JP2008030097A - High-pressure diffusion welding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make diffusion welding possible in a high-pressure state for a plurality of joining members simultaneously. <P>SOLUTION: The high-pressure diffusion welding equipment uses equipment having an electric power source 7 for generating a pulsed current or an AC current and a vacuum furnace or an atmospheric furnace with a mechanism for pressurizing joining members 10, 11 by means of an air or hydraulic cylinder 14 or the like. A heating element is installed on the outer periphery of the joining members and, using its radiation heat and heat transfer, diffusion welding is performed while the joining members 10, 11 are pressurized without making an electric current flow directly in the joining members. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

      The present invention relates to diffusion bonding in which bonding members are diffusion bonded.

  Currently, desktop chemical reactors called microreactors are attracting attention in the field of fine chemical synthesis. The microreactor is formed by laminating a joining member composed of several thin plates in a reaction channel. As a conventional diffusion bonding method, a solid phase diffusion bonding method is used. As a typical method, a DC pulse current is passed while a bonding member is abutted and pressurized in a vacuum as shown in Japanese Patent No. 3548509. A method has been adopted in which one step is performed, and then a second step of diffusion heat treatment is performed, thereby making the joining members one by one.

  FIG. 7 shows the current-carrying joining by this conventional pulse direct current. It is configured such that electricity flows directly from the upper and lower electrodes 1 and 2 to the joining members 10 and 11, and the interface of the joining member generates heat due to contact resistance due to pulsed direct current or alternating current, and is joined by the generated Joule heat. The bonding interface between the members 10 and 11 was solid phase diffusion bonded.

  Further, as a diffusion method for simultaneously joining a plurality of joining members, there are two methods, a first step in a vacuum atmosphere in which pressure is applied and heated by a weight, and a second step in the air, as disclosed in JP-A-7-75882. A step method is shown.

  In the method of solid phase diffusion bonding of bonding members using pulsed direct current shown in Japanese Patent No. 3548509 of the conventional method, there is a case where members are arranged in parallel between electrodes so as to process a large number of bonding members at a time. There is a risk that current is biased in one member, causing an abnormal temperature rise, and the joining member melts. Therefore, in order to process a plurality of joining members at once, it is necessary to arrange the joining members in series so that a pulsed direct current flows equally to each joining member. However, in order to arrange the joining members in series, there is a limit in one furnace, and productivity is low. Moreover, in order to prepare several furnaces, the expense concerning an installation becomes huge.

Next, in the method disclosed in Japanese Patent Application Laid-Open No. 7-75882, a weight is placed on the joining member and pressurized, so that a plurality of joining members can be processed at one time. Otherwise, floating occurs on the joint surface, resulting in joint failure.
Japanese Patent No. 3548509 JP-A-7-75882

  Then, the subject of this invention is providing the novel diffusion bonding apparatus which can carry out the diffusion bonding of several joining members simultaneously.

  In order to solve the above-mentioned problem, in order to join a plurality of joining members simultaneously, a structure that pressurizes the joining members and generates heat by an electric current by a diffusion joining apparatus having a mechanism for pressurizing the joining members in a vacuum or an inert atmosphere. A body is used to perform diffusion bonding by heating a plurality of bonding members.

  Since this diffusion bonding device is equipped with a pressure mechanism, it is possible to apply a load to the bonding member that is impossible to achieve with conventional weights, so there is almost no floating between the bonding members and almost no defective bonding occurs. Disappear.

  Further, since the pressurizing mechanism of the apparatus can generate a high pressurizing force that cannot be realized by the weight, the mutual diffusion of the elements of the joining member can be remarkably advanced together with the heating.

  Next, since the current is interrupted by the insulating material in each bonding member, the plurality of bonding members are heated by the radiant heat or heat transfer of the heating element, so that the current flows through only one bonding member. A plurality of joined members are heated almost uniformly to the temperature required for joining without causing abnormal temperature rise, and a large number of joined bodies can be manufactured.

  By incorporating an elastic mechanism into the connection structure between the heating element and the electrode according to claim 2, when the joining member is heated and expands, the pressing mechanism is expanded and the current between the electrode and the heating element is separated. The risk of being blocked is prevented, and the joining member can be sufficiently heated to the temperature required for joining.

  According to the third aspect of the present invention, an elastic mechanism base is prepared for each joining member so that the pressure is uniformly applied to the plurality of joining members, so that the plurality of joining members can be uniformly pressurized by one pressurizing mechanism. To do.

  In the present invention, heating can be performed without passing an electric current through the bonding member up to a desired temperature required for diffusion bonding under high pressure, so that a plurality of bonding members can be bonded simultaneously.

