluate the characteristics of the coating layers obtained in Examples 1 to 8 above, the following heating test was conducted.

1) Test conditions Each tubular member was attached to a heating evaluation device that burns propane gas to generate high-temperature gas, and an inner surface heating test was conducted under the conditions shown in Table 2.

Table 2 2) Corrosion Prevention Test (Oxidation Weight Gain Test) Under the conditions shown in Table 2, the thickness of the oxidized layer on the bonded surface due to combustion gas after each test time was measured using a scanning electron microscope (SBM).

The results are shown in Table 3 together with Comparative Example 1 without a coating layer.

The antioxidant effect of each example is about 6 to 90 times that of the case without coating. This shows that the weight gain due to oxidation is significantly reduced due to the heat insulating effect of the coating layer.

3) Heat Insulation Test The surface temperature of the metal tubular member was measured under the conditions shown in Table 2 to examine the heat insulation properties. The results are shown in Table 4 together with Comparative Example 1 which does not have a coating layer.

Examples 1 to 3, which have a heat insulating layer but not a fireproof layer, have a member surface temperature of 6
It can be seen that the temperature is 5 to 85°C lower and has a good heat insulating effect. Furthermore, in Examples 4 and 5, which have both a heat insulating layer and a fireproof layer, the member surface temperature is 125°C lower. This shows that the heat insulating effect of the heat insulating layer can be further enhanced by using the heat insulating layer and the fireproof layer together.

4) Durability test As a result of conducting 100 cycles of repeated heating and cooling tests in which the product was heated for 30 minutes and then cooled to room temperature under the conditions shown in Table 2, no cracks or peeling were observed in the coating layer, and the durability was fully satisfied. The matter was confirmed.

The functions and effects of each layer in the above embodiment will be explained.

A bonding layer 3 with a thickness of approximately 30 μm is provided on the inner surface of the metal tubular member 2.
is being generated. This bonding layer 3 is dense and glassy and adheres well to the casting, contributing to the bonding between the heat insulating layer 4 and/or the refractory layer 6 and the casting.

The heat insulating layer 4 formed on the surface of this bonding layer 3 has a thickness of 1500 mm.
It was μm. The heat insulating layer of Example 8 was formed of hollow ceramic particles using a mixture of inorganic scale particles, a binder, and a hardening agent as a matrix, so it had sufficient flexibility even against sudden thermal shock. , and has excellent heat insulation properties.

Moreover, the fireproof layer 6 of Example 7 had a thickness of 1000 μm. Note that this fireproof layer 6 is a fireproof material that can sufficiently withstand high-temperature exhaust gas exceeding 1100° C., and when formed on the surface of the heat insulating layer 4, it is a layer that can be firmly bonded to the heat insulating layer 4.

Moreover, the surface layer 5 had a thickness of 8 μm. Since this surface layer 5 is a dense and thin layer that fills the open pores of the heat insulating layer 4 or the fireproof layer 6, it has an excellent effect in preventing oxidation of the adhesive surface between the metal tubular member 2 and the bonding layer 3. has. Although this embodiment has been described with respect to a manifold, it can be similarly applied to port liners, front tubes, turbochargers, etc.

〔Effect of the invention〕

As detailed above, the ceramic-metal bonded body of the present invention has a bonding layer that has the effect of strengthening the bond between the metal and the ceramic layer, and has a heat insulating layer or a fireproof layer thereon. There is no risk of peeling or cracking of the ceramic layer even under high-temperature heating conditions, and the corrosion resistance is extremely good. Therefore, the ceramic-metal bonded body of the present invention,
For example, if used for internal combustion engine exhaust system equipment, etc., the temperature will exceed 800℃.
It can sufficiently withstand sudden repeated thermal shocks caused by exhaust gas at temperatures exceeding The ceramic-metal bonded body of the present invention having such effects is particularly suitable for use in engine exhaust gas manifolds, exhaust pipes, and the like.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a metal member to which the present invention can be applied; FIGS. 2 to 81! I 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: Metal tubular member 3: Bonding layer 4: Heat insulating layer 5: Surface layer 6: Refractory layer 7: Hollow spherical particles 8: Refractory particles Figure 2 Figure 3 Figure 4 Figure 8

Claims (17)

