JP2005230823A - Joining apparatus and joining method with pulse energization - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining apparatus and a joining method with a pulse energization with which even when a joining member is thermally expanded by the raised temperature at the joining time, the pressure applied to the joining member is lightened without bringing about a time-lag and a joined body can be obtained without damaging the accuracy. <P>SOLUTION: In the joining apparatus with the pulse energization provided with one pair of electrodes 2 for supplying the pulse current to the joining member 1, a pulse current generating unit 3 for supplying the pulse current to the electrodes, and a pressurizing means 4 for pressurizing the electrodes, the electrodes have elastic force. In the joining method with the pulse energization, by which the joining surfaces of the joining members are butted to each other and while pressurizing with a prescribed pressure so as to closely attach the butted joining surfaces, one pair of electrodes are butted in an optional direction of the joining members and only joining members are energized and joined, the electrodes having the elastic force as the electrode for supplying the pulse current to the joining member, are used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a joining apparatus and a joining method using pulse energization.

In recent years, a joining method using pulse energization is used for joining various members.
In this joining method using pulse energization, pulse energization is performed while pressurizing the joining member.
The pressure applied to the joining member during joining is controlled using a pressure sensor (see, for example, Patent Document 1).

However, it is difficult to join with high accuracy in a highly accurate joining member or a joining member that easily collapses when temperature is applied. This is because a pressure control mechanism that can respond immediately to a signal from the pressure sensor cannot be realized.
In the invention described in Patent Document 1, pressure control is performed by driving a ball screw with an electric motor. However, a time lag occurs in the pressure control due to thermal expansion of the joining member accompanying a temperature rise during joining, and There was a problem of causing collapse.

JP 2003-112264 A

  The present invention eliminates such conventional problems, and reduces the pressure applied to the joining member without causing a time lag even if the joining member thermally expands due to the temperature rise during joining, and the joined body without losing accuracy. It is an object of the present invention to provide a joining apparatus and a joining method by pulse energization that can obtain the above.

If the pressure applied during joining is reduced as much as possible, the joining member will not collapse due to thermal expansion due to temperature rise, but if the initial pressure is abnormally low, a slight gap will occur between the electrode and the joining member, causing abnormal heat generation. I found out that In this case, the joining member has a problem that it melts due to this abnormal heat generation.
On the other hand, if the initial pressure is increased in order to avoid this abnormal heat generation, the joining member thermally expands at an elevated temperature, and the pressure further increases and the joining member is crushed.
Therefore, the present inventor has intensively studied to achieve the above object.
As a result, the present inventor has provided elasticity to the electrode structure that supplies the pulse current to the joining member, so that the initially set pressure can be maintained even when the temperature expands due to the temperature rise, and the joining member is crushed. Has been found to be able to be avoided, and the present invention has been completed based on this finding.
Furthermore, the present inventor has found that by using carbon for the electrode structure in contact with the joining member, it can be used without deterioration of the electrode structure up to a high temperature exceeding 1000 ° C., and the present invention is completed based on this knowledge. It came to.

The present invention according to claim 1 is a pair of electrodes for supplying a pulse current to a joining member that can be energized, a pulse current generator for energizing the electrode with a pulse current, and a pressurizing means for pressurizing the electrode In the joining apparatus by pulse energization provided with the above, the joining apparatus by pulse energization in which the electrode is an electrode having elasticity is provided.
The present invention according to claim 2 provides the joining apparatus according to claim 1, wherein carbon is used for at least part of the material of the electrode having elasticity.
According to a third aspect of the present invention, a pair of electrodes are arranged in an arbitrary direction of the bonding member while pressing the bonding surfaces of the bonding members that can be energized to each other and pressurizing at a predetermined pressure so as to closely contact the butted bonding surfaces. In the joining method by pulse energization in which only the joining member is subjected to pulse energization, an electrode having elasticity is used as an electrode for supplying a pulse current to the joining member. To do.
The present invention according to claim 4 provides the joining method according to claim 3, wherein carbon is used as at least a part of the material of the electrode having elasticity.

