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

Abstract

This brazing material for joining dissimilar or the same type of metal members includes Cu, Mg, and at least one Mg evaporation suppression element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi. Cu has the highest content among the elements constituting the brazing 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] In various components, including electronic components and heat exchangers, metal components made of the same or different metals are often combined and used. Methods for combining these metal components include, for example, caulking, welding, and brazing. Among these, brazing is considered desirable because it causes little change in the metal structure of the components and offers a high degree of design freedom. Brazing is a technique in which a brazing material with a lower melting point than the metal components is interposed between the metal components and melted to join the metal components. Brazing materials containing silver (Ag), for example, have been proposed as such brazing materials (see, for example, Patent Document 1).

[0003] However, when brazing metal members together, particularