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

Abstract

A brazing material comprising: Cu; Mg; at least one first element selected from the group consisting of Sn, Sb, and Bi; and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

Description

Brazing filler metal, jointed body, method for manufacturing brazing filler metal, and method for manufacturing jointed body

[0001] The present disclosure relates to a brazing filler metal, a joined body, a method for manufacturing a brazing filler metal, and a method for manufacturing a 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 a material containing an active metal that does not have Ag as a main phase 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 technique for increasing the joint strength of a joint using an active brazing metal material that does not contain Ag as a main phase.

[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; and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

[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 ceramic; and a joining layer formed on the joining surface between the first member and the second member, wherein the joining layer includes Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi, and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

[0007] According to yet another aspect of the present disclosure, there is provided a method for manufacturing a brazing filler metal used for joining a metal member and a ceramic member, the brazing filler metal containing Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi, and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

[0008] According to yet another aspect of the present disclosure, there is provided a method for manufacturing a joined body, comprising: an arrangement step of arranging 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, so that they are stacked with a brazing filler metal interposed therebetween; 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 is a material containing at least one first element selected from the group consisting of Cu, Mg, Sn, Sb, and Bi, and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

[0009] According to the present disclosure, the bonding strength of the bonded body can be increased.

[0010] 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 ) is a diagram illustrating a state in which a metal member 10 and a ceramic member 20 are arranged via a brazing filler metal 50, FIG. 4( b ) is a diagram illustrating a state in which a laminate of the metal member 10 and the ceramic member 20 is heated while being pressurized, and FIG. 4( c ) is a diagram illustrating 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 is a partial cross-sectional enlarged photograph of the bonding layer of Sample 1. FIG. 7 is a partial cross-sectional enlarged photograph of the bonding layer of Sample 8. FIG. 8 is a partial cross-sectional enlarged photograph of the bonding layer of Sample 15.

[0011] Brazing filler metals are required not only not to significantly change the structure of the materials to be joined when heated, but also to produce a strong bonded 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.

[0012] However, in the Cu-Mg binary eutectic composition, the vapor pressure of Mg is high, and when Mg alone is added, the temperature rises above 600°C, resulting in MgCu ２ It is known that when Mg is added as a brazing material, evaporation proceeds rapidly at temperatures above 780°C. The temperature at which it can be joined as a brazing material is 720°C, the Cu-Mg eutectic point at which the liquid phase begins to form, but considering the wettability of the liquid phase, it is necessary to heat to a higher temperature, which tends to make the evaporation of Mg more likely to proceed. 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 MgCu, ２ 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.

[0013] The present inventors have investigated methods for suppressing the evaporation of Mg from a Cu-Mg eutectic composition. They have devised the addition of an element that combines with Mg to form a compound with a higher melting point than Mg, while forming 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).

[0014] Therefore, the present inventors added the above elements to a Cu-Mg-based active metal brazing material 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 elements such as Si tend to be more reactive with the active metal elements described below than with Mg, and therefore the intended effect of reacting with Mg and suppressing its evaporation cannot be achieved.

[0015] 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 as Mg evaporation suppressing elements, which react with Mg to form compounds with higher melting points than Mg.

[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 (mainly Cu with Mg as an essential component) active metal brazing filler metal with Cu as the main component (e.g., 50 at% or more Cu). 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 the "Mg evaporation suppressing element"), and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er (hereinafter also referred to as the "active metal element"). The brazing filler metal preferably contains Mg, the Mg evaporation suppressing element, the active metal element, and unavoidable impurities, with the balance being Cu. In addition, by not including Ag, the migration resistance of the brazing filler metal can be further improved. The brazing filler metal can be used to join metal members to ceramic members or to join metal members to each other. Note that the inevitable impurities are elements other than those intentionally added when preparing the brazing filler metal, such as elements derived 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 with 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 is formed as a eutectic, which melts at the joining temperature but prevents the molten components, such as Mg, from evaporating. Therefore, the Mg evaporation inhibitor reacts with Mg during joining to suppress Mg evaporation. Furthermore, the Mg evaporation inhibitor forms a ternary intermetallic compound with Cu and Mg when the brazing filler metal is heated, and acts to improve the strength of the intermetallic compound. The Mg evaporation inhibitor can be at least one element selected from the group consisting of Sn, Sb, and Bi. More preferably, the Mg evaporation inhibitor must contain at least one of Sn and Sb (except when Bi is used alone). Even more preferably, the first element consists of at least one of Sn and Sb (without Bi).

[0022] The active metal element reacts with the ceramic member to form a compound when the brazing material is heated, and acts to increase the bonding strength between the ceramic member and the bonding layer. As the active metal element, for example, at least one 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), calcium (Ca), cerium (Ce), lanthanum (La), samarium (Sm), ytterbium (Yb), neodymium (Nd), gadolinium (Gd), and erbium (Er) can be used. Note that when the ceramic member is Si, ３ N ４ In the case of AlN or AlN, it is particularly preferable to use at least one active metal element selected from the group consisting of Ti, V, Nb, Cr, Mo, and Ca, with Ti being particularly preferred.

[0023] The content of each element is not particularly limited. For example, the Cu content is preferably 50 at% to 95 at%, more preferably 55 at% to 80 at%. The Mg content is preferably 1 at% to 15 at%, more preferably 3 at% to 12 at%. The Mg evaporation inhibitor content is preferably 1 at% to 20 at%, more preferably 3 at% to 15 at%. The active metal element content is preferably 0.1 at% to 10 at%, more preferably 1 at% to 10 at%. A portion of Cu can be contained with other elements in a range of 1 at% or less. Furthermore, when the Mg content is X at% and the Mg evaporation inhibitor content is Y at%, it is preferable that X-6≦Y≦X+6, and more preferably X-5≦Y≦X+5. Containing each element in such a content is preferable for achieving a predetermined bonding strength in the bonding layer while lowering the bonding temperature of the brazing material.

[0024] The form of the brazing material is not particularly limited, and it can be, for example, a paste, foil, or wire. Among these, a paste is preferable from the viewpoint of obtaining a uniform phase structure in the bonding layer, which will be described later. The paste brazing material is composed of powder containing the elements described above. In the case of a foil, either roll quenching or rolling can be selected as the manufacturing method. In the case of a wire, a general wire drawing method can be used as the manufacturing method.

[0025] In the paste-like brazing filler metal, the addition form 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 addition form of each element will be described below.

[0026] Mg may be, for example, Mg alone, an Mg solid solution containing other elements, or a compound with Cu (MgCu ２It is preferable to add Mg in the form of a powder containing at least one of the following: a compound with an active metal element; a compound with an Mg evaporation inhibitor; and a compound with an Mg evaporation inhibitor. Of these, it is preferable to add Mg in the form of a powder containing at least a portion of an intermetallic compound with an Mg evaporation inhibitor. For example, Mg can be added as an alloy powder formed from Mg and an intermetallic compound containing an Mg evaporation inhibitor, or as an alloy powder formed from an intermetallic compound containing Mg and an Mg evaporation inhibitor and an Mg evaporation inhibitor. Alternatively, the alloy powder can be mixed with at least one of Mg powder and an Mg-Cu intermetallic compound powder. By preforming at least a portion of the Mg into an intermetallic compound with an Mg evaporation inhibitor, Mg evaporation during melting of the brazing filler metal can be more reliably suppressed. Note that the alloy powder does not refer to a mixture of a powder containing one element and a powder containing another element, but rather refers to a powder in which each element is contained in the form of an alloy within a single particle. Furthermore, a solid solution containing another element refers to a solid solution in which a part of the element constituting the solid solution in the crystal is replaced with another element, or a solid solution in which another element has penetrated into the gaps in the crystal lattice.

[0027] 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 inhibiting element is Sb, Mg ３ Sb ２ When the magnesium evaporation inhibiting element is Bi, Mg ３ Bi ２ , CuMgBi, etc. can be used.

[0028] The alloy powder may be prepared by mixing and dissolving Mg, the Mg evaporation inhibiting element, and optionally Cu, and then atomizing the mixture to form spherical powders containing the elements. The atomization method may be selected from gas atomization, disk atomization, water atomization, and plasma atomization.

[0029] The amount of the alloy powder containing Mg and an Mg evaporation inhibiting element added is not particularly limited, but it is preferable to add an amount such that the content of Mg derived from the alloy powder is 40% or more of the total content of Mg contained in the brazing filler metal. For example, when using an alloy powder containing Mg and an Mg evaporation inhibiting element in combination with at least one of an Mg metal powder, an Mg-active metal alloy powder, an Mg-Cu intermetallic compound powder, etc., it is preferable to adjust the amount of the alloy powder containing Mg and an Mg evaporation inhibiting element added so that the content of Mg derived from the alloy powder containing Mg and an Mg evaporation inhibiting element is 40% or more of the total content of Mg contained in the brazing filler metal. The amount of the alloy powder added may be 100% of the total content of Mg contained in the brazing filler metal, i.e., only the alloy powder may be added. By adding such an amount, Mg evaporation can be more stably suppressed.

[0030] 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 inhibitor 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 a powder containing at least one of Cu alone and an alloy formed by a solid solution and an intermetallic compound formed with Cu.

[0031] The Mg evaporation inhibiting element may be added 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 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.

[0032] The active metal element may be added 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 of Mg, Cu, and an Mg evaporation inhibiting element.

[0033] The amount of powder containing each element added is not particularly limited, and it is preferable that the brazing filler metal contains each powder so that, for example, the Cu content is 50 at% to 80 at%, the Mg content is 1 at% to 15 at%, the Mg evaporation inhibitor content is 1 at% to 20 at%, and the active metal element content is 0.1 at% to 10 at%. By setting the content of each element within the above ranges, it is possible to more reliably achieve the effects of lowering the joining temperature by Mg and suppressing Mg evaporation by the Mg evaporation inhibitor.

[0034] In brazing filler metals, the particle size of each powder containing Cu, Mg, a Mg evaporation inhibitor, and an 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 structures, the particle size may be large, preferably an average particle size D50 of 45 μm to 150 μm. Furthermore, for example, when the goal is to reduce the thermal resistance of a joined body such as a circuit board, it is desirable to form a thin joining layer with lower thermal conductivity than pure metals, and an average particle size D50 of 45 μm or less is preferable. On the other hand, while there is no particular lower limit for the average particle size, an average particle size D50 of 5 μm or more is preferable in order to suppress the effects of surface oxidation of the powder. The average particle size D50 can be calculated, for example, using a laser diffraction particle size analyzer.

[0035] 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.

[0036] The method for preparing the brazing filler metal is not particularly limited, and any conventionally known method may be used.

[0037] (2) Bonded Body Next, the 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.

[0038] 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.

[0039] (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, iron-based alloy, cobalt-based alloy, molybdenum-based alloy, etc. Examples of pure copper include oxygen-free copper, tough pitch copper, and phosphorus-deoxidized copper. Examples of copper alloys include alloys containing copper (Cu) as the main element and 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). Examples of iron-based alloys include Invar®, Kovar®, high-speed steel, and die steel.

