JP6528257B1 - Brazing bonding method of alumina dispersion strengthened copper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize braze bonding of alumina dispersion strengthened copper. SOLUTION: GlidCop (registered trademark) which is an alumina dispersion strengthened copper and other metals are prepared, and after mirror-finishing the surfaces to be joined, a brazing alloy BNi-6 which is a nickel alloy containing 11% of phosphorus. Insert the material and apply pressure. In this state, heat treatment is performed at a heat treatment temperature of 960 ° C. for 10 minutes. Then, after natural cooling sufficiently, quenching is performed using nitrogen gas. By doing this, it is possible to realize brazing connection of alumina dispersion strengthened copper and other metals. [Selected figure] Figure 1

Description

  The present invention relates to a method of brazing and joining alumina dispersion strengthened copper.

Tungsten may be used at locations exposed to high temperatures, such as divertors in fusion reactors, but copper is used to further cool the tungsten. Copper has the property of high thermal conductivity, but also has the problem of low mechanical strength, and copper alloys are often used for the purpose of overcoming this. Such oxide dispersion strengthened copper, which is a type of such copper alloy, has high strength but can not be joined. In particular, in the case of alumina dispersion-strengthened copper in which alumina is dispersed as an oxide, mutual bonding has not yet been realized.
As a technique of joining alumina dispersion strengthened copper, Patent Document 1 discloses a technique of laminating alumina dispersion reinforced copper and oxygen free copper so that oxygen free copper is present on the surface and enabling brazing. Patent document 2 discloses the technique which enables brazing joining by forming plating layers, such as copper and silver, on the surface of alumina dispersion strengthening copper.

Unexamined-Japanese-Patent No. 2-243331 JP, 2010-120034, A

The prior art disclosed in Patent Document 1 and Patent Document 2 do not allow bonding of alumina dispersion strengthened copper itself. By forming a laminated structure as in Patent Document 1 or forming a plating layer as in Patent Document 2, the processability of the alumina dispersion-strengthened copper is limited, and the application thereof is limited.
On the other hand, it is known that bonding by brazing can be realized between alumina dispersion strengthened copper and a metal having a high melting point such as tungsten. However, there is no guarantee that even if other metals can be brazed to tungsten, it is not guaranteed that other metals can be brazed as well, in fact, alumina dispersion-strengthened copper and metals other than tungsten There was no realized brazing joint between them.
An object of the present invention is to provide a technique for realizing brazing and joining of alumina dispersion strengthened copper and another metal, in view of such problems.

The present invention is a bonding method of brazing and bonding a first member made of alumina dispersion strengthened copper and a second member made of a metal to be bonded,
(A) preparing a brazing material containing phosphorus;
(B) a heat treatment step of sandwiching the brazing material with the first member and the second member and heating the brazing material at a predetermined heat treatment temperature for a predetermined time;
(C) cooling the joined first and second members after the heat treatment step;
The bonding metal is a metal whose melting point is lower than tungsten and higher than the heat treatment temperature,
The heat treatment temperature can be configured as a bonding method set in a range lower than the melting point of copper and higher than the melting point of copper lowered by the eutectic reaction of phosphorus and copper.

The inventor of the present invention has made it possible to braze the joining metal having a melting point lower than tungsten (melting point 3422.degree. C.), specifically alumina dispersion strengthened copper (melting point 1085.degree. C.) and stainless steel (melting point 1400.degree. As a result of experimenting, it has been found that brazing can be performed according to the above-described process and heat treatment temperature. Although the principle that enables brazing can not always be clarified, the melting point of the electrode surface of alumina dispersion strengthened copper in contact with the brazing material is eutectic with phosphorus by using a brazing material containing phosphorus. It is believed that the reaction is slightly lowered by the reaction and that diffusion occurs with the metal to be joined at the joint surface. Since the heat treatment temperature is lower than the melting point of copper, the first member does not melt except at the bonding portion. Therefore, melting occurs only at the joint portion, and brazing of the first member and the second member is realized.
Although it is alumina dispersion strengthening copper and stainless steel which were confirmed by experiment, it is thought that the brazing joint with tungsten was also realized by the same principle. Therefore, the inventor has found, as a result of experiments, that the brazing can be realized by the method of the present invention to the bonding metal having a melting point lower than that of tungsten.

