JP6526944B2 - Structure - Google Patents

Description

The present invention relates to a structure.

In order to treat harmful substances contained in the exhaust gas discharged from the engine, a catalytic converter is provided in the path of the exhaust pipe.
In order to enhance the purification efficiency of harmful substances by the catalytic converter, it is necessary to maintain the temperature of the exhaust gas and the exhaust pipe through which the exhaust gas circulates at a temperature suitable for catalyst activation (hereinafter also referred to as catalyst activation temperature).

In the conventional exhaust gas purification system, since the temperature of the catalytic converter at the start of the engine is lower than the catalyst activation temperature, the catalyst does not function and it is difficult to completely prevent the emission of harmful substances at the start of the engine.
For this reason, it is required that the temperature of the exhaust pipe connected to the engine be raised to the catalyst activation temperature in a short time after the start of the engine.

In order to meet such requirements, Patent Documents 1 to 3 are composed of a metal base and an inorganic material surface layer made of crystalline and non-crystalline inorganic material, and the heat of the inorganic material surface layer is A structure or the like has been proposed in which the conductivity is lower than the thermal conductivity of the base, and the infrared emissivity of the surface layer of the inorganic material is higher than the infrared emissivity of the base.

JP, 2008-69383, A JP, 2009-133213, A JP, 2009-133214, A

The structures proposed in Patent Documents 1 to 3 have a certain adiabaticity, but have sufficient adiabaticity to raise the temperature of the catalytic converter to the catalyst activation temperature in a short time from the start of the engine. I could not say that.

In addition, the exhaust gas temperature has risen significantly along with the recent tightening of exhaust gas regulations, etc., so in a structure used as an exhaust system component such as an exhaust pipe, the adhesion between the substrate and the surface coating layer is more than ever Is considered to be required.

The present invention has been made to solve such problems, and it is an object of the present invention to provide a structure having sufficient heat insulation and having excellent adhesion between a substrate and a surface coating layer.

The inventor examined the cause of the insufficient heat insulation of the structures described in Patent Documents 1 to 3. As a result, in the structures described in Patent Documents 1 to 3, a transition metal oxide is used as a crystalline inorganic material contained in the surface layer (hereinafter, also referred to as a surface covering layer), and the heat of the transition metal oxide is used. It was thought that the high conductivity affected the adiabaticity. Therefore, a transition metal oxide is not used as the crystalline inorganic material, the content of the transition metal oxide as the crystalline inorganic material is reduced, and a crystalline inorganic material having a thermal conductivity lower than that of the transition metal oxide, etc. It was considered to lower the thermal conductivity of the surface coating layer and to improve the heat insulation of the structure by the method of

However, it has been found that the surface coating layer formed by the above-mentioned method has a new problem that the adhesion with the substrate is low.

Based on such examination results, the present inventor forms the first layer having high adhesion to the substrate on the substrate, and forms the second layer having high thermal insulation on the first layer, whereby the structure is obtained. The inventors have found that both the heat insulation of the body and the adhesion to the substrate can be improved to complete the present invention.

That is, the structure of the present invention comprises a substrate made of metal,
A surface coating layer coated on the surface of the substrate and comprising at least an amorphous inorganic material,
The surface coating layer has a first layer that covers the substrate and a second layer that covers the first layer,
The first layer contains, as a crystalline inorganic material, at least one selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide,
The second layer does not contain any of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide as a crystalline inorganic material, or from manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide And at least one selected from the group consisting of: less than the first layer.

In the structure of the present invention, crystalline manganese oxide or the like (hereinafter, “manganese oxide or the like” is a manganese oxide, etc. contained in the second layer formed on the outside of the surface coating layer (opposite to the substrate). The amount of at least one selected from the group consisting of iron oxide, copper oxide, cobalt oxide and chromium oxide is relatively small. Therefore, the thermal conductivity of the surface coating layer can be lowered, and the heat insulation of the structure can be improved.
On the other hand, when the amount of crystalline manganese oxide or the like contained in the surface coating layer is small, the difference between the thermal expansion coefficient of the substrate and the surface coating layer becomes large, so the adhesion between the substrate and the surface coating layer is descend. Therefore, in the structure of the present invention, the thermal expansion coefficients of the base and the first layer can be made close by forming the first layer on the base with a relatively large amount of crystalline manganese oxide or the like. As a result, the base material and the first layer can be firmly adhered. Further, the first layer and the second layer both have high adhesion because they contain an amorphous inorganic material. Therefore, in the structure of the present invention, the surface coating layer adheres firmly to the substrate as a whole.
Thus, in the present invention, a structure having sufficient thermal insulation and excellent adhesion between the substrate and the surface coating layer can be obtained.

In addition, since the thermal expansion coefficient of manganese oxide or the like is 10 to 15 × 10 ⁻⁶ / ° C., when the surface coating layer contains the above-mentioned oxide, the thermal expansion coefficients of the base and the surface coating layer can be approximated. The adhesion between the substrate and the surface coating layer can be further improved.

In the following, the term "surface covering layer" refers to both the first layer and the second layer. Moreover, when layers other than 1st layer and 2nd layer are formed in the base-material surface of the structure of this invention, these layers also say it as a surface coating layer.

In the structure of the present invention, the second layer preferably further contains at least one of alumina and zirconia as a crystalline inorganic material.
Alumina and zirconia are crystalline inorganic materials excellent in heat resistance. Therefore, even when the surface coating layer is exposed to a high temperature, alumina or zirconia present in the second layer is not easily softened, so that it is possible to prevent the second layer from peeling off from the first layer. Alumina or zirconia is also a crystalline inorganic material excellent in corrosion resistance. Therefore, when the surface coating layer is directly exposed to high temperature exhaust gas, the surface coating layer is prevented from being corroded by nitrogen oxides (NOx) and / or sulfur oxides (SOx) contained in the exhaust gas. Can. Furthermore, when alumina is contained in the second layer, it also contributes to the improvement of the insulation of the structure.

In the structure of the present invention, it is desirable that the first layer contains iron oxide and the second layer contains zirconia. More preferably, the first layer contains Fe ₂ O ₃ and the second layer contains yttria-stabilized zirconia.

In the structure of the present invention, the thermal conductivity at 25 ° C. of the surface coating layer is desirably 0.05 to 2 W / m · K.
When the thermal conductivity of the surface coating layer is in the above range, a structure having excellent heat insulating properties is obtained.

In the structure of the present invention, the thickness of the surface coating layer is desirably 52 μm or more from the viewpoint of maintaining heat insulation and adhesion well.

In the structure of the present invention, if the thickness of the first layer is too thin, the adhesion between the substrate and the surface coating layer will not be sufficient, while if the thickness of the first layer is too thick, the heat insulation will be sufficient. It will not be. Therefore, the thickness of the first layer is desirably 2 to 50 μm.

In the structure of the present invention, when the thickness of the second layer is too thin, the heat insulation is not sufficient, while when the thickness of the second layer is too thick, the temperature difference between the substrate and the second layer is large. As a result, the surface covering layer including the second layer tends to be broken. Therefore, the thickness of the second layer is preferably 50 to 1000 μm.