[0040] 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.

[0041] (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 carbides include silicon carbide (SiC) and diamond. Examples of oxides include aluminum oxide (Al ２ O ３ ) etc.

[0042] 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.

[0043] (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 material described above, and contains Cu, Mg, a Mg evaporation inhibiting element, and an active metal element.

[0044] 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.

[0045] The first layer 31 has a solid solution phase in which at least one of Mg and an Mg evaporation inhibiting element is dissolved in Cu, and a compound phase containing an intermetallic compound containing Cu, Mg, and the Mg evaporation inhibiting element. The solid solution of Mg and the Mg evaporation inhibiting element may vary depending on the type of Mg evaporation inhibiting element. The compound phase contains a ternary intermetallic compound containing Cu, Mg, and the Mg evaporation inhibiting element.

[0046] (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 .

[0047] As shown in FIG. 2, the first layer 31 is composed of a solid solution phase 31A and a compound phase 31B dispersed therein.

[0048] The solid solution phase 31A is mainly composed of a solid solution of at least Mg and at least one of a Mg evaporation inhibitor element and Cu. When the Mg evaporation inhibitor element is Sn, Mg and Sn may be dissolved in the solid solution phase 31A. When the Mg evaporation inhibitor element 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 element is Bi, at least Mg may be dissolved in the solid solution phase 31A, but Bi may not be dissolved. In addition, the solid solution phase 31A may contain active metal elements contained in the brazing filler metal, Si, Al, etc. contained in the ceramic member 20. The solid solution of each element in the solid solution phase 31A can improve the strength of the solid solution phase 31A through solid solution strengthening.

[0049] The compound phase 31B contains 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 an active metal element may be used.

[0050] In the first layer 31, a solid solution phase 31A having excellent malleability and ductility is preferably configured as a continuous phase. More preferably, as shown in FIG. 2, the first layer 31 has a structure in which a compound phase 31B is phase-separated into a sea-island structure within the solid solution phase 31A. 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 areas corresponding to stress concentration points, crack propagation cannot be stopped when stress load is applied to the compound phase 31B, which may significantly decrease the bonding strength. In this regard, by having the sea-island structure shown in FIG. 2, the bonding layer 30 can maintain a higher bonding strength.

[0051] In the first layer 31, the compound phase 31B is preferably present uniformly dispersed throughout substantially the entire thickness and width of the first layer 31, without being present as a layered continuous phase at stress concentration locations. 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.

[0052] 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.

[0053] 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.

[0054] Specifically, in the bonding layer 30, when the first layer 31 is observed in a cross section perpendicular to the bonding surfaces 10s and 20s, the thickness is approximately 10,000 μm. ２ It 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 less than one, and even more preferably, the number of voids having a size of 1 μm or more is less than one.

[0055] In the solid solution phase 31A, at least one of Mg and the Mg evaporation inhibiting element is dissolved in the Cu crystal, and the amount of each element dissolved 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 inhibiting 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. The amount of solid solution can be measured, for example, by energy dispersive X-ray analysis (EDX) of the solid solution phase 31A.

[0056] When the Mg evaporation inhibiting element in the solid solution phase 31A is Sn, it is more preferable that the ratio A / B be 0.5 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 such a ratio, the bonding strength of the bonding layer 30 can be further increased.

[0057] In addition, at the interface on the metal member 10 side of the first layer 31, metal may diffuse from the metal member 10 to the first layer 31, forming an interfacial reaction layer containing elements derived from the metal member 10 and elements derived from the bonding layer 30.

[0058] (Second Layer) The second layer 32 of the bonding layer 30, which forms the interface with the ceramic member 20, contains 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 mainly 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 mainly composed of titanium carbide (TiC) as a compound containing the active metal element. The compound of the active metal element that forms the second layer 32 may also contain a Mg evaporation inhibitor element.

[0059] In this embodiment, the second layer 32 may further contain a silicide or an aluminide of an active metal element. ３ N４ 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.

[0060] (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 more. Furthermore, a shear strength of 50 MPa or more can be obtained. Furthermore, a shear strength of 80 MPa or more can be obtained. The tensile strength of the bonding layer 30 in this embodiment is 40 MPa or more. Furthermore, a tensile strength of 90 MPa or more can be obtained. Furthermore, a tensile strength of 140 MPa or more can be obtained.

[0061] 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).

[0062] (3) Method for Manufacturing Metal / Ceramic Bonded Body Next, a method for manufacturing the above-described metal / ceramic bonded body 100 will be described with reference to FIGS. 4(a) to 4(c).

[0063] 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.

[0064] The brazing filler metal 50 can be any of the brazing filler metals described above, including, for example, a material containing 50 to 80 at% Cu, 1 to 15 at% Mg, 1 to 20 at% Mg evaporation inhibitor, and 0.1 to 10 at% active metal element. In the brazing filler metal 50, Cu, Mg, the Mg evaporation inhibitor, and the active metal element 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 added 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, and a powder containing an active metal element may be appropriately mixed so that the respective elements have predetermined contents.

[0065] The brazing filler metal 50 can be disposed on the intended joining surfaces 10s', 20s' of the metal member 10 and the ceramic member 20 by known methods such as screen printing, transfer printing, dispensing, inkjet printing, spray coating, sputtering, and vapor deposition, with screen printing being preferred. In the case of a powder-based dispensing method such as screen printing or dispensing, the powder is preferably used in the form of a paste as described above. The brazing filler metal 50 may be formed into a preform shape and used. Furthermore, the brazing filler metal 50 may be integrated with the metal member 10 or the ceramic member 20 before lamination and bonded thereto. The integration method may be cladding by rolling or metallizing by heat treatment.