In the present invention, the phosphorus content of the brazing material can be determined arbitrarily, but in the experiment, a nickel alloy having a content of 11%, specifically, BNi-6 was used.
The heat treatment time can be set experimentally based on the type of metal to be joined and the result of bonding. In the experiment, it was 10 minutes, but it may be shorter.
Further, the shape and dimensions of the first member and the second member do not matter.
The metal to be joined is a metal having a melting point lower than that of tungsten, and, for example, molybdenum (melting point 2623 ° C.), iridium (melting point 2466 ° C.), etc. can be considered.
GlidCop (registered trademark) can be used as the alumina dispersion strengthened copper.

In the present invention,
The metal to be joined may be alumina dispersion strengthened copper or stainless steel.

  As described above, it was confirmed by experiments that brazed bonding is possible for these metals to be bonded. Such a result is also at least a brazing joint which has not been realized at least conventionally.

In the present invention,
The metal to be joined is alumina dispersion strengthened copper,
The heat treatment temperature may be 960 ° C. as a bonding method.

  More specifically, when alumina dispersion strengthened copper is used as a metal to be joined, the heat treatment temperature can be set to 960 ° C. However, it is not limited to such temperature.

In the present invention,
(D) Prior to the heat treatment step, the method further comprises the step of surface finishing the surfaces to be joined of the first member and the second member to a fine mirror surface,
The brazing material in the heat treatment step may have a thickness of 1 to 100 micrometers.

  Although the surface finish and the thickness of the brazing material during brazing can be arbitrarily determined, it has been found that setting as in the above-described embodiment can achieve brazing with excellent adhesion. The thickness is more preferably 38 to 76 micrometers, and more preferably about 38 micrometers.

In the present invention,
In the heat treatment step, pressure may be applied to the first member and the second member in a direction in which the first member and the second member are joined.

By doing this, it is possible to further improve the adhesion of the joint portion.
The pressure may be applied in various ways.
For example, the first member and the second member may be sandwiched and pressed by a hot press, that is, a press provided in a heat treatment furnace. When this method is adopted, it is preferable to set the heat treatment process in consideration of the heat capacity of the press.
As another method, a method called hot isostatic pressing (HIP) may be adopted. Since hot isostatic pressing can apply pressure isotropically, it is useful when joining in a plurality of directions is required.

The method of applying pressure is, for example,
Providing first and second end plates fastened together and a central plate disposed between them;
Sandwiching the first member and the second member by the first end plate and the center plate;
An elastic body may be interposed between the second end plate and the central plate to apply pressure to the first member and the second member disposed between the first end plate and the central plate.

According to such a method, since pressure is applied through the plate-like first and second end plates and the central plate, there is an advantage that it is easy to apply pressure relatively uniformly to the first member and the second member. It also has the advantage of being relatively easy to apply in that it is relatively inexpensive to apply pressure and does not require the use of special equipment such as hot pressing or hot isostatic pressing.
Although the material of the plate can be selected arbitrarily, it is preferable to select a rigid material.
In addition, although an elastic body can be variously selected, it is preferable that the elastic body be a material to which an elastic force can be applied also in the heat treatment process, and for example, a carbon spring can be used.
Although the magnitude of the pressure can also be determined arbitrarily, the pressure at which a significant effect can be obtained can be, for example, 0.54 MPa.

In the case of the above embodiment,
It is preferable that the first and second end plates and the center plate have a thickness such that the pressure distribution applied to the first and second members is substantially uniform.

By so doing, pressure can be applied uniformly to the first member and the second member, and non-uniform bonding can be realized.
The specific thickness of the first and second end plates and the central plate can be determined experimentally or analytically by the size of these materials and pressure.

In the present invention,
The step (c) may be natural cooling.

Since the heat treatment temperature is very high, in the case of natural cooling, the first member and the second member are cooled over a very long time such as several hours to 48 hours. Cooling for a long time as described above has an advantage of being able to relieve the thermal stress generated by the heat treatment. The time for cooling can be determined according to the type of metal to be bonded. For example, in the case of alumina dispersion strengthened copper and a metal having a thermal expansion coefficient relatively close to each other, it has been confirmed that a cooling time of about 8 hours causes no problem.
After cooling to a temperature at which thermal expansion of both members is considered to be sufficiently alleviated, such as 100 ° C., natural cooling may be followed by forced cooling using a refrigerant.

The present invention is applicable not only to the case where there is only one type of metal to be joined, but also to the case where there are a plurality of types. In such a case, the order of joining can be determined at will.
For example,
When there are a plurality of second members made of a plurality of types of metals,
The first member may be joined sequentially from a second member formed of a metal having a thermal expansion coefficient close to that of the alumina dispersion-strengthened copper forming the first member.

  In the case of sequentially bonding a plurality of types of metals to be bonded, the metal first bonded is repeatedly subjected to heat treatment. Since the thermal stress between the first member and the second member is caused by the difference in thermal expansion coefficient between the members, if they are joined in the order of close thermal expansion coefficient as in the above embodiment, they are generated by repeated heat treatment Thermal stress can be relieved.

As a specific example of a plurality of types of bonded metals, for example,
The plurality of second members are respectively formed of alumina dispersion strengthened copper, stainless steel, and tungsten.
The first member may be joined in order of the alumina dispersion strengthened copper, stainless steel, and a second member formed of tungsten.

The present invention can be used to produce various structures, but
For example,
The first member is a member which is formed of alumina dispersion-strengthened copper and in which a refrigerant flow path of a heat remover is formed,
The second member may be a member formed of alumina dispersion-strengthened copper and covering the flow passage.

According to such a method, the refrigerant flow path can be formed inside the heat remover by using the bonding method of the present invention.
In the above embodiment, the shape of the flow path is not limited.
In the above aspect, various members may be further joined. For example, stainless steel may be joined to form a supply unit that supplies a coolant to the flow channel, and a discharge unit that discharges the flow channel from the flow channel.

The various features of the present invention described above do not necessarily have to be all-inclusive, and the present invention may be configured by partially omitting or combining them.
Further, the present invention may be configured not only as the bonding method but also as a structure based on the bonding method.

It is a flowchart which shows the process of a brazing joining process. It is explanatory drawing which shows the analysis result of the junction center vicinity. It is explanatory drawing which shows the hardness test result of a joining layer. It is explanatory drawing which shows the influence of the pressure added at the time of joining. It is explanatory drawing which shows the influence by the thickness of brazing filler metal. It is explanatory drawing which shows the joining result of GlidCop (trademark) and SUS. It is an explanatory view showing an example of manufacture of a diverter.

FIG. 1 is a flowchart showing the steps of the brazing and bonding process. In this step, first, members to be joined are prepared (step S10). In this example, GlidCop (registered trademark), which is alumina dispersion-strengthened copper, is bonded to each other. The shape of the members to be joined is optional, but it is required that the joining surfaces be mutually flat.
Next, the bonding surface is subjected to fine mirror surface finishing (step S11). In general, the surface finish is divided into coarse finish, regular finish, fine mirror finish, and mirror finish in rough order, but the fine mirror finish among these is. The reason for the fine mirror finish is as follows. When mirror bonding is performed when brazing is performed, the bonding surface may be excessively smooth and strong bonding may not be realized. On the other hand, if the surface finish is rough, in extreme terms, it will be close to joining members at points instead of faces, and strong joining may not be realized again. As a result of examining bonding with various surface finishes, the inventor has found that it is preferable to use a fine mirror finish.

Next, prepare the brazing material. In this example, BNi-6, which is a nickel alloy containing 11% of phosphorus in nickel, was used. As the brazing material, various choices are possible as long as it contains phosphorus.
Then, the brazing material is sandwiched between the members to be joined, and pressure is applied (step S13). The figure shows how to apply pressure. In the present embodiment, three steel plates are prepared. The lower end will be referred to as a first end plate (or lower plate), a center plate (or middle plate), and a second end plate (or upper plate). Then, the joining member is sandwiched between the first end plate and the center plate. Also, sandwich a carbon spring between the center plate and the second end plate. The first and second end plates are bolted together. By using such a structure, the elastic force of the carbon spring is applied to the joint member as pressure via the central plate. Although the pressure can be arbitrarily determined, it was 0.54 MPa in this example.
The carbon spring is used in the present embodiment because a material that can withstand heat treatment described later is selected. Other materials may be used.
Moreover, applying pressure is not necessarily required, and heat treatment may be performed without applying pressure. However, in order to ensure the airtightness of the joint surface, it is desirable to apply pressure.