In the structure of the present invention, the non-crystalline inorganic material is desirably made of low melting point glass having a softening point of 300 to 1000 ° C.
In the structure of the present invention, when the non-crystalline inorganic material is made of low melting glass having a softening point of 300 to 1000 ° C., a coating layer is formed on the surface of the substrate using a means such as coating. Afterward, the surface coating layer can be formed relatively easily by heating.
If the softening point of the low melting glass is less than 300 ° C., the temperature of the softening point is too low, so that the layer to be the surface coating layer easily flows due to melting or the like during the heat treatment, and a layer having an appropriate thickness It becomes difficult to form. On the other hand, if the softening point of the low melting point glass exceeds 1000 ° C., it is necessary to set the temperature of the heat treatment extremely high conversely, there is a possibility that the mechanical properties of the substrate may be deteriorated by heating. In addition, the surface coating layer containing the amorphous inorganic material can not follow the thermal expansion change due to the temperature of the base material, and there is a possibility that the surface coating layer may be cracked to cause a drop.

In the structure of the present invention, the low melting point glass is desirably a glass containing at least one of barium glass, boron glass, strontium glass, alumina silica glass, soda zinc glass, and soda barium glass.
In the structure of the present invention, when a low melting point glass made of the above material is used as the non-crystalline inorganic material, a surface coating layer having a low thermal conductivity and having heat resistance, durability, and insulation properties is used as a substrate. It can be formed on the surface of

In the structure of the present invention, the substrate may have a convex portion and / or an edge portion and a flat portion on the surface. Further, the first layer may be formed on at least the surface of the convex portion and / or the edge portion. In addition, as for the said convex part, it is desirable to originate in a weld bead and / or a weld spatter.

When the structure of the present invention is used as an exhaust system component such as an exhaust pipe, the exhaust system component has a weld bead generated during welding and a projection called a weld spatter. Moreover, when a part of exhaust pipe is a double pipe, an edge part will exist in the end part of the exhaust pipe which exists in part inside or outside. In the present invention, even when used as such an exhaust system component, effects such as excellent heat insulation, adhesion and insulation can be exhibited.
In addition, the site | part which a convex part and an edge part mean is mentioned later.

FIG. 1 is a cross-sectional view schematically showing an example of the structure of the present invention. FIG. 2 is a cross-sectional view schematically showing another example of the structure of the present invention. FIG. 3 is a cross-sectional view schematically showing still another example of the structure of the present invention. FIG. 4 is a cross-sectional view schematically showing still another example of the structure of the present invention. FIG. 5 is a cross-sectional view schematically showing still another example of the structure of the present invention. Fig.6 (a) is sectional drawing which shows typically another example of the structure of this invention, FIG.6 (b) expanded the convex part vicinity in the structure shown to Fig.6 (a). It is an expanded sectional view, and Drawing 6 (c) is an expanded sectional view which expanded edge part vicinity in a structure shown in Drawing 6 (a). FIG. 7 (a) is a cross-sectional view schematically showing an example of an exhaust system component when the base material is a cylindrical body, and FIG. 7 (b) is an exhaust system component shown in FIG. 7 (a) It is sectional drawing which cut | disconnected in half. FIG. 8 is a schematic cross-sectional view of a pull strength measurement sample. FIG. 9 is an external view of a tensile test by a tensile tester. FIG. 10 is an exploded perspective view schematically showing an automobile engine according to the structure of the present invention and an exhaust manifold connected to the automobile engine. 11 (a) is a cross-sectional view of the automobile engine and the exhaust manifold shown in FIG. 10 taken along the line A-A, and FIG. 11 (b) is a cross-sectional view of the exhaust manifold shown in FIG. It is.

(Detailed Description of the Invention)
Hereinafter, the present invention will be specifically described. However, the present invention is not limited to the following contents, and can be appropriately modified and applied without departing from the scope of the present invention.

First, the structure of the present invention will be described.
The structure of the present invention is a substrate made of metal,
A surface coating layer coated on the surface of the substrate and comprising at least an amorphous inorganic material,
The surface coating layer has a first layer that covers the substrate and a second layer that covers the first layer,
The first layer contains, as a crystalline inorganic material, at least one selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide,
The second layer does not contain any of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide as a crystalline inorganic material, or from manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide And at least one selected from the group consisting of: less than the first layer.
As described above, at least one selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide is collectively referred to as "manganese oxide etc."

FIG. 1 is a cross-sectional view schematically showing an example of the structure of the present invention.
A structure 1A shown in FIG. 1 includes a base 10a made of metal and a surface coating layer 20a formed on the surface of the base 10a.

In the structure 1A, the surface coating layer 20a has a first layer 21a that covers the base 10a and a second layer 22a that covers the first layer 21a. That is, in the structure 1A, the surface coating layer 20a has a structure in which two layers are laminated in the order of the first layer 21a and the second layer 22a from the side of the base material 10a.

The surface covering layer 20 a (the first layer 21 a and the second layer 22 a) contains an amorphous inorganic material 31. Specifically, the first layer 21 a and the second layer 22 a are each formed of a layer of the amorphous inorganic material 31. Note that pores and the like may be included in the layer of the amorphous inorganic material 31 (the same applies to the other examples described below).

The first layer 21 a further contains manganese oxide or the like 41 as a crystalline inorganic material. Specifically, in the first layer 21 a, particles of manganese oxide 41 or the like are dispersed in the layer of the amorphous inorganic material 31.

The second layer 22 a does not contain manganese oxide 41 or the like as a crystalline inorganic material, and further contains alumina 51 as a crystalline inorganic material. Specifically, in the second layer 22 a, particles of alumina 51 are dispersed in the layer of the amorphous inorganic material 31.

In the structure 1A shown in FIG. 1, the example in which the second layer 22a includes the alumina 51 is shown, but in the structure of the present invention, the second layer contains zirconia as a crystalline inorganic material instead of alumina. And may contain both alumina and zirconia. The same applies to the example including alumina 51 shown below.

FIG. 2 is a cross-sectional view schematically showing another example of the structure of the present invention.
The structure 1B shown in FIG. 2 has the same structure as the structure 1A shown in FIG. 1 except that the structure of the second layer of the surface covering layer is different.

The structure 1B shown in FIG. 2 includes a base 10a made of metal and a surface coating layer 20b formed on the surface of the base 10a.
In the structure 1B, the surface coating layer 20b includes a first layer 21a that covers the base 10a and a second layer 22b that covers the first layer 21a.
The second layer 22 b does not contain manganese oxide 41 or the like as a crystalline inorganic material.

FIG. 3 is a cross-sectional view schematically showing still another example of the structure of the present invention.
Structure 1C shown in FIG. 3 has the same structure as structure 1A shown in FIG. 1 except that the structure of the second layer of the surface covering layer is different.

Structure 1C shown in FIG. 3 includes base material 10a made of metal and surface coating layer 20c formed on the surface of base material 10a.
In the structure 1C, the surface coating layer 20c includes a first layer 21a that covers the base 10a and a second layer 22c that covers the first layer 21a.
The second layer 22c further contains, as a crystalline inorganic material, manganese oxide 41 or the like in an amount smaller than 41 contained in the first layer 21a. The second layer 22c may contain at least one of alumina and zirconia as a crystalline inorganic material.

The base material which comprises the structure of this invention says the member used as the object which forms a surface coating layer. The shape of the substrate may be flat, semi-cylindrical, or cylindrical, and the shape of the outer edge of the cross section may be any shape such as oval or polygon.
When the substrate is a tubular body, the diameter of the substrate may not be constant along the longitudinal direction, and the cross-sectional shape perpendicular to the longitudinal direction may not be constant along the longitudinal direction.

Examples of the material of the base material constituting the structure of the present invention include metals such as stainless steel, steel, iron and copper, and nickel alloys such as inconel, hastelloy and invar. As described later, the substrate made of these metal materials has an adhesion between the surface coating layer and the substrate made of metal by bringing the layer of the amorphous inorganic material constituting the surface coating layer into close proximity with the thermal expansion coefficient. Can be improved.

