JPH0653623B2 - Method of joining ceramic body and metal body - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention (1) Field of Industrial Application The present invention relates to a method for joining a metal body and a ceramic body obtained through a forming and sintering process.

(2) Conventional Technology Conventionally, as this kind of joining method, it has been known to join a metal body and a ceramic body by brazing (Japanese Patent Publication No. S61-61).
-91073).

(3) Problems to be Solved by the Invention However, since the brazing means is simply aimed at the wettability of the brazing material with respect to both the surfaces of the ceramic body and the metal body, it can be used under severe conditions such as high temperature. However, there is a problem that the bonding strength is insufficient. Further, there is a possibility that the brazed portion may break due to the difference in thermal expansion coefficient between the metal body and the ceramic body.

In view of the above, it is an object of the present invention to provide the above-mentioned joining method capable of greatly improving and stabilizing the joining strength between the metal body and the ceramic body.

B. Structure of the Invention (1) Means for Solving the Problems The present invention relates to joining a metal body and a ceramic body obtained through a forming and sintering process, and forming the ceramic body from the ceramic body prior to forming the same. A large number of continuous pores opened on the joint surface of the ceramic body are dissolved by allowing the acid to flow and applying ultrasonic vibration to the acid. And a step of contacting the surface layer portion in the molten state of the metal body with the joint surface of the ceramic body, and then pressing the metal body and the ceramic body to make the surface layer portion continuous with the ceramic body. And a step of impregnating the pores under pressure.

(2) Action During the elution of elutable particles, the acid is circulated and ultrasonic vibration is applied to the acid, so that the soluble salts generated from the elutable particles are prevented from depositing in the continuous pores and the elution reaction is promoted. As a result, continuous pores can be formed quickly and reliably.

Since the continuous pores of the ceramic body are pressure-impregnated with the molten metal surface layer portion, the anchor effect by the surface layer portion can be reliably generated, and thereby the bonding strength between the two can be significantly improved.

In addition, since the eluable particles that have been mixed in advance are eluted, the porosity of the ceramic body depends on the amount of the particles mixed,
Therefore, it is easy to stabilize the anchor effect by the pressure impregnation of the surface layer portion, and thereby the bonding strength between the both can be stabilized.

Further, the continuous pore forming part of the ceramic body is converted into a composite part composed of the constituent material of the ceramic body and the constituent material of the metal body, and the coefficient of thermal expansion of the composite part exhibits an intermediate value between the coefficients of thermal expansion of the ceramic body and the metal body. By the composite portion, the difference in the coefficient of thermal expansion between the two can be relaxed, and breakage due to the difference in the joint portion between the two can be prevented.

Furthermore, since a metallic joining material such as a brazing material is unnecessary, the cost required for the joining material and the man-hours required for the installation can be reduced, and the joining cost can be reduced.

(3) Example FIG. 1 (a) shows a turbine impeller 1 as a ceramic body, and FIG. 1 (b) shows a superheat-resistant / corrosion-resistant alloy rotating shaft as a metal body joined to the turbine impeller 1. 2 is shown. As this seed alloy, Ni-Cr alloy (for example, Inconel 713C), Ni-Cr-Mo steel (for example, JIS S
NCM447) or the like is used.

The turbine impeller 1 includes an impeller body 3 and a joint shaft portion 4 integrated with the impeller body 3. The impeller body 3 includes a support portion 6 having a plurality of blades 5 and a large-diameter shaft continuous with the support portion 6. The small diameter shaft portion 8 is provided so as to project from the end portion 7 and the large diameter shaft portion 7. The joining shaft portion 4 is integrated with the impeller main body 3 in a state where the small diameter shaft portion 8 is allowed to fit therein and the end face abuts against the end face of the large diameter shaft portion 7.

The turbine impeller 1 is manufactured through the steps of raw material preparation, molding and sintering.

The raw material is different between the impeller main body 3 and the joining shaft portion 4, and as the raw material of the impeller main body 3, ceramic powder, a sintering aid that exhibits a sintering action at the sintering temperature of the powder, or the like is used. In the raw material of the shaft portion 4, in addition to the above, the joint shaft portion 4 has a three-dimensional network structure having a large number of continuous pores opening to the outer surface as the joint surface, and therefore, elutable particles that can be eluted by an acid are included. Used.

As the ceramic powder, Si ₃ N ₄ , SiC, ZrO is used.
₂ , single powders of TiC, TiN, and the like, and mixed powders selected from these powders are applicable.

As a sintering aid, Al ₂ O ₃ , Y ₂ O ₃ , MgO, S
Single powders such as iO ₂ and mixed powders selected from these are applicable.

Examples of particles that can be eluted include Al ₂ O ₃ , Na ₂ O, and SiO.
Those produced through the steps of mixing, melting, cooling and solidifying, and finely pulverizing ₂ , MgO, K ₂ O, B ₂ O ₃ , CaO and, if necessary, CaCl ₂ are applicable.

In preparing the raw materials, the various constituent substances are mixed for a predetermined time using a mixer such as a ball mill to uniformly disperse them.

When a molded body is obtained using the raw material, a pressure molding method,
An injection molding method, a slip casting method using water as a dispersion medium, or the like is used.

The conditions for subjecting the molded body to the sintering treatment are 1600 to 2000 ° C. and 0.5 ° C. in an inert gas atmosphere such as N ₂ gas.
~ 12 hours.

By the sintering process, the turbine impeller 1 having a dense structure can be obtained. The degree of densification of the turbine impeller 1 is mainly controlled by the compounding amount of the sintering aid and the temperature and time in the sintering process. Further, since the elutable particles also function as a sintering aid, the compounding amount of the particles in the joining shaft portion 4 is also a factor involved in the densification.

As the acid used for eluting the elutable particles from the joining shaft portion 4, single acids such as nitric acid and hydrochloric acid, mixed acids thereof,
The single acid or the mixed acid to which a small amount of hydrofluoric acid is added is used.

The particles that can be eluted by each acid are changed to soluble salts and eluted from the joint shaft portion 4 to form the joint shaft portion 4 into a three-dimensional network structure having a large number of continuous pores. At that time, the acid is circulated and ultrasonic vibration is applied thereto, thereby avoiding the deposition of soluble salts in the continuous pores, and promoting the elution reaction,
The continuous pores can be formed quickly and reliably.

In this case, the strength of the joining shaft portion 4 mainly depends on the size (diameter) of the pores and the porosity.

FIG. 2 shows the relationship between the porosity of the joining shaft portion 4 and the bending strength. Considering joining with the rotating shaft 2 under pressure, the porosity is preferably 10 to 30%. Further, the size of the continuous pores is appropriately 1 to 10 μm. By setting the size and porosity of the continuous pores in this manner, the bonding shaft portion 4 can be provided with the required strength due to the crystal growth of the ceramic powder accompanying the densification in the sintering process.

Since the size and porosity of the continuous pores depend on the particle size and blending amount of the elutable particles, the particle size and blending amount are determined so that the appropriate range can be obtained.

The alloy rotating shaft 2 is composed of each shaft portion 9 having a quadrangular cross section having one side larger than the diameter of the large diameter shaft portion 7 in the impeller body 3, and a small diameter shaft portion 10 connected to the shaft portion 9. The shaft portion 9 is formed with a hole portion 11 which is fitted with the joining shaft portion 4 of the turbine impeller 1.

When the turbine impeller 1 and the rotating shaft 2 are integrated with each other, the joint shaft portion 4 after the elution treatment has the hole portion 11 of the angular shaft portion 9 in which the surface layer portion is melted by the heat treatment in the atmosphere or under vacuum. And then press the square shaft portion 9 from the outer periphery thereof in the atmosphere or under vacuum to form the hole portion 11
The continuous pores of the joining shaft part 4 are pressure-impregnated with the surface layer part.

In this case, it is more effective to increase the bonding strength by performing the heat treatment and the pressurizing process of the square shaft portion 9 under vacuum because the square shaft portion 9 can be prevented from being oxidized.

An anchor effect occurs due to the pressure impregnation of the surface layer portion, whereby the joint strength between the joint shaft portion 4 and the angular shaft portion 9, and thus between the turbine impeller 1 and the rotary shaft 2 can be greatly improved. In this case, if a metal thin film is formed on the outer surface of the bonding shaft portion 4 and the inner surface of the continuous pores by a method such as vapor deposition, the wettability of the surface layer portion with respect to the inner surface of the continuous pores becomes good.

Further, since the eluable particles that have been oriented in advance are eluted, it is easy to stabilize the porosity of the joining shaft portion 4, and hence the anchor effect due to the impregnation of the surface layer portion, by the blending amount of the particles. The joint strength between the impeller 1 and the rotary shaft 2 can be stabilized.

