JP4482654B2 - Heat resistant material for high energy density equipment - Google Patents

Description

  The present invention relates to a heat-resistant member such as an electrode used at a high temperature and high load such as an X-ray source utilizing high energy density and a power generation device.

  In recent years, the severe discharge load and heat load on members such as electrodes of high energy density beam utilization equipment such as high power fixed X-ray anode, MHD (Magneto-Hydro-Dynamics) power generation, fusion reactor, etc. The material which can endure is required. On the other hand, the use of tungsten (W) and W alloy with high melting point, high heat resistance and low discharge consumption is desired, but its difficult workability, high specific gravity and mechanical brittleness, or a member during assembly Difficult to join between the two becomes a problem. Therefore, as such a heat-resistant member for high energy density utilization equipment, development of a joined body with another material base material, particularly a base material made of copper (Cu) and Cu alloy having excellent workability and thermal conductivity is advanced. ing. Furthermore, development of a joined body with a Ni alloy or a stainless steel base material that can be used at a higher temperature than Cu and Cu alloy is desired.

  For example, X-ray transmission devices used for industrial non-destructive inspection require high output or high current density for fixed X-ray anodes that are X-ray sources due to the demand for high-definition observation of inspection objects. Yes. Along with this, higher input electron beams and smaller electron beam diameters have progressed, and the thermal load or thermal load density of the anode has increased. Therefore, in the conventional brazing joint, the interface temperature exceeds the melting point of the brazing material, the generation of voids due to the melting of the brazing material, and the decrease in heat conduction due to the voids, the melting range of the brazing material will be expanded due to further increase in temperature, There is a growing risk of eventually becoming unusable.

  The MHD generator is a generator that directly converts thermal energy into electric power by flowing a conductive gas of fossil fuel such as coal in a high magnetic field. In this MHD generator, the electrode member on the inner wall of the generator generates an electrical load as well as a large heat load. That is, the electrical load means that when an electric current flows through the electrode, the atmosphere is a conductive gas, so that an arc is generated when the electric current flows in and out and the electrode is damaged.

  Also, the plasma facing material of a fusion reactor is subject to a large heat load, and erosion due to a high energy charged particle beam, that is, the sputtering wear caused by receiving a large amount of particle load, is significant for the continuous generation of the fusion reaction. It is regarded as a problem to influence.

  Cu and Cu alloys with high melting point, excellent arc resistance and erosion resistance, high wear resistance, high heat conductivity and water cooling effect against the above large heat load and arc discharge wear and erosion. As a result, it is possible to reduce the thermal load compared to the electrode unit of W alone and to expect a longer life.

  In these joined bodies, when there is a void or the like in the joined portion, not only the thermal conductivity is lowered, but heat concentration (heat spot) is generated and there is a risk of peeling due to local melting or the like. Therefore, a bonded body with good adhesion that does not decrease thermal conductivity is required. Further, it is necessary to have a sufficient bonding strength that does not cause deformation or dropout under a high heat load.

  Since W and Cu do not dissolve or diffuse with each other, they are representatives of dissimilar material bonding that is difficult to bond simply by contacting and heating.

  Usually, as a joining method used for joining different kinds of materials, there are fusion welding (welding) using an arc, TIG, laser, electron beam or the like, brazing welding, a friction welding method, a casting method, and the like.

  Fusion welding is generally referred to as “welding” and is a method in which the parts to be welded are heated and fused with a filler metal to create a molten metal, which is solidified and joined. Widely used for joining structures.

  However, since it is necessary to melt the base material in the fusion welding method, it is essential to heat to a temperature higher than the melting point of the base material. In addition, structural changes due to melting and solidification of the base metal, that is, recrystallization and coarsening thereof are unavoidable. Therefore, residual stress deformation and structural changes cause changes in properties such as embrittlement near the welded joint and reduced strength. . Therefore, the material becomes brittle due to the coarsening of crystal grains accompanying melting and solidification, so that it is difficult to apply to W which is a heat resistant material.

  Brazing is also called brazing, and without melting the base material, it melts a metal having a melting point lower than that of the base material called filler metal, and joins it by utilizing its capillary phenomenon and reaction with the base metal. This is a method of joining by spreading over the gaps between the surfaces. Therefore, there is an advantage that the crystal grain coarsening and embrittlement accompanying the melting and solidification of the base material do not occur, the thermal stress can be suppressed because the construction temperature is low, and there is no structural change of the base material. Furthermore, brazing is suitable for joining materials such as hardly fusible metals that require high energy for melting the base material, or materials that are prone to cracking during solidification or dissimilar materials.

  However, brazing not only has a bonding strength lower than that of the fusion welding method, but also has a problem that reliability is low due to large variation. In addition, there is a drawback that heat spots such as voids are likely to occur, and the thermal conductivity is likely to decrease. In addition, the operating temperature is limited by the melting point of the brazing material used.

In addition, as a method for directly joining W and Cu plates, HIP joining is proposed in Patent Document 1. In the case of joining by HIP (Hot Isostatic Press), the apparatus is large and disadvantageous in terms of cost. In addition, for uniform transmission of pressure, it is necessary to vacuum seal in a capsule covering the entire bonding material, and there is a great limitation in shape. Moreover, since pressure from a three-dimensional direction is applied, the shape restriction is also great from this point. However also many shapes requests the W electrodes protruding from Cu cooling unit in the electrode body or the like, the HIP bonding is impossible correspond. Furthermore, capsules are generally made of mild steel because of the need for workability and deformability. However, when the temperature becomes high, iron may diffuse in W and the W portion may become brittle.

A friction welding method has also been proposed as a method for joining W and Cu. For example, in Patent Document 2, the bonding method has been proposed about the W group friction welding method for a metal material and the Cu-based metal material using the insert metal. In this method, the use of an insert material causes a problem that the thermal conductivity is lowered due to the presence of an intermediate layer such as niobium (Nb) having a lower thermal conductivity coefficient than Cu between W and Cu. This method is generally used for joining circular cross-section materials, and there is an example in which one of the materials to be joined is a square cross section. In any case, there is a shape restriction such as the need for a round bar material. Furthermore, the rotation centers of the members to be joined need to coincide with each other, and cannot be applied to an electrode body in which a large number of electrodes are installed on one base material.

  The cast-in method is often used for joining W and Cu. That is, this is a method in which a W base material having a high melting point is set in a mold, and a molten metal in which low melting point Cu is melted is poured and solidified to fix the W base material. In this case, since it is difficult to control the shrinkage nest at the time of gas entrainment or solidification, there is a defect that heat spots such as voids are likely to occur and the thermal conductivity is likely to be lowered. Further, since the Cu base portion becomes a cast body, the mechanical properties are inferior to those of a base material processed from a Cu material subjected to general plastic processing.

  Furthermore, it is necessary for Cu to wrap around at least a part of the periphery of the W base material joining surface, so that joining of the one surface is impossible, and the shape of the joined body that can be applied is limited.

  Other lamination methods include PVD and CVD film formation methods.

  However, there are many demands for a shape in which the W electrode protrudes from the Cu cooling part in the electrode body or the like. In addition, there is an increasing demand for thicker electrode bodies having a planar shape because of reduced life and cooling capacity. Even in the thermal spraying method capable of forming a relatively thick film, the limit is about 1 mm, the adhesion strength and the reliability are low, the presence of pores is unavoidable, and the production of protruding products is impossible. There are drawbacks.

  As described above, there has been a demand for the development of a bonding method that can provide good adhesion and practically sufficient strength that do not lower the thermal conductivity with respect to the bonding of W and Cu, and that is not limited by the application shape.

  On the other hand, the present inventors have developed a composite in which a tapered portion is formed on a part of a W member and press-fitted into a Cu base material in order to directly solid-phase bond W and Cu (see Patent Document 3). The joined body disclosed in Patent Document 3 meets the above requirements. However, because W and Cu are not a solid solution / interdiffusion of each other, the flow of Cu, the reaction force of plastic deformation and heat Adhesion is obtained by mechanical contact such as tightening force generated from the difference in expansion. Therefore, the existence of a non-contact portion at the microstructure level cannot be denied at the interface portion between W and Cu, and the problem of a decrease in thermal conductivity was considered.

  In general, brazing and cast-in methods are used to manufacture W and Cu joints, but there are significant problems such as a decrease in thermal conductivity due to voids and other defects, generation of heat spots, and differences in thermal expansion coefficients. If this problem can be eliminated, the present invention can be applied to a dissimilar material joined body having a large difference in thermal expansion coefficient other than the combination of W and Cu. For example, other than Cu, nickel (Ni), a Ni alloy, a stainless alloy, or the like having a large thermal expansion coefficient can be used as a heat sink or backing plate that can withstand higher temperatures than Cu.

Here, according to the nonpatent literature 1, a thermal expansion coefficient is W: 4.6, Cu18.3, Ni15.2, 18-8 stainless steel 18.4 (* 10 < ^-6 > / K) in 20-500 degreeC. It is.

  Although the joined body disclosed in Patent Document 3 can meet the demand, as described above, the existence of a non-contact portion at the micro level cannot be denied at the interface portion between W and Cu. There is a need to improve the thermal resistance.

JP-A-11-190787 JP-A-8-323485 JP 2001-293576 A Metal Data Book (Edited by the Japan Institute of Metals, 3rd edition) “Progress of Functionally Gradient Materials as Hyperrefractive Metals”, Metals '97 -February, pages 117-124

  The technical problem of the present invention is to further reduce the cooling capacity by further improving the thermal conductivity, further improving the conventional joined body, and dissimilar materials having a large difference in thermal expansion coefficient such as W and Cu or Ni Is to provide a heat-resistant member for high energy density utilization equipment such as a joined body having excellent adhesion and improved thermal conductivity, and a method for producing the same.

  The present invention has been made in view of the above-mentioned circumstances, and uses a high energy density resistant device comprising a joined body having good thermal conductivity in joining different materials having a large difference in thermal expansion coefficient such as W and Cu. In order to obtain a heat-resistant member for use, the problem in the joined body disclosed in Patent Document 3, that is, the elimination of the non-contact portion at the micro level of the interface portion between W and Cu is solved.