[0066] 4(b), the laminate 100' of the metal member 10 and the ceramic member 20 arranged with the brazing filler metal 50 interposed therebetween is heated and held in a predetermined atmosphere while being pressurized in the lamination direction. The predetermined atmosphere may be any one of a vacuum atmosphere (reduced pressure atmosphere), an inert gas atmosphere, and a reducing atmosphere.

[0067] The heating temperature during bonding may be, for example, equal to or higher than the melting point of the brazing filler metal 50 and equal to or lower than the melting point of the metal member 10. The temperature is preferably equal to or lower than 115% of the melting point (°C) of the brazing filler metal 50, and more preferably equal to or higher than 101% and equal to or lower than 110% of the melting point (°C) of the brazing filler metal 50. This improves the diffusibility of the active metal element, making it easier to form the second layer 32. When using the brazing filler metal 50 of this embodiment, the heating temperature is preferably equal to or higher than 720°C and equal to or lower than 1000°C, and more preferably equal to or lower than 850°C. The heat treatment furnace used for bonding may be a known furnace, such as a stationary batch furnace, a multi-chamber furnace, a belt conveyor furnace, or a roller hearth kiln.

[0068] Other conditions for bonding are exemplified as follows: Oxygen concentration: 0.01 vol ppm or more and 1000 vol ppm or less, or 0.1 vol ppm or more and 100 vol ppm or less Pressurization: 0.5 kPa or more Holding time: not particularly limited, but for example, 3 minutes or more and 120 minutes or less

[0069] During heating, a liquid phase must be formed in a portion of the brazing filler metal 50, and the active metal element must be molten within the liquid phase. For example, when a Cu-Mg-Sb alloy is used, with Ti as the active metal and Sb as the Mg evaporation inhibitor, this state can be achieved by heating the alloy at 720°C or higher. However, if the heating temperature is too high, the Mg evaporation may exceed the effect of the Mg evaporation inhibitor, making it difficult to form a liquid phase or resulting in voids in the resulting bonding layer 30. Setting the heating temperature to 1000°C or lower can avoid these issues. Applying a pressure of 0.5 kPa or higher can maintain the tight contact between the metal member 10 and the ceramic member 20 via the brazing filler metal 50, thereby increasing the bonding strength between the metal member 10 and the ceramic member 20. There is no particular upper limit to the pressure, but it can be set to, for example, approximately 20 kPa.

[0070] Thereafter, the heated laminate 100' is cooled, resulting in the metal / ceramic bonded body 100 shown in FIG.

[0071] (4) Effects According to this aspect, one or more of the following effects can be obtained.

[0072] (a) The brazing filler metal of this embodiment contains Cu, Mg, at least one Mg evaporation inhibitor selected from Sn, Sb, and Bi, and an active metal element. Therefore, when the brazing filler metal is heated and joined, at least Cu, Mg, and the Mg evaporation inhibitor combine to form an intermetallic compound. This intermetallic compound melts easily at the joining temperature due to a eutectic reaction with Cu, and is also characterized by its bond with the Mg evaporation inhibitor, which prevents Mg from evaporating from the eutectic melt during melting. In other words, Mg is bonded to the Mg evaporation inhibitor and other elements during the time between melting and solidifying of the components contained in the brazing filler metal, thereby suppressing its evaporation. As a result, the formation of voids associated with Mg evaporation is reduced in the joining layer 30 obtained by heating the brazing filler metal, allowing for the formation of a dense phase structure and achieving high joining strength.

[0073] (b) Furthermore, the brazing filler metal contains Mg, which can lower the melting point of Cu, and therefore can achieve high bonding strength at a low heating temperature, for example, in the range of 720° C. to 1000° C. Furthermore, the inclusion of Mg can improve wettability to the metal member 10 and the ceramic member 20.

[0074] (c) The brazing filler metal contains 1 at% to 15 at% Mg, 1 at% to 20 at% Mg evaporation inhibitor element, and 0.1 at% to 10 at% active metal element, with the Mg content being X at% and the Mg evaporation inhibitor content being Y at% so that X-6≦Y≦X+6 holds. By including each element in such amounts, the effect (a) can be more stably achieved.

[0075] (d) The brazing filler metal preferably contains Cu powder containing Cu and an alloy powder formed from an intermetallic compound containing at least Mg and an Mg evaporation inhibiting element, and is configured in a paste form. By previously converting Mg into an intermetallic compound with the Mg evaporation inhibiting element, evaporation of Mg can be more reliably inhibited when the brazing filler metal is heated. As a result, the joining strength can be more reliably increased.

[0076] (e) The brazing filler metal preferably contains alloy powder such that the content of Mg derived from the alloy powder is 40% or more of the total content of Mg contained in the brazing filler metal, thereby more reliably achieving the effect of (d) above.

[0077] (f) When the brazing filler metal of this embodiment is used to join a metal member 10 and a ceramic member 20, the joining layer 30 is formed by stacking a first layer 31 that forms the interface with the metal member 10 and a second layer 32 that forms the interface with the ceramic member 20. The first layer 31 has a solid-solution phase formed by Cu solid-solving at least one of Mg and an Mg evaporation inhibitor, and a compound phase including Cu, Mg, and an intermetallic compound containing the Mg evaporation inhibitor, thereby suppressing the generation of voids in the first layer 31. Furthermore, the compound phase 31B further contains the Mg evaporation inhibitor, thereby exhibiting higher strength than a phase without the Mg evaporation inhibitor. The second layer 32 contains a compound of an active metal element and acts to enhance the bonding between the metal member 10 and the joining layer 30. The joining layer 30 having such a phase structure can firmly join the metal member 10 and the ceramic member 20, achieving high bonding strength.