In order to improve the adhesion to the surface coating layer, the surface of the substrate may be subjected to a sandblasting treatment or a roughening treatment with a chemical or the like.
The surface roughness Rz _JIS of the surface of the base material formed by the roughening treatment is preferably 1.5 to 20 μm. The surface roughness Rz _JIS of the above-described roughened surface is a ten-point average roughness defined by JIS B 0601 (2001), and the measurement distance is 10 mm.
When the surface roughness Rz _JIS of the roughened surface of the substrate is less than 1.5 μm, the surface area of the substrate is reduced, so that the adhesion between the substrate and the surface coating layer is not sufficiently obtained. On the other hand, when the surface roughness Rz _{JIS of the} roughened surface of the substrate exceeds 20 μm, it becomes difficult to form a surface coating layer on the surface of the substrate. This is because when the surface roughness Rz _{JIS of the} roughened surface of the substrate is too large, the slurry (raw material composition for the surface coating layer) does not enter the valley portion of the unevenness formed on the surface of the substrate, It is considered that this is because a void is formed in the part.
In addition, surface roughness Rz _JIS of the roughening surface of the base material of a structure shall be measured in accordance with JIS B 0601 (2001) using Tokyo Seimitsu make, Handysurf E-35B, with a measurement distance of 10 mm. Can.

In the structure of the present invention, the desirable lower limit of the thickness of the substrate is 0.2 mm, more desirably 0.4 mm, and the desirable upper limit is 10 mm, and the more desirable upper limit is 4 mm.
If the thickness of the substrate is less than 0.2 mm, the strength of the structure is insufficient. In addition, when the thickness of the base exceeds 10 mm, the weight of the structure becomes large, and for example, it becomes difficult to mount it on a vehicle such as a car and it becomes difficult to be suitable for practical use.

In the structure of the present invention, the types of manganese oxide etc. contained in the first layer or the second layer are manganese oxide (MnO ₂ , MnO, Mn ₂ O ₃ ), iron oxide (FeO, Fe ₂ O ₃ , Fe) ₃ O ₄ ), copper oxide (CuO, Cu ₂ O), cobalt oxide (CoO, Co ₂ O ₃ , Co ₃ O ₄ ), chromium oxide etc. (CrO, Cr ₂ O ₃ , CrO ₂ ). These may be 1 type and may be 2 or more types. Of these, iron oxide is desirable, and Fe ₂ O ₃ is more desirable.
Moreover, when said oxide is contained in both a 1st layer and a 2nd layer, the kind of oxide may be the same or different by 1st layer and a 2nd layer.

In the structure of the present invention, the second layer does not contain any of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide as a crystalline inorganic material, or manganese oxide, iron oxide, copper oxide And at least one selected from the group consisting of cobalt oxide and chromium oxide, as compared to the first layer. In other words, the weight ratio of manganese oxide or the like contained in the second layer is smaller than the weight ratio of manganese oxide or the like contained in the first layer.

In the present specification, regarding the crystalline inorganic material and the non-crystalline inorganic material contained in the first layer, the value calculated using the following equation (1) "
[Weight of crystalline inorganic material / (weight of crystalline inorganic material + weight of non-crystalline inorganic material)] × 100 (1)
In particular, regarding crystalline manganese oxide and the like contained in the first layer, a value calculated using the following equation (2) is defined as "weight ratio of manganese oxide and the like contained in the first layer".
[Weight of manganese oxide etc./(Weight of manganese oxide etc. + weight of crystalline inorganic material other than manganese oxide etc. + weight of non-crystalline inorganic material)] × 100 (2)
Similarly, with regard to the crystalline inorganic material and the non-crystalline inorganic material contained in the second layer, the values calculated using the above equations (1) and (2) can be expressed respectively as “the crystalline inorganic material contained in the second layer And the “weight ratio of manganese oxide etc. contained in the second layer”.

The weight ratio of manganese oxide or the like contained in the first layer is desirably 5 to 70% by weight, and more desirably 10 to 60% by weight.
If the weight ratio of manganese oxide or the like contained in the first layer is less than 5% by weight, the thermal expansion coefficients of the first layer and the substrate deviate greatly, and the substrate contains chromium as in SUS. Even in such a case, there is a problem that chromium, manganese oxide and the like can not sufficiently exhibit the covalent bond through oxygen, and the base material and the first layer are separated. In addition, when the weight ratio of manganese oxide or the like contained in the first layer exceeds 70% by weight, the weight ratio of the non-crystalline inorganic material contained in the first layer relatively decreases. The adhesion between the first layer and the second layer is mainly due to the fact that the non-crystalline inorganic materials of the respective layers express covalent bonds, so the weight ratio of the non-crystalline inorganic material contained in the first layer is The reduction is a problem that the adhesion between the first layer and the second layer is reduced.

As the amount of manganese oxide or the like contained in the second layer is smaller, the thermal conductivity of the surface coating layer can be lowered, and the heat insulation of the structure can be improved. Therefore, it is desirable that the second layer does not contain manganese oxide or the like. When the second layer contains manganese oxide or the like, the weight ratio of manganese oxide or the like contained in the second layer is preferably 0.05 to 10% by weight, and 0.05 to 5% by weight Is more desirable.

The average particle diameter of particles of manganese oxide and the like contained in the first layer and the second layer is not particularly limited, but is preferably 0.1 to 25 μm, and more preferably 1 to 15 μm. If the average particle size of particles of manganese oxide or the like contained in the first layer and the second layer is less than 0.1 μm, the high temperature viscosity of the first layer and the second layer becomes high, and there is a problem that film formation can not be performed . In addition, when the average particle diameter of particles of manganese oxide or the like contained in the first layer and the second layer exceeds 25 μm, particles of manganese oxide or the like will pop out from the surfaces of the first layer and the second layer. Due to this phenomenon, in the first layer, the area where the non-crystalline inorganic material exists on the surface is reduced, and the adhesion with the second layer is reduced. In the second layer, the surface roughness of the surface As a result, the flow of gas passing over the surface is disturbed, and as a result, there is a problem that the heat transfer coefficient from the gas to the structure increases and the adiabatic efficiency decreases.

In the present specification, the average particle size of the particles of the crystalline inorganic material refers to the average particle size of the particles of the crystalline inorganic material added to the material when preparing the material to form the surface coating layer. The particle size measured using a laser diffraction type particle size distribution measuring device (SALD-300V) manufactured by corporation. Thereby, the average particle diameter of particles of oxides such as manganese oxide, and crystalline inorganic materials such as alumina or zirconia can be measured.

In the structure of the present invention, when the second layer contains alumina as a crystalline inorganic material, specific examples of alumina include, for example, α-alumina and the like. In the structure of the present invention, when the second layer contains zirconia as a crystalline inorganic material, specific examples of zirconia include, for example, yttria stabilized zirconia, CaO stabilized zirconia, MgO stabilized zirconia, zircon, CeO Stabilized zirconia etc. are mentioned. The alumina and / or the zirconia contained in the second layer may be of one type or of two or more types.
Among these, α-alumina and yttria-stabilized zirconia, which are excellent in heat resistance and corrosion resistance, are desirable.

The weight proportion of alumina and / or zirconia contained in the second layer is desirably 5 to 70% by weight, and more desirably 10 to 60% by weight.
When the weight ratio of alumina and / or zirconia contained in the second layer is in the range of 5 to 70% by weight, the second layer is peeled from the first layer even when the surface coating layer is exposed to high temperatures In addition, the surface coating layer is less susceptible to corrosion even if the surface coating layer is directly exposed to high temperature exhaust gas. Furthermore, when the second layer contains alumina, the insulation of the structure is also improved.