  As a specific means, the present inventors formed an intermediate layer that reacts with W and the base material, for example, Cu at the interface part, and diffused each of W and the intermediate layer, and the intermediate layer and the base material. The inventors have found a method for producing a metallographic bond layer and improving the adhesion at the micro level of the interface, and have made the present invention.

According to the present invention, it has a tungsten member having a tapered portion at a tip portion, has a groove formed on the tapered portion and formed inward from the side surface of the tapered portion, and includes the groove. an intermediate layer formed tapered portion is provided, wherein the tungsten member at a temperature above the softening point before Kimotozai large substrate coefficient of thermal expansion than the tungsten member, press-bonding the tungsten member in the axial direction Thus, the intermediate layer has a metallic bond formed between the tungsten member and the base material, and the base material bites into the groove. A heat resistant member is obtained.

Further, according to the present invention is characterized by having the high energy density utilizing equipment heat member odor Te, the metal binding as the intermediate layer in a part of the interface between the pre-Symbol tungsten member and said base A heat-resistant member for equipment using high energy density is obtained.

According to the present invention, in the heat-resistant member for high energy density utilization equipment, the metallic bond is formed over the entire surface of the tip including the inside of the groove formed by the groove processing of the tungsten member. Thus, a heat-resistant member for high energy density utilization equipment can be obtained.

Further, according to the present invention, the in any one of the high energy density utilizing heat member equipment, the metallic binding is tungsten - nickel or nickel - high energy density, characterized in that it is formed of copper A heat-resistant member for use equipment is obtained.

Further, according to the present invention, in any one of the heat resistant members for high energy density utilization equipment, the metallic bond is obtained by press-bonding the tungsten member to the substrate, and the tungsten member and the substrate. The heat-resistant member for high energy density utilization equipment characterized by being formed by heating two layers of nickel and copper or a single nickel layer provided between the two .

Further, according to the present invention, in the heat-resistant member for high energy density utilization equipment, the metallic bond is obtained by heating a nickel coating layer having a thickness of 0.5 μm or more and 3 μm or less during the press-fitting. Thus, a heat-resistant member for high energy density utilization equipment can be obtained.

  Further, according to the present invention, in any one of the heat resistant members for high energy density utilization equipment, one or more tungsten members are press-fitted and joined to one base material. A heat-resistant member for energy density utilization equipment is obtained.

Further, according to the present invention, in the heat-resistant member for high energy density utilization equipment, heating and cooling are performed 3000 times in each 15-second cycle at an input thermal energy of 5 MW / m ^{2 and} heating at an input thermal energy of 10 MW / m ² . A heat-resistant member for a high energy density utilization device is obtained, which withstands 1000 heat cycle tests with a cooling time of 15 seconds each and does not deteriorate the heat transfer performance of the joint.

Further, according to the present invention, a process for preparing heat-resistant member for a high energy density utilizing apparatus having a large base of thermal expansion coefficient than tungsten member and tungsten, comprising a tapered portion at the tip of the tungsten member, wherein A step of grooving the tapered portion from the side surface of the tapered portion toward the inside of the tapered portion, and an intermediate layer for generating a metallic bond with the tungsten member and the base material in a part of the tungsten member The tungsten member is press-fitted in the axial direction to the base material at a temperature equal to or higher than the softening point of the base material, and the metallic layer serves as the intermediate layer between the tungsten member and the base material. A method for producing a heat-resistant member for a high energy density utilization device.

Further, according to the present invention, in the manufacturing method of the high energy density utilizing equipment heat-resistant member, and the tungsten member and the substrate over the entire surface of the tip portion including the groove formed by the grooving The manufacturing method of the heat-resistant member for high energy density utilization apparatuses characterized by producing | generating the said metallic bond is obtained.

Further, according to the present invention, the high energy density in the manufacturing method of the utilizing device for heat-resistant member, prior Symbol intermediate layer on the tungsten member and nickel and copper to produce respectively the metal binding to both of the substrate 2 The manufacturing method of the heat-resistant member for high energy density utilization apparatuses characterized by using a layer or a nickel single layer is obtained.

According to the present invention, in the method for producing a heat-resistant member for high energy density utilization equipment, nickel plating having a thickness of 0.5 μm or more and 3 μm or less is used for the intermediate layer. A heat-resistant member manufacturing method is obtained.

  According to the present invention, in any one of the methods for producing a heat-resistant member for high energy density equipment, one or two or more tungsten members are press-fitted and joined to one base material. The manufacturing method of the heat-resistant member for high energy density utilization apparatuses is obtained.

  The present invention will be described more specifically in the case where Cu is used as a base material. A part of a W member is press-fitted into a Cu base material in which a hole having a predetermined diameter and depth is previously formed, and a joined body. However, Ni and Cu are inserted as intermediate layers in the part of the W member that is in contact with the Cu base material, and interdiffusion between the W and Ni intermediate layers, the Ni intermediate layer and the Cu intermediate layer, and the Cu intermediate layer and the Cu base material is performed. This is a configuration that can improve the cooling performance and reduce the thermal resistance between the Cu base and the W member, that is, improve the thermal conductivity of the joined body, thereby obtaining a joined body having heat resistance.

  Furthermore, in the present invention, it is possible to obtain a joined body having improved pulling strength while maintaining thermal conductivity by performing composition processing on the tapered portion of the W member and filling the inside of the groove with a Cu base material. It is a possible configuration. That is, the tensile strength is the strength that leads to the shear fracture of the Cu base material filled in the groove.

  Here, the intermediate layer is preferably formed by a coating method such as plating, PVD, or CVD. However, depending on the shape and dimensions, the foil or foil formed by drawing or the like can be formed. In some cases, it can be formed simply by swallowing.

  According to the present invention, in a dissimilar material having a large difference in thermal expansion coefficient such as W and Cu or Ni, a bonded body having excellent adhesion without defects that are harmful to thermal conductivity at the bonded portion and having practically sufficient bonding strength It is possible to provide a heat-resistant member for a high energy density utilization device such as a manufacturing method thereof.

  Hereinafter, the present invention will be described in more detail.

  The present invention will be described in more detail. In the present invention, the thermal adhesion in a dissimilar material having a large difference in thermal expansion coefficient such as W and Cu or Ni is improved, that is, the thermal conductivity is improved, and the heat resistance is further improved. Invented as a heat-resistant member for high energy density utilization equipment.

  That is, this is a method for obtaining a joined body having a practically sufficient tensile strength without causing a decrease in thermal conductivity due to the occurrence of defects such as voids or heat spots at the joint between the Cu base members 20 and 25 and the W member 10. This is because, in a joined body used for a heat-resistant member such as an electrode of a high energy density beam application device, if there is a void or the like in the joined portion, not only the thermal conductivity is lowered but also a heat concentrated portion (heat spot). There is a risk of peeling due to local melting or the like of the base material, and further damage to the entire surface due to the progress of melting. For this reason, a bonded body with good adhesion without a decrease in thermal conductivity is required. In addition, since no external mechanical force is applied, a bonding strength greater than necessary is not required, but a bonding strength that does not separate when used at a high temperature is necessary.

  Specifically, the W member and Cu base material of the joined body constituting the heat-resistant member for high energy density utilization equipment of the present invention will be described.

  FIG. 1 is a sectional view showing a joined body according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view mainly showing a joint portion of the W round bar of FIG.

  Referring to FIG. 1, a joined body 101 according to the first embodiment includes a grooved W round bar 10 provided with a groove 4 provided in a circumferential direction on a tip portion 2 on a Cu base material 20 provided with a hole 21. This tip portion 2 is press-fitted.

  Referring to FIG. 2, a grooved W round bar 10 as a W member includes a distal end portion 2 and a base portion 7. The distal end portion 2 has a truncated cone shape, and is provided in the circumferential direction between the first tapered portion 3 at the distal end, the second tapered portion 5 on the base side, and between the first and second tapered portions 3, 5. And a groove 4 having a semicircular cross section. A ring-shaped end surface 6 is provided between the second tapered portion 5 and the base portion 7.

  A metal plating layer 1 composed of at least one layer is provided over the entire surface of the tip 2.

  3A and 3B are views showing a joined body according to the second embodiment of the present invention, in which FIG. 3A is a side view and FIG. 3B is a front view. FIG. 4 is a cross-sectional view of the joined body of FIGS. 3 (a) and 3 (b).

  Referring to FIGS. 3 (a), 3 (b), and 4, the bonded body 102 according to the second embodiment is shown in FIG. 2 on a Cu base 25 having a plurality of holes 26 arranged at one end. It is the structure which press-fitted this front-end | tip part 2 of the W round bar 10 with a groove | channel provided with the groove | channel 11 provided in the circumferential direction of the shape similar to the thing.

  The present invention will be described more specifically with reference to FIGS. First and second tapered portions 3 and 5 having circumferential grooves 4 formed by grooving are formed on one end of a W round bar 10 that is a W member, and a portion that contacts the Cu base 20 is coated with Ni and Cu. A bonded body 101 was obtained by providing a coating and press-fitting the Cu base material, which was previously provided with a cylindrical hole 21 by machining, at a temperature equal to or higher than the softening point of the Cu base material. As a result, a bonded body 101 having good thermal conductivity was obtained. The Ni coating and the Cu coating are easiest to form with the plating layer 1. Hereinafter, the case where the metal plating layer 1 is used as an intermediate layer will be described.

  The reason why Cu is not directly plated on W is that, since no diffusion occurs between W and Cu plating, adhesion is poor, and it is practically desirable to apply Ni plating as a base plating.

Ni plating has good diffusibility and adhesion to W, and is often used for surface modification treatment of W members to impart solder wettability to W which cannot be directly soldered. Moreover, subjected to Cu plated on the Ni plating, the plating baking process, resulting a complete solid solution layer of Ni-Cu to Ni plating layer and the Cu plating layers, Cu-rich layer further Ni is diffused to the surface of Cu is obtained . By applying Cu plating, which is the same material as the Cu base material, good adhesion between the Cu base material and the Cu material, which is the same material, combined with the pressure-bonding effect even during a short heating / cooling time during the press-fitting operation. Ni is diffused to the surface of the Cu plating, and a Ni—Cu reaction layer is formed, resulting in higher adhesion.

