Brazing material, joined body, and method for producing joined body

Abstract

This brazing material comprises Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi, at least one second element selected from the group consisting of Ag, In, and Mn, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, wherein the content ratio of Cu is the highest among Cu, Mg, the first element, and the second element contained in the b razing material.

Description

Brazing material, jointed body, and method for manufacturing the jointed body

[0001] The present disclosure relates to a brazing material, a joined body, and a method for manufacturing the joined body.

[0002] A joined body formed by joining a metal member such as copper to a ceramic material is sometimes used as a constituent material of a power control device mounted on an electric vehicle or a hybrid vehicle. A technique using an active metal brazing filler metal containing silver (Ag) is known for joining metal members to ceramic materials. Recently, in order to solve problems such as Ag migration and high costs, a joining technique using an active metal brazing filler metal that does not contain Ag as a main component has been proposed (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2018-140929

[0004] An object of the present disclosure is to provide a low-melting point active metal brazing material and a joined body using the brazing material.

[0005] According to one aspect of the present disclosure, there is provided a brazing filler metal comprising: Cu; Mg; at least one first element selected from the group consisting of Sn, Sb, and Bi; at least one second element selected from the group consisting of Ag, In, and Mn; and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, wherein the content of Cu is the highest among the Cu, Mg, the first element, and the second element.

[0006] According to another aspect of the present disclosure, there is provided a joined body comprising: a first member made of metal; a second member joined to the first member and made of the same or different metal as the first member, or a ceramic; and a joining layer formed on the joining surface between the first member and the second member, wherein the joining layer contains: Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi; at least one second element selected from the group consisting of Ag, In, and Mn; and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, and wherein Cu has the highest content among the elements constituting the joining layer.

[0007] According to yet another aspect of the present disclosure, there is provided a method for manufacturing a joined body, the method comprising: an arrangement step of stacking a first member made of a metal and a second member made of the same or a different metal as the first member, or a ceramic, via a brazing filler metal; and a heating step of heating and holding the stack of the first member and the second member while applying pressure in the stacking direction, wherein the brazing filler metal contains at least one first element selected from the group consisting of Cu, Mg, Sn, Sb, and Bi, at least one second element selected from the group consisting of Ag, In, and Mn, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, and the brazing filler metal contains a material with the highest Cu content among the elements contained in the brazing filler metal.

[0008] According to the present disclosure, it is possible to provide a low-melting point active metal brazing material and a bonded body using the brazing material.

[0009] FIG. 1 is a partial cross-sectional view of a metal / ceramic bonded body 100 according to one embodiment of the present disclosure. FIG. 2 is a partial enlarged view of the dashed-line region A in FIG. 1. FIG. 3( a) is a schematic diagram illustrating shear stress applied to the bonding layer 30, and FIG. 3( b) is a schematic diagram illustrating tensile stress applied to the bonding layer 30. FIG. 4( a) illustrates a state in which a metal member 10 and a ceramic member 20 are arranged via a brazing filler metal 50. FIG. 4( b) illustrates a state in which a laminate of the metal member 10 and the ceramic member 20 is heated while being pressurized. FIG. 4( c) illustrates the manufactured metal / ceramic bonded body 100. FIG. 5 is a schematic diagram illustrating a state in which a shear strength test is performed. FIG. 6 illustrates a cross-sectional SEM photograph (left side of the figure) and the results of EDX analysis (right side of the figure) of Sample 4 according to an embodiment of the present disclosure. Fig. 7 shows a cross-sectional SEM photograph (left side) and EDX analysis results (right side) of Sample 67 according to an embodiment of the present disclosure. Fig. 8 shows a cross-sectional SEM photograph (left side) and EDX analysis results (right side) of Sample 80 according to an embodiment of the present disclosure. Fig. 9 shows the results of differential thermal analysis according to an embodiment of the present disclosure.

[0010] <Findings Obtained by the Inventors> Brazing filler metals are required not only not to significantly change the structure of the joined materials when heated, but also to produce a strong joining layer. The inventors focused on a Cu-Mg eutectic composition, which can significantly lower the melting point of Cu, as a composition of an active metal brazing filler metal that satisfies these requirements.

[0011] However, in the Cu-Mg binary eutectic composition, the vapor pressure of Mg is high, and when Mg alone is added to the brazing material, the temperature rises above 600°C, resulting in MgCu. ２ It is known that when Mg is added to a brazing filler metal as a brazing filler metal, evaporation of Mg proceeds rapidly at temperatures above 780°C. The temperature at which brazing filler metal can be used is 725°C, the Cu-Mg eutectic point at which the liquid phase begins to form, but considering the wettability of the liquid phase to the materials to be joined, it is necessary to heat to a higher temperature, which tends to make the evaporation of Mg more likely. As a result, voids may form due to Mg evaporation before a strong joining structure is formed, and joining layers containing such voids tend to have low joining strength. Also, if excessive Mg is added, joining is possible before the Mg evaporates, but in the case of MgCu２ and CuMg ２ However, a large amount of intermetallic compounds known for their brittleness is formed, making it difficult to maintain high bonding strength. Although the Cu-Mg binary eutectic composition can significantly lower the melting temperature, there are also many factors that reduce bonding strength, making it difficult to achieve high-strength bonding.

[0012] The present inventors have investigated methods for suppressing the evaporation of Mg from a Cu-Mg eutectic composition. They have devised a method of adding to the brazing filler metal an element that combines with Mg to form a compound with a higher melting point than Mg, and that forms a eutectic with each of Cu and Mg, or a ternary eutectic with Cu and Mg. They have focused on elements that cause such eutectic reactions, such as silicon (Si), germanium (Ge), tin (Sn), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi).

[0013] Therefore, the present inventors added the above elements to a Cu-Mg-based active metal brazing filler metal and investigated the resulting bonding layer. As a result, it was confirmed that, among the above elements, Sn, Sb, and Bi can improve the bonding strength, but Si, Ge, P, and As cannot sufficiently improve the bonding strength. Further investigation into this point revealed that Si and P tend to be more reactive with the active metal elements described below than with Mg, and that the intended effect of reacting with Mg and suppressing its evaporation is not very effective.