In the present specification, with respect to crystalline alumina and / or zirconia contained in the second layer, a value calculated using the following equation (3) is referred to as "weight ratio of alumina and / or zirconia contained in the second layer" I assume.
[Weight of alumina and / or zirconia / (weight of alumina and / or zirconia + weight of crystalline inorganic material other than alumina and / or zirconia + weight of non-crystalline inorganic material)] × 100 (3)

The average particle size of the alumina and / or zirconia particles contained in the second layer is not particularly limited, but is preferably 0.01 to 50 μm, and more preferably 0.1 to 25 μm.
If the average particle size is less than 0.01 μm, the particles are too small to be easily aggregated to cause peeling and pinholes. On the other hand, when the average particle diameter exceeds 50 μm, the distance between the surface of the surface coating layer and the particles increases in many places, and a crack is easily generated on the surface even with a slight stress such as bending.

In the structure of the present invention, the first layer contains iron oxide, and the second layer contains zirconia, which is desirable. It is more preferable that the first layer contains Fe ₂ O ₃ and the second layer contains yttria-stabilized zirconia.

The non-crystalline inorganic material contained in the surface coating layer constituting the structure of the present invention is desirably a low melting glass having a softening point of 300 to 1000 ° C. In the present invention, a low melting point glass having a softening point in the above range can be used as an amorphous inorganic material also when forming the first layer and when forming the second layer. As the non-crystalline inorganic material, different materials may be used in the first layer and the second layer, but it is desirable to use the same material.

The type of the low melting point glass is not particularly limited, but it is desirable that the glass contains at least one of barium glass, boron glass, strontium glass, alumina silica glass, soda zinc glass, and soda barium glass. .
As mentioned above, these glasses may be used alone, or two or more types of glasses may be mixed.

When the softening point is in the range of 300 to 1000 ° C., the low melting point glass as described above melts the low melting point glass and is applied (coated) on the surface of the substrate (metal material), and then heated and fired. By applying, it is possible to easily form a surface coating layer on the surface of a substrate made of metal and to form a surface coating layer with excellent adhesion to the substrate.

When the softening point of the low melting glass is less than 300 ° C., the temperature of the softening point is too low, so that the layer to be the surface coating layer easily flows due to melting or the like during heat treatment, and a layer having a uniform thickness is obtained. On the other hand, when the softening point of the low melting glass exceeds 1000 ° C., it is necessary to set the temperature of the heat treatment extremely high, and the mechanical properties of the substrate are degraded by heating. There is a risk of
The softening point may be measured, for example, using an automatic glass softening point / strain point measuring apparatus (SSPM-31) manufactured by limited company Opto-Company based on the method defined in JIS R 3103-1: 2001. it can.

In the structure of the present invention, if the thickness of the first layer is too thin, the adhesion between the substrate and the surface coating layer will not be sufficient, while if the thickness of the first layer is too thick, the heat insulation will be sufficient. It will not be. Therefore, the thickness of the first layer is desirably 2 to 50 μm.

In the structure of the present invention, when the thickness of the second layer is too thin, the heat insulation is not sufficient, while when the thickness of the second layer is too thick, the temperature difference between the substrate and the second layer is large. As a result, the surface covering layer including the second layer tends to be broken. Therefore, the thickness of the second layer is preferably 50 to 1000 μm.

Therefore, in the structure of the present invention, the thickness of the surface coating layer is desirably 52 μm or more from the viewpoint of maintaining the heat insulation and the adhesion well.
The thickness (hereinafter, also referred to as film thickness) of the surface covering layer such as the first layer and the second layer can be measured by a film thickness meter.

In the structure of the present invention, the thermal conductivity at 25 ° C. of the surface coating layer is preferably 0.05 to 2 W / m · K.
When the thermal conductivity at 25 ° C. of the surface coating layer is in the above range, the structure of the present invention is excellent in thermal insulation, and the thermal conductivity does not easily rise even at high temperatures, so the temperature of exhaust gas etc. decreases. Can be prevented.
The thermal conductivity of the surface coating layer at 25 ° C. can be measured by a laser flash method.

In the structure of the present invention, the surface roughness Rz _JIS of the surface of the first layer is desirably 0.1 to 10 μm. The surface roughness Rz _JIS of the surface of the second layer is preferably 0.01 to 10 μm.
The surface roughness Rz _JIS of the surface of the first layer or the second layer can be measured by the same method and conditions as the surface roughness Rz _{JIS of the} roughened surface of the base material.

In the structure of the present invention, as long as the surface covering layer has the first layer and the second layer of the above-mentioned constitution, it may have other layers.

FIG. 4 is a cross-sectional view schematically showing still another example of the structure of the present invention.
Structure 1D shown in FIG. 4 has the same configuration as structure 1A shown in FIG. 1 except that a third layer is formed outside the second layer of the surface covering layer.

Structure 1D shown in FIG. 4 is provided with the base material 10a which consists of metals, and the surface coating layer 20d formed on the surface of the base material 10a.
In the structure 1D, the surface covering layer 20d has a first layer 21a covering the base 10a, a second layer 22a covering the first layer 21a, and a third layer 23a covering the second layer 22a. doing.
The third layer 23a contains alumina 51 in an amount smaller than that of the alumina 51 contained in the second layer 22a. The second layer 22a and the third layer 23a may contain zirconia as a crystalline inorganic material instead of alumina, and may contain both alumina and zirconia. The third layer 23a may be formed between the first layer 21a and the second layer 22a.

FIG. 5 is a cross-sectional view schematically showing still another example of the structure of the present invention.
Structure 1E shown in FIG. 5 has the same configuration as structure 1A shown in FIG. 1 except that a third layer is formed between the first layer and the second layer of the surface covering layer. .

The structure 1E shown in FIG. 5 includes a base 10a made of metal and a surface coating layer 20e formed on the surface of the base 10a.
In the structure 1E, the surface covering layer 20e has a first layer 21a for covering the base 10a, a third layer 23b for covering the first layer 21a, and a second layer 22a for covering the third layer 23b. doing.
The third layer 23 b contains manganese oxide 41 or the like in a larger amount than manganese oxide 41 or the like contained in the first layer 21 a. The third layer 23 b may contain at least one of alumina and zirconia as a crystalline inorganic material.

In the structure of the present invention, not only the third layer having the above-described configuration, but any suitable third layer may be formed, and the fourth layer, the fifth layer, etc. other than the third layer may be formed. It may be done.

In the structure of the present invention, the base material may have projections and / or edge portions and flat portions on the surface.

Fig.6 (a) is sectional drawing which shows typically another example of the structure of this invention, FIG.6 (b) expanded the convex part vicinity in the structure shown to Fig.6 (a). It is an expanded sectional view, and Drawing 6 (c) is an expanded sectional view which expanded edge part vicinity in a structure shown in Drawing 6 (a).
Structure 1F shown in FIG. 6 has the same configuration as structure 1A shown in FIG. 1 except that a convex portion and an edge portion are formed on the surface of the base material.

In the present specification, the convex portion refers to a portion surrounded by the substrate surface line and the virtual surface line in a section in which the substrate surface line and the virtual surface line are different in a cross section perpendicular to the substrate surface. .
Here, the substrate surface line refers to a line that actually constitutes the surface of the substrate in a cross section perpendicular to the substrate surface, and the virtual surface line refers to a flat portion in a cross section perpendicular to the substrate surface The line which made the substrate surface line stretched.
When this is shown in the figure, the convex portion is a base in a section where the base material surface line 11A and the virtual surface line 11B are different in an enlarged cross-sectional view in which the vicinity of the convex portion of the structure shown in FIG. The part surrounded by material surface line 11A and virtual surface line 11B is said.