  In a preliminary experiment, after Ni plating was plated to a thickness of 1.5 μm, specimens were prepared by applying Cu plating to 3, 5, 7, and 10 μm, respectively, and annealed at 800 ° C. and the subsequent press-fitting temperature. After carrying out a certain heat treatment at 900 ° C., the specimen was cut at the central section to obtain an observation test piece. As a result of confirming the diffusion state of the press-fit joint interface of the observation test piece by the line analysis of the X-ray microanalyzer, both Ni and the interdiffusion layer were confirmed, and Ni was diffused to the Cu plating surface. As a result, it was confirmed that the Cu plating thickness was 10 μm, and that even thick plating was effective. However, since an increase in plating thickness leads to an increase in cost, the present invention was evaluated at 5 μm.

  Furthermore, the thickness of the Ni plating layer was changed to 0.1, 0.5, 1.0, 3.0, and 5 μm, and a test piece with Cu plating of 5 μm formed thereon was produced, and annealed at 800 ° C. After carrying out the treatment and press-fitting at 900 ° C., the specimen was cut at the central section to obtain an observation test piece. The results of confirming the interface diffusion state by X-ray microanalyzer line analysis are shown in FIGS. 5 to 9, respectively.

In both cases, interdiffusion layers were observed between W and Ni and between Ni and Cu, respectively. However, when the Ni plating in FIG. 5 is 0.1 μm, since the Ni plating thickness is thin, Cu reaches the interface between W and Ni, and the W / Cu interface is generated. Since W and Cu have poor adhesion, it is not desirable that W and Cu be in direct contact. Therefore, the Ni plating thickness needs to be 0.5 μm or more. As shown in FIG. 9, when the Ni plating thickness was 5 μm, a single Ni layer was observed between the W layer and the Cu layer. Since Ni has a lower thermal conductivity than W and Cu, it is considered that the presence of Ni single layer is not preferred, Ni plating layer is preferably 3μm or less. That is, as shown in FIG. 8. FIG 6, W and Ni, respectively between the Ni and Cu have occurred interdiffusion, and it is preferable that W / Cu interface and Ni single layer to obtain an interface that does not exist.

  In addition, since the diffusion between W and Cu plating does not occur, the adhesion is poor, and it has been described that it is practically desirable to apply Ni plating as a base plating. It is also possible to directly form Cu on W by sputtering. In that case, if sufficient adhesion strength is obtained, it can be easily imagined that it can be applied to this application.

  However, in practical use, the film formation base is required because it is necessary to reliably form the side surfaces (peripheral surfaces) of the first and second truncated cone-shaped tip portions and the inside of the grooves formed on the peripheral surfaces. It is considered that manufacturing problems such as rotation of the material occur and become a factor of high cost and productivity. Therefore, if necessary, the intermediate layer forming method may be selected by comparison and is not limited to plating.

  In the present invention, Cu has been described as an example of the material of the base material. However, it is not necessary to be pure Cu such as oxygen-free copper, and Cu alloy or Ni which is expected to be used under a higher temperature load and its Metals and alloys having a thermal expansion coefficient larger than W and having a certain degree of rigidity, such as alloys or high alloy steels such as stainless steel, can also be applied. In that case, an intermediate layer material that causes a diffusion reaction may be selected in accordance with the base material. Preferably, it should be made of the same material as the base material, but in the case of an alloy base material, any main element can be used. Although the example of Ni and Cu was shown as an intermediate | middle layer of Cu and Cu alloy above, for example, in the case of a Ni and Ni alloy base material or a stainless steel base material, the same effect is acquired even if an intermediate | middle layer is only Ni.

  The dimensions and shape of the first and second taper portions 3 and 5 including the groove 4 which is the length of the tip portion of the W member 10 are determined by the W required length or the joint area and shape of the Cu base 20. However, in order to facilitate centering of the hole 21 for joining the Cu base material 20 and the center of the W round bar 10, the taper tip diameter of the W thick bar, that is, the tip diameter of the first taper portion 3 is The diameter is preferably slightly smaller than the diameter of the hole 21 of the Cu base 20. Further, in order to cause plastic deformation around the bonding hole 21 of the Cu base material 20, the diameter of the base portion of the second tapered portion needs to be larger than the hole diameter of the Cu base material 20.

  The outer diameter of the large diameter side of the 2nd taper part 5 and a raw material round bar does not need to be the same diameter. The diameter on the large diameter side of the second tapered portion 5 may be smaller than the outer diameter of the material round bar. The shape of the W member 10 need not be a round bar but may be a square bar.

  Moreover, you may give the groove | channel 4 to the 1st and 2nd taper parts 3 and 5 side surface. As the shape of the groove 4, for example, a semicircle, a U-shaped groove or a V-shaped groove can be used. The effect of improving the joint strength can be expected by, for example, Cu biting into the groove 4 due to flow or plastic deformation during press fitting, or by tightening due to thermal contraction during cooling after press fitting.

  FIG. 1 schematically shows the joined body.

  What is necessary is just to determine arbitrarily the dimension and quantity of the groove | channel 4 by the magnitude | size of the 1st and 2nd taper parts 3 and 5. FIG.