Further, the joint shaft portion 4 is converted into a composite portion composed of the ceramic material and the metal material of the angular shaft portion 9, and the thermal expansion coefficient of the composite portion is an intermediate value between the thermal expansion coefficients of the turbine impeller 1 and the rotating shaft 2. Since it is present, the difference in the coefficient of thermal expansion between the turbine impeller 1 and the rotary shaft 2 can be alleviated by the combined portion, and breakage due to the difference in the joint portion between the two can be prevented.

[Example I]

(a) Preparation of raw material for impeller body Ceramic powder 90% by weight of Si ₃ N _{4 having an} average particle size of 0.5 μm and maximum particle size of 5 μm Sintering aid powder Y ₂ O ₃ 6% by weight Al ₂ O ₃ 4% by weight Mix in a ball mill for 24 hours.

(b) Preparation of Bonding Shaft Raw Material First, elutable particles are manufactured using the following method.

Al ₂ O ₃ 5.9 wt%, _Na 2 O11.4 wt%, SiO ₂ 2
5.2 wt%, MgO 13.0 wt%, K ₂ O 4.0 wt%, B ₂
A mixture consisting of 38.0 wt% O ₃ and 2.5 wt% CaO is thoroughly mixed in a ball mill, the mixture is heated to 1400 ° C. to be melted, and then the melt is cooled and solidified. The solidified material is subjected to fine pulverization treatment to obtain elutable particles having an average particle size of 0.5 μm and a maximum particle size of 5 μm. The particle size distribution of the elutable particles is matched to that of the ceramic powder.

Ceramic powder having an average particle size of 0.5 μm and a maximum particle size of 5 μm Si ₃ N ₄ 81% by weight Sintering aid powder Y ₂ O ₃ 2% by weight Al ₂ O ₃ 3% by weight Elutable particles 14% by weight in a ball mill 24 Mix for hours.

Using the raw material (a) and water as the dispersion medium, the slip casting method is applied to obtain a molded body corresponding to the impeller body 3.

Using the raw material (b) and water as a dispersion medium, a slip casting method is applied to obtain a molded body corresponding to the joint shaft portion 4, and at the same time, the molded body and the molded body are integrated to form a turbine impeller 1 The final molded body corresponding to is manufactured.

The final molded body is placed in a sintering furnace, the temperature inside the furnace is raised to 1600 ° C. while N ₂ gas is passed through the furnace, and this temperature is maintained for 2 hours.

The turbine impeller 1 is obtained by this sintering process.

The density of the turbine impeller 1 is 95 which is the theoretical density.
% Or more and is very dense, and the bending strength at room temperature is 85 to 90 kgf / mm ² in a three-point bending test.
Further, when the fracture surface was observed using a scanning electron microscope, the grain size of the ceramic powder was 3 to 4 μm as the crystal grew.
It is a hexagonal columnar crystal, and no abnormal crystal growth is observed.

The joining shaft portion 4 of the turbine impeller 1 is subjected to the elution treatment described below.

A mixed acid composed of 25% nitric acid and 0.1% hydrofluoric acid is heated to 50 ° C., the mixed acid is circulated and ultrasonic vibration is applied to the mixed acid. Immerse to elute the elutable particles.

The weight reduction rate of the joining shaft part 4 was 15.0%, which means that almost all the elutable particles were eluted.

By observing the fracture surface of the joining shaft portion 4, it has been confirmed that the size of the continuous pores in the joining shaft portion 4 is about 2 μm and the porosity is 16%, and most of the pores are continuous. Since the porosity after sintering was apparently 0%, it was about 1%.
There will be closed pores in the.

As shown in FIG. 3, a Ni-Cr alloy (Inconel 71
3C) of the rotary shaft 2 is heated to about 1200 ° C., the pre-heated joining shaft part 4 of the turbine impeller 1 is fitted into the hole 11 thereof, and both 1 and 2 are pressed. Install in 12. Then, under vacuum, the upper and lower punches 13, 14
Thus, the angular shaft portion 9 is pressurized with a pressure of 200 kgf / mm ² , and the surface layer portion in the molten state at the hole portion 11 is impregnated into the continuous pores of the joining shaft portion 4.

After the joining work, the angular shaft portion 9 of the rotary shaft 2 is subjected to finish processing to obtain a joined body of the turbine impeller 1 and the rotary shaft 2 shown in FIG.