The film thickness of the above-mentioned convex part draws a perpendicular line to the tangent of each contact of the substrate surface line which forms a convex part, and the line segment which the perpendicular line is specified by each contact and the structure surface is Line segments that only cross the surface covering layer are arbitrarily extracted at 10 points, and the 10 line segments are averaged. When using a dual scope MP40 manufactured by Fisher Instruments Inc. as an example of the measurement method, film thickness correction is performed using any 30 points, and then film thickness measurement is performed on 10 points, and the measured values thereof Take an average of When film thickness measurement is performed on 10 points, it is desirable to take any 10 points so that there is no bias in the measurement region within the measurement region. For example, there is a method such as performing measurement at equal intervals of 1 mm.

Further, in the present specification, the edge portion means a substrate surface line in a section in which the substrate surface line and the imaginary surface line are different except for the convex portion in a cross section perpendicular to the substrate surface. A vertical line is drawn on the tangent to the tangent line at the end point of the edge surface line segment on the substrate surface line, and the substrate surface line constituting the both vertical lines and the edge surface line segment is enclosed It says a part.
When this is shown in the figure, the edge portion refers to a base material in a section in which the base material surface line 11C and the virtual surface line 11D are different in an enlarged cross-sectional view in which the vicinity of the edge portion in the structure shown in FIG. With the surface line 11C as the edge part surface line segment, a vertical line is drawn on the substrate surface line 11C with respect to the tangent at the point 11P which is both end points of the edge part surface line segment, both vertical lines G and edge part surface line It refers to a portion surrounded by the substrate surface line 11C that constitutes the minute.

Also, with the film thickness of the edge part, in the substrate surface line forming the edge part, a vertical line is drawn for each of the 10 contact points extracted arbitrarily, and the vertical line corresponds to each contact and the structure surface The length obtained by averaging the lengths of defined line segments. When using a dual scope MP40 manufactured by Fisher Instruments Co., Ltd. as an example of the measurement method, film thickness correction is carried out using any 30 points, and then film thickness measurement is carried out for 10 points. Take the average.
When film thickness measurement is performed on 10 points, it is desirable to take any 10 points so that there is no bias in the measurement region within the measurement region. For example, there is a method such as performing measurement at equal intervals of 1 mm.

Structure 1F shown to Fig.6 (a) is equipped with the base material 10b which consists of metals, and the surface coating layer 20f formed on the surface of the base material 10b.
In the structure 1F, the surface coating layer 20f includes a first layer 21a that covers the base 10b and a second layer 22a that covers the first layer 21a.

In the structure 1F shown in FIG. 6A, the flat portion 11a, the convex portion 11b, and the edge portion 11c are formed on the surface of the base material 10b.
Although the specific convex part 11b is not specifically limited, The weld bead and welding spatter which generate | occur | produce at the time of welding correspond to this convex part 11b. In the base material 10b, main surfaces having a large area are present on the front side and the back side, and usually, either main surface is a target for forming the surface coating layer 20f, but two main surfaces have surface coating layers. You may form. Further, in some cases, it may be necessary to form a surface coating layer not only on the main surface of the base 10b but also on the side surface of the base 10b. It will form a layer. For example, in the case where the exhaust pipe is partially double-piped, the inner pipe is formed inside, and the surface coating layer is formed also on the side surface of the inner pipe, the edge is present as a covering object .
In the structure 1F shown in FIG. 6A, the convex portion 11b and the edge portion 11c exist in the base material 10b, but only one of the convex portion 11b or the edge portion 11c is present in the base material 10b. May exist.

The height of the convex portion 11 b is assumed to be 0.01 to 15 mm, and the width of the convex portion 11 b is assumed to be 0.01 to 20 mm. The angle of the edge portion 11c in the cut surface when cut perpendicularly to the main surface of the substrate 11 is usually 90 °, but the angle of the edge portion 11c is not limited to 90 °, and 70 to 70 It may be in the range of 110 °.

In the structure of the present invention, the surface coating layer may be formed on both sides of the substrate regardless of the shape of the substrate.

The structure of the present invention can be applied to an electrically heated catalyst (hereinafter referred to as EHC) to exhibit an insulating effect. EHC is an exhaust gas purification catalyst provided in an exhaust passage of an internal combustion engine, and is an exhaust gas purification catalyst which is heated to a temperature at which the catalyst becomes active by a heat generating element that generates heat by being energized. By applying the structure of the present invention to EHC, it is possible to prevent the leakage of electricity to other than EHC.

When the structure of the present invention is used for insulation of EHC, the first layer of the surface coating layer is selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide as a crystalline inorganic material. The second layer of the surface coating layer desirably contains at least one of alumina and zirconia (desirably alumina) as the crystalline inorganic material.

Even when the structure of the present invention is used for insulation application of EHC, the configuration of the substrate and the surface coating layer is as described above.

For example, the weight ratio of manganese oxide or the like contained in the first layer is desirably 5 to 70% by weight, and more desirably 10 to 60% by weight.

In addition, it is preferable that the second layer does not contain manganese oxide or the like, and if the second layer contains manganese oxide or the like, the weight ratio of manganese oxide or the like contained in the second layer is 0.05 It is desirable that the amount is 10 to 10% by weight, and more preferably 0.05 to 5% by weight.

Furthermore, the proportion by weight of alumina and / or zirconia (desirably alumina) contained in the second layer is desirably 5 to 70% by weight, and more desirably 10 to 60% by weight.

Next, the method for producing the structure of the present invention will be described.
The structure of the present invention can be produced by applying a coating composition for forming a surface coating layer on the surface of a metal base to form a surface coating layer.
In the following description, the paint composition for forming the first layer of the surface coating layer is referred to as the first paint composition, and the paint composition for forming the second layer is referred to as the second paint composition. Here, when it only says a coating composition, both a 1st coating composition and a 2nd coating composition shall be meant.

As a material of the coating composition for forming a surface coating layer, the powder of the amorphous inorganic material mentioned above and the powder of a crystalline inorganic material are mentioned. Besides, a dispersion medium, an organic binder and the like may be blended.

Examples of the dispersion medium include water, and organic solvents such as methanol, ethanol and acetone. Although the compounding ratio of the powder of the non-crystalline inorganic material contained in a coating composition and a dispersion medium is not specifically limited, For example, with respect to 100 weight part of powder of non-crystalline inorganic materials, 50 dispersion media are. It is desirable that it is -150 parts by weight. It is because it becomes a viscosity suitable for apply | coating to a base material.
Examples of the organic binder include polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose and the like. These may be used alone or in combination of two or more. Also, the dispersion medium and the organic binder may be used in combination.

When producing the structure of the present invention, the first paint composition contains a weight ratio of crystalline manganese oxide or the like to the total amount of the crystalline inorganic material and the non-crystalline inorganic material contained in the second paint composition. The weight ratio of crystalline manganese oxide or the like to the total amount of the crystalline inorganic material and the non-crystalline inorganic material to be

The weight ratio of crystalline manganese oxide or the like to the total amount of the crystalline inorganic material and the non-crystalline inorganic material contained in the first coating composition is desirably 5 to 79% by weight, preferably 15 to 50% by weight. It is more desirable to have. The weight ratio of crystalline manganese oxide or the like to the total amount of the crystalline inorganic material and the non-crystalline inorganic material contained in the second coating composition is preferably 2 to 50% by weight, and 5 to 39% by weight. It is more desirable to be%.

Hereinafter, preparation of the above-mentioned paint composition and a method of manufacturing a structure using the same will be described.