According to the first and second aspects of the present invention, it is easy to join a joining member with strict dimensional accuracy, and the joining member can be prevented from being crushed without requiring an expensive device such as a pressure sensor or a feedback device. A joining apparatus using pulse energization is provided.
Further, according to the third and fourth aspects of the present invention, it is easy to join the joining member with strict dimensional accuracy, and the collapsing of the joining member is avoided without requiring an expensive device such as a pressure sensor or a feedback device. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
According to the first aspect of the present invention, a pair of electrodes for supplying a pulse current to an energized joining member (hereinafter simply referred to as “joining member”), and a pulse for energizing the electrode with a pulse current. In a joining apparatus by pulse energization provided with a current generator and a pressurizing means for pressurizing the electrode, the joining apparatus by pulse energization, in which the electrode is an electrode having elasticity.
FIG. 1 is an explanatory view showing an embodiment of a joining apparatus using pulse energization according to the first aspect of the present invention.
In FIG. 1, the code | symbol 1 shows the joining member and the code | symbol 2 has shown the electrode. Reference numeral 3 represents a pulse current generator, and reference numeral 4 represents a pressurizing means (for example, an air cylinder or a hydraulic cylinder) for pressurizing the electrode.
In FIG. 1, reference numeral 2A denotes an upper ram electrode, and reference numeral 2B denotes a lower ram electrode. However, the upper and lower ram electrodes may be integrated with the upper and lower electrodes 2, respectively. Reference numeral 5 denotes a vacuum chamber that can be evacuated. The vacuum chamber is not limited to a vacuum atmosphere, but can be an inert gas atmosphere as necessary.

In FIG. 1, the joining member 1 is sandwiched between elastic electrodes 2 and 2, which are in contact with the upper and lower ram electrodes 2A and 2B, respectively.
The lower ram electrode 2B is configured to lift and pressurize the joining member 1 by a pressurizing means for pressurizing the electrode provided at the lower portion thereof. Examples of the pressurizing means for pressurizing the electrode include an air cylinder and a hydraulic cylinder.
Although FIG. 1 shows a case where a pair of upper and lower electrodes are provided, the present invention is not limited to this. For example, a large number of joined bodies can be obtained at a time by using the elastic electrode featured in the present invention between the upper and lower electrodes arranged in parallel.

In the invention which concerns on Claim 1, it is necessary to use the electrode 2 which has elastic force as an electrode which supplies a pulse current to a joining member.
As a pulse energization joining apparatus, a pair of electrodes for supplying a pulse current to a joining member, which is basically used, except for “an electrode having elastic force”, which is characterized by the method of the present invention, It is possible to use a pulse energization joining device provided with a pulse current generator for energizing the electrode with a pulse current and a pressurizing means for pressurizing the electrode. The present invention is not necessarily limited to the pulse current bonding apparatus as shown in FIG.

Examples of the electrode 2 having elasticity include those using a spring such as a helical spring. The spring material may be made of stainless steel, but is preferably made of carbon because it has high heat resistance and the material itself has some elasticity. In the case of one-time use, the electrode 2 having elastic force can be obtained by stacking carbon sheets.
That is, as the electrode 2 having elastic force in the invention according to claim 1, as described in claim 2, carbon is preferably used for at least a part of the material of the electrode having elastic force. By using carbon for the electrode structure in contact with the bonding member, the electrode structure can be used up to a high temperature exceeding 1000 ° C. without deterioration of the electrode structure.
Hereinafter, the “electrode having elasticity” may be simply referred to as “elastic electrode”. The “carbon electrode having elasticity” may be simply referred to as “elastic carbon electrode”.

Usually, a spring member 7 (upper spring member 7A and lower spring member 7B) made of a carbon block flat plate or the like is disposed above and below such a spring as the electrode 2 having elastic force. FIG. 2 is an explanatory cross-sectional view showing an electrode 2 in which spring members 7 (upper spring member 7A and lower spring member 7B) made of carbon block flat plates are arranged above and below such a spring 6. As shown in FIG.
In addition to the spring 6 alone, a material in which a carbon chip or carbon fiber 8 is filled around the spring 6 can be used as the electrode 2 having elasticity. FIG. 3 shows an electrode 2 in which a carbon chip or carbon fiber 8 is filled around such a spring 6, and a spring member 7 (an upper spring member 7A and a lower spring member made of a flat carbon block) is formed above and below the electrode. FIG. 7B is a cross-sectional explanatory view showing the arrangement of 7B).