[0014] From these findings, the present inventors have found that in order to suppress the decrease in joint strength due to evaporation of Mg in Cu-Mg based active metal brazing filler metals, it is effective to add Sn, Sb and Bi to the brazing filler metal as Mg evaporation suppressing elements, which react with Mg to form compounds with higher melting points than Mg.

[0015] Furthermore, as a result of further intensive research by the present inventors, it was discovered that the melting point of the active metal brazing filler metal can be further lowered by adding at least one element selected from the group consisting of Ag, indium (In), and manganese (Mn) to the brazing filler metal. This enables bonding at lower temperatures, thereby reducing residual stress around the bonding layer. It also prevents the structure and shape of the substrate from changing due to heat. Furthermore, it was discovered that by appropriately controlling the amount (content) of the above elements added, it is possible to improve the wettability of the brazing filler metal and impart corrosion resistance.

[0016] The present invention was made based on the above findings.

[0017] <One Aspect of the Present Disclosure> One aspect of the present disclosure will be described below with reference to the above-mentioned drawings. Note that all drawings used in the following description are schematic. The dimensions and proportions of each element shown in the drawings do not necessarily correspond to those in reality. Furthermore, the dimensions and proportions of each element do not necessarily correspond between drawings. Furthermore, in this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits.

[0018] (1) Brazing Filler Metal The brazing filler metal of this embodiment is a Cu-Mg based active metal brazing filler metal containing Cu as the main component (for example, a Cu content of 35 at % or more). Specifically, the brazing filler metal contains Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi (hereinafter also referred to as a "Mg evaporation suppressing element"), at least one second element selected from the group consisting of Ag, In, and Mn (hereinafter also referred to as a "melting point depressing element"), and at least one active metal element selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), yttrium (Y), cerium (Ce), lanthanum (La), samarium (Sm), ytterbium (Yb), neodymium (Nd), gadolinium (Gd), and erbium (Er), and the content (at %) of Cu is the highest among the metal elements (here, Cu, the Mg, the first element, and the second element) constituting the brazing filler metal. The brazing filler metal may contain Mg, a magnesium evaporation suppressing element, a melting point depressing element, an active metal element, and inevitable impurities, with the balance being Cu. The brazing filler metal can be used to join metal members to ceramic members, or to join metal members to metal members. Note that inevitable impurities refer to elements other than those intentionally contained in the brazing filler metal when preparing the brazing filler metal, such as elements derived from the raw materials that could not be completely removed from the raw materials.

[0019] Cu is an element that forms a solid solution that mainly constitutes the bonding layer when the brazing filler metal is heated to bond the material, and Cu also contributes to the ductility and malleability of the bonding layer.

[0020] Mg acts to lower the melting point of Cu, thereby lowering the joining temperature of the brazing filler metal, and also acts to increase the wettability of the brazing filler metal to metal members and ceramic members.

[0021] The Mg evaporation inhibitor is an element that readily reacts with Mg when the brazing filler metal is heated, and acts to form a compound with Mg by reacting with Mg. This compound has a higher melting point than Mg and melts at the joining temperature, but is formed as a eutectic in which the molten components, such as Mg, are less likely to evaporate. Therefore, the Mg evaporation inhibitor reacts with Mg during joining to suppress Mg evaporation. For example, the Mg evaporation inhibitor forms a ternary intermetallic compound with Cu or Mg when the brazing filler metal is heated, and acts to improve the strength of the intermetallic compound. As the Mg evaporation inhibitor, at least one element selected from the group consisting of Sn, Sb, and Bi can be used.

[0022] The melting point depressant acts to lower the melting point of the brazing filler metal. It also contributes to improving the wettability of the brazing filler metal. At least one element selected from the group consisting of Ag, In, and Mn can be used as the melting point depressant. The melting point depressant exists in a solid solution in Cu or diffused in the materials to be joined. There are cases where only Ag exists as a single phase in the joining layer.

[0023] The active metal element reacts with the ceramic member to form a compound (e.g., a nitride) when the brazing filler metal is heated, thereby enhancing the bonding strength between the ceramic member and the bonding layer. When bonding with a nitride ceramic member, an active metal element having a low standard free energy of formation of an active metal nitride (when bonding with an oxide ceramic member, an active metal oxide) and easily reacting with the ceramic member may be used as the active metal element. For example, at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er may be used. Ti is particularly preferred. When the brazing filler metal is heated, the compound formed by reaction with the ceramic member (e.g., a nitride) may be, for example, TiN when Ti is selected as the active metal, ZrN when Zr is selected, HfN when Hf is selected, or V when V is selected. ２ If N or Nb is selected, it becomes NbN. If Ta is selected, it becomes TaN. If Cr is selected, it becomes Cr. ２ If you select N or Mo,２ If N or W is selected, it becomes WN; if Y is selected, it becomes YN; if Ce is selected, it becomes CeN; if La is selected, it becomes LaN; if Sm is selected, it becomes SmN; if Yb is selected, it becomes YbN; if Nd is selected, it becomes NdN ３ When Gd is selected, GdN is obtained, and when Er is selected, ErN is obtained.

[0024] As for the content of each metal element constituting the brazing filler metal, for example, the Cu content is preferably 35 to 89 at% (more preferably 40 to 85 at%), the Mg content is preferably 1 to 20 at%, the total content of Mg evaporation inhibitor elements is preferably 1 to 20 at%, the total content of melting point depressant elements is preferably 1 to 35 at%, and the total content of active metal elements is preferably 0.1 to 10 at%.

[0025] Furthermore, when the content of Mg is X at % and the content of the Mg evaporation inhibitor element is Y at %, it is preferable that X-5≦Y≦X+5. By containing each element at such a content, it is possible to achieve a predetermined bonding strength in the bonding layer while lowering the bonding temperature of the brazing material. Note that Y is greater than 0 and does not exceed 100.

[0026] The form of the brazing filler metal is not particularly limited, but from the viewpoint of obtaining a uniform phase structure described later in the bonding layer, a paste-like brazing filler metal is preferably used. The paste-like brazing filler metal contains powders containing the above-mentioned elements, a solvent, a binder, etc.