In this joined body, the joining shaft portion 4 which is a continuous pore forming portion
Is a structure in which the alloy A fills the continuous pores P between the ceramic materials C mainly composed of Si ₃ N ₄ , as shown in FIG.
Therefore, it is converted into a composite part composed of both C and A.

In this case, the thermal expansion coefficients of the turbine impeller 1 and the rotating shaft 2 are 3.0 × 10 ^-6 / ° C and 1.67 × 10 ^-6 / ° C, respectively.
C., and that of the composite part is 10.5.times.10.sup.- ⁶ / .degree. C., so that the coefficient of thermal expansion of the composite part takes an approximately intermediate value between both 1 and 2.

FIG. 6 shows the creep characteristics of the ceramic material single part, the composite part and the alloy single part. Measurement conditions are temperature 1000 ℃,
The load is 7.7 kg / mm ² . The line x _{1 corresponds} to the ceramic material single part, the line x _{2 corresponds} to the composite part, and the line x ₃ corresponds to the alloy single part.

As is apparent from FIG. 6, the strain rate of the composite portion (line x ₂ ) is close to that of the single ceramic material portion (line x ₁ ), and thus the composite portion has high strength.

Example II

The particle size distribution of the leachable particles of Example I was determined to be 0.8 μm average particle size.
m, and the maximum particle size was changed to 10 μm, and the same turbine impeller 1 as in Example I was obtained.

The joint shaft portion 4 of the turbine impeller 1 is subjected to the same elution treatment as in Example I to form continuous pores having a size of about 10 μm.

Cu-Ni is formed on the outer peripheral surface of the joint shaft portion 4 and the inner surface of the continuous pores.
The alloy is deposited by vapor deposition to form a thin film. In this case, since the size of the continuous pores is as large as about 10 μm, the clogging can be avoided.

By the same operation as in Example I, the joining shaft portion 4 and the square shaft portion 9
Integrate with.

When the fracture surface of the composite portion thus obtained was observed, it was found that the Ni—Cr alloy was bonded to the joint shaft portion 4 through the thin film.
It has been confirmed that they are sufficiently bonded to the outer surface and the inner surface of the open pores.

FIG. 7 shows the relationship between the Ni—Cr alloy impregnated amount in the composite part and the bending strength at room temperature, and FIG. 8 shows the composite part (line y ₁ ) and the Ni—Cr alloy impregnated amount of 30 volume% and Ni. −
The relationship between temperature and bending strength in the composite part (line y ₂ ) having a Cr alloy impregnation amount of 15% by volume is shown.

It can be seen from FIGS. 7 and 8 that the strength of the composite portion at room temperature and high temperature does not change significantly depending on the impregnated amount of the Ni—Cr alloy.

Example III

(a) Preparation of raw material for impeller body Ceramic powder Si ₃ N ₄ 90 wt% with an average particle size of 0.4 μm and maximum particle size of 5 μm Sintering aid powder Y ₂ O ₃ 5 wt% Al ₂ O ₃ 5 wt% Mix in a ball mill for 24 hours.

(b) Preparation of Bonding Shaft Raw Material It has been reported that Al ₂ O ₃ , MgO components, etc. of the elutable particles form a solid solution with Si ₃ N ₄ which is a ceramic powder. Halide as a new component to change the compounding amount and suppress abnormal crystal growth,
In the examples, CaCl ₂ is used, and elutable particles are manufactured using the following method.

Al ₂ O ₃ 8.6 wt%, _Na 2 O10.3 wt%, SiO ₂ 2
4.2 wt%, MgO 15.0 wt%, K ₂ O 2.1 wt%, B ₂
A mixture consisting of 39.16% by weight of O _3, 0.6% by weight of CaO, and 0.05% by weight of CaCl _{2 is} thoroughly mixed in a ball mill, the mixture is heated to 1200 ° C. to be melted, and then the melt is cooled and solidified. . The solidified product is subjected to fine pulverization treatment to obtain elutable particles having an average particle size of 1.2 μm and a maximum particle size of 3 μm.

Also, since it is feared that the particles that can be dissolved out will react with the sintering aid and that some of the sintering aids will be eluted by the above-mentioned elution treatment, the sintering aid is excluded and the average particle size of the ceramic powder is 0.4 93% by weight of Si ₃ N _{4 having} a maximum particle size of 5 μm and 7% by weight of elutable particles are mixed in a ball mill for 24 hours.

Using the raw material (a) and water as the dispersion medium, the slip casting method is applied to obtain a molded body corresponding to the impeller body 3.

Using the raw material (b) and water as a dispersion medium, a slip casting method is applied to obtain a molded body corresponding to the joint shaft portion 4, and at the same time, the molded body and the molded body are integrated to form a turbine impeller 1 The final molded body corresponding to is manufactured.

The final molded body is placed in a sintering furnace, the temperature inside the furnace is raised to 1600 ° C. while N ₂ gas is passed through the furnace, and this temperature is maintained for 2 hours.

The turbine impeller 1 is obtained by this sintering process.

The density of the turbine impeller 1 is 95 which is the theoretical density.
It is ˜97% and is very dense, and the bending strength at room temperature is about 80 kgf / mm ² in the three-point bending test. When the fracture surface was observed using a scanning electron microscope,
Along with the crystal growth, the ceramic powder became hexagonal columnar crystals with a grain size of 3 to 4 μm, and no abnormal crystal growth was observed.

The joining shaft portion 4 of the turbine impeller 1 is subjected to the elution treatment described below.

A mixed acid composed of 25% nitric acid and 0.1% hydrofluoric acid is heated to 50 ° C., the mixed acid is circulated and ultrasonic vibration is applied to the mixed acid. Immerse to elute the elutable particles.

The weight reduction rate of the joint shaft portion 4 was 5.8%, which was smaller than the blending amount of the elutable particles, but this was because Al ₂ O ₃ , MgO, etc., among the components of the elutable particles, formed a solid solution with Si ₃ N _4. It is considered that this is due to the fact that SiO ₂ is nitrided.

By observing the fracture surface of the joining shaft portion 4, it was confirmed that the maximum size of continuous pores in the joining shaft portion 4 was about 3 μm and the porosity was 25%, and there were no closed pores and all pores were continuous. It was

As shown in FIG. 3, Ni-Cr-Mo steel (JIS S
The angular shaft portion 9 of the rotary shaft 2 made of NCM447) is about 120
After heating to 0 ° C., the joint shaft portion 4 of the preheated turbine impeller 1 is fitted into the hole 11 thereof, and the both 1 and 2 are pressed.
Install in 2. Then, in the atmosphere, the upper and lower punches 13 and 14 press the square shaft portion 9 at a pressure of 200 kgf / mm ² , and the surface layer portion in the molten state in the hole portion 11 is impregnated into the continuous pores of the joining shaft portion 4.

After the joining work, the angular shaft portion 9 of the rotary shaft 2 is subjected to finish processing to obtain a joined body of the turbine impeller 1 and the rotary shaft 2 shown in FIG.

In this joined body, the joining shaft portion 4 which is a continuous pore forming portion
As shown in FIG. 5, the structure is such that the continuous pores P between the ceramic materials C mainly composed of Si ₃ N ₄ are filled with the steel A, so that they are converted into a composite portion composed of both C and A.

In this case, each thermal expansion coefficient of the turbine impeller 1 and the rotating shaft 2 is ^{3.0 × 10 -6 /℃,23.6×10 -6 / ℃} , also that of the composite portion is 11.8 × 10 ^-6 / ℃, thus the composite section The coefficient of thermal expansion of is approximately the intermediate value of both 1 and 2.

Strength at room temperature of the composite portion is 50 kgf / mm ^2, the strength at 0 to 100 ° C. is 45~55kgf / mm ^2.

Further, the joined body was held in a furnace at 300 ° C. for 5 minutes, then immediately water-cooled, and a heat cycle test in which this operation was repeated 1000 times was performed. Thereafter, the joint portion between the joint shaft portion 4 and the square shaft portion 9 was X-treated. When the structural change was examined with a scanning electron microscope by performing stress diffraction with a line, the bonding shaft 4
It has been confirmed that there is no loosening or cracking between the and the shaft portion 9.

Example IV

The particle size distribution of the elutable particles of Example III is 0.5 μm in average particle size.
m, and the maximum particle size was changed to 5 μm, and the same turbine impeller 1 as in Example III was obtained.

The joint shaft portion 4 of the turbine impeller 1 is subjected to the same elution treatment as in Example III to form continuous pores having a size of about 10 μm.