Next, while the pressure is applied, the bonding member is heat-treated (step S14). The sequence of heat treatment is shown in the figure.
Phase A is a temperature raising phase for preheating. The temperature may be raised promptly to the target preheating temperature.
Phase B is the preheating phase. In this example, the temperature was 860 ° C. for 60 minutes. The preheating temperature and time may be determined on the basis of a furnace for heat treatment, dimensions of bonding members, temperature of heat treatment, and the like.
Phase C is a temperature raising phase up to the heat treatment temperature. The temperature may be raised promptly to the target heat treatment temperature.
Phase D is a heat treatment phase. In this example, heat treatment was performed at 960 ° C. for 10 minutes. The heat treatment temperature of 960 ° C. can be determined as follows. The bonding member of this embodiment is alumina dispersion strengthened copper, and the heat treatment temperature must be lower than 1085 ° C., which is the melting point of copper, in order to avoid melting of the member. In the present embodiment, the principle that brazing is realized is realized by melting the electrode surface of the joint member as a result of the melting point of copper decreasing due to the eutectic of phosphorus and copper contained in the brazing material it is conceivable that. Therefore, the heat treatment temperature needs to be higher than the melting point of copper at the eutectic reaction. In this example, 960 ° C. was selected as the heat treatment temperature from such a temperature range. The heat treatment time can also be determined arbitrarily. In this embodiment, it is 10 minutes, but brazing can be performed even for about 2 to 3 minutes.
Phase E is a cooling phase. In this phase, cooling is performed gradually over a long period of time to relieve thermal stress. In this example, natural cooling was performed to about 100 ° C. in about 8 hours in the furnace. The cooling time can be arbitrarily determined in the range of several hours to 48 hours, etc. in consideration of the material of the materials to be joined and the like.
Phase F is a quenching phase. Since it is judged that the thermal expansion of both the members is sufficiently relieved by the cooling of the phase E, the members may be quenched after that. In the present embodiment, cooling with nitrogen gas was performed to prevent oxidation of the members. The quenching phase is not necessarily provided, and the cooling of phase E may be continued to normal temperature.
The brazed bonding of this embodiment is realized by the above steps.

  In this example, both the heat treatment and the cooling were vacuum heat treatment and cooling in a vacuum. The term "vacuum" as used herein means a state in which the pressure in the furnace is sufficiently reduced by evacuation with a vacuum pump, and is not limited to a perfect vacuum. In other words, it may be called extremely low pressure. By thus setting the vacuum or the extremely low pressure, the oxidation of the bonding member can be suppressed. However, heat treatment and cooling may be performed at atmospheric pressure.

FIG. 2 is an explanatory view showing an analysis result in the vicinity of the bonding center. FIG. 2 (a) is an enlarged photograph of the bonding surface. The left side of the portion shown as the bonding center in the figure is the first member, and the right side is the second member. In the present embodiment, both the first member and the second member are GlidCop (registered trademark). At the center of bonding, a bonding surface is observed in a slightly linear fashion. In addition, a portion with a color change is confirmed with a width of about 1 mm across the bonding center. The portion where the color is changed is referred to as a bonding layer.
The distribution of each metal component contained in a joining member is shown in Drawing 2 (b). The position of the bonding portion is shown in the left and right direction, and the change in the content of copper, nickel, phosphorus and aluminum is shown from the top. Since the brazing material contains nickel and phosphorus and does not contain copper, if the brazing material remains in the bonding layer like an adhesive, copper is detected from the bonding layer. Not detected, or if detected, the amount should be greatly attenuated. However, as shown in FIG. 2 (b), copper is detected with almost no concentration change over the entire area. In addition, phosphorus and nickel are more significantly detected in the bonding layer than in the other regions. From these facts, it is considered that the brazing material is realized in the state of being absorbed by the base material copper in the joining layer. Moreover, since phosphorus is detected from the bonding layer, it is suggested that the eutectic reaction of copper and phosphorus is related to brazing, and as shown in the heat treatment, the melting point of copper due to the eutectic reaction It can be said that degradation is involved in the principle of achieving brazed joints. The finding that the lowering of the melting point of copper due to the eutectic reaction between copper and phosphorus as described above plays an important role in brazing and joining has not been made clear in the past, and has been clarified by experiments of the inventor.
Also, according to FIG. 2 (b), it can be seen that aluminum has no peak throughout the entire area and is uniformly detected. That is, the conditions of the heat treatment in the present example can realize brazing without any segregation of alumina in alumina dispersion strengthened copper, that is, without substantially reducing the quality of GlidCop (registered trademark) in the vicinity of the bonding layer. It can be said that
What was shown in FIG. 2 is a result when it joins only by gravity, without applying a pressure. Therefore, it was confirmed that brazing can be realized without applying pressure.