[0027] In the brazing filler metal, the form of inclusion (form of addition) of each element is not particularly limited, and each element may be contained as a single powder or as a compound powder containing each element. The form of inclusion of each element will be described below.

[0028] Mg may be, for example, Mg alone, an Mg solid solution containing other elements, or a compound with Cu (MgCu ２Preferably, the brazing filler metal contains at least one of the following in the form of a powder: a compound with an active metal element, a compound with an Mg evaporation inhibitor, and a compound with a melting-point depressant (the powder is added to the brazing filler metal). Among these, it is preferable that at least a portion of Mg is contained in the form of a powder containing an intermetallic compound with an Mg evaporation inhibitor. For example, the Mg may contain an alloy powder formed from Mg and an intermetallic compound containing an Mg evaporation inhibitor, or an alloy powder formed from an intermetallic compound containing an Mg evaporation inhibitor and an Mg evaporation inhibitor. Alternatively, the brazing filler metal may contain a mixture of the above-mentioned alloy powder and at least one of Mg powder, Mg—Cu intermetallic compound powder, etc. By previously forming at least a portion of the Mg into an intermetallic compound with an Mg evaporation inhibitor, evaporation of Mg during melting of the brazing filler metal can be more reliably suppressed. The alloy powder does not mean a mixture of a powder containing one element and a powder containing another element, but means a powder in which each element is contained in the form of an alloy in a single particle. The solid solution containing another element means a solid solution in which a part of the element constituting the solid solution in the crystal is replaced with the other element, or a solid solution in which the other element has penetrated into the gaps in the crystal lattice.

[0029] The alloy powder may contain at least Mg and an Mg evaporation inhibiting element, and may further contain Cu. When the Mg evaporation inhibiting element is Sn, the alloy powder may contain, for example, Mg ２ Sn and Cu ４ MgSn, etc. can be used. When the Mg evaporation inhibitor element is Sb, Mg ３ Sb ２ When the magnesium evaporation inhibiting element is Bi, Mg ３ Bi ２ , CuMgBi, etc. can be used.

[0030] The alloy powder may be prepared by mixing and melting Mg, an element that inhibits evaporation of Mg, and optionally Cu and an element that lowers the melting point, and then atomizing the mixture to form a powder containing each element.

[0031] The content (addition rate) of the alloy powder containing Mg and an Mg evaporation inhibiting element is not particularly limited, but it is preferable to set the content so that the amount of Mg derived from the alloy powder is 40% or more of the total amount of Mg contained in the brazing filler metal. For example, when the alloy powder containing Mg and an Mg evaporation inhibiting element is used in combination with at least one of Mg metal powder, Mg-active metal alloy powder, Mg-Cu intermetallic compound powder, etc., it is preferable to adjust the content of the alloy powder containing Mg and an Mg evaporation inhibiting element so that the amount of Mg derived from the alloy powder containing Mg and an Mg evaporation inhibiting element is 40% or more of the total amount of Mg contained in the brazing filler metal. The content of the alloy powder may be 100% of the total amount of Mg contained in the brazing filler metal, that is, the brazing filler metal may contain only the alloy powder. By setting the content in this way, Mg evaporation can be more stably suppressed.

[0032] Cu may be, for example, a simple Cu, a Cu solid solution containing other elements, or an intermetallic compound with Mg (e.g., MgCu ２ etc.), intermetallic compounds with Mg evaporation suppressing elements or melting point lowering elements (e.g. Cu ３ Sn, Cu ３ Sb, etc.), intermetallic compounds with active metal elements (e.g., Cu-Ti compounds (Cu ４ Ti and Cu ３ Ti ２ ) or the like), or a powder containing at least one of Cu alone or an alloy formed by a solid solution and an intermetallic compound formed with Cu.

[0033] The Mg evaporation inhibiting element may be contained in the form of a powder containing at least one of, for example, a simple substance, a solid solution containing other elements, a compound formed with at least one of Mg, Cu, a melting-point depressant element, and an active metal element, or an alloy formed by an intermetallic compound formed with the simple substance or solid solution of the Mg evaporation inhibiting element and Cu.

[0034] The melting-point depressing element may be contained in the form of a powder containing at least one of, for example, a simple substance, a solid solution containing other elements, a hydride, or an intermetallic compound formed with at least one element selected from Mg, Cu, a Mg evaporation inhibiting element, and an active metal element.

[0035] The active metal element may be contained in the form of a powder containing at least one of, for example, a simple substance, a solid solution containing other elements, a hydride, or an intermetallic compound formed with at least one element selected from Mg, Cu, a Mg evaporation inhibitor element, and a melting point depressant element.

[0036] In brazing filler metals, the particle size of each powder containing Cu, Mg, Mg evaporation suppressing element, melting point depressant element, and active metal element can be appropriately adjusted depending on the size of the materials to be joined and the thickness of the joining layer. For example, in the case of macrostructures such as heat exchangers and hermetically sealed bodies, the particle size may be large, preferably a median diameter D50 of 45 μm to 150 μm. Furthermore, for example, when the goal is to reduce the thermal resistance of a joining body such as a circuit board, it is desirable to form a thin joining layer with lower thermal conductivity than pure metals, preferably a median diameter D50 of 45 μm or less. On the other hand, while there is no particular lower limit for the median diameter, a median diameter D50 of 5 μm or more is preferred from the viewpoint of suppressing the effects of surface oxidation of the powder. The median diameter D50 is measured, for example, using a laser diffraction particle size distribution analyzer, and represents the particle size at 50% of the volume-based cumulative distribution curve.

[0037] The brazing material can be used as a paste of metal powder as needed, and may contain binders, solvents, surfactants, plasticizers, dispersants, etc. in addition to the metal powder. Examples of binders that can be used include polyvinyl alcohol, ethyl cellulose, polymethacrylic acid, and polyacrylic. Examples of solvents that can be used include alcohols such as terpineol and butanediol, and toluenes. Examples of surfactants that can be used include cationic, anionic, and nonionic activators.

[0038] The method for preparing the brazing material is not particularly limited, and any conventionally known method may be used.