[0078] (g) By suppressing the generation of voids in the first layer 31 of the bonding layer 30, when the first layer 31 is observed in a cross section perpendicular to the bonding surface, the voids are 10,000 μm ２ It is preferable that no voids having a circular equivalent diameter of 8 μm or more are observed within any field of view.

[0079] (h) The first layer 31 of the bonding layer 30 preferably has a phase structure in which the solid solution phase 31A forms a continuous phase as a sea phase, which is a parent phase, and the compound phase 31B is dispersed as an island phase. If the compound phase 31B is locally present, the localized portion is prone to breakage when a load is applied to that portion. However, by dispersing the compound phase 31B, breakage due to a load can be suppressed, and the bonding strength can be more reliably increased.

[0080] (i) In the bonding layer 30, 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 20% or more and 40% or less. When the area ratio of the compound phase 31B falls within the predetermined range, the compound phase 31B is finely dispersed in the solid-solution phase 31A, and the effect of (h) described above can be more reliably obtained.

[0081] (j) In the first layer 31 of the bonding layer 30, the solid solution phase 31A is preferably configured as a continuous phase connecting the second layer 32 and the metal member 10. This allows the first layer 31 to have a path made of the solid solution phase 31A, thereby more reliably increasing the bonding strength.

[0082] (k) When the bonding layer 30 has any one of the phase structures (f) to (j) above, the shear strength of the bonding layer 30 can be increased to 20 MPa or more. Also, the tensile strength of the bonding layer 30 can be increased to 40 MPa or more.

[0083] (l) By forming the bonding layer 30 using a brazing material containing Cu as the main phase, migration caused by Ag as the main phase can be suppressed. In other words, high migration resistance can be achieved in the bonding layer 30.

[0084] 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.

[0085] 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.

[0086] 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. The metal / ceramic bonded body 100 is not limited to use as an insulated circuit board and can be widely used for various applications, such as heat sinks and components of internal combustion engines and power generating machines. Even in these cases, the same effects as those of the above-described embodiment can be obtained.

[0087] In this example, the prepared brazing filler metal was used to join a metal member and a ceramic member, or to join two metal members together, and the joining strength of the resulting joined bodies was evaluated.

[0088] (1) Preparation As the metal members, a copper material made of oxygen-free copper having a thickness of 2.0 mm, an iron alloy material (42ALLOY) having a thickness of 6.0 mm, and a steel material (SUS304) having a thickness of 6.0 mm were prepared. As the ceramic members, a silicon nitride (Si) material having a thickness of 0.3 mm was prepared. ３ N ４ ), a 0.3 mm thick silicon carbide (SiC) plate, a 0.3 mm thick AlN plate, and a 0.3 mm thick Al ２ O ３ A plate material made of 0.3 mm thick diamond was prepared.

[0089] Furthermore, powders containing Cu, Mg, an Mg evaporation inhibiting 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. A Cu powder was prepared as a powder containing Mg and an Mg evaporation inhibiting element. ４Alloy powders formed from MgSn and Cu, alloy powders formed from CuMgSb and Cu, alloy powders formed from CuMgBi and Cu, Cu ２ Alloy powder formed from Mg and Cu, Cu ３ Five types of alloy powders formed from Sn and Cu were prepared. As a powder containing Mg, a simple metal powder of Mg was prepared. As a powder containing an active metal element, TiH ２ powder, alloy powder consisting of CuCaSn and Cu, Cu ４ MgY and Cu ２ Alloy powder consisting of Mg and Cu, Cu ６ Ce and Cu ２ Alloy powders made of Mg and Cu were prepared. The average particle size (D50) of each powder was set to 45 μm or less. The alloy powders were produced by atomization.

[0090] (2) Preparation of Brazing Filler Metals First, the above-mentioned powders were mixed so that the contents of Cu, Mg, Mg evaporation inhibitor, and active metal element were as shown in Tables 1 to 6, and then pastes were formed to prepare brazing filler metals 1 to 42 and 45 to 232. Samples 214 to 232 contain one of the active metal elements Cr, Mo, V, Nb, or Zr, as described below. For the paste formation, polyethylene glycol and diethylene glycol monobutyl ether with a molecular weight of 400 or less were used as solvents, with the solvent content in the paste being 9 mass%. The brazing filler metal for Sample 43 was prepared in the same manner as Samples 1 to 42, except that the Cu and Mg evaporation inhibitor were not added. The brazing filler metal for Sample 44 was prepared in the same manner as Samples 1 to 42, except that only Mg elemental metal powder was used. In Tables 1 to 5, the content X represents the Mg content [at %], and the content Y represents the total content [at %] of the Mg evaporation inhibitor elements.

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] (3) Fabrication of Joint Next, for Samples 1 to 213, the prepared paste brazing material was applied by screen printing to the intended joining surface of the first member shown in Tables 1 to 6. Next, the second member was placed directly on top of the applied paste film, and pressed with a force of 8 kPa in the stacking direction, and a pressure of 1.0 × 10 －２ The bonded bodies of Samples 1 to 213 were produced by performing a heat treatment at 800°C for 60 minutes in a vacuum atmosphere of 100 Pa or less (820°C for Samples 43 and 44 only). For Samples 214 to 232, a predetermined molar amount of an active metal element selected from Cr, Mo, V, Nb, and Zr was sputtered onto the intended bonding surface of the first member shown in Table 6, and the prepared brazing filler metal paste was applied thereon by screen printing. The brazing filler metal element ratio column in Table 6 indicates the ratio including the sputtered active metal element. Next, the second member was placed directly on top of the applied paste film, and a pressure of 8 kPa was applied in the stacking direction, and a 1.0 x 10 －２ The bonded bodies of samples 214 to 232 were fabricated by heat treatment at 800° C. for 60 minutes in a vacuum atmosphere of 100 Pa or less.