  In addition, since the heating element of this device can have a heating structure of a size corresponding to the joining member, it is suitable for joining members of various sizes, unlike when the heating element is fixed to the furnace. Can be selected each time. Therefore, since it becomes easy to obtain appropriate joining conditions depending on the material of the joining member, the reliability of the joined product is improved, and there is no waste of time required for diffusion joining, and the production efficiency can be increased.

  The bonding member is pressurized by a diffusion bonding apparatus having a mechanism for pressing the bonding member in an inert atmosphere, and a plurality of bonding members are heated by a structure that generates heat by current to perform diffusion bonding. The heating element and the electrode are electrically connected by an elastic mechanism so as to absorb the thermal expansion of the joining member.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an overall view of the apparatus of the present invention. The high pressure diffusion bonding apparatus includes a power source 7 and a vacuum furnace or atmosphere furnace 8 and a cylinder 14. The power source 7 can generate a direct current pulse direct current or an alternating current. A current 15 is supplied from the power source 7 to the vacuum furnace or the atmospheric furnace 8 through the upper electrode 1 and the lower electrode 2. In the case of pulsed direct current, the pulse ratio can be varied, and in the case of alternating current, the frequency can be varied. The current condition can be appropriately selected according to the joining member.

  The vacuum furnace or atmosphere furnace 8 includes upper and lower electrodes 1 and 2, and either electrode has a structure in which the joining members 10 and 11 can be pressurized by a cylinder 14 that can be driven by air or hydraulic pressure.

  The upper and lower electrodes 1 and 2 and the vacuum furnace or atmosphere furnace 8 are hermetically sealed with an O-ring so that a vacuum or an inert gas atmosphere in the furnace can be maintained.

  The joining members 10 and 11 are installed between the upper and lower electrodes 1 and 2, and an insulator 12 for interrupting current is disposed at least above or below.

  Further, a heating element 9 is installed between the upper and lower electrodes 1 and 2 so as to surround the joining members 10 and 11. An elastic carbon felt 13 is disposed between the heating element 9 and the carbon die 3 or 4 so that an electric current flows through this elastic mechanism.

  In this apparatus, the joining members 10 and 11 and the insulator 12 are pressurized with air or hydraulic pressure, and a pulse direct current or alternating current is supplied from the power source 7 while the furnace is evacuated or in an inert gas atmosphere.

  The heating element 9 generates heat by the pulse direct current or the alternating current and heats the joining members 10 and 11. The joining member is heated by the radiant heat of the heating element and the heat transferred from the upper and lower carbon dies 3, 4, 5, 6 and is maintained up to a desired diffusion joining temperature.

  After the joining members 10 and 11 reach the desired temperature, the temperature is maintained for a required time at that temperature, and then the current is turned off and cooled to a temperature at which the joining members 10 and 11 can be taken out. It is also possible to inject an inert gas into the furnace in order to shorten the time for cooling the joined body.

  FIG. 2 shows a structural diagram of the heat generating portion of the present invention. Between the upper and lower electrodes 1 and 2, a heating element 9 made of a carbon material is disposed around the SUS316 block 10 and the SUS316 thin plate 11 which are joining members. Carbon felts 13 and 131 are sandwiched between the upper and lower portions of the heating element 9 so that they can be electrically connected even if there is a gap between the heating element 9 and the upper and lower carbon dies 31 and 401. .

  Due to the elasticity of the carbon felts 13 and 131, even if the bonding members 10 and 11 are heated to expand and behave so as to widen the upper and lower electrodes 1 and 2, the current supply from the electrodes to the heating element is not interrupted. It becomes possible to continue heating the joining members 10 and 11 to a desired temperature.

  This joining apparatus is provided with a power source 7 capable of generating a direct current pulse direct current up to 10,000A.

  A quartz plate 12, which is an insulator, is disposed above the joining members 10 and 11, so that the upper and lower electrodes 1 and 2 are not short-circuited, and only the radiant heat and heat transfer from the heating element 9 are used. 11 are heated. The insulator is not limited to a quartz plate but may be an alumina plate or a zirconium plate.

  The joining member 11 is a thin plate of SUS316 having a thickness of 0.5 mm, and the joining member 10 is a block of SUS316 having a width of 60 mm, a length of 30 mm, and a height of 20 mm. The joining surfaces of these joining members were mirror finished with a parallelism of 2 micrometers or less and a surface roughness of 0.2 micrometers or less.

  The pressurizing structure for the joining member is configured such that the carbon die 5 is sandwiched between the carbon sheets 16 so that pressurization can be applied to the dimensional accuracy of the joining member. Thereby, even if it causes a dimensional change when the joining member is in a high temperature state of diffusion joining, the carbon sheet 16 can be prevented from being deformed and the pressure distribution being changed. Further, the carbon sheet may be sandwiched between the carbon dies 4 and 401 even in the lower carbon die configuration.