(1) Step of preparing a base made of metal A base made of metal (hereinafter, also simply referred to as a base) is used as a starting material, and first, a cleaning process is performed to remove impurities on the surface of the base.
The washing treatment is not particularly limited, and a conventionally known washing treatment can be used. Specifically, for example, a method of performing ultrasonic washing in an alcohol solvent can be used.

In addition, after the above-mentioned washing treatment, the surface of the substrate is subjected to a roughening treatment to increase the specific surface area of the surface of the substrate or adjust the surface roughness of the substrate, if necessary. May be Specifically, for example, roughening treatment such as sand blasting treatment, etching treatment, high temperature oxidation treatment, etc. may be performed. These may be used alone or in combination of two or more.
After the roughening treatment, a washing treatment may be further performed.

(2) Step of Preparing a Coating Composition A crystalline inorganic material, an amorphous inorganic material and the like are mixed to prepare a first coating composition and a second coating composition.
For example, a powder of a crystalline inorganic material and a powder of an amorphous inorganic material are prepared to have predetermined particle sizes and shapes, respectively, and each powder is dry mixed at a predetermined compounding ratio to prepare a mixed powder. Further, water is further added, and the first paint composition and the second paint composition are prepared by wet mixing in a ball mill. When preparing a 2nd coating composition, the powder of a crystalline inorganic material may not be added.
Here, the compounding ratio of the mixed powder and water is not particularly limited, but it is desirable that about 100 parts by weight of water is with respect to 100 parts by weight of the mixed powder. It is because it becomes a viscosity suitable for apply | coating to a base material. In addition, as described above, a dispersion medium such as an organic solvent, an organic binder, and the like may be added to the first coating composition and the second coating composition, as necessary.

(3) Step of Applying the Coating Composition to the Surface of the Substrate After the first coating composition is applied to the surface of the substrate, the second coating composition is applied thereon.
As a method of applying the first coating composition and the second coating composition, for example, methods such as spray coating, electrostatic coating, inkjet, transfer using a stamp or roller, brush coating, electrodeposition coating, etc. It can be used.

(4) Step of Forming a Surface Coating Layer The base on which the first paint composition and the second paint composition are applied is subjected to a baking treatment.
For example, after drying the base material which apply | coated the said coating composition, it heat-fires and forms a surface coating layer. Desirably, after the substrate coated with the first coating composition is dried, the second coating composition is applied, dried, and heated and fired.
The baking temperature is desirably equal to or higher than the softening point of the non-crystalline inorganic material, and preferably 700 ° C. to 1100 ° C., although it depends on the type of non-crystalline inorganic material blended. By setting the firing temperature to a temperature equal to or higher than the softening point of the non-crystalline inorganic material, the base material and the non-crystalline inorganic material can be firmly adhered, and a surface covering layer firmly adhered to the base material is formed. It is because

In addition, after apply | coating a 1st coating composition to the surface of a base material and performing baking processing, you may apply a 2nd coating composition on it and may perform baking processing. However, from the viewpoint of production efficiency, it is preferable that the number of times of the baking treatment is one, so it is preferable to subject the substrate coated with the first paint composition and the second paint composition to the baking treatment.

Moreover, when forming the 3rd layer of a surface coating layer, a 4th layer, etc., after preparing the 3rd coating composition which has a predetermined composition, a 4th coating composition, etc. and applying to an appropriate part, A firing process may be performed.

By the above procedure, the structure of the present invention can be manufactured.

Hereinafter, exhaust system parts which are an example of a structure of the present invention will be described.
FIG. 7 (a) is a cross-sectional view schematically showing an example of an exhaust system component when the base material is a cylindrical body, and FIG. 7 (b) is an exhaust system component shown in FIG. 7 (a) It is sectional drawing which cut | disconnected in half.

An exhaust system component 2A shown in FIG. 7A includes a base 10c made of a cylindrical body like an exhaust pipe, and a first layer 21a and a first layer for covering the base 10c inside the base 10c. A surface covering layer 20g is formed which includes a second layer 22a covering the layer 21a.
The exhaust pipe having such a configuration is extremely excellent in heat insulation. Therefore, by using this exhaust pipe, the temperature can be raised to the catalyst activation temperature in a short time from the start of the engine, and the performance of the catalytic converter can be sufficiently exhibited from the start of the engine.

Hereinafter, an example of a method of manufacturing an exhaust system component in which the base material is a cylindrical body and the surface coating layer is formed on the inner surface of the cylindrical body will be described.
When the exhaust system component (cylindrical body) 2A shown in FIG. 7A is long, it is difficult to form a surface coating layer on the entire inside, although this is not impossible. Therefore, usually, an exhaust system component (half member) 2B (see FIG. 7B) obtained by cutting a cylindrical body of a base material constituting the exhaust system component in half is used.
In this case, after the surface covering layer 20h including the first layer 21a and the second layer 22a is formed on the surface of the base 10d, the two exhaust system parts (half members) 2B are united to form the base 10c. The exhaust system component 2A which consists of a cylindrical body in which 20 g of surface coating layers were formed in the inside of this is produced.

First, a first half member and a second half member obtained by cutting a cylindrical body in half are prepared as a base material. Next, for the first half member and the second half member, the paint composition is applied to the inner surfaces of the first half member and the second half member, which have smaller areas. Subsequently, the first half member and the second half member are subjected to a firing treatment to form a surface covering layer including the second surface covering layer on the surfaces of the first half member and the second half member. Then, the first half member and the second half member are joined by welding or the like to form a cylindrical body.
According to the above procedure, an exhaust system component in which the base material is a cylindrical body and the surface coating layer is formed on the inner surface of the cylindrical body can be manufactured.

The effects of the structure of the present invention are listed below.
In the structure of the present invention, the amount of crystalline manganese oxide and the like contained in the second layer formed on the outer side of the surface coating layer (opposite to the substrate) is relatively small. Therefore, the thermal conductivity of the surface coating layer can be lowered, and the heat insulation of the structure can be improved.

Further, in the structure of the present invention, the thermal expansion coefficients of the base and the first layer can be made close to each other by forming the first layer having a relatively large amount of crystalline manganese oxide or the like on the base. As a result, the base material and the first layer can be firmly adhered. Further, the first layer and the second layer both have high adhesion because they contain an amorphous inorganic material. Therefore, in the structure of the present invention, the surface coating layer adheres firmly to the substrate as a whole.

Thus, in the present invention, a structure having sufficient thermal insulation and excellent adhesion between the substrate and the surface coating layer can be obtained.

(Example)
Hereinafter, the example which disclosed the structure of this invention more concretely is shown. The present invention is not limited to only these examples.

Example 1
(1) Preparation of substrate As a substrate made of metal to be coated, a plate-like stainless steel substrate (made of SUS430) measuring 40 mm long × 40 mm wide × 1.5 mm thick is used as a material in an alcohol solvent. Sonic cleaning was performed, followed by sand blasting to roughen the surface (both sides) of the substrate. Sandblasting was performed for 10 minutes using # 100 Al ₂ O ₃ abrasive grains.
When the surface roughness of the metal substrate was measured at a measurement distance of 10 mm using a surface roughness measuring machine (Handysurf E-35B, manufactured by Tokyo Seimitsu Co., Ltd.), the surface roughness of the metal substrate was Rz _{The JIS} was 8.8 μm.
A flat substrate was produced by the above treatment.