FIG. 3 is an explanatory view showing a hardness test result of the bonding layer. Fig.3 (a) shows the result at the time of joining without applying a pressure, and FIG.3 (b) has shown the result at the time of applying the pressure of 0.54 MPa. Position 0 of the horizontal axis corresponds to the bonding center.
According to FIGS. 3 (a) and 3 (b), it can be seen that the Vickers hardness is reduced in each of the bonding layers. Also, it can be seen that the bonding layer is thinner when pressure is applied (FIG. 3 (b)) than when pressure is not applied (FIG. 3 (a)). That is, by applying pressure, the portion where the Vickers hardness decreases can be kept thin, so it can be said that the decrease in the mechanical strength of the entire bonding member can be suppressed.

FIG. 4 is an explanatory view showing the influence of pressure applied at the time of bonding.
FIG. 4A shows the shape and the like of the members to be joined. The member A is a member of GlidCop (registered trademark), and the illustrated flow path is cut. The member B is a plate-like member of GlidCop (registered trademark) which covers the flow path. The periphery of the flow path is the joint between the member A and the member B.
The state which applied the pressure to each member was shown in FIG. 4 (b1) and FIG. 4 (b2). The lower plate and the upper plate are bolted together, and it is common that the joining member is sandwiched between the lower plate and the middle plate, and the carbon spring is sandwiched between the middle plate and the upper plate. Also, the elastic modulus of the carbon spring is the same. The difference is that the thickness of each plate is about 2.5 to 3.5 times that in FIG. 4 (b1) in FIG. 4 (b2).
4 (c1) and 4 (c2) show the inspection results by ultrasonic flaw detection corresponding to FIGS. 4 (b1) and 4 (b2), respectively. A state where the periphery of the flow path is viewed from above is shown. In FIG. 4 (c1), many streaky patterns can be confirmed around the flow path. This represents a point of poor bonding where the members A and B are not sufficiently joined. On the other hand, in FIG. 4 (c2), such a joint failure is not seen.
In Fig. 4 (b1) and Fig. 4 (b2), since the pressure applied by the carbon spring is the same, the pressure applied to the members should be equal, but in Fig. 4 (b2) where the plates are thick It is considered that the pressure is uneven in FIG. 4 (b1) in which each plate is thin, while it is uniformly applied. Thus, it is preferable that the thickness of the plate used to apply the pressure be sufficiently thick. As for concrete thickness, it is considered preferable that deflection by pressure is sufficiently suppressed, as shown in FIG. 4 (b1) and FIG. 4 (b2), bonding is performed with various thicknesses, and bonding failure It can be determined experimentally by confirming the presence or absence of Here, the results of the two types of thickness are shown, but if more experiments are performed, it is possible to determine the thickness required to avoid the joint failure.

FIG. 5 is an explanatory view showing the influence of the thickness of the brazing material. The thickness of the brazing material is the thickness of the layer of brazing material interposed between the two members. The left row in FIG. 5 shows the results when the brazing material thickness is 38 micrometers, and the right row shows the results when the brazing material thickness is 76 micrometers. .
5 (a1) and 5 (a2) show a state in which the joined members are viewed from directly above. In this example, two rectangular members of constant thickness are joined, and a rectangular window is formed at the center of the upper member. Both members are formed of GlidCop (registered trademark). As shown in FIG. 5 (a1) and FIG. 5 (a2), it can be confirmed that the brazing material slightly protrudes from the joint surface to the inside of the window, and the thicker brazing material protrudes in FIG. 5 (c2) Know that
FIG. 5 (b 1) and FIG. 5 (b 2) show the joined members as viewed from the side. It is confirmed that the portion in which the color is changed is larger in FIG. 5 (b2) where the brazing material is thicker.
FIG. 5 (c 1) and FIG. 5 (c 2) show the window part as viewed obliquely. It is confirmed that a large amount of brazing material is protruded in FIG. 5 (c2) in which the brazing material is thick.
FIG. 5 (d 1) and FIG. 5 (d 2) show inspection results by ultrasonic flaw detection. It is confirmed that the brazing material protrudes to the inside of the rectangular frame corresponding to the window. Further, in FIG. 5 (d2) where the brazing material is thick, many streaky joint failure portions are confirmed around the window, but in FIG. 5 (d1) where the brazing material is thin, such bonding failure is not confirmed.
From the above, it can be seen that the brazing material is not necessarily preferred to be thick. It is believed that the suitable brazing material thickness will depend on the degree of surface finish. In the case of fine mirror surface finishing, it can be said that 38 micrometers is preferable to 76 micrometers. In this example, although the results of the two-step thickness are shown, it is possible to determine a suitable brazing material thickness by performing bonding and inspection at more multi-step thicknesses. Moreover, in the present embodiment, although the presence or absence of the bonding defect due to the ultrasonic flaw detection is inspected, the mechanical strength of the bonding may be measured together.