[0039] (2) Bonded Body Next, a bonded body will be described with reference to Fig. 1. In this embodiment, a bonded body (hereinafter also referred to as a metal / ceramic bonded body) in which a metal member (first member) and a ceramic member (second member) are bonded together will be described as an example. Fig. 1 is a partial cross-sectional view of a metal / ceramic bonded body according to one embodiment of the present disclosure.

[0040] As shown in FIG. 1 , a metal / ceramic bonded body 100 includes a metal member 10, a ceramic member 20 bonded to the metal member 10, and a bonding layer 30 formed on the bonding surface between the metal member 10 and the ceramic member 20.

[0041] (Metal Member) The metal member 10 is made of pure copper, copper alloy, pure nickel, nickel alloy, titanium alloy, stainless steel (SUS), chromium-based alloy, etc. Examples of pure copper that can be used include oxygen-free copper, tough pitch copper, and phosphorus-deoxidized copper. Examples of copper alloys that can be used include alloys containing copper (Cu) as the main element and containing at least one element selected from the group consisting of zinc (Zn), tin (Sn), phosphorus (P), aluminum (Al), beryllium (Be), cobalt (Co), nickel (Ni), iron (Fe), and manganese (Mn).

[0042] There are no particular limitations on the shape or dimensions of the metal member 10, but when the metal / ceramic bonded body 100 is used as a constituent material of an insulating circuit board, it can be, for example, a flat plate having a thickness in the range of 0.1 mm to 6.0 mm.

[0043] (Ceramic Member) The ceramic member 20 is composed of, for example, at least one of a nitride, a carbide, and an oxide. As the nitride, for example, silicon nitride (Si ３ N ４ Examples of the carbides include silicon carbide (SiC) and diamond. Examples of the oxides include aluminum oxide (Al ２ O ３ ) etc.

[0044] There are no particular limitations on the shape or dimensions of the ceramic member 20. However, when the metal / ceramic bonded body 100 is used as a constituent material of an insulating circuit board, the ceramic member 20 may be, for example, a flat plate having a thickness in the range of 0.2 mm to 4.0 mm.

[0045] (Bonding Layer) A bonding layer 30 is formed along bonding surfaces 10s, 20s between the metal member 10 and the ceramic member 20. The bonding layer 30 is formed from the brazing filler metal described above, and contains Cu, Mg, a Mg evaporation suppressing element, a melting point lowering element, and an active metal element, with Cu having the highest content (at %) of all the elements constituting the bonding layer 30.

[0046] 1, the bonding layer 30 has a laminated structure of a first layer 31 that forms an interface with the metal member 10, and a second layer 32 that forms an interface with the ceramic member 20 and is in contact with the first layer 31. The thickness of the first layer 31 is, for example, 1 μm to 2000 μm, and the thickness of the second layer 32 is, for example, 2 nm to 5000 nm.

[0047] The first layer 31 is composed of a solid solution phase in which other metal elements are dissolved in Cu, and an intermetallic compound containing Cu, Mg, and an Mg evaporation inhibiting element (for example, Cu ４ and a compound phase containing CuMgSn, CuMgSb, CuMgBi).

[0048] (First Layer) The first layer 31 will now be described in detail with reference to Fig. 2. Fig. 2 is a partial enlarged view of the dashed line area A in Fig. 1 .

[0049] As shown in FIG. 2, the first layer 31 is composed of a solid solution phase 31A and a compound phase 31B dispersed therein.

[0050] The solid solution phase 31A is mainly composed of a solid solution of Cu and other metal elements. When the Mg evaporation inhibitor is Sn, Mg and Sn may be dissolved in the solid solution phase 31A. When the Mg evaporation inhibitor is Sb, at least Sb may be dissolved in the solid solution phase 31A, but Mg may not be dissolved. When the Mg evaporation inhibitor is Bi, at least Mg may be dissolved in the solid solution phase 31A, but Bi may not be dissolved. Furthermore, the solid solution phase 31A may contain melting-point depressing elements and active metal elements contained in the brazing filler metal, as well as Si and Al contained in the ceramic member 20. When each element is dissolved in the solid solution phase 31A, the strength of the solid solution phase 31A can be improved by solution strengthening.

[0051] The compound phase 31B contains, for example, a ternary intermetallic compound containing Cu, Mg, and an Mg evaporation inhibiting element. The compound phase 31B is formed, for example, by the precipitation of an intermetallic compound. The compound phase 31B contains an intermetallic compound according to the type of Mg evaporation inhibiting element. Specifically, when the Mg evaporation inhibiting element is Sn, the ternary intermetallic compound contains Cu. ４ The ternary intermetallic compound is CuMgSn. When the Mg evaporation inhibiting element is Sb, the ternary intermetallic compound is CuMgSb. When the Mg evaporation inhibiting element is Bi, the ternary intermetallic compound is CuMgBi. When two or more Mg evaporation inhibiting elements are used, the ternary intermetallic compound is CuMg (Sn, Sb, Bi) in which Sn, Sb, and Bi are partially substituted. Note that the compound phase 31B contains at least a ternary intermetallic compound, but Cu, Mg, and the Mg evaporation inhibiting element may also be contained as intermetallic compounds in other forms. For example, binary intermetallic compounds composed of two of Cu, Mg, and the Mg evaporation inhibiting element, simple metals of each element, or intermetallic compounds further containing a melting-point depressant or an active metal element may be mentioned.

[0052] In the first layer 31, a solid solution phase 31A having excellent malleability and ductility is preferably configured as a continuous phase. More preferably, the first layer 31 has a sea-island structure in which a compound phase 31B is dispersed in the solid solution phase 31A, as shown in FIG. 2 . The compound phase 31B containing an intermetallic compound is more brittle than the solid solution phase 31A containing a solid solution, which can cause a decrease in the bonding strength of the bonding layer 30. If this compound phase 31B is continuous in a layered structure throughout the bonding layer 30 and is formed in a region corresponding to a stress concentration point, crack propagation cannot be stopped when stress is applied to the compound phase 31B, which may significantly decrease the bonding strength. In this regard, when the bonding layer 30 has a sea-island structure as shown in FIG. 2 , the bonding strength can be maintained even higher due to precipitation hardening.