  FIG. 3 shows a top view a and a side view b of the components of the heating element. The heating element is made of a carbon material, and the heating component has a semi-cylindrical shape having a notch 91. The two parts shown in FIG. 3 are assembled so as to be a mantle facing each other to form a heating element.

A diagram of the assembly is shown in FIG. The heating element combines the component parts 19 and 20 so that the notches 91 and 910 face each other. By this assembly, a rectangular window 92 is formed at the center by the notches 91 and 910. The purpose of the square window 92 is to observe the behavior of the joining member during diffusion joining.

  FIG. 5 shows a joining method when there are a plurality of joining members.

  When a plurality of joining members 10 and 11 are prepared and joined at the same time, a carbon die 601 having a plurality of holes corresponding to the joining member is prepared in a lower carbon die on which the joining members are arranged, and a carbon sheet is provided in each hole. Plural pieces of 161 are arranged.

  Next, a cylindrical carbon die 17 matching the size of the hole is placed in each hole, and the joining members 10 and 11 are disposed on the carbon die 17, respectively.

  In order to insulate the joining members 10 and 11 and the electrodes 1 and 2, a quartz plate 12 is arranged, and the upper and lower electrodes 1 and 2 are pressurized using a cylinder to apply pressure to the joining member, and a current 15 flows. The current 15 heats the outer heating element 9 to heat the plurality of joining members to a desired temperature by radiant heat and heat transfer.

  The material of the insulating plate used for electrical insulation is not limited to quartz, and any material that can withstand a desired heating temperature, such as alumina or zirconium, is not limited.

  FIG. 6 shows another joining method when there are a plurality of joining members.

  In addition to arranging the heating element on the outer periphery, a carbon die 18 is arranged in the center to increase the number of heating points. In the carbon die 18, the carbon felt 162 is arranged up and down like the heating element 9. The current 15 flows between the outer heating element 9 and the central carbon die 18, and each generates heat.

  When the heating element has such a configuration, the number of heat generation points increases, and it becomes possible to create a stable heating state up to the temperature of diffusion bonding by radiant heat and heat transfer.

The temperature and pressure conditions when the joining members 10 and 11 were pressurized and heated to perform diffusion joining in the configuration of FIG. 2 were as follows.
・ Degree of vacuum 6.1Pa
・ Temperature 1,030 degrees Celsius
・ Pressure 10MPa
・ Time from room temperature to 1,030 degrees Celsius in 20 minutes
1,030 degree (Celsius) holding 2 minutes, then natural cooling

Moreover, after this joined body was joined under the above conditions, a diffusion heat treatment was additionally performed in a vacuum furnace. The conditions were as follows.
・ Degree of vacuum 0.5Pa
・ Temperature 1,030 degrees (Celsius) 1 hour ・ Return 250 degrees (Celsius) 2 hours

  The joined bodies that were diffusion-bonded under these joining conditions were firmly joined to each other and could not be peeled off.

  By using an apparatus composed of a high pressure mechanism and a heat generating structure, a large number of bonding members can be diffusion bonded at a time with high productivity.

  Further, a member that is difficult to process as an integral part can be processed by dividing it into several parts and joined together by the method of the present invention, so that it can be finished as an integral part.

Overall view of the device of the present invention Structural diagram of the heat generating part of the present invention Heating element components Assembly drawing of heating element Configuration diagram of apparatus when there are a plurality of joining members of the present invention Another block diagram when there are a plurality of joining members of the present invention Configuration diagram of current-carrying junction using pulsed direct current

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper electrode 2 Lower electrode 3 Carbon die 4 Carbon die 5 Carbon die 6 Carbon die 7 Power source 8 Vacuum furnace or atmosphere furnace 9 Heating element 10 Joining member 11 Joining member 12 Insulator 13 Carbon felt 14 Cylinder 15 Current

Claims (3)

  In a diffusion bonding apparatus that includes a pressure mechanism that pressurizes a bonding member in a vacuum or in an inert atmosphere, and in which the pressure bonding mechanism serves as an electrode, the pressure mechanism serves as an electrode and generates heat when a direct current or an alternating current flows. The high pressure diffusion bonding apparatus according to claim 1, wherein the bonding member is heated to prevent an electric current from flowing through the bonding member with an insulating material.   The high pressure diffusion bonding apparatus according to claim 1, wherein the structure is configured by a member that generates heat by electric current, and has a structure in which a current supply mechanism from the electrode has elasticity. The high pressure diffusion bonding apparatus according to claim 1, wherein the pressurizing mechanism is provided with an elastic mechanism so that the pressure applied to each bonding member is made uniform.

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