[Claims] (1) A metal member has a bonding layer formed by reacting an oxide film and a silicate on the surface thereof, and a heat insulating layer formed by sintering a heat insulating material mainly composed of inorganic hollow particles on the surface of the bonding layer. Ceramic-metal bonded body. (2) The ceramic-metal bonded body according to claim 1, wherein the surface of the heat insulating layer has a dense and thin surface layer made of an inorganic binder and/or an organic metal binder. body. (3) The ceramic-metal bonded body according to claim 1, further comprising a refractory layer formed by sintering and hardening a refractory material mainly composed of inorganic particles on the surface of the heat insulating layer. (4) The ceramic-metal bonded body according to claim 3, wherein the surface of the refractory layer has a dense and thin surface layer made of an inorganic binder and/or an organic metal binder. body. (5) A bonding layer formed by reacting an oxide film and a silicate on the surface of the metal member, and a refractory layer formed by baking and hardening a refractory material mainly composed of inorganic particles on the surface of the bonding layer. Ceramic/metal bonded body. (6) The ceramic-metal bonded body according to claim 5, wherein the refractory layer has a dense and thin surface layer made of an inorganic binder and/or an organometallic binder on the surface thereof. zygote. (7) The ceramic according to any one of claims 1 to 6.
A ceramic-metal joined body, wherein the metal member is an exhaust system device. (8) The ceramic according to any one of claims 1 to 7.
In the metal bonded body, the bonding layer has a thickness of 50 μm or less, the heat insulation layer has a thickness of 200 to 2000 μm, the fireproof layer has a thickness of 100 to 2000 μm, and the surface layer has a thickness of 15 μm or less. Characteristic ceramic/metal bonded body. (9) In a method for manufacturing a ceramic-metal bonded body, (a) a metal member is heat-treated in a steam atmosphere to form an oxide film on its surface, and (b) silicate is bonded on the oxide film. (c) applying a mixture of a heat insulating material mainly composed of inorganic hollow particles, a silicate binder, and a hardening agent to the surface of the bonding layer to form a heat insulating layer; (d) followed by curing. , dried, and (e) fired in an atmosphere with an oxygen partial pressure of 10 mmHg or less to form a bonding layer by a reaction between the oxide film and the silicate and to harden the heat insulating layer.・Metal joint manufacturing method. (10) In the method for manufacturing a ceramic-metal bonded body, (a) a silicate is applied to the surface of a metal member, the surface of the metal member is oxidized by heat treatment in a steam atmosphere, and the reaction with the silicate causes forming a bonding layer; (b) applying a mixture of a heat insulating material based on inorganic hollow particles, a silicate binder, and a hardening agent to the surface of the bonding layer to form a heat insulating layer; A method for producing a ceramic-metal bonded body, which comprises curing, drying, and (d) firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less to harden the bonding layer and the heat insulating layer. (11) In the method for producing a ceramic-metal bonded body according to claim 9 or 10, (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 bonded body, which comprises forming a surface layer, and (b) then firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less. (12) In the method for producing a ceramic-metal bonded body according to claim 9 or 10, (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 bonded body, which comprises forming a surface layer, and (b) then drying at 110°C to 500°C. (13) In a method for manufacturing a ceramic-metal bonded body, (a) a metal member is heat-treated in a steam atmosphere to form an oxide film on its surface, and (b) silicate is bonded on the oxide film. (c) applying a mixture of a refractory material, a silicate binder, and a curing agent to the surface of said bonding layer to form a refractory layer; (d) followed by curing and drying; (e) A method for producing a ceramic-metal bonded body, characterized in that firing is performed in an atmosphere with an oxygen partial pressure of 10 mmHg or less to form a bonding layer through a reaction between the oxide film and the silicate and to harden the refractory layer. (14) In the method for manufacturing a ceramic-metal bonded body, (a) silicate is applied to the surface of a metal member, and the surface of the metal member is oxidized by heat treatment in a steam atmosphere, and the reaction with the silicate causes forming a bonding layer; (b) applying a mixture of a refractory material, a silicate binder, and a curing agent to the surface of the bonding layer to form a refractory layer; (c) followed by curing and drying; (d) ) A method for producing a ceramic-metal bonded body, which comprises firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less to harden the bonding layer and the refractory layer. (15) In the method for producing a ceramic-metal bonded body according to claim 13 or 14, (a) after drying the refractory layer, an inorganic binder and/or an organometallic binder is applied to the surface thereof. A method for producing a ceramic-metal bonded body, which comprises forming a surface layer, and (b) then firing in an atmosphere with an oxygen partial pressure of 10 mmHg or less. (16) In the method for producing a ceramic-metal bonded body according to claim 13 or 14, (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 bonded body, which comprises forming a surface layer, and (b) then drying at 110°C to 500°C. (17) In the method for manufacturing a ceramic-metal bonded body according to any one of claims 9 to 12, (a) after curing and drying the heat insulating layer, a refractory material, a silicate binder, and a hardening agent are combined. A ceramic material characterized in that the mixture is applied to the surface of the heat insulating layer to form a refractory layer, (b) it is then cured and dried, and (c) it is then fired in an atmosphere with an oxygen partial pressure of 10 mmHg or less. Manufacturing method for metal joints.