[0053] In the first layer 31, the compound phase 31B preferably does not exist as a continuous phase throughout substantially the entire thickness direction and the entire width direction of the first layer 31, but exists dispersedly in the solid-solution phase 30A. Specifically, when any region in 10 μm thickness units is extracted from the first layer 31 and the area ratio of the compound phase 31B in the any region is measured, it is preferable that all area ratios are 40% or less. The presence of the compound phase 31B in any region at a predetermined area ratio allows the compound phase 31B to be dispersed in the solid-solution phase 31A, thereby suppressing the local appearance of the compound phase 31B and the resulting decrease in bonding strength. The area ratio of the compound phase 31B is calculated by dividing the total area of ​​the compound phase 31B dispersed in the extracted region by the area of ​​the extracted region.

[0054] Furthermore, in the first layer 31, the solid solution phase 31A is preferably configured as a continuous phase connecting the second layer 32 and the metal member 10. That is, the first layer 31 preferably has a path formed by the solid solution phase 31A connecting the second layer 32 and the metal member 10. The solid solution phase 31A is mainly formed of a solid solution containing Cu and has excellent malleability and ductility. Such a solid solution phase 31A is configured to continuously connect the second layer 32 and the metal member 10 without being interrupted by the compound phase 31B, thereby enabling a strong bond between the metal member 10 and the ceramic member 20 and improving the bonding strength. To form the continuous phase, it is preferable to form the compound phase 31B so that it is finely dispersed. More specifically, when observing the bonding layer 30 in a cross section perpendicular to the bonding surfaces 10s and 20s, the solid solution phase 31A preferably has a path (a path extending in the thickness direction of the bonding layer 30) with a width of 2 μm or more in a direction parallel to the bonding surfaces 10s and 20s within an arbitrary field of view of 50 μm × 50 μm. This means that the solid solution phase 31A forms a good path.

[0055] Furthermore, the bonding layer 30 is formed using the above-described brazing filler metal, thereby suppressing the occurrence of voids. When the metal member 10 and the ceramic member 20 are bonded using a brazing filler metal containing Mg, there is a concern that voids or pinholes (hereinafter collectively referred to as voids) may occur in the first layer 31 due to evaporation of the Mg contained in the brazing filler metal. The presence of such voids can reduce the bonding strength between the metal member 10 and the ceramic member 20. In this regard, in the present embodiment, the brazing filler metal contains an element that suppresses Mg evaporation, thereby suppressing the evaporation of Mg and reducing the occurrence of voids in the bonding layer 30.

[0056] Specifically, when the bonding layer 30 (particularly the first layer 31) is observed in a cross section perpendicular to the bonding surfaces 10s and 20s, the thickness of the bonding layer 30 is approximately 10,000 μm. ２It is preferable that no voids having a circular equivalent diameter of 8 μm or more are observed within any field of view. More preferably, no voids having a circular equivalent diameter of 4 μm or more are observed, and even more preferably, no voids having a circular equivalent diameter of 1 μm or more are observed. In other words, the number of voids having a circular equivalent diameter of 8 μm or more is 10,000 μm. ２ More preferably, the number of voids having a size of 4 μm or more is one or less, and even more preferably, the number of voids having a size of 1 μm or more is one or less.

[0057] In the solid solution phase 31A, other metal elements are dissolved in the Cu crystal, and the amount of each element in the solid solution is not particularly limited. For example, the amount of solid solution of Mg is preferably 5 at% or less. Also, for example, among the Mg evaporation inhibitor elements, the amount of solid solution of Sn is preferably 5 at% or less. Also, for example, the amount of solid solution of Sb is preferably 4 at% or less. Also, for example, the amount of solid solution of Bi is preferably 1 at% or less. Also, for example, among the melting point depressing elements, the amount of solid solution of Ag is preferably 5 at% or less. Also, for example, the amount of solid solution of In is preferably 5 at% or less. Also, for example, the amount of solid solution of Mn is preferably 20 at% or less. The amount of solid solution can be measured, for example, by energy dispersive X-ray analysis (EDX) of the solid solution phase 31A.

[0058] When the Mg evaporation inhibiting element in the solid solution phase 31A is Sn, it is more preferable that the ratio A / B be 0.1 or more and 2.0 or less, where A is the amount of dissolved Mg in the solid solution phase 31A and B is the amount of dissolved Mg evaporation inhibiting element. By dissolving Mg and Sn in Cu in such a ratio, the bonding strength of the bonding layer 30 can be further increased.

[0059] At the interface of the first layer 31 on the metal member 10 side, an interfacial reaction layer containing elements derived from the metal member 10 and elements derived from the bonding layer 30 may be formed as a result of diffusion of metal from the metal member 10 to the first layer 31. Furthermore, at the interface of the metal member 10 on the first layer 31 side, a phase in which elements derived from the bonding layer 30 are dissolved in the metal member 10, or an interfacial reaction layer containing elements derived from the metal member 10 and elements derived from the bonding layer 30 may be formed as a result of diffusion of metal from the first layer 31 to the metal member 10.

[0060] (Second Layer) The second layer 32 of the bonding layer 30, which forms the interface with the ceramic member 20, may contain a compound of an active metal element. The compound of the active metal element may contain an element derived from the ceramic member 20. For example, when the active metal element is Ti and the ceramic member 20 contains a nitride such as silicon nitride, the second layer 32 is primarily composed of titanium nitride (TiN) as a compound containing the active metal element. For example, when the active metal element is Ti and the ceramic member 20 contains a carbide such as silicon carbide, the second layer 32 is primarily composed of titanium carbide (TiC) as a compound containing the active metal element. Even in the case of other active metal elements, the second layer 32 may contain a carbide of the active metal element if the ceramic member 20 contains a carbide such as silicon carbide, or a nitride of the active metal element if the ceramic member 20 contains a nitride such as silicon nitride. The compound of the active metal element that forms the second layer 32 may also contain a magnesium evaporation inhibitor element.

[0061] In this embodiment, the second layer 32 may further contain a silicide or an aluminide of an active metal element. ３ N ４ In the case where the second layer 32 is made of Ti ５ Si ３ If the ceramic member 20 is made of AlN, the second layer 32 may include an aluminide of the active metal element, such as TiAl.