  However, when the size and quantity of the groove 4 are too large, the volume of the groove 4 is too large compared to the amount of plastic deformation and heat shrinkage of the Cu base 20, and the amount of Cu biting into the groove 4 is reduced. Care must be taken because the groove 4 cannot be filled and remains as a space.

  When the groove 4 is processed, it is necessary to form an intermediate layer up to the inside of the groove 4. Therefore, the intermediate layer can be easily coated by plating, PVD, CVD, etc. A foil formed by drawing or the like can be formed, and in some cases, the foil can be formed only by sandwiching the foil.

  The depth of the hole 21 needs to be the same as or shorter than the taper length in order to cause plastic deformation at the peripheral part of the base material 20 and the bottom part of the hole.

  It is also possible to install a large number of electrodes on the integrated base material 20.

  3 and 4 are diagrams schematically showing an external appearance when a large number of W members are press-fitted and joined to one base material.

  The press-fit temperature is in a trade-off relationship with the press-fit load. If possible, the press-fit load can be reduced by hot press-fitting if possible, and it can be manufactured with a hot press machine with a small load capacity, or many with the same capacity. Although it is advantageous from the point that it is possible to manufacture individual pieces at the same time, by raising the temperature, damage such as evaporation of the base material is considered in relation to the vapor pressure under vacuum pressure even at temperatures below the melting point. May be determined arbitrarily from the relationship with the load. Of course, it is natural to keep it below the melting point of the substrate 25. In addition, when the temperature is too low, a large press-fitting load is required, and damage to the base material 25 or the W member 10 itself or an effect that the Cu part holds and tightens the W member is reduced.

  The requirements for improving good thermal adhesion and tensile strength are summarized as follows (a) to (c).

(I) The plating layer causes mutual diffusion between the W and Ni intermediate layer, the Ni intermediate layer and the Cu intermediate layer, the Cu intermediate layer and the Cu base material, and at the micro level between the Cu base materials 20 and 25 and the W member 10. This prevents the occurrence of non-contact parts and improves thermal adhesion.

(B) When thermal shrinkage occurs during cooling after press-fitting, the shrinkage of the holes 21 and 26 of the Cu base materials 20 and 25 due to the difference in thermal expansion coefficient is the amount of shrinkage of W that is press-fitted into the holes 21 and 26. Since it is larger, the Cu portion holds the W portion in the entire tip portion 2 including the first and second tapered portions 3 and 5 and the groove 4 and exerts an effect of tightening.

(C) By press-fitting at a temperature equal to or higher than the softening point of the base materials 20 and 25, the Cu base materials 20 and 25 flow along the surface of the W member to the inside of the groove 4 between the tapered portions of the tip portion 2 and undergo plastic deformation. Arise.

  As a result, it is possible to obtain a bonded body that does not have a decrease in thermal conductivity due to defects such as voids or the occurrence of heat spots in the joint, and that has sufficient strength for practical use, and is exposed to severe discharge loads and heat loads. It can be used as a heat-resistant member such as an electrode of a device utilizing a high density beam.

  Specific examples of the present invention will be described below.

(Example 1)
Overall length 15 mm, one end to the tip diameter of the W rod of diameter 6 mm .phi.3.5 mm, taper referred 1:10 subjected to tapering of the length 5 mm, further depth 0.3mm from the taper end to the position of 2.5 mm, a width A semicircular groove processing of 0.3 mm was performed to form the first and second tapered portions 3 and 5 and the groove 11 therebetween. The taper and grooved W round bar taper portion and the end portion 6 in contact with the Cu base were plated with Ni plating at 1.5 μm and Cu plating at 5 μm. Annealing treatment was performed at 800 ° C. after each plating to produce a diffusion layer of W and Ni and Ni and Cu , thereby ensuring adhesion of the plating layer. On the other hand, on one surface of the oxygen-free copper substrate 30 × 30 × 30 mm cubic shape, depth 4 mm, the drilling diameter 3.7 mm X, from the position of 3mm from the side with the Y direction, with their respective 6mm pitch 5 X 5 places, that is, 25 places in total. Twenty-five W round bars with taper were simultaneously press-fitted into the substrate 25. The press-in temperature was 900 ° C., the press-in load was 12.5 Ton (500 Kg / piece), and it was performed in a vacuum atmosphere. The appearance is shown in the side view of FIG. 3A, the front view of FIG. 3B, and the schematic cross-sectional view of FIG. FIG. 2 shows an external view of a tapered W round bar after plating.

In order to investigate the heat conduction state of the bonded body 102 at a high temperature, a cooling copper pipe penetrating the center of the side surface of the oxygen-free copper base material 25 was installed, and a heating test by electron beam heating was performed. Input thermal energy, for example in the MHD power generator electrodes, as described in Non-Patent Document 2, since it is necessary to withstand the heat flux 0.5~3MW / ^{m 2,} more severe 5 MW / ^{m 2} And 10 MW / m ² . When the time required for the temperature state of the joined body to reach a steady state with this input energy was measured, all were about 15 seconds. The average surface temperature of the W element 10 at that time, 1380 ° C. at 5 MW / ^{m 2,} was 2200 ° C. at 10 MW / ^{m 2.}

In addition, as a comparative example, a test body was manufactured by press-fitting a tapered W round bar, which was grooved in the same manner as described above, into a Cu base without plating, and a heating test by electron beam heating was performed under the same conditions as described above. The average surface temperature of the W portion of that time, 1450 ° C. at 5 MW / ^{m 2,} was about 2700 ° C. at 10 MW / ^{m 2.}

That 70 ° C. at 5 MW / ^{m 2} by performing Ni plating and Cu plating, so that the cooling capacity of about 500 ° C at 10 MW / ^{m 2} is improved.

Furthermore, a thermal cycle test was carried out on the test specimen with plating produced in the same manner. The input time of 5 MW / m ² and 10 MW / m ² were set to 15 seconds for the heating time and the cooling time, respectively.

3000 cycles at 5 MW / ^{m 2} in this condition, 10 MW / ^{m 2} at but 1000 cycles of the thermal cycle test was conducted respectively, omission of W element in any of the specimens, the bonding strength decreases or anoxic copper base of the float, etc. There were no defects in melting of the material.

  Further, during any of the thermal cycle tests, no significant change was observed in the surface temperature of the W member. This indicates that there was no deterioration in the heat transfer performance of the joint. Moreover, from the line analysis result by EPMA of the obtained joining part, it has confirmed that interdiffusion had arisen between W and Ni intermediate | middle layer, Ni intermediate | middle layer and Cu intermediate | middle layer, and Cu intermediate | middle layer and Cu base material. For this reason, it is considered that the thermal conductivity between the Cu base member 25 and the W member 10 is improved as compared with the state without plating and the cooling ability is improved.

(Example 2)
To confirm the adhesion strength, total length 40 mm, similar to the tip diameter as the Example 1 at one end of the W rod of diameter 6 mm .phi.3.5 mm, taper referred 1:10 subjected to tapering of the length 5 mm, 2 from further taper end A semicircular groove processing having a depth of 0.3 mm and a width of 0.3 mm was performed at a position of 0.5 mm, and the first and second tapered portions 3 and 5 and the groove 4 were formed therebetween. Ni plating 1.5 μm and Cu plating 5 μm were applied to the first and second taper portions of the tapered and grooved W round bar and the end portion 2 provided with the groove 4 and the end face 6 in contact with the Cu substrate 20. . In addition, after each plating, the annealing process was implemented at 800 degreeC and the adhesiveness of plating was ensured. This is to facilitate handling up to the press-fitting operation. After that, the taper part of this W round bar is press-fitted into an oxygen-free copper base material with a depth of 4 mm and a diameter of 3.7 mm, φ20 mm x length 40 mm under a press-fitting temperature of 900 ° C., a press-fitting load of 500 kg, and a vacuum atmosphere. did.

  FIG. 2 shows the shape of a round W bar after plating with a grooved taper. FIG. 1 is a schematic cross-sectional view of the obtained bonded body. It was confirmed that a part of the oxygen-free copper member bites into the groove 4 and has a good joint.

Further, a tensile test was performed on the obtained joined body. The results are shown in Table 1 below as average values for 10 conditions. Temperature in the vicinity of the interface test temperature W member and Cu substrate, under the conditions of Example 1, about 300 ° C. at 5 MW / ^{m 2,} because it was 500 ° C. at 10 MW / ^{m 2,} room temperature, 300 ° C., and 500 The temperature was set to ° C. The tensile speed was 1 mm / sec.

In the case where bonding strength tapered portion as in the present invention is evaluated, or to evaluate the bonding cross section in which part, because there is no general indication, shown by the pull-out load here. In either case, the fracture was caused by the shear fracture of the Cu portion that digged into the groove 4 formed between the first and second tapered portions 3 and 5.

For comparison, Table 2 below also shows the tensile test results of the joined body disclosed in Patent Document 3. In this case, since the press-in temperature is 600 ° C. at maximum and there is no groove or intermediate layer in the taper portion, the same high-temperature tensile test result at 500 ° C. provides only a joint strength of 57.2 kg and about 43% of 134 kg of the present invention. It is not done.

  From this result, it was confirmed that the joined body of the present invention was superior in both thermal conductivity and joining strength to the joined body disclosed in Patent Document 3 of the related art. When used as an electrode or the like, a mechanical external force is generally not applied to the electrode portion, and the pull-out load shown in Table 1 is a bonding strength that can withstand practical use.

  The joined body as a heat-resistant member for a high energy density utilization device according to the present invention is applied to a heat-resistant member such as an electrode used at a high temperature and high load such as a high energy density utilization X-ray source or a power generation device.