Furthermore, without using a spring, a carbon chip or carbon fiber filled between an upper spring member 7A and a lower spring member 7B made of a flat plate of a carbon block may be used as the electrode 2 having elastic force. it can. FIG. 4 is an explanatory cross-sectional view showing an electrode 2 in which a carbon chip or carbon fiber 8 is filled between an upper spring member 7A and a lower spring member 7B made of a flat carbon block without using a spring 6. is there.
Since the carbon chip or the carbon fiber 8 has elasticity when it becomes a lump and becomes a path for the pulse current at the time of bonding, the pulse current can be supplied to the bonding member 1 more efficiently.
Further, since the carbon chip or the carbon fiber 8 generates heat by a pulse current, it is possible to supply heat to the bonding member 1.

Usually, the outer periphery of the spring member 7 (upper spring member 7A and lower spring member 7B) made of a carbon block flat plate, the spring 6, the carbon chip or the carbon fiber 8 has a thickness of 0.2 mm as shown in FIG. It is wound twice with a carbon sheet 9 of a degree.
Of the spring members 7 (upper spring member 7A and lower spring member 7B) made of a carbon block flat plate or the like, one spring member is fixed by being bound with a wire made of SUS or the like, and the other spring member is free. It is preferable to be able to move up and down.

  As shown in FIG. 6, the electrode 2 is not only one in which the spring members 7 (the upper spring member 7A and the lower spring member 7B) made of the carbon block flat plate 7 are arranged above and below the spring 6, as shown in FIG. As described above, the lower spring member 7B may have a shape in which the carbon block is hollowed out instead of the flat plate of the carbon block. In this case, the carbon sheet 9 wound around the outer periphery can be omitted.

Further, as shown in FIGS. 7 to 10, either one or both of the upper and lower spring members 7 (upper spring member 7 </ b> A and lower spring member 7 </ b> B) is not a flat plate of the carbon block, but a central portion of the flat plate of the carbon block. It can be made into the shape where the protrusion 10 was provided.
6 to 10, any one of the upper and lower spring members 7 (the upper spring member 7 </ b> A and the lower spring member 7 </ b> B) can move up and down.
FIG. 7 shows an example in which a lower spring member 7B having a shape in which a protrusion 10 is provided at the center of a flat plate of the carbon block is used instead of the flat plate 7 of the carbon block. In the case of FIG. 7, two springs 6 are used.
FIG. 8 shows an example in which one spring 6 is used in FIG.
FIG. 9 shows an example in which, in the example of FIG. 7, not only the lower spring member 7B but also the upper spring member 7A has a shape in which a protrusion 10 is provided at the center of a flat plate of the carbon block.
FIG. 10 is a cross-sectional explanatory view showing an example in which one spring 6 is used in FIG. That is, FIG. 10 shows an example in which, in the example of FIG. 8, not only the lower spring member 7B but also the upper spring member 7A has a shape in which a protrusion 10 is provided at the center of the flat plate of the carbon block. Yes. In other words, one spring 6 may be provided surrounding the protrusion 10, or two or more springs 6 may be used with the protrusion 10 interposed therebetween.

  As shown in FIGS. 7 to 10, one or both of the upper and lower spring members 7 (upper spring member 7 </ b> A and lower spring member 7 </ b> B) is not a flat plate of the carbon block, but a projection 10 at the center of the flat plate of the carbon block. In the case of the shape provided with, it functions as a so-called door stop, and has a structure in which the spring member 7 is pushed by the protrusion 10 before the spring 6 is completely compressed. Therefore, it is effective when the initial weight needs to be increased.

  In the present invention according to claims 1 and 2, a generally used pulse current bonding apparatus can be used as it is, except for the “electrode having elasticity” as described above.

Next, the present invention according to claim 3 provides a joining method by pulse energization characterized by using an electrode having elasticity as an electrode for supplying a pulse current to the joining member in the joining method by pulse energization. The present invention according to claim 4 provides the joining method according to claim 3, wherein carbon is used as at least part of the material of the electrode having elasticity.
Also in the present invention according to claims 3 and 4, basically the generally used pulse energization joining method can be used as it is, except for the “electrode having elasticity” as described above. Basically, the conditions in the pulsed current joining method generally used can be adopted as the conditions for the pulsed current joining.
The pulse energization joining method is basically a joining method using self-heating by pulse energization.
The “electrode having elasticity” is as described in the present invention according to claims 1 and 2 above.