[0062] Furthermore, when the ceramic member 20 contains an oxide such as alumina, the second layer 32 may contain MgO.

[0063] (Bonding Strength) In this embodiment, the bonding layer 30 is formed from the brazing filler metal, thereby providing a high bonding strength between the metal member 10 and the ceramic member 20. Specifically, the shear strength of the bonding layer 30 in this embodiment is 20 MPa or greater. The tensile strength of the bonding layer 30 can be calculated from the shear strength using the von Mises equation, and is approximately 1.73 times the shear strength. Therefore, the tensile strength of the bonding layer 30 in this embodiment is 34.6 MPa or greater.

[0064] The shear strength of the bonding layer 30 refers to the magnitude of the shear load per unit area required to fracture the bonding layer 30 when stress (shear stress) is applied to the bonding layer 30 so as to displace the metal member 10 and the ceramic member 20 in opposite directions parallel to the bonding surfaces 10s and 20s, as shown in Fig. 3(a). The tensile strength of the bonding layer 30 refers to the magnitude of the tensile load per unit area required to fracture the bonding layer 30 when stress (tensile stress) is applied to the bonding layer 30 so as to pull the metal member 10 and the ceramic member 20 apart in a direction perpendicular to the bonding surfaces 10s and 20s, as shown in Fig. 3(b).

[0065] (3) Method for Manufacturing the Bonded Body Next, a method for manufacturing the metal / ceramic bonded body 100 will be described with reference to FIGS. 4(a) to 4(c).

[0066] First, as shown in FIG. 4( a ), the metal member 10 and the ceramic member 20 are arranged so as to be stacked with the brazing material 50 interposed therebetween.

[0067] The brazing filler metal 50 may be any of the brazing filler metals described above, including, for example, a material containing 35 to 89 at% Cu (preferably 40 to 85 at%), 1 to 20 at% Mg, 1 to 20 at% Mg evaporation inhibitors in total, 1 to 35 at% melting-point depressant elements in total, and 0.1 to 10 at% active metal elements in total. In the brazing filler metal 50, the Cu, Mg, Mg evaporation inhibitors, melting-point depressant elements, active metal elements, and the like may be contained as powders in the form of the aforementioned compounds. In this case, it is preferable that at least a portion of the Mg is contained in the form of an alloy powder formed from an intermetallic compound containing at least Mg and the Mg evaporation inhibitor. For example, a powder containing Cu, an alloy powder formed from an intermetallic compound containing at least Mg and the Mg evaporation inhibitor, a powder containing a melting-point depressant, and a powder containing an active metal element may be appropriately mixed so that the respective elements have predetermined content ratios.

[0068] Known methods such as screen printing, transfer, dispensing, inkjet printing, spray coating, sputtering, and vapor deposition can be used to arrange the brazing filler metal 50 on the intended joining surfaces 10s′ and 20s′ of the metal member 10 and the ceramic member 20. In the case of an arrangement method using powder such as screen printing or dispensing, it is preferable to use the powder in the form of the above-mentioned paste.

[0069] 4(b), the laminate 100' of the metal member 10 and the ceramic member 20 arranged with the brazing filler material 50 interposed therebetween is heated in a predetermined atmosphere while being pressurized in the lamination direction to melt the brazing filler material 50, and the laminate is maintained so that the brazing filler material fills the space between the joining surfaces of the joining objects. The predetermined atmosphere may be any one of a vacuum atmosphere (reduced pressure atmosphere), an inert gas atmosphere, and a reducing atmosphere.

[0070] The heating temperature during bonding is preferably, for example, above the melting point of the brazing material 50 and below 800°C. Bonding at such a low temperature can reduce residual stress around the bonding layer. It can also prevent the structure and shape of the base material from changing due to heat. Furthermore, it can prevent Mg evaporation and the generation of voids. Note that known furnaces such as a stationary batch furnace, a multi-chamber furnace, a belt conveyor furnace, and a roller hearth kiln can be used as the heat treatment furnace used for bonding.

[0071] Other conditions for bonding are exemplified as follows: Oxygen concentration: 0.01 volume ppm or more and 1000 volume ppm or less Pressure: 0.5 kPa or more Holding time: Not particularly limited, but for example, 30 minutes or more and 180 minutes or less

[0072] By applying a pressure of 0.5 kPa or more, it is possible to maintain a tight contact state between the metal member 10 and the ceramic member 20 via the brazing filler metal 50, and to increase the bonding strength between the metal member 10 and the ceramic member 20. There is no particular limitation on the upper limit of the pressure, but it can be set to, for example, about 20 kPa.

[0073] Thereafter, the heated laminate 100' is cooled, resulting in the metal / ceramic bonded body 100 shown in FIG.

[0074] Other Aspects of the Present Disclosure The above describes specific aspects of the present disclosure. However, the present disclosure is not limited to the above aspects and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0075] In the above-described embodiment, the case where the metal member 10 and the ceramic member 20 are joined has been described, but the present invention is not limited to this, and two metal members 10 may be joined together. In this case, the two metal members 10 may be made of the same type of metal or different types of metal.

[0076] The metal / ceramic bonded body 100 of this embodiment can be used, for example, as an insulated circuit board. In this case, for example, to form a circuit pattern on the metal member 10, etching may be performed after applying an etching resist to the metal member 10. The type of etching resist is not particularly limited, and known resists such as thermosetting and ultraviolet-curing resists can be used. The method for applying the etching resist is also not particularly limited, and methods such as applying a film-like resist, screen printing, and inkjet coating can be used. Furthermore, after removing unnecessary portions of the metal member 10 from the metal / ceramic bonded body 100 by etching, unnecessary portions of the bonding layer 30 may be further removed. Furthermore, the metal / ceramic bonded body 100 is not limited to applications as an insulated circuit board and can be widely applied to various applications, such as heat sinks, wiring boards for electronic components, components of internal combustion engines and power generating machines, and machining tools. Even in these cases, the same effects as those of the above-described embodiment can be obtained.

[0077] In this example, a metal member and a ceramic member were joined using the prepared brazing filler metal, and the joint strength and cross-sectional structure of the resulting joint were evaluated. Furthermore, differential thermal analysis of the prepared brazing filler metal was performed to evaluate the melting point of the brazing filler metal. Specifically, the following was done.