It is sectional drawing which shows the conjugate | zygote by the 1st Embodiment of this invention. It is sectional drawing which mainly shows the junction part of W round bar of FIG. (A) And (b) is a figure which shows the conjugate | zygote by the 2nd Embodiment of this invention, (a) is a side view, (b) is a front view. It is sectional drawing of the joined body of Fig.3 (a) and (b). It is a figure which shows the confirmation result of the diffusion state of the interface by the line analysis of the X-ray microanalyzer of the test piece whose thickness of the Ni plating layer of this invention is 0.1 micrometer. It is a figure which shows the confirmation result of the diffusion state of the interface by the line analysis of the X-ray microanalyzer of the test piece whose thickness of the Ni plating layer of this invention is 0.5 micrometer. It is a figure which shows the confirmation result of the diffusion state of the interface by the line analysis of the X-ray microanalyzer of the test piece whose thickness of the Ni plating layer of this invention is 1.0 micrometer. It is a figure which shows the confirmation result of the diffusion state of the interface by the line analysis of the X-ray microanalyzer of the test piece whose thickness of the Ni plating layer of this invention is 3.0 micrometers. It is a figure which shows the confirmation result of the diffusion state of the interface by the line analysis of the X-ray microanalyzer of the test piece whose thickness of the Ni plating layer of this invention is 5 micrometers.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal plating layer 2 Tip part 3 1st taper part 4,11 Groove 5 2nd taper part 6 End surface 7 Base 10 W member (W round bar with a groove)
20, 25 Cu base material 21, 26 hole 101, 102 joined body

Claims (13)

It has a tungsten member having a tapered portion at a tip portion, and has a groove formed on the tapered portion from the side surface of the tapered portion toward the inside of the tapered portion, and is formed in the tapered portion including the groove. intermediate layer is provided, at a temperature above the softening point before Kimotozai the tungsten member to a large base of thermal expansion coefficient than the tungsten member, by press-fitting joining the tungsten member in the axial direction, the intermediate The layer has a metallic bond formed between the tungsten member and the base material, and the base material bites into the inside of the groove.   The heat-resistant member for a high energy density utilization device according to claim 1, wherein the metallic member is provided as the intermediate layer at a part of an interface between the tungsten member and the base material. Heat resistant material.   2. The heat-resistant member for high energy density utilization equipment according to claim 1, wherein the metallic bond is formed over the entire surface of the tip including the inside of the groove formed by the groove processing of the tungsten member. A heat-resistant member for equipment using high energy density.   The heat-resistant member for high energy density utilization equipment according to any one of claims 1 to 3, wherein the metallic bond is formed of tungsten-nickel or nickel-copper. Heat-resistant material for equipment using density.   5. The heat-resistant member for a high energy density utilization device according to claim 1, wherein the metallic bonding is performed when the tungsten member and the base are joined during press-fitting of the tungsten member to the base material. A heat-resistant member for high energy density utilization equipment, which is formed by heating two layers of nickel and copper or a single nickel layer provided between the two.   The heat-resistant member for a high energy density utilization device according to claim 5, wherein the metallic bond is obtained by heating a nickel coating layer having a thickness of not less than 0.5 µm and not more than 3 µm during the press-fitting. A heat-resistant member for equipment using high energy density.   The heat-resistant member for a high energy density utilization device according to any one of claims 1 to 6, wherein one or two or more tungsten members are press-fitted and joined to one base material. Heat resistant member for high energy density equipment. The heat-resistant member for a high energy density utilization device according to any one of claims 1 to 7, wherein heating and cooling are performed 3000 times in each 15-second cycle at an input thermal energy of 5 MW / m ² and an input thermal energy of 10 MW. / M ² with a heat and cooling time of 15 seconds each, withstanding 1000 heat cycle tests, and no heat transfer performance deterioration of the joint between the tungsten member and the substrate Heat-resistant material for equipment using density. In a method of manufacturing a heat-resistant member for high energy density utilization equipment having a tungsten member and a base material having a larger thermal expansion coefficient than tungsten,
A step of providing a taper portion at a tip portion of the tungsten member, and forming a groove in the taper portion from a side surface of the taper portion toward the inside of the taper portion ;
Forming an intermediate layer for generating a metallic bond with the tungsten member and the substrate on a part of the tungsten member;
Forming the metallic bond as the intermediate layer between the tungsten member and the base material by press-fitting the tungsten member to the base material in an axial direction at a temperature equal to or higher than the softening point of the base material; The manufacturing method of the heat-resistant member for high energy density utilization apparatuses characterized by having.   10. The method for manufacturing a heat-resistant member for a high energy density utilization device according to claim 9, wherein the tungsten member and the base material are metalized over the entire surface of the tip including the inside of the groove formed by the groove processing. The manufacturing method of the heat-resistant member for high energy density utilization apparatuses characterized by producing | generating a coupling | bonding.   The method for manufacturing a heat-resistant member for a high energy density utilization device according to claim 9, wherein two layers of nickel and copper, or nickel alone, cause the intermediate layer to form the metallic bond in both the tungsten member and the base material, respectively. A method for producing a heat-resistant member for high energy density utilization equipment, comprising using a layer.   The heat-resistant member for high energy density utilization equipment according to claim 11, wherein the intermediate layer is made of nickel plating having a thickness of 0.5 µm to 3 µm. Manufacturing method.   In the manufacturing method of the heat-resistant member for high energy density utilization apparatuses as described in any one of Claim 9 to 12, the said tungsten member is press-fitted and joined to one base material, It is characterized by the above-mentioned. The manufacturing method of the heat-resistant member for high energy density utilization apparatuses made into.

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