JPH1171185A - Joining of ceramic to metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for joining a ceramic to a metal by charging a laminate comprising the ceramic and the metal into a mold, disposing an elastic member between the laminate and a pressing element, pressing the laminate through the elastic member, and subsequently applying a pulse voltage to the laminate. SOLUTION: This method for joining a ceramic substrate 12 to a metal 18 comprises charging a laminate comprising the ceramic substrate 12, the first intermediate layer (a 0.5-3 μm thick electroless-plated gold plate) 16 and a metal (titanium block) 18 into a mold 30, disposing an elastic member 31 between an upper side pressing element 32 and the metal 18, compressing the laminate 1 with a pair of pressing boards 33, 35 through the pressing elements 32, 34 and the elastic member 31, and subsequently applying a pulse voltage to the laminate 1 through the mold 30, the pressing elements 32, 34 and the pressing boards 33, 35. The laminate 1 is pressed with only an elastic force accumulated in the elastic member. The mold 30, the pressing elements 32, 34 and the pressing boards 33, 35 are made from conductive materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining ceramics and metal.

[0002]

2. Description of the Related Art Conventionally, as a method of joining ceramics and metal, there have been used an adhesive method of bonding ceramics and metal using an organic adhesive or the like, a metallizing method of plating ceramics with metal, and a method of adhering ceramics and metal. A solid-phase diffusion method in which heat treatment is performed for a long time is known.

[0003] However, the bonding method has a problem that the bonding strength is weak, and the metallization method has a problem that the process is complicated due to pretreatment of plating and the like. Furthermore, the solid-phase diffusion method has a problem that a heat treatment at a high temperature (about 1400 to 1600 ° C. for general ceramics) is required.

Accordingly, in recent years, a bonding method has been proposed in which a laminate of ceramics and metal is pressed and a pulse voltage is applied to the laminate to melt and join the joint surface of ceramics and metal in a short time. (JP-A-6-287076, etc.). The pressing mechanism that presses the laminate has a pair of pressers that sandwich and press the laminate, and is driven by hydraulic pressure or the like. Generally, it is difficult for a hydraulic mechanism to drive with a low pressing force (operating force). For this reason, the laminate is pressed with a somewhat high pressing force (for example, 250 kg) so that stable pressing drive can be performed.
f).

[0005]

[Problem to be solved]
When the laminated body is pressed with a high urging force of 50 kgf, a pressure close to 150 kgf / cm 2 is applied to the laminated body (when the laminated body is a pellet of a substrate having a diameter of 15 mm), and cracks are generated in the ceramics of the laminated body. There is a problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of joining ceramics and metal, which can provide good joining properties and does not cause cracks or the like at the time of joining.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, a method for joining ceramics and metal according to the present invention comprises:
A stacked body in which ceramics and metal are stacked is loaded inside a mold, and the stacked body is pressed by pressing means.
In a joining method of joining ceramics and metal by applying a pulse voltage to the laminate by voltage applying means, an elastic member is interposed between the pressing means in the mold and the laminate. It is assumed that. According to this structure, since the pressing force applied to the laminate is only the elastic force accumulated in the elastic member, cracks are prevented from being generated in the ceramics.

The pressing means includes a pair of pressing members for sandwiching the laminate, and a pair of pressing members for urging the pair of pressing members in the pressing direction. In this case, when the interval between the pair of pressing members is minimized, the pair of pressing members abuts on the molding die, and in this state, the laminate is pressed by the elastic force accumulated in the compressed elastic member. It is possible to be constituted so that. With this configuration, the pressing force of the pressing member is dispersed to the pressing element and the mold,
Only the pressing force necessary to keep the elastic member compressed can be applied to the pressing element side. That is, since the pressing force by the pressing member can be increased, the driving of the press device is stabilized.

[0009]

FIG. 1 is a schematic diagram showing a basic configuration of a joining method according to an embodiment. In the present embodiment, a ceramic base 12 which is a sintered body of calcium phosphate ceramic and a block 18 made of titanium are joined. A first intermediate layer 14 which is a thin gold film is provided between the ceramic base 12 and the titanium block 18 as an intermediate layer.
The second intermediate layer 16 which is a gold plate is interposed.