The brazed joint of the embodiment is not limited to GlidCop (registered trademark), but bonding of GlidCop (registered trademark) to other materials is also possible.
FIG. 6 is an explanatory view showing a bonding result of GlidCop (registered trademark) and SUS. The bonding process is as described in FIG. 1 including the conditions of heat treatment.
FIG. 6A is an enlarged photograph of the vicinity of the bonding center. The material A is a SUS material. Although SUS316L was used in the present embodiment, other stainless steel may be used. Material B is GlidCop (registered trademark).
FIG. 6 (b) is an enlarged photograph of the vicinity of the bonding center. As illustrated, the bonding layer is formed, and it can be seen that in the bonding layer, the material A and the material B are mixed. In GlidCop (registered trademark), it is considered that brazing bonding is realized by the portion of the electrode surface whose melting point is lowered due to the eutectic reaction of phosphorus of the brazing material into the SUS material.
FIG. 6 (c) shows the test results of Vickers hardness. In the bonding layer, the Vickers hardness is locally hardened locally, and it is confirmed that the bonding is firmly performed.
Thus, it was confirmed that bonding of GlidCop® to other materials is also possible.

  Braze bonding with GlidCop® was previously known to be feasible with tungsten (melting point 3422 ° C.). According to the inventor's experiments, it is confirmed that the brazing bonding process of the example is capable of brazing even between GlidCop (registered trademark) (melting point 1085 ° C.) and between SUS (smelting point 1401 to 1500 ° C.). The Moreover, it was confirmed that the principle is related to the lowering of the melting point of copper due to the eutectic reaction of copper and phosphorus. Generally, the conditions for brazing need to be determined experimentally depending on the metal, but it has been confirmed that brazing can be performed with metals having a melting point lower than that of tungsten, and copper and phosphorus Since the principle of bonding using lowering of the melting point of copper by eutectic reaction is considered to be commonly applicable to other metals, as a result of the example, the melting points are tungsten and GlidCop (registered trademark) It is also considered possible to bond metal with SUS and a metal such as molybdenum (melting point 2623 ° C.) or iridium (melting point 2466 ° C.).

The brazing process of the embodiment described above is applicable to the manufacture of various structures.
FIG. 7 is an explanatory view showing a manufacturing example of the diverter. A diverter is a structure provided in a nuclear fusion reactor for heat removal and the like, and is exposed to a very high temperature, so tungsten is used as a material of the heat receiving surface. In order to further cool the tungsten, alumina dispersion reinforced copper having high thermal conductivity and strong mechanical strength can be bonded to the back side of the heat receiving surface.
First, as shown in FIG. 7A, members A to C constituting the diverter are prepared. In this example, the members A and B are GlidCop (registered trademark), and the member C is SUS316L. In the member A, a flow path for flowing the refrigerant is formed by cutting, and the member B is a plate-like member that covers the flow path. These members A to C are respectively joined by brazing. The member B and the member C are respectively brazed to the member A. In the present embodiment, the members are joined in order from a member having a thermal expansion coefficient close to that of the member A. That is, the member B formed of the same material as the member A is first joined, and then the member A and the member C are joined.
When the bonding is repeatedly performed as described above, the members once bonded to each other are again exposed to the heat treatment environment to bond the next member. In the case where the thermal expansion coefficients of the members are significantly different, the repetition of the heat treatment causes a large thermal stress. Joining members having similar thermal expansion coefficients is to avoid such an adverse effect and to suppress the occurrence of thermal stress. That is, since the member A and the member B are the same material, in order to join the member C after joining the two, even when exposed to the heat treatment environment again, it is possible to suppress the occurrence of thermal stress. .