  The pulse current bonding is usually performed in a vacuum or an inert gas atmosphere. That is, it is desirable to perform a pulse energization bonding in a vacuum atmosphere, but it may be performed in an inert gas atmosphere such as nitrogen gas or argon gas.

  The joining member is not particularly limited as long as it can be energized, but it is preferable to use a member subjected to dimensional processing with extremely high accuracy. Moreover, it is desirable that both surfaces or one surface of the joining member be cleaned in advance to remove dirt and adhered matters. Specifically, for example, it is desirable to clean both surfaces or one surface of the bonding member using an ultrasonic solvent or the like and an organic solvent such as isopropanol. Alternatively, both surfaces or one surface of the bonding member may be cleaned by sputtering, cleaning liquid, or the like, and bonding may be performed by removing foreign matter, oxide film, passive film, or the like at the bonding interface. Furthermore, interface modification by plasma treatment under an argon atmosphere or plasma irradiation treatment under atmospheric pressure may be performed on both surfaces or one surface of the bonding member. By performing such interface modification by plasma treatment in an argon atmosphere, the oxide film and the like at the interface can be removed, and the bonding can be facilitated.

Furthermore, as a joining member, the thing by which the mirror surface thru | or smoothing process was given to both surfaces or one side of the joining surface is preferable. Examples of a method for applying a mirror surface or a smoothing treatment to both surfaces or one surface of the joint surface include known methods such as polishing and buffing. It is desirable to finish the surface roughness of the joining surface to a mirror surface or a smooth surface of 0.5 μm or less by this treatment.
In joining by pulse energization, a joining member may perform exact positioning using a V block etc. as needed.

In the present invention, the reason why an electrode having elasticity is used as an electrode for supplying a pulse current to the bonding member 1 is as follows.
That is, the temperature of the bonding member 1 is increased during pulse current bonding, and when the temperature exceeds a certain temperature, the bonding member 1 is softened and the yield stress is attenuated. When the joining member 1 is softened, the applied pressure is dispersed and lateral deformation occurs. When the deformation which swells laterally occurs, the pressure is dispersed in the lateral direction and does not apply in the joining direction, so that the responsiveness of the applied pressure is deteriorated and a good result cannot be obtained. Therefore, it is desirable to gradually lower the applied pressure in a range below that as the joining member 1 rises in temperature and the yield stress attenuates. That is, it is good to adjust to the joining pressure with the most appropriate responsiveness of the yield stress and the pressure.
In addition, since the bonding member 1 generates heat and expands due to heating during pulse energization, it is necessary to consider an increase in pressure due to heat expansion.
For this reason, compared with the initial stage of pulse energization joining, the applied pressure is lowered in the subsequent stage. Thereby, the fall of joining force can be prevented and joining force can be increased compared with the case where adjustment of applied pressure is not performed.
However, in order to appropriately measure the expansion due to heating of the joining member 1 or to appropriately measure the attenuation of the yield stress, and to weaken the applied pressure one by one, an expensive device such as a pressure sensor or a feedback device is required. And In addition, there is a problem that a time lag occurs in the pressure control due to thermal expansion of the joining member accompanying a temperature rise during joining, and the joining member is crushed.
In the present invention, by using the electrode 2 having elastic force, an expensive device such as a pressure sensor or a feedback device is not required, and there is a time lag in the pressure control due to the thermal expansion of the joining member accompanying the temperature rise at the time of joining. And the rise of the pressurizing force by the heating expansion at the time of pulse energization can be appropriately suppressed without causing the problem of causing the joining member to be crushed. As a result, a product with good dimensional accuracy can be finished.

That is, in a stage after the initial stage of pulse energization joining, the joining member 1 becomes considerably hot and expands due to self-heating, so it is necessary to weaken the applied pressure by the amount of expansion.
In this case, if the electrode has no normal elasticity, it is necessary to appropriately measure the amount of expansion due to heating and to weaken the applied pressure one by one. For this purpose, expensive devices such as pressure sensors and feedback devices are required. In addition, there is a problem that a time lag occurs in the pressure control due to thermal expansion of the joining member accompanying a temperature rise during joining, and the joining member is crushed.
However, when an electrode (elastic carbon electrode) 2 having such an elastic force is used, the expansion due to heating is absorbed, and so-called increase in pressure caused by heating expansion during pulse energization is automatically suppressed to some extent. be able to. Moreover, the uneven pressure applied to the joining member 1 can be prevented, and a finish with higher dimensional accuracy can be achieved.
If a normal carbon electrode is used, the dimensions of each part of the joining member 1 vary, and accuracy cannot be ensured. However, by using such an elastic carbon electrode 2, a pressure sensor, a feedback device, etc. Without requiring an expensive device, it is possible to eliminate a deviation in the dimensions of each part of the joining member 1 and achieve a finish with high dimensional accuracy. In addition, by using an electrode having such an elastic force, a pressure change between the electrodes due to a negative pressure in the vacuum chamber can be absorbed.