The bonding method according to the embodiment includes: (1) forming a first intermediate layer 14 on the surface of a ceramic base 12;
(2) Ceramic substrate 1 on which first intermediate layer 14 is formed
2, a second intermediate layer 16 and a titanium block 18 are stacked, and the layers are joined by applying a pulse voltage while pressing from above and below. Hereinafter, (1) and (2) will be described.

First, a method for forming the first intermediate layer 14 on the ceramic base 12 will be described. FIG.
(D) is a schematic diagram showing a step of forming a first intermediate layer 14 on the ceramic base 12. The first intermediate layer 14 is
It is formed as a gold coating by the method described in JP-A-7-144985. That is, (a) a composite film 122 of titanium oxide and zinc oxide is formed on the surface of the ceramic base 12,
(B) The ceramic substrate 12 is immersed in an acid or alkali solution to remove the zinc oxide in the composite film by etching, thereby forming irregularities on the surface of the composite film. Then, (c) the ceramic substrate 12 is immersed in a palladium chloride solution to form a palladium nucleus 124 serving as a plating catalyst nucleus, and (d) gold is deposited by electroless gold plating. Thus, thickness 0.5
A first intermediate layer 14 which is a gold film of about 3 μm is formed.

Here, the first formed by the process of FIG.
The thickness of the intermediate layer 14 is about several μm. However, since gold has the property of being diffused and absorbed by titanium, if the titanium block 18 and the first intermediate layer 14 are joined in direct contact with each other, , The gold of the first intermediate layer 14 is all titanium block 1
8 may be absorbed. Therefore, the first intermediate layer 14
The second intermediate layer 16 is provided between the first intermediate layer 16 and the titanium block 18. The second intermediate layer 16 is made of the same material as the first intermediate layer 14, that is, gold, so that it can be easily joined to the first intermediate layer 14. Also, the titanium block 1
The second intermediate layer 16 is formed to be relatively thick (0.1 to 2.0 mm) so that the second intermediate layer 16 may be absorbed.

Next, the second intermediate layer 16 and the titanium block 1 are placed on the ceramic substrate 12 on which the first intermediate layer 14 is formed.
The method of laminating 8 and pressing and heating will be described. FIG. 3 is a schematic view showing a main part of the electric discharge sintering apparatus 2 for pressing and heating the laminate. The discharge sintering apparatus 2 is used for joining and sintering powder, and is configured to compress a workpiece and apply a pulse voltage at the same time.

As shown in FIG. 3, a laminate 1 composed of a base 12, a first intermediate layer 14, a second intermediate layer 16, and a titanium block 18 is loaded in a mold 30. The laminate 1 is
It is compressed by a pair of upper and lower pressing elements 32 and 34. A ceramic spring 31 is provided between the upper pressing element 32 and the titanium block 18. Upper presser 32
An upper pressing plate 33 is provided above the lower pressing member 3.
A lower pressurizing plate 35 is provided below 4. In addition,
The molding die 30 is installed on the lower pressing plate 35, and the lower pressing plate 35 is raised toward the upper pressing plate 33, so that the pressing members 32, 34 and the spring 31 are interposed between the pressing plates 33, 35. The laminate 1 is compressed.

Further, the molding die 30 and the pressing elements 32, 34,
The pressing plates 33 and 35 are made of conductive carbon, and a pulse current generated by a power source for sintering described below is applied to the laminated body 1 via the molding die 30, the pressers 32 and 34, and the pressing plates 33 and 35. It is configured to flow to. Note that carbon paper 36 is provided as a cushion material between the pressers 32 and 34 and the inner periphery of the molding die 30. Because of the carbon paper 36, the pressers 32 and 34 can smoothly slide without digging into the inner periphery of the mold 30. Further, the titanium block 18 (which easily reacts with carbon) is prevented from sticking to the wall surface of the mold 30.

FIG. 4 shows the overall configuration of the spark sintering apparatus. The molding die 30, the pressing elements 32 and 34, and the pressing plates 33 and 35
It is housed in a vacuum chamber 25 provided with a vacuum pump 26. The control unit 20 of the discharge sintering apparatus 2 drives and controls a sintering power supply 22 that generates a pulse voltage, a pressing drive mechanism 24 that presses the laminate 1, and a vacuum pump 26 that degass a vacuum chamber 25. It is.