(2) Preparation of the first coating composition for the first layer of the surface coating layer As a powder of amorphous inorganic material, K4006A-100M (Bi ₂ O ₃ -B ₂ O ₃ system glass, softening point by Asahi Glass Co., Ltd.) Prepared at 770 ° C.
Further, as a powder of a crystalline inorganic material, were prepared powders of Fe ₂ O ₃ is a transition metal oxide.
The weight ratio of Fe ₂ O ₃ to the total amount of the crystalline inorganic material and the amorphous inorganic material was 30% by weight.

Furthermore, methylcellulose (product name: METOLOSE-65SH) manufactured by Shin-Etsu Chemical Co., Ltd. was prepared as an organic binder, and it was blended so that the concentration with respect to the entire first coating composition was 0.05% by weight.
In preparation of the coating for surface coating layer formation used for surface coating layer formation, water is further blended so that the concentration to the whole 1st coating composition may be 7% by weight, and the first coating is obtained by wet mixing with a ball mill The composition was prepared.

(3) Preparation of Second Coating Composition for Second Layer of Surface Coating Layer Second Coating Composition for Second Layer According to the Same Method of Preparing the First Coating Composition for the First Layer Described Above Was prepared.
As a powder of the amorphous inorganic material, K4006A-100M manufactured by Asahi Glass Co., Ltd., which is the same as in the case of the first coating composition, was used. Moreover, (alpha)-alumina was used as a crystalline inorganic material. The weight ratio of α-alumina to the total amount of the amorphous inorganic material and the crystalline inorganic material was 5% by weight. The average particle size of the α-alumina used was 10 μm.
In addition, 0.005 parts by weight of carbon as a pore forming material was added to 100 parts by weight of the second coating composition. The average particle diameter of the pore forming material was 1 μm.

Here, the average particle diameter of the powder of the crystalline inorganic material is the average particle diameter of the powder of the crystalline inorganic material added to the raw material when preparing the raw material for forming the surface coating layer. It is the value measured using the diffraction type particle size distribution measuring apparatus (SALD-300V).

(4) Production of Structure The surface of the roughened substrate was coated by the spray coating method using the prepared first coating composition, and dried at 70 ° C. for 20 minutes in a dryer. Furthermore, the prepared second coating composition was applied by a spray coating method, and dried at 70 ° C. for 20 minutes in a dryer. Thereafter, the resultant was heat-fired in air at 850 ° C. for 90 minutes to form a surface covering layer having the first layer and the second layer, thereby producing a structure.

(5) Evaluation of the obtained structure (i) Measurement of film thickness With respect to the obtained structure, the film thickness of the first layer and the second layer of the surface coating layer is measured by Dual Scope MP40 manufactured by Fisher Instruments Inc. It measured by.

(Ii) Measurement of Pull Strength In order to evaluate the adhesion between the surface coating layer and the substrate, the pull strength was measured by the following method.

FIG. 8 is a schematic cross-sectional view of a pull strength measurement sample.
The stud pin 50 was attached to the surface of the surface coating layer 20a of the structure 1A using a clip and heated at 150 ° C. for 1 hour to fix it, thereby producing a measurement sample. As the stud pin 50, P / N 901106 (a stud pin made of 2.7 mm epoxy adhesive Al) manufactured by QUAD GROUP was used.

FIG. 9 is an external view of a tensile test by a tensile tester.
The tensile testing machine 500 was used to pull the stud pin 50 fixed with the surface covering layer 20a. The pull strength was calculated from the maximum value of the force applied until the surface coating layer 20a in contact with the stud pin 50 was peeled off from the substrate 10a and the cross-sectional area of the stud pin 50. As a tensile tester 500, Autograph AGS50A manufactured by Shimadzu Corporation was used.

A sample having a pull strength of 50 MPa or more is regarded as “o”, and one having a pull strength of less than 50 MPa is regarded as “x”.

(Iii) Measurement of the thermal conductivity of the surface coating layer The thermal conductivity (25 ° C.) of the surface coating layer (first layer and second layer) is measured using a laser flash device (thermal constant measuring device: NETZSCH LFA 457 Microflash) did.
Moreover, it was 25 W / mK when the thermal conductivity (25 degreeC) of the base material (stainless steel base material) was similarly measured.

When the thermal conductivity of the surface coating layer was less than 2 W / mK, it was evaluated as "o", and when it was 2 W / mK or more as "x".

(Iv) Overall Judgment Based on the evaluation results of pull strength and thermal conductivity, both of those with ○ were comprehensively judged as “○”, and those with at least 1 with “×”.

In the structure of Example 1, the film thickness of the first layer is 25 μm, the film thickness of the second layer is 200 μm, the pull strength is 68 MPa, and the thermal conductivity of the surface coating layer is 0.70 W / mK. It became ○.

(Example 2)
In Example 2, the weight ratio of Fe ₂ O ₃ to the total amount of the crystalline inorganic material and the non-crystalline inorganic material in the first coating composition was set to 20% by weight. In addition, as powder of the crystalline inorganic material contained in the second coating composition, yttria-stabilized zirconia (YSZ) is used instead of α-alumina, and YSZ of the total amount of the crystalline inorganic material and the non-crystalline inorganic material is used. The weight ratio was 40% by weight. The average particle size of YSZ used was 25 μm.
A structure was manufactured in the same manner as Example 1 except for the above.

The structure of Example 2 was evaluated in the same manner as in Example 1. The thickness of the first layer was 5 μm, the thickness of the second layer was 500 μm, the pull strength was 59 MPa, and the thermal conductivity of the surface coating layer was 0. It was 40 W / mK, and the overall judgment was ○.

(Comparative example 1)
In Comparative Example 1, the first coating composition was not prepared, and the first layer was not formed. Moreover, the powder of the crystalline inorganic material was not added to a 2nd coating composition, and only the amorphous inorganic material was used. In addition, 0.006 parts by weight of carbon as a pore forming material was added to 100 parts by weight of the second coating composition.
A structure was manufactured in the same manner as Example 1 except for the above.

The structure of Comparative Example 1 is evaluated in the same manner as in Example 1. The film thickness of the second layer is 500 μm, the pull strength is 49 MPa, and the thermal conductivity of the surface coating layer is 0.30 W / mK. It became x.

(Comparative example 2)
In Comparative Example 2, the first coating composition was not prepared, and the first layer was not formed. In addition, as a powder of the crystalline inorganic material contained in the second coating composition, YSZ is used instead of α-alumina, and the weight ratio of YSZ to the total amount of the crystalline inorganic material and the noncrystalline inorganic material is 40% by weight And The average particle size of YSZ used was 25 μm. Further, 0.004 parts by weight of carbon as a pore forming material was added to 100 parts by weight of the second coating composition.
A structure was manufactured in the same manner as Example 1 except for the above.

The structure of Comparative Example 2 was evaluated in the same manner as in Example 1. As a result, the film thickness of the second layer was 750 μm, the pull strength was 40 MPa, and the thermal conductivity of the surface coating layer was 0.35 W / mK. It became x.

(Comparative example 3)
In Comparative Example 3, the second paint composition was not prepared, and the second layer was not formed. The composition of the first paint composition is the same as in Example 1.
A structure was manufactured in the same manner as Example 1 except for the above.

The structure of Comparative Example 3 is evaluated in the same manner as in Example 1. The film thickness of the first layer is 25 μm, the pull strength is 70 MPa, and the thermal conductivity of the surface coating layer is 2.50 W / mK. It became x.

Hereinafter, specific examples of the structure of the present invention will be described with reference to the drawings.
The structure of the present invention can be used for an exhaust pipe component used as a member constituting an exhaust system connected to an internal combustion engine such as an automobile engine. The configuration of the exhaust system component described here is the same as the above-described structure except that the base material is a cylindrical body.