[0078] (1) Preparation A Cu plate with a thickness of 5 mm was prepared as the metal member. A silicon nitride (Si) plate with a thickness of 0.3 mm was prepared as the ceramic member. ３ N ４ A plate made of ) was prepared.

[0079] Powders containing Cu, Mg, a Mg evaporation suppressing element, a melting point lowering element, and an active metal element were prepared as powders for preparing brazing filler metals. Specifically, a Cu powder was prepared as a powder containing Cu. Powders containing Mg and a Mg evaporation suppressing element were prepared as follows: ４Three types of alloy powders were prepared: an alloy powder formed of MgSn and Cu, an alloy powder formed of CuMgSb and Cu, and an alloy powder formed of CuMgBi and Cu. As the powder containing Mg, a simple metal powder of Mg was prepared. As the powder containing a melting point depressant, simple metal powders of Ag, In, and Mn were prepared. As the powder containing an active metal element, TiH ２ Powders were prepared. The median diameter D50 of each powder was set to 45 μm or less. The alloy powders were produced by atomization.

[0080] (2) Preparation of Brazing Filler Metals First, the above powders were mixed so that the Cu, Mg, Mg evaporation inhibitor element, melting point depressant element, and active metal element contents were as shown in Tables 1 to 4, and the mixture was made into a paste to prepare the brazing filler metals of Samples 1 to 91. In preparing the brazing filler metals of Samples 1 to 91, the amount of Mg derived from the Mg-containing alloy powder was adjusted to 40% or more of the total amount of Mg contained in the brazing filler metal. Terpineol and polyisobutyl methacrylate were used as the binder to make the paste, and the total amount of the solvent and binder in the paste was 17 mass%. In Tables 1 to 4, the content of each element is expressed in at%.

[0081]

[0082]

[0083]

[0084]

[0085] (3) Fabrication of a Joint Next, the brazing filler metal of Samples 1 to 91 prepared was applied by screen printing to the surface to be joined of the first member (Cu plate). Subsequently, the second member (silicon nitride plate) was placed directly on the applied paste film, and a pressure of 8 kPa was applied in the stacking direction to form a 1.0 × 10 －２ The bonded bodies of Samples 1 to 91 were fabricated by performing a heat treatment at a temperature of 800° C. in a vacuum atmosphere of 100 Pa or less.

[0086] (4) Bonding Strength Evaluation The bonding strength of the bonding layer of the bonded bodies of Samples 1 to 91 was evaluated by a shear strength test. Specifically, for the bonded bodies, the copper material was processed into a cylindrical shape with a diameter of 3 mm and a height of 2 mm, and the bonding surface of the surrounding ceramic material was exposed to prepare a test piece. Then, as shown in FIG. 5, with the ceramic material of the test piece fixed, the cylindrical copper material was pressed using a displacement jig in a direction parallel to the bonding surface. The magnitude of the stress when the bonding layer broke (shear fracture) was measured, and the shear strength of the bonding layer was calculated based on this value. The shear test position (contact height H of the displacement jig) was set at a height of 200 μm from the exposed surface of the ceramic material, and the displacement axis movement speed was 100 μm / s. The results are shown in Tables 1 to 4.

[0087] As shown in Tables 1 to 4, the bonding strength (shear strength of the bonding layer) of Samples 1 to 91 was all 20 MPa or more, confirming that the samples had high bonding strength.

[0088] (5) Evaluation of Cross-Sectional Structure The cross-sectional structures of the joined bodies of Samples 1 to 91 were observed using an SEM, and the distribution of Ti was analyzed by EDX. Fig. 6 shows a cross-sectional SEM photograph (left side of the figure) and the results of EDX analysis (right side of the figure) of Sample 4, Fig. 7 shows a cross-sectional SEM photograph (left side of the figure) and the results of EDX analysis (right side of the figure) of Sample 67, and Fig. 8 shows a cross-sectional SEM photograph (left side of the figure) and the results of EDX analysis (right side of the figure) of Sample 80.

[0089] As shown in the cross-sectional SEM photographs of FIGS. 6 to 8, (a) the solid solution phase 31A (dark gray portion) and the compound phase 31B (light gray portion) have a sea-island structure, (b) paths (continuous phases) made of the solid solution phase 31A that connect the second layer 32 and the metal member 10 are secured in the first layer 31, and (c) the thickness of the first layer 31 is approximately 10,000 μm. ２ It was confirmed that no voids with a circle equivalent diameter of 8 μm or more were observed in the bonding layer 30 within the field of view. The same was true for the other samples. Furthermore, as shown in the cross-sectional SEM photograph of Figure 8, it was confirmed that a single Ag phase (white portion) was present in sample 80, which used Ag as the melting point depressant.

[0090] 6 to 8, it was confirmed that the second layer 32 contained a compound of the active metal element (Ti). The same was true for the other samples.

[0091] (6) Differential Thermal Analysis Differential thermal analysis (DTA) was performed on the brazing filler metal (Cu-Mg-Sn-Mn) of Sample 4, the brazing filler metal (Cu-Mg-Sn-In) of Sample 67, and the brazing filler metal (Cu-Mg-Sn-Ag) of Sample 80. The results are shown in Figure 9. For comparison, Figure 9 also shows the results of a brazing filler metal (Cu-Mg-Sn: Cu80.52-Mg9.54-Sn9.94 at%) that does not contain a melting-point depressant.

[0092] 9, it was confirmed that the brazing filler metals of Samples 4, 67, and 80, which contain a melting-point depressant, have a lower melting start temperature than the brazing filler metals which do not contain a melting-point depressant. In other words, it was confirmed that the melting point of the brazing filler metal can be lowered by adding a melting-point depressant to the brazing filler metal.

[0093] <Preferred Aspects of the Present Disclosure> Preferred aspects of the present disclosure are described below. Note that any combination of the technical matters described in the following supplementary notes is possible and will bring about useful effects.