A Cu ^- Ni alloy is attached to the outer surface of the bonding shaft portion 4 and the inner surface of the continuous pores by a vapor deposition method to form a thin film. In this case, since the size of the continuous pores is as large as about 10 μm, the clogging can be avoided.

By the same operation as in Example III, the joining shaft portion 4 and the square shaft portion 9
Integrate with. Observation of the fracture surface of the composite part thus obtained confirmed that the steel was sufficiently bonded to the outer surface of the bonding shaft part 4 and the inner surface of the continuous pores through the thin film.

FIG. 9 shows the relationship between the Ni—Cr—Mo steel impregnation amount in the composite part and the bending strength at room temperature. From FIG. 9, it can be seen that the strength of the composite part does not change significantly with the impregnation amount of Ni-Cr-Mo steel.

The present invention is not limited to joining the turbine impeller and the rotating shaft, but is also applicable to joining various ceramic bodies and metal bodies, for example, joining plate-shaped ceramic bodies and plate-shaped metal bodies. When forming continuous pores in the ceramic body, the whole ceramic body may be made to have continuous porosity, or only the surface layer portion may be made to have continuous porosity.

C. According to the present invention, the formation of continuous pores in the ceramic body,
It can be carried out quickly and reliably by adopting a means of blending elutable particles, elution of the particles with an acid, and circulation of the acid and application of ultrasonic vibration thereto. Also, since the ceramic body has already been sintered, it has sufficient strength even after the formation of continuous pores, has good handleability, and should be destroyed during the pressure impregnation of the molten metal surface layer. Nor.

Furthermore, the anchor effect is generated by pressure impregnation of the surface layer of the metal body into the ceramic body, and the anchor effect is stabilized, which significantly improves the bonding strength between the ceramic body and the metal body and stabilizes the stability. Can be realized.

In addition, the pressure impregnation converts the continuous pore forming part of the ceramic body into a composite part composed of the constituent material of the ceramic body and the constituent material of the metal body, and the coefficient of thermal expansion of the composite part has a thermal expansion coefficient of both the ceramic body and the metal body. Since the intermediate value of the coefficient is exhibited, it is possible to alleviate the difference in the coefficient of thermal expansion between the two due to the composite portion, and to avoid breakage due to the difference in the joint portion between the two.

Further, since a metallic joining material such as a brazing material is unnecessary, it is possible to reduce the joining cost accordingly.

Therefore, by the joining method according to the present invention, it is possible to inexpensively provide a joined body of a ceramic body and a metal body that has sufficient durability under severe conditions.

[Brief description of drawings]

1 (a) is a vertical sectional front view of a turbine impeller as a ceramic body, FIG. 1 (b) is a longitudinal sectional front view of a main portion of a rotating shaft as a metal body, and FIG. 2 is a joining shaft portion of a turbine impeller. Is a graph showing the relationship between the porosity and bending strength of Fig. 3, Fig. 3 is a vertical sectional front view showing the impregnation work of the surface layer of the rotating shaft under pressure,
FIG. 4 is a longitudinal sectional front view of a main part of the joined body, FIG. 5 is an enlarged view of a portion indicated by an arrow V in FIG. 4, FIG. 6 is a graph showing creep characteristics, and FIG. 7 is a Ni—Cr alloy impregnation in a composite portion. 8 is a graph showing the relationship between the amount and bending strength, FIG. 8 is a graph showing the relationship between temperature and bending strength in the composite part, and FIG. 9 is a relationship between the Ni—Cr—Mo steel impregnation amount and bending strength in the composite part. It is a graph which shows. DESCRIPTION OF SYMBOLS 1 ... Turbine impeller as a ceramic body, 2 ... Rotating shaft as a metal body, A ... Ni-Cr alloy, Ni-Cr-Mo steel, C ... Ceramic material, P ... Continuous pores

Claims (1)

[Claims] 1. When joining a metal body (2) and a ceramic body (1) obtained through a molding and sintering process, the ceramic body (1) was blended prior to its molding. , The eluable particles that can be eluted by an acid are eluted while the acid is being circulated and the ultrasonic vibration is applied to the acid, and the ceramic body (1) has a large number of continuous pores ( P) is formed; and after the molten surface layer portion of the metal body (2) is brought into contact with the bonding surface of the ceramic body (1), the metal body (2)
And a step of pressurizing the ceramic body (1) to impregnate the surface layer portion into the continuous pores (P) of the ceramic body (1) under pressure; Joining method.