  In the present invention, in order to prevent heat diffusion of the bonding member 1 and to prevent temperature unevenness, a single or multiple reflectors can be installed on the outer periphery of the bonding member 1.

Hereinafter, the conditions of pulse energization will be described with reference to the present invention according to claims 3 and 4.
According to the third and fourth aspects of the present invention, the joining surfaces of the joining members 1 that can be energized are abutted to each other, and are pressed at a predetermined pressure so that the abutted joining surfaces are brought into close contact with each other. The present invention relates to a joining method by pulse energization in which a pair of electrodes 2 are applied and only the joining member 1 is pulsed and joined.
The present invention according to claims 3 and 4 is characterized in that, in such a joining method by pulse energization, an electrode having elasticity is used as the electrode 2 for supplying a pulse current to the joining member 1.
Here, as an electrode having elasticity as the electrode 2 for supplying a pulse current to the bonding member 1, those described in the present invention according to claims 1 and 2 can be used.

In the present invention according to claims 3 and 4, as a pulse energization joining method, a generally used pulse energization joining method can be used.
That is, the bonding surfaces of the bonding members 1 are abutted with each other, and a pair of electrodes 2 are applied in an arbitrary direction of the bonding member while applying pressure to the bonding members 1 so that the butted bonding surfaces are brought into close contact with each other. Energize.
In FIG. 1, the electrode direction and the bonding interface pressure direction are the same, but the electrode direction and the bonding interface pressure direction may be different or the same.
The shape of the electrode 2 in contact with the bonding member 1 may be a disk shape, a roller shape that can be energized, or may be engraved according to the shape of the bonding member 1.

Here, “only energize” means not using anything other than the joining member, and in other words, carbon that surrounds the joining member, which is generally used in the spark plasma sintering method. This means that no type is used.
By not using a carbon type that can be energized to enclose a joining member other than the joining member between the electrodes, a decrease in current density due to the use of a carbon type that can be energized is prevented, and direct temperature control of the band part on the side of the joining member is achieved. In addition, it enables efficient joining, and at the same time, it eliminates the shape restrictions of joining members that have only been able to be made only in the shape of a disk or a cylinder in the carbon mold so far. The joint range was expanded.

At this time, it is possible to energize the vicinity of the butted joint surfaces while forcibly heating from the outside. Thereby, a long member etc. can be joined efficiently in a short time.
The means for forcibly heating from the outside is not particularly limited, but induction heating methods such as microwave induction heating, millimeter wave induction heating, and submillimeter wave induction heating are most preferable. In addition, high-frequency heating and the like can be mentioned, and one of these can be used alone, or two or more can be used in combination.
The heating time for forcibly heating from the outside may generally be 60 minutes or less.

As the pulse current, direct current is normally used. In the present invention according to claims 3 and 4, the duty ratio, that is, the ON / OFF ratio of the pulse (ON / ON + OFF) is 86 to 99.9%, preferably 90 to 90%. It is preferable to flow a 99.9% pulse current.
It is preferable that a pulse current having a high ON time ratio of such a pulse is supplied, the temperature of the entire member is gradually increased by self-heating, and the temperature of the entire member is increased as uniformly as possible.

  Moreover, as a pulse current, the thing of the range of 100-50000A, Preferably 300-30000A is used, and a voltage is 100V or less. In the present invention, such energization processing using a pulse current can be performed in two stages.

In the present invention according to claims 3 and 4, it is preferable to perform heat treatment at a predetermined temperature after joining by pulse energization.
During bonding by pulse energization, the temperature is raised to a predetermined temperature by self-heating, but since the heat treatment is not due to pulse energization, it is necessary to raise the temperature by external heating to the predetermined temperature.