The upper and lower pressure plates 33, 35 are fixed to a pair of upper and lower pressure rams 42, 44, respectively. Press drive mechanism 2
4 raises the lower pressing ram 44 with respect to the upper pressing ram 42 (fixed) and presses the laminated body 1 between the upper and lower pressing elements 31 and 32 via the upper and lower pressing boards 33 and 35. I do. The control unit 20 controls the sintering power supply 22 such that the temperature of the laminate 1 detected by a thermocouple (not shown) provided in the molding die 30 matches a preset temperature rising curve. . The pressing elements 32 and 34 are connected to power supply terminals (not shown) provided in the pressing rams 42 and 44 by the power source 22 for sintering.
Is connected to

Next, a joining process by the discharge sintering apparatus configured as described above will be described. FIG. 5 shows the relationship between the interval between the upper and lower pressure plates and the control temperature. The control unit 20
First, the pressing drive mechanism 24 is driven, and the lower pressing plate 35
The ascent starts from the state shown in. As a result, the interval between the upper and lower pressure plates 33 and 35 is reduced (FIG. 5A),
Is gradually compressed and the elastic force is accumulated. As shown in FIG. 6, the lower pressure plate 35 continues to be raised until the lower pressure plate 35 contacts the mold 30. The pressing urging force of the pressing drive mechanism 24 is 250 kgf.

Then, as shown in FIG.
When the interval between the members 3 and 35 is reduced to W1, the pressing plates 33 and 35 directly sandwich the mold 30 from above and below as shown in FIG. Here, since the pressing plates 33 and 35 directly sandwich the forming die 30 from above and below, most of the urging force of the pressing plates 33 and 35 is applied to the forming die 30. Then, only a pressure of 1 kgf / cm 2 is applied to the laminate 1 by the elastic force of the spring 31 compressed from the length shown in FIG. 3 to the length shown in FIG.

Here, the control unit 20 includes the pressing plates 33 and 35
Then, a pulse voltage is applied to the laminate 1 via the pressing elements 32 and 34. The pulse voltage is a pulse having a DC voltage on / off pattern as shown in FIG.
Each turn on / off forms one pulse t. In addition, 1
At each on / off, the ratio of the on-state duration t1 to the off-state duration t0 ranges from 1: 1 to 12: 1. By applying such a pulse voltage, the laminate 1
Is rapidly heated as shown in FIG.

Due to the pressing and the application of the pulse voltage as described above, the unbonded boundary (the first boundary) of the laminate 1 shown in FIG.
Discharge phenomena and electric field diffusion effects occur at the boundary 15 between the intermediate layer 14 and the second intermediate layer 16 and at the boundary 17) between the second intermediate layer 16 and the titanium block 18, and the melting and diffusion of the surfaces of the gold and titanium particles are promoted. You. The promotion of melting and diffusion of the particle surface promotes solid-phase diffusion between the first intermediate layer 14 and the second intermediate layer 16 and between the second intermediate layer 16 and the titanium block 18.

Further, the first intermediate layer 14 and the second intermediate layer 16
Are made of the same material (gold), so they are easily diffused in the solid phase.
The intermediate layer 16 and the titanium block 18 easily diffuse in the solid phase due to the good compatibility between gold and titanium. Thus, the first intermediate layer 1
4 and the second intermediate layer 16, and the second intermediate layer 16 and the titanium block 18 can be joined in a short time and at a low temperature.

As described above, according to the bonding method of the present embodiment, the pressure applied to the laminate 1 is only 1 kgf / cm 2 due to the elastic force of the spring 31, so that the ceramic base 12 does not crack. Also, 250
Since pressing is performed with a high pressing urging force of kgf, stable pressing can be performed even when the pressing driving mechanism 24 is a hydraulic mechanism (that is, when pressing is performed with a low pressing urging force, some kind of pressing is performed). A gap does not occur between the presser and the laminate due to the time signature, and plasma is not generated in the gap.)