Specifically, the structure of the present invention can be suitably used, for example, as an exhaust manifold or the like.
Hereinafter, the structure of the present invention will be described by taking an exhaust manifold connected to an internal combustion engine such as an automobile engine as an example.

FIG. 10 is an exploded perspective view schematically showing an automobile engine according to the structure of the present invention and an exhaust manifold connected to the automobile engine.
11 (a) is a cross-sectional view of the automobile engine and the exhaust manifold shown in FIG. 10 taken along line AA, and FIG. 11 (b) is taken along the line BB of the exhaust manifold shown in FIG. 11 (a). FIG.

As shown in FIGS. 10 and 11A, an exhaust manifold 110 (the structure shown in FIG. 1 and the like) is connected to the automobile engine 100.
A cylinder head 102 is attached to the top of the cylinder block 101 of the automotive engine 100. An exhaust manifold 110 is attached to one side surface of the cylinder head 102.

The exhaust manifold 110 has a globe-like shape, and includes branch pipes 111a, 111b, 111c and 111d according to the number of cylinders, and a collecting portion 112 for connecting the branch pipes 111a, 111b, 111c and 111d. Prepare.
A catalytic converter provided with a catalyst support is connected to the exhaust manifold 110. The exhaust manifold 110 has a function of collecting the exhaust gas from each cylinder and further transmitting the exhaust gas to a catalytic converter or the like.
Then, the exhaust gas G discharged from the automobile engine 100 (in FIG. 11A, the exhaust gas is indicated by G and the flowing direction of the exhaust gas is indicated by an arrow) flows into the catalytic converter through the inside of the exhaust manifold 110. It is purified by the catalyst supported on the catalyst carrier and discharged from the outlet.

As shown in FIG. 11 (b), the exhaust manifold 110 (structure of the present invention) includes a substrate 120 made of metal and a surface coating layer 130 formed on the surface of the substrate 120.
In the exhaust manifold 110 (the structure of the present invention) shown in FIG. 11B, the base material 120 is a cylindrical body, and the surface coating layer 130 is formed on the inner surface of the base material.

In the structure (exhaust manifold) of the present invention, the same structure as the surface covering layer in the above-mentioned structure can be adopted as the structure of the surface covering layer.
The exhaust manifold 110 shown in FIG. 11B shows an example having the same structure as the surface covering layer 20a in the structure 1A shown in FIG. 1 as the surface covering layer 130, and the surface covering layer 130 The first layer 131 and the second layer 132 are provided.

In the structure (exhaust manifold) of the present invention, the surface coating layer is desirably formed on the entire inner surface of the substrate. This is because the area of the surface coating layer in contact with the exhaust gas is the largest, and the heat resistance is particularly excellent. However, the surface coating layer may be formed only on a part of the inner surface of the substrate.
In addition, in the structure of the present invention, the surface coating layer may be formed on the outer surface in addition to the inner surface of the substrate, or may be formed only on the outer surface of the substrate.

So far, the exhaust manifold used for exhaust system parts has been described as an example of the structure of the present invention, but the use range of the structure of the present invention is not limited to the exhaust manifold, and an exhaust pipe, catalytic converter It can also be suitably used as a tube that constitutes or a turbine housing or the like.
The number of branch pipes constituting the exhaust manifold may be the same as the number of cylinders of the engine, and is not particularly limited. In addition, as a cylinder of an engine, a single cylinder, 2 cylinders, 4 cylinders, 6 cylinders, 8 cylinders etc. are mentioned, for example.

When the structure of the present invention is manufactured, the structure of the present invention is the same as that of the structure of the present invention described with reference to FIG. 1 except that the shape of the base is different. Can be manufactured.
In the structure of the present invention, when the surface coating layer is formed on the inner surface of the base material, as described above, it is desirable to use the base material composed of the first half member and the second half member.

Also in the exhaust system component of the present invention described here, the same effect as the effect of the structure described with reference to FIG. 1 can be obtained.

In the structure of the present invention, the surface coating layer does not necessarily have to be formed entirely on the surface of the substrate.
For example, in the case of using the structure of the present invention as an exhaust pipe, the surface coating layer may be formed on the inner surface of a cylindrical body as a base material, but in the case of forming on the inner surface of a cylindrical body It is not necessary to form on the entire surface of the inner surface of the cylindrical body, but it is sufficient to form a surface coating layer at least at a portion where exhaust gas directly contacts.

In the structure of the present invention, the surface coating layer has a first layer covering the substrate and a second layer covering the first layer, and the first layer is a manganese oxide as a crystalline inorganic material. And the like, and it is essential that the second layer does not contain manganese oxide or the like as a crystalline inorganic material, or contains a smaller amount of manganese oxide or the like than the manganese oxide or the like contained in the first layer. It is an element.
A desired effect can be obtained by appropriately combining the above-described essential components with the various configurations described above (for example, the configuration of the surface coating layer, the shape of the substrate, the exhaust manifold, etc.).

1A, 1B, 1C, 1D, 1E, 1F Structure 2A, 2B Exhaust system parts 10a, 10b, 10c, 10d, 120 Base material 11a Flat portion 11b Convex portion 11c Edge portion 20a, 20b, 20c, 20e, 20f , 20 g, 20 h, 130 first surface coating layer 21a, 131 first surface layer 22a, 22b, 132 second surface layer 23a, 23b third surface layer 31 third layer 31 amorphous inorganic material Inorganic material (at least one selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide)
51 Crystalline inorganic material (alumina and / or zirconia)
100 Automotive Engine 110 Exhaust Manifold

Claims (13)

A substrate made of metal,
A surface coating layer coated on the surface of the substrate and comprising at least an amorphous inorganic material,
The surface coating layer has a first layer coating the substrate and a second layer coating the first layer,
The first layer contains, as a crystalline inorganic material, at least one selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide,
The second layer, as the crystalline inorganic material, include less than the acid manganese, iron oxide, copper oxide, at least one member selected from the group consisting of cobalt oxide and chromium oxide first layer,
The structure in which the second layer further includes at least one of alumina and zirconia as a crystalline inorganic material. The structure according to claim 1, wherein the first layer contains iron oxide, and the second layer contains zirconia. The structure according to claim 1, wherein the first layer contains Fe ₂ O ₃ and the second layer contains yttria-stabilized zirconia. The structure according to any one of claims 1 to 3, wherein the thermal conductivity at 25 ° C of the surface coating layer is 0.05 to 2 W / m · K. The thickness of the said surface coating layer is 52 micrometers or more, The structure in any one of Claims 1-4. The thickness of the said 1st layer is 2-50 micrometers, The structure in any one of Claims 1-5. The thickness of the said 2nd layer is 50-1000 micrometers, The structure in any one of Claims 1-6. The structure according to any one of claims 1 to 7, wherein the amorphous inorganic material comprises a low melting point glass having a softening point of 300 to 1000 ° C. The structure according to claim 8, wherein the low melting point glass is a glass containing at least one of barium glass, boron glass, strontium glass, alumina silicate glass, soda zinc glass, and soda barium glass. The structure according to any one of claims 1 to 9, wherein the base material has on the surface at least one of a convex portion and an edge portion and a flat portion. The structure according to claim 10, wherein the first layer is formed on at least the surface of the convex portion and / or the edge portion. The structure according to claim 10, wherein the convex portion is derived from a weld bead and / or a weld spatter. The weight ratio of at least one selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide contained in the first layer is 5 to 70% by weight,
The weight ratio of at least one selected from the group consisting of manganese oxide, iron oxide, copper oxide, cobalt oxide and chromium oxide contained in the second layer is 0.05 to 10% by weight. The structure described in any one.

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