In the present invention according to claims 3 and 4, as described above, the current density is increased by passing only the joining member 1 without using the carbon mold surrounding the joining member, and a pulse current is caused to flow between the joining interfaces. As a result, a joining process is performed by applying a pulse.
At the time of joining by pulse energization, the above-described pulse current is passed and energized while forcibly heating from the outside as necessary, and 65% or more of the melting point (1083 ° C.) of the joining member, for example, a copper ring-shaped cell. The temperature is raised by self-heating to less than 90%. More specifically, as described above, the temperature is raised to 700 ° C. or more and 1000 ° C. or less by self-heating. By holding the temperature (peak temperature) when this temperature band is reached for about 0.5 to 60 minutes, the joining process by pulse energization is performed. In this case, a vacuum atmosphere is desirable, but it may be performed in an inert gas atmosphere such as nitrogen gas or argon gas.

In this invention which concerns on Claim 1, after performing the joining process by pulse energization in this way, it heat-processes on predetermined conditions. Since this heat treatment causes mutual diffusion, this heat treatment can also be referred to as “interdiffusion bonding treatment”. By performing such an interdiffusion bonding process, it is possible to bond completely and in a short time. Since it may be considered that a single interdiffusion bonding process does not completely bond, the interdiffusion bonding process may be performed not only once but multiple times.
In the past, so-called tempering treatment has been performed after sintering, so that joining in a solid state has been performed, but this and this interdiffusion joining treatment are completely different. No other interdiffusion bonding process in pulse energization has been found so far.

  Such an interdiffusion bonding process can be performed at 70% or more and less than 90% of the melting point (1083 ° C.) of a bonding member, for example, a copper ring-shaped cell. More specifically, as described above, the temperature is 800 ° C. or higher and 1000 ° C. or lower. This temperature is the same as or slightly higher than the temperature during the interatomic micromelting. As described above, since this heat treatment is not performed by pulse energization, it is necessary to increase the temperature by external heating.

  The “temperature” in the present invention refers to the temperature when the surface in the vicinity of the joint surface, that is, the surface of the joint surface side band is measured using, for example, an infrared pyroscope, a radiation thermometer, a thermocouple, or the like. At present, the temperature of the bonding interface cannot be actually measured. The bonding interface is actually in a very small range, and it is assumed that the temperature above the melting point is repeated in a very short time, and the plastic flow is promoted by repeating the high-temperature and high-pressure vapor state of the material components in the minute local area.

  When this interdiffusion bonding process is performed, no pulse current flows. Further, although pressurization is not particularly necessary, pressurization from the previous stage may be performed as it is. When performing this interdiffusion bonding treatment, the temperature (peak temperature) when the temperature reaches 800 ° C. or higher and 1000 ° C. or lower is maintained for 0.5 to 3 hours, preferably 0.5 to 1.5 hours. Is desirable. Thereby, it can join very strongly and in a short time.

In the present invention according to claims 3 and 4, after performing the bonding process by pulse energization as described above, the interdiffusion bonding process of performing heat treatment under a predetermined condition is subsequently performed, that is, the bonding process by pulse energization is performed. It is preferable to carry out an interdiffusion bonding treatment after the phase state.
The interdiffusion bonding process after the liquid phase state is used refers to the mutual diffusion bonding process after the liquid phase state in pulse energization, and is different from the conventionally known liquid phase diffusion bonding. The conventionally known liquid phase diffusion bonding refers to a phenomenon that occurs when a low melting point member is inserted between the bonding surfaces, and clearly differs from the mutual diffusion bonding processing after the liquid phase state described here. However, it has been found that such diffusion in the liquid phase state occurs even in pulse energization. In addition, this “interdiffusion bonding treatment after being in a liquid phase state” is “solid phase diffusion” in which it is not melted but diffused in a solid phase state in that it is melted and then liquid phase state is allowed to cause mutual diffusion. Are clearly different.

  According to the heat treatment (interdiffusion bonding treatment) after making the liquid phase state in such pulse energization, in the torsion test or the like, a strong bonding enough to be recognized as having the same characteristics as the base material is obtained, The joining member 1 can be joined extremely firmly and reliably in a short time and at low cost.

  The present invention is as described above. As described above, according to the present invention, it is possible to easily join a joining member with strict dimensional accuracy, and it is possible to avoid crushing the joining member without requiring an expensive device such as a pressure sensor or a feedback device. In addition, after completion of joining, desired various known heat treatments can be performed.

EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not restrict | limited at all by these.
Example 1
(1) Joining Pulse energization joining apparatus as shown in FIG. 1, that is, a pair of electrodes 2 for supplying a pulse current to the joining member 1, a pulse current generator 3 for energizing the electrode 2 with a pulse current, and the electrodes 2 and pressurizing means 4 for pressurizing, and further, joining by pulse energization was performed using a joining apparatus by pulse energization provided with a vacuum chamber 5.
As the electrode 2, as an upper electrode, an elastic carbon electrode having a structure in which a carbon chip 8 is filled around a spring 6 as shown in FIGS. 3 and 5 and a carbon block flat plate 7 is disposed above and below the carbon chip 8. (Diameter 100 mm × Thickness 93 mm) was used. Further, as the lower electrode, an elastic carbon electrode (diameter: 100 mm × thickness: 67 mm) having a structure in which the carbon chip 8 is filled between the flat plates 7 of the carbon block without using the spring 6 as shown in FIG. Using.

Further, as the joining member 1, ten oxygen-free copper ring-shaped cells having a surface roughness of 0.5 μm or less and having a cavity having a diameter of 20 mm in the center of a disc having a diameter of 61 mm and a thickness of 8.74 mm are used. It was. Note that the bonding area is 25 cm ² .
The ring cell 1 was first washed with isopropanol using ultrasonic waves.
Subsequently, 10 stages of the ring-shaped cells 1 were stacked, and a weight of 100 kg was applied to perform joining by pulse energization (first stage joining). The pulse ratio was 98: 2. At this time, the temperature rose to a maximum of 310 ° C. The pulse current was 400A.
During the above operation, the atmosphere was kept at a vacuum of 10 Pa or less.
Thereafter, in a state where a pressure of 100 kg is applied, a pair of electrodes is applied to both ends of the joining member 1, and only the joining member 1 is energized to increase the current density, and the pulse ratio is 98: 2 between the joining interfaces. By applying a pulse current (600 A), joining by pulse energization (second stage joining) was performed. The junction temperature (joint side band surface temperature) at this time was 800 ° C., and the holding time was 3 minutes.
At this time, the reflector was wrapped around the joining member 1 in a single layer and covered.

Thereafter, pulse energization was stopped and heat treatment was performed at a temperature of 850 ° C. by external heating.
During the above operation, the atmosphere was kept at a vacuum of 5 Pa or less.
That is, the ten-stage bonding member 1 after the inter-atomic minute melting in the liquid phase was subjected to an interdiffusion bonding process by holding the ten-stage bonding member 1 at a temperature of 850 ° C. for 110 minutes.
In this way, a 10-stage ring-shaped cell joined body was produced.

(2) Torsional fracture test About the test piece cut out from the 10-stage ring-shaped cell joined article thus obtained, a torsional fracture test was performed using a wrench so as to twist the joint surface. FIG. 11 is a photographic image showing a state after a torsional fracture test is performed on a test piece cut out from a 10-stage ring-shaped cell joined body. FIG. 11 also shows a ten-stage ring-shaped cell joint after the test piece is cut out.
As a result, as shown in FIG. 11, even when both the joining pieces were greatly deformed and twisted with a wrench, they were not peeled and broken from the joined portion.

(3) Dimensional change measurement results Next, with respect to the 10-stage ring-shaped cell joined body thus obtained, the dimensional changes at the four measurement sites (A, B, C, D) shown in FIG. Examined. The results are shown in FIG.
According to FIG. 13, it can be seen that the dimensional change is remarkably small by using the elastic carbon electrode as in the present invention. That is, the deviation is only within 8 μm (size ratio is 0.009% or less), and it can be seen that the finish can be made with very high dimensional accuracy.

Comparative Example 1
In Example 1, except that a normal carbon electrode was used instead of the elastic carbon electrode, bonding was performed in the same manner as in Example 1 (1), and dimensional change was measured in the same manner as in Example 1 (3). . The results are shown in FIG.
As can be seen from FIG. 14, the dimensional change is large when a normal carbon electrode is used. That is, it can be seen that the deviation is large and the dimensional accuracy varies.
Also, looking at the current value at this time, 2800 A was also necessary.