Although a normal metal spring cannot expect an elastic force at a high temperature, the present embodiment uses a spring 31 made of ceramics (for example, partially stabilized zirconia). The required elasticity is maintained.

[0025]

Next, embodiments of the present invention will be described. (Example 1) In Example 1, the ceramic base was
Using a hydroxyapatite substrate having a diameter of 15 mm, a gold thin film (first intermediate layer) having a thickness of 1 μm is formed on the hydroxyapatite substrate. This hydroxyapatite substrate is loaded into a mold 30 and a thickness of 0.3
mm metal plate (second intermediate layer), a titanium block, and a ceramic (partially stabilized zirconia) spring. Ceramics The pressing force is 250 kgf, the maximum temperature is 900 ° C., and the holding time is 5 minutes. The joined body obtained in this manner exhibited good joining properties, and no crack was observed on the hydroxyapatite substrate.

(Embodiment 2) In Embodiment 2, the second intermediate layer in Embodiment 1 is made of gold powder instead of a metal plate. That is,
After loading a hydroxyapatite substrate on which a gold thin film has been formed into a mold, a gold powder having a particle size of 5 μm is poured,
A titanium block and a spring made of ceramics (partially stabilized zirconia) are placed thereon. The pressing biasing force is 25
0 kgf, the maximum temperature is 900 ° C, and the holding time is 5 minutes. The joined body obtained in this manner exhibited good joining properties as in Example 1.

[0027]

As described above, in the method for joining ceramics and metal according to the present invention, a laminate in which ceramics and metal are laminated is loaded into a mold, and pressure and pulse voltage are applied to the laminate. In the joining method for joining ceramics and metal, an elastic member is interposed between the pressing means in the mold and the laminate. Accordingly, the force applied to the laminate is only the elastic force accumulated in the elastic member, so that the occurrence of cracks in the ceramics can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a bonding method according to an embodiment.

FIG. 2 is a view schematically showing a method of forming a first intermediate layer.

FIG. 3 is a schematic view showing a main part of the spark sintering apparatus.

FIG. 4 is a schematic view showing an overall view of the spark sintering apparatus of FIG. 2;

FIG. 5 is a schematic diagram illustrating an example of a pressure curve and a temperature curve in the bonding method according to the embodiment.

FIG. 6 is a schematic view showing a main part of the spark sintering apparatus.

FIG. 7 is a schematic diagram showing an example of a pulse voltage applied to a laminate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated body 2 Electric discharge sintering device 12 Ceramic base 14 1st intermediate layer 16 2nd intermediate layer 18 Titanium block 20 Control part 22 Power supply for sintering 24 Press drive mechanism 30 Mold 31 Spring (elastic member) 32, 34 Presser 33 , 35 Pressing plate (pressing member)

Claims (9)

[Claims] 1. A lamination in which a ceramic and a metal are laminated is loaded in a molding die, and the lamination is pressed by pressing means, and a pulse voltage is applied to the lamination by voltage applying means. A joining method for joining the ceramic and the metal, wherein an elastic member is interposed between the pressing means and the laminate in the molding die. 2. The pressing means includes a pair of pressing members for sandwiching the laminate, and a pair of pressing members for urging the pair of pressing members in the pressing direction. The method for joining ceramics and metal according to claim 1. 3. The molding die, the pressing element and the pressing member are made of a conductive material, and the pulse voltage is applied to the laminate via the pressing member, the pressing element and the molding die. 3. The method according to claim 2, wherein the ceramic and the metal are joined together. 4. The method according to claim 2, wherein the elastic member is provided between at least one of the pair of pressers and the laminate. 5. The elastic force accumulated in the compressed elastic member in this state, when the pair of press members minimizes the distance between the pair of press members, the pair of press members contact the molding die. The method according to any one of claims 2 to 4, wherein the laminate is pressed by the following method. 6. The method according to claim 1, wherein the elastic member is a ceramic spring. 7. The method for joining a ceramic and a metal according to claim 1, wherein a gold layer is interposed between the ceramic and the metal. 8. The ceramic according to claim 1, wherein the ceramic is a calcium phosphate ceramic.
The method for bonding a ceramic and a metal according to any one of the above. 9. The method according to claim 1, wherein the metal is titanium.