[0098] (4) Evaluation The phase structure and bonding strength of the bonding layer of the produced bonded bodies were evaluated by the following methods.

[0099] The cross section of the bonding layer of the bonded body was observed to evaluate the phase structure of the bonding layer. Specifically, the first layer was observed in a cross section perpendicular to the bonding surface, and it was confirmed that (1) the solid solution phase and the compound phase had a sea-island structure, (2) paths (continuous phases) consisting of the solid solution phase connecting the second layer and the copper material were secured in the first layer, and (3) the bonding layer had a thickness of approximately 10,000 μm. ２ It was confirmed that no voids having a circular equivalent diameter of 8 μm or more were observed in the first layer within the field of view.

[0100] The elements dissolved in the solution phase of the first layer were quantitatively determined. Specifically, the content of the elements dissolved in the solution phase was measured using an energy dispersive X-ray analyzer (EDX).

[0101] The bond strength of the bonded structure was evaluated by a shear strength test. Specifically, for the bonded structure, 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, and 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 movement speed of the displacement axis was set to 100 μm / s.

[0102] The tensile strength of the bonding layer was calculated based on the results of the shear strength test. The tensile strength of the bonding layer can be calculated from the shear strength using the von Mises equation, and its magnitude is approximately 1.73 times the shear strength.

[0103] The results are shown in Tables 1 to 6.

[0104] (5) Evaluation Results (Samples 1 to 7) Cross-sectional observation of the bonding layer of Sample 1 confirmed the phase structure shown in FIG. 6 . FIG. 6 is a partial cross-sectional enlarged photograph of the bonding layer of Sample 1. As shown in FIG. 6 , a second layer 32 containing a compound of an active metal element was formed at the interface of the bonding layer 30 on the ceramic member 20 side. It was also confirmed that a first layer 31 was formed on the second layer 32. It was confirmed that the first layer 31 had a sea-island structure, with the compound phase 31B dispersed as an island phase in the solid solution phase 31A of the matrix sea phase. Furthermore, it was confirmed that paths (continuous phases) consisting of the solid solution phase 31A connecting the second layer 32 and the copper material were secured within the first layer 31. It was also confirmed that the first layer 31 did not contain any voids with a circle-equivalent diameter of 1 μm or greater.

[0105] Furthermore, EDX measurement revealed that the compound phase 31B is an intermetallic compound of Cu, Mg, and Sn, specifically Cu ４It was confirmed that the solid solution phase 31A was formed of MgSn. On the other hand, it was confirmed that the solid solution phase 31A was formed by dissolving Mg and Sn in the Cu phase. The amount of dissolved Mg was 1.0 at % and the amount of dissolved Sn was 1.6 at %.

[0106] Furthermore, as shown in Table 1, it was confirmed that Sample 1 had a shear strength of 186.4 MPa, and the tensile strength converted from this was 322.9 MPa. In other words, it was confirmed that high bonding strength could be achieved.

[0107] In Samples 2 to 7, as shown in Table 1, the contents of Mg and Sn in the brazing filler metal were changed from Sample 1, but it was confirmed that a phase structure similar to that of Sample 1 could be realized. In addition, in all samples, like Sample 1, the solid solution phase 31A is composed of Mg and Sn dissolved in a Cu phase, and the compound phase 31B is composed of Cu. ４ It was confirmed that the samples contained MgSn. The amount of dissolved Mg was 5.0 at% or less, and the amount of dissolved Sn was 5.0 at% or less. Furthermore, it was confirmed that the shear strength of each sample was 20 MPa or more, and the converted tensile strength was 40 MPa or more.

[0108] (Samples 8 to 14) Cross-sectional observation of the bonding layer of Sample 8 confirmed that it had a phase structure as shown in FIG. 7 . FIG. 7 is a partial cross-sectional enlarged photograph of the bonding layer of Sample 8. As shown in FIG. 7 , bonding layer 30 of Sample 8 was confirmed to have a phase structure similar to that of bonding layer 30 of Sample 1. In particular, it was confirmed that first layer 31 had a sea-island structure in which compound phase 31B was dispersed as island phases in solid solution phase 31A of the matrix sea phase. Furthermore, it was confirmed that paths (continuous phases) consisting of solid solution phase 31A connecting second layer 32 and the copper material were secured in first layer 31. It was also confirmed that there were no voids in first layer 31 having a circle-equivalent diameter of 1 μm or greater.

[0109] Furthermore, EDX measurement confirmed that the compound phase 31B was formed of an intermetallic compound of Cu, Mg, and Sb, specifically CuMgSb. On the other hand, it was confirmed that the solid solution phase 31A was formed of Cu phase in which Sn was dissolved, but Mg was not. The amount of Sb dissolved was 3.1 at%.

[0110] Furthermore, as shown in Table 1, it was confirmed that Sample 8 had a shear strength of 139.5 MPa, and the tensile strength converted from this was 241.6 MPa. In other words, it was confirmed that high bonding strength could be achieved.

[0111] In Samples 9 to 14, as shown in Table 1, the contents of Mg and Sb in the brazing filler metal were changed from those in Sample 8, but it was confirmed that a phase structure similar to that of Sample 8 could be achieved. In all samples, like Sample 8, it was confirmed that the solid solution phase 31A was composed of Sb solid-solubilized in the Cu phase without Mg solid-solubilizing, and the compound phase 31B was composed of CuMgSb. The amount of Sb solid-solubilized was 4.0 at% or less. Furthermore, it was confirmed that the shear strength of all samples was 20 MPa or more, and the tensile strength converted based on this was 40 MPa or more.

[0112] (Samples 15 to 18) Cross-sectional observation of the bonding layer 30 of Sample 15 confirmed that it had a phase structure as shown in FIG. 8 . FIG. 8 is a partial cross-sectional enlarged photograph of the bonding layer 30 of Sample 15. As shown in FIG. 8 , the bonding layer 30 of Sample 15 was confirmed to have a phase structure similar to that of the bonding layer 30 of Sample 1. In particular, the first layer 31 was confirmed to have a sea-island structure in which the compound phase 31B was dispersed as an island phase in the solid solution phase 31A of the sea phase, which was the parent phase. Furthermore, it was confirmed that paths (continuous phases) consisting of the solid solution phase 31A connecting the second layer 32 and the copper material were secured in the first layer 31. It was also confirmed that the first layer 31 did not have a single void with a circle equivalent diameter of 1 μm or greater.

[0113] Furthermore, EDX measurement confirmed that the compound phase 31B was formed of an intermetallic compound of Cu, Mg, and Sb, specifically CuMgBi. On the other hand, it was confirmed that the solid solution phase 31A contained Mg in the Cu phase but not Bi. The amount of Mg in solid solution was 0.4 at%.

[0114] Furthermore, as shown in Table 1, it was confirmed that Sample 15 had a shear strength of 24.8 MPa, and the converted tensile strength was 43 MPa. In other words, it was confirmed that high bonding strength could be achieved.

[0115] In Samples 16 to 18, as shown in Table 1, the Mg and Bi contents in the brazing filler metal were changed from those in Sample 15, but it was confirmed that a phase structure similar to that of Sample 15 could be achieved. In all samples, like Sample 15, it was confirmed that the solid solution phase 31A was composed of Mg solid-solubilized in the Cu phase without Bi solid-solubilized, and the compound phase 31B was composed of CuMgBi. In all samples, the amount of Mg solid-solubilized was 5.0 at% or less. Furthermore, it was confirmed that the shear strength of all samples was 20 MPa or more, and the tensile strength converted based on this was 40 MPa or more.

[0116] (Samples 19 to 25) In Samples 19 to 25, the contents of Mg, Sn, and Sb were changed from those in Samples 1 and 8, but it was confirmed that a phase structure similar to that of Samples 1 and 8 could be achieved. In all of the samples, it was confirmed that a sea-island structure of solid solution phase 31A and compound phase 31B was formed, paths made of solid solution phase 31A connecting second layer 32 and the copper material were formed in first layer 31, and there was not a single void with a circle equivalent diameter of 1 μm or more.

[0117] (Samples 26 to 33) For Samples 26 to 33, the brazing filler metal was prepared to contain two elements, Sn and Sb, as Mg evaporation inhibitors. The bonding layer 30 of Samples 26 to 33 had a phase structure similar to that of Sample 1. It was also confirmed that a sea-island structure of a solid solution phase 31A and a compound phase 31B was formed, that paths made of the solid solution phase 31A connecting the second layer 32 and the copper material were formed in the first layer 31, and that there were no voids with a circle-equivalent diameter of 1 μm or greater.

[0118] Furthermore, EDX measurement confirmed that the compound phase 31B was formed from an intermetallic compound of Cu, Mg, Sn, and Sb. This intermetallic compound was composed of Cu, Mg, Sn, and Sb partially substituted for Cu. On the other hand, it was confirmed that the solid solution phase 31A was formed by dissolving Mg, Sn, and Sb in the Cu phase.

[0119] Furthermore, as shown in Table 1, it was confirmed that the shear strength of all the samples was 20 MPa or more, and the tensile strength calculated based on this was 40 MPa or more.

[0120] (Samples 34 to 39) In Samples 34 to 39, as shown in Table 1, the type of ceramic member was Si ３ N ４ From SUS304, AlN, Al ２ O ３ Brazing filler metals were prepared in the same manner as in Sample 1, except that SiC or diamond was used, and bonded bodies were fabricated.

[0121] The bonding layer 30 of Samples 34 to 39 was confirmed to have a phase structure similar to that of Sample 1. It was also confirmed that a sea-island structure of the solid solution phase 31A and the compound phase 31B was formed, that paths made of the solid solution phase 31A connecting the second layer 32 and the copper material were formed in the first layer 31, and that there was not a single void with a circle equivalent diameter of 1 μm or more.

[0122] Furthermore, as shown in Table 1, it was confirmed that the shear strength of all the samples was 20 MPa or more, and the tensile strength calculated based on this was 40 MPa or more.

[0123] (Samples 40 to 42) As shown in Table 1, samples 40 to 42 consisted of an iron alloy material (42ALLOY) as the metal member and a Si alloy material (42ALLOY) as the ceramic member. ３ Ni ４ It was confirmed that all of the samples had the same phase structure as Sample 1 and the like, and that a predetermined bonding strength was obtained.

[0124] (Samples 43 and 44) ​​Sample 43, which used a brazing filler metal containing Mg and Ti, and Sample 44, which used a brazing filler metal containing only Mg, had a shear strength of less than 20 MPa and a tensile strength of less than 40 MPa, as shown in Table 1, and it was confirmed that practical bonding strength was not obtained (they were essentially unbonded). Note that these samples did not have a bonding strength that could withstand processing for cross-sectional structure observation, so it was not possible to observe the bonding layer in a cross section perpendicular to the bonding surface.