[0094] According to one aspect of the present disclosure, there is provided a brazing filler metal comprising: Cu; Mg; at least one first element selected from the group consisting of Sn, Sb, and Bi; at least one second element selected from the group consisting of Ag, In, and Mn; and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, wherein the content of Cu is the highest among the Cu, Mg, the first element, and the second element.

[0095] Preferably, the Cu content is 40 to 85 at%, the Mg content is 1 to 20 at%, the total content of the first elements is 1 to 20 at%, the total content of the second elements is 1 to 35 at%, and the total content of the active metal elements is 0.1 to 10 at%.

[0096] Preferably, when the content of the Mg is X at % and the content of the first element is Y at %, X-5≦Y≦X+5.

[0097] Preferably, the paste contains Cu powder containing Cu, alloy powder formed from an intermetallic compound containing at least Mg and the first element, powder containing the second element, and powder containing the active metal element.

[0098] Preferably, the amount of Mg derived from the alloy powder is 40% or more of the total amount of Mg contained in the brazing filler metal.

[0099] According to another aspect of the present disclosure, there is provided a joined body comprising: a first member made of metal; a second member joined to the first member and made of the same or different metal as the first member, or a ceramic; and a joining layer formed on the joining surface between the first member and the second member, wherein the joining layer contains: Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi; at least one second element selected from the group consisting of Ag, In, and Mn; and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, and wherein Cu has the highest content among the elements constituting the joining layer.

[0100] Preferably, the bonding layer has: a first layer that forms an interface with the first member and includes a solid solution phase in which Cu and other metal elements are solid-dissolved, and a compound phase that includes an intermetallic compound containing Cu, Mg, and the first element; and a second layer that forms an interface with the second member and is in contact with the first layer.

[0101] Preferably, the second layer contains a compound of the active metal element.

[0102] Preferably, the second layer contains MgO.

[0103] Preferably, when the bonding layer is observed in a cross section perpendicular to the bonding surface, the number of voids having a circle equivalent diameter of 8 μm or more is 10,000 μm or more. ２There is one or less per

[0104] Preferably, the shear strength of the bonding layer is 20 MPa or more.

[0105] Preferably, the bonding layer has a tensile strength of 34.6 MPa or more.

[0106] According to another aspect of the present disclosure, there is provided a method for manufacturing a joined body, the method comprising: an arrangement step of stacking a first member made of a metal and a second member made of the same or a different metal as the first member, or a ceramic, via a brazing filler metal; and a heating step of heating and holding the stack of the first member and the second member while applying pressure in the stacking direction, wherein the brazing filler metal contains at least one first element selected from the group consisting of Cu, Mg, Sn, Sb, and Bi, at least one second element selected from the group consisting of Ag, In, and Mn, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, and the brazing filler metal contains a material with the highest Cu content among the elements contained in the brazing filler metal.

[0107] Preferably, in the heating step, the heating is performed at a temperature equal to or higher than the melting point of the brazing material and equal to or lower than 800°C.

[0108] REFERENCE SIGNS LIST 100 Metal / ceramic bonded body 100' Laminated body 10 Metal member (first member) 10s Bonding surface 20 Ceramic member (second member) 20s Bonding surface 30 Bonding layer 31 First layer 31A Solid solution phase 31B Compound phase 32 Second layer 50 Brazing material

Claims

1. A brazing filler metal comprising Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi, at least one second element selected from the group consisting of Ag, In, and Mn, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, wherein the Cu content is the highest among the Cu, Mg, the first element, and the second element.

2. The brazing filler metal according to claim 1, wherein the Cu content is 40 to 85 at%, the Mg content is 1 to 20 at%, the total content of the first elements is 1 to 20 at%, the total content of the second elements is 1 to 35 at%, and the total content of the active metal elements is 0.1 to 10 at%.

3. The brazing filler metal according to claim 1, wherein X-5≦Y≦X+5, where X is the content of said Mg and Y is the content of said first element.

4. The brazing filler metal according to claim 1, which is formed in a paste form and contains Cu powder containing Cu, an alloy powder formed from an intermetallic compound containing at least Mg and the first element, a powder containing the second element, and a powder containing the active metal element.

5. The brazing filler metal according to claim 4, wherein the amount of Mg derived from the alloy powder is 40% or more of the total amount of Mg contained in the brazing filler metal.

6. A bonded body comprising: a first member made of metal; a second member joined to the first member and made of the same or a different metal as the first member, or a ceramic; and a bonding layer formed on the bonding surface between the first member and the second member, wherein the bonding layer contains: Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi; at least one second element selected from the group consisting of Ag, In, and Mn; and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, and wherein the Cu content is the highest among the elements constituting the bonding layer.

7. The joined body according to claim 6, wherein the joining layer comprises: a first layer that forms an interface with the first member and includes a solid solution phase in which another metal element is solid-dissolved in Cu, and a compound phase that includes an intermetallic compound containing Cu, Mg, and the first element; and a second layer that forms an interface with the second member and is in contact with the first layer.

8. The joint body according to claim 7, wherein the second layer contains a compound of the active metal element.

9. When observing the bonding layer in a cross section perpendicular to the bonding surface, the number of voids having a circular equivalent diameter of 8 μm or more is 10,000 μm or more. ２ 7. The conjugate of claim 6, wherein the number of the nuclei is one or less per nucleus.

10. The bonded body according to claim 6, wherein the shear strength of the bonding layer is 20 MPa or more.

11. The bonded body according to claim 6, wherein the bonding layer has a tensile strength of 34.6 MPa or more.

12. A method for manufacturing a joined body, comprising: an arrangement step of stacking a first member made of metal and a second member made of the same or a different metal as the first member, or a ceramic, via a brazing filler metal; and a heating step of heating and holding the laminate of the first member and the second member while applying pressure in the stacking direction, wherein the brazing filler metal contains at least one first element selected from the group consisting of Cu, Mg, Sn, Sb, and Bi, at least one second element selected from the group consisting of Ag, In, and Mn, and at least one active metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ce, La, Sm, Yb, Nd, Gd, and Er, and the brazing filler metal has the highest Cu content among the elements contained in the brazing filler metal.

13. The method for manufacturing a joined body according to claim 12, wherein the heating step involves heating at a temperature equal to or higher than the melting point of the brazing material and equal to or lower than 800°C.

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