In FIG.7 (b), the state to which member AC was joined was shown.
Next, as shown in FIG. 7C, the member C is processed so as to be the inlet and the outlet of the flow path of the refrigerant. The reason for forming the pipe-shaped member C (SUS316L) by brazing is that, when welding a cooling pipe from the outside, welding is almost impossible with GlidCop (registered trademark), so the member C (SUS316L) is final It is because it is preferable that it is an end. Further, the upper surface of the member A is processed so as to bond tungsten.
Then, as shown in FIG. 7D, the member D made of tungsten is brazed to the upper surface of the member A. The bonding process is as shown in FIG. 1 including the heat treatment conditions. In addition, it has been found that in the case of tungsten and GlidCop (registered trademark) brazed joints, no problem occurs in the performance as a diverter even if no particular pressure is applied to the joint surfaces.
Through these steps, the diverter shown in FIG. 7 (d) is manufactured. The shape of the diverter shown in the figure is merely an example, and other materials or other shapes may be used.

As explained above, according to the brazing method of the embodiment, various metals can be brazed to alumina dispersion strengthened copper.
The present invention is not limited to the examples, and can be realized in various aspects. Moreover, the present invention can be used not only for divertors, but also for manufacturing various structures.

The present invention can be utilized for brazing of alumina dispersion strengthened copper.

Claims (10)

A bonding method for brazing a first member made of alumina dispersion strengthened copper and a second member made of a metal to be joined,
The metal to be joined is alumina dispersion strengthened copper or stainless steel,
(A) preparing a brazing material containing phosphorus;
(B) a heat treatment step of sandwiching the brazing material with the first member and the second member and heating the brazing material at a predetermined heat treatment temperature for a predetermined time;
(C) cooling the joined first and second members after the heat treatment step ;
The heat treatment temperature is a bonding method which is set in a range lower than the melting point of copper and higher than the melting point of copper lowered by the eutectic reaction of phosphorus and copper. The bonding method according to claim 1,
The metal to be joined is alumina dispersion strengthened copper,
The heat treatment temperature is 960 ° C. The bonding method according to claim 1 or 2 , wherein
(D) Prior to the heat treatment step, the method further comprises the step of surface finishing the surfaces to be joined of the first member and the second member to a fine mirror surface,
The bonding method in which the brazing material in the heat treatment step has a thickness of 1 to 100 micrometers. The bonding method according to any one of claims 1 to 3 , wherein
The bonding method of applying a pressure to the first member and the second member in a direction in which the first member and the second member are bonded in the heat treatment step. The bonding method according to claim 4 ,
Providing first and second end plates fastened together and a central plate disposed between them;
Sandwiching the first member and the second member by the first end plate and the center plate;
A bonding method for applying pressure to the first member and the second member disposed between the first end plate and the central plate by interposing an elastic body between the second end plate and the central plate. The bonding method according to claim 5 , wherein
The bonding method, wherein the first and second end plates and the center plate have a thickness such that pressure distribution applied to the first and second members is substantially uniform. The bonding method according to any one of claims 1 to 6 , wherein
The bonding method in which the step (c) is natural cooling. It is a joining method in any one of Claims 1-7, Comprising :
When there are a plurality of second members made of a plurality of types of metals,
The joining method joined in order from the 2nd member formed with the metal whose thermal expansion coefficient is close to said alumina dispersion strengthening copper which forms said 1st member. The bonding method according to claim 8 , wherein
The plurality of second members are respectively formed of alumina dispersion strengthened copper, stainless steel, and tungsten.
A bonding method for bonding the first member in order of the second member formed of the alumina dispersion strengthened copper, stainless steel, and tungsten. The bonding method according to claim 1,
The first member is a member which is formed of alumina dispersion-strengthened copper and in which a refrigerant flow path of a heat remover is formed,
The bonding method, wherein the second member is a member formed of alumina dispersion-strengthened copper and covering the flow path.