From the above results, it can be seen that by using the elastic carbon electrode as in the present invention, the dimensional change is remarkably small and the finish can be made with very high dimensional accuracy.
Also, when looking at the current value at this time, when a normal carbon electrode was used, 2800 A was required, whereas when an elastic carbon electrode was used as in the present invention, it was 600 A. It can be seen that it can be joined and a significantly lower current value is sufficient.
This is presumably because the elastic carbon electrode of the present invention has a spring structure and the current density is increased and heat is generated, so that the heat supply to the joining member is facilitated.

According to the present invention, it is easy to join a joining member with strict dimensional accuracy, and it is possible to avoid crushing the joining member without requiring an expensive device such as a pressure sensor or a feedback device.
Therefore, the present invention can be used extremely effectively for joining of joining members having particularly strict dimensional accuracy. Further, for example, by using the elastic electrode between the electrodes provided in pairs in parallel, a large number of joined bodies can be obtained at one time, and the productivity can be remarkably increased.

It is explanatory drawing which shows the one aspect | mode of the joining apparatus by the pulse electricity supply of this invention concerning Claim 1. FIG. 6 is a cross-sectional explanatory view showing an electrode 2 in which spring members 7 (upper spring member 7A and lower spring member 7B) made of carbon block flat plates are arranged above and below a spring 6; As the electrode 2, a carbon chip or carbon fiber 8 is filled around the spring 6, and a spring member 7 (upper spring member 7 </ b> A and lower spring member 7 </ b> B) made of a flat carbon block is disposed above and below the electrode 6. FIG. FIG. 5 is an explanatory cross-sectional view showing an electrode 2 in which a carbon chip or carbon fiber 8 is filled between an upper spring member 7A and a lower spring member 7B made of a flat carbon block without using a spring 6; In the electrode shown in FIG. 3, a carbon sheet 9 is wound around the outer periphery of a spring member 7 (upper spring member 7A and lower spring member 7B) made of a carbon block flat plate, spring 6, carbon chip or carbon fiber 8. It is explanatory drawing which shows. In the electrode shown in FIG. 2, it is sectional explanatory drawing which shows the example using the shape which hollowed the carbon block instead of the flat plate of the carbon block as the lower side spring member 7B. 2 is an explanatory cross-sectional view showing an example in which the lower spring member 7B has a shape in which a protrusion 10 is provided at the center of a flat plate of the carbon block, instead of the flat plate 7 of the carbon block. is there. In FIG. 7, it is sectional explanatory drawing which shows the example using one spring 6. In FIG. In the electrode shown in FIG. 2, not only the lower spring member 7B but also the upper spring member 7A is an explanatory cross-sectional view showing an example using a shape in which a protrusion 10 is provided at the center of a flat plate of a carbon block. . In FIG. 9, it is sectional explanatory drawing which shows the example using one spring 6. In FIG. It is a photograph image figure which shows the state after performing a torsional fracture test about the test piece cut out from the 10-stage ring-shaped cell joined body in Example 1. FIG. It is explanatory drawing which shows the measurement site | part (A, B, C, D) of the dimensional change of each site | part in Example 1. FIG. 4 is a graph showing measurement results of dimensional changes at respective parts in Example 1. 10 is a graph showing measurement results of dimensional changes at respective parts in Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joining member 2 Electrode 2A Upper ram electrode 2B Lower ram electrode 3 Pulse current generator 4 Pressurizing means 5 Vacuum chamber 6 Spring 7 Spring member 7A Upper spring member 7B Lower spring member 8 Carbon chip or carbon fiber 9 Carbon sheet 10 Protrusion

Claims (4)

  An apparatus for joining by pulse energization, comprising a pair of electrodes for supplying a pulse current to an energizable joining member, a pulse current generator for energizing the electrodes with a pulse current, and a pressurizing means for pressurizing the electrodes A joining apparatus by pulse energization in which the electrode is an electrode having elasticity.   The bonding apparatus according to claim 1, wherein carbon is used for at least a part of a material of the electrode having elasticity.   While joining the joining surfaces of energizable joining members to each other and applying a predetermined pressure so that the joined joining surfaces are brought into close contact with each other, a pair of electrodes are applied in an arbitrary direction of the joining member, and a pulse is applied only to the joining member. In the joining method by pulse energization for energization and joining, an electrode having elasticity is used as an electrode for supplying a pulse current to the joining member. 4. The bonding method according to claim 3, wherein carbon is used for at least a part of the material of the electrode having elasticity.

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