[0125] (Samples 45 to 232) As shown in Tables 2 to 6, it was confirmed that Samples 45 to 232 all had a shear strength of 20 MPa or more, and that the tensile strength calculated based on this was 40 MPa or more.

[0126] <Preferred Aspects of the Present Disclosure> Preferred aspects of the present disclosure are described below. These aspects can be combined with each other.

[0127] (Supplementary Note 1) A brazing filler metal comprising: Cu; Mg; at least one first element selected from the group consisting of Sn, Sb, and Bi; and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

[0128] (Supplementary Note 2) In Supplementary Note 1, preferably, the content of the Mg is 1 at% or more and 15 at% or less, the content of the first element is 1 at% or more and 20 at% or less, the content of the second element is 0.1 at% or more and 10 at% or less, and when the content of the Mg is X at% and the content of the first element is Y at%, X-6≦Y≦X+6 holds.

[0129] (Supplementary Note 3) In Supplementary Note 1 or Supplementary Note 2, preferably, the powder contains Cu powder containing Cu, and an alloy powder having an intermetallic compound containing at least Mg, the first element, and the second element, and is configured in a paste form.

[0130] (Supplementary Note 4) A bonded 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 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; and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

[0131] (Supplementary Note 5) In Supplementary Note 4, preferably, the bonding layer has: a first layer that forms an interface with the first member and includes a solid solution phase in which Mg and at least one of the first element are solid-solved 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, includes a compound of the second element, and is in contact with the first layer.

[0132] (Supplementary Note 6) In Supplementary Note 5, preferably, when the first 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. ２ There is less than one per

[0133] (Supplementary Note 7) In Supplementary Note 5, preferably, the first layer has a path made of the solid solution phase connecting the second layer and the first member.

[0134] (Supplementary Note 8) In any one of Supplementary Notes 4 to 7, preferably, the shear strength of the bonding layer is 20 MPa or more.

[0135] (Supplementary Note 9) In any one of Supplementary Notes 4 to 8, preferably, the tensile strength of the bonding layer is 40 MPa or more.

[0136] (Appendix 10) A method for manufacturing a brazing filler metal used for joining a first member made of a metal to a second member made of the same or different metal as the first member, or made of ceramics, the method comprising: mixing a powder containing Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi, and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er, with a solvent to obtain a paste-like brazing filler metal.

[0137] (Supplementary Note 11) A method for manufacturing a joined body, 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, with a brazing filler metal interposed therebetween; and a heating step of heating and holding a stack of the first member and the second member while applying pressure in a stacking direction, wherein the brazing filler metal is a material containing at least one first element selected from the group consisting of Cu, Mg, Sn, Sb, and Bi, and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

[0138] (Supplementary Note 12) In Supplementary Note 11, preferably, the brazing filler metal contains Cu powder containing Cu and alloy powder formed from an intermetallic compound containing at least Mg and the first element, and is configured in a paste state.

[0139] (Supplementary Note 13) In Supplementary Note 11 or Supplementary Note 12, preferably, in the heating step, the laminate is heated at 720°C or higher and 1000°C or lower.

[0140] 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; and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

2. The brazing filler metal according to claim 1, wherein the Mg content is 1 at% or more and 15 at% or less, the first element content is 1 at% or more and 20 at% or less, the second element content is 0.1 at% or more and 10 at% or less, and when the Mg content is X at% and the first element content is Y at%, X-6≦Y≦X+6.

3. The brazing material according to claim 1 or 2, which contains Cu powder containing Cu and an alloy powder having an intermetallic compound containing at least Mg, the first element and the second element, and is configured in a paste form.

4. A bonded body comprising: a first member made of a metal; a second member joined to the first member and made of the same or a different metal as the first member, or of ceramics; and a bonding layer formed on a 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; and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

5. The joint body described in claim 4, wherein the joining layer comprises: a first layer forming an interface with the first member and including a solid solution phase in which Mg and at least one of the first element are solid-solved in Cu, and a compound phase including an intermetallic compound containing Cu, Mg and the first element; and a second layer forming an interface with the second member, including a compound of the second element, and in contact with the first layer.

6. When the first layer is observed 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 The conjugate of claim 5, wherein the number of nuclei per unit area is less than one.

7. The joint body according to claim 5, wherein the first layer has a path made of the solid solution phase connecting the second layer and the first member.

8. The bonded body according to claim 4 or 5, wherein the bonding layer has a shear strength of 20 MPa or more.

9. The bonded body according to claim 4 or 5, wherein the bonding layer has a tensile strength of 40 MPa or more.

10. A method for manufacturing a brazing filler metal used for joining a first member made of a metal to a second member made of the same or a different metal as the first member, or made of ceramics, comprising mixing a powder containing Cu, Mg, at least one first element selected from the group consisting of Sn, Sb, and Bi, and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er, with a solvent to obtain a paste-like brazing filler metal.

11. A method for manufacturing a joined body, comprising: an arrangement step of arranging 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, so as to be stacked with a brazing material interposed therebetween; 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 material is a material containing at least one first element selected from the group consisting of Cu, Mg, Sn, Sb, and Bi, and at least one second element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Ca, Ce, La, Sm, Yb, Nd, Gd, and Er.

12. The method for manufacturing a joint body according to claim 11, wherein the brazing material contains Cu powder containing Cu and alloy powder formed from an intermetallic compound containing at least Mg and the first element, and is configured in a paste form.

13. The method for producing a bonded body according to claim 11 or 12, wherein in the heating step, the laminate is heated at 720°C or higher and 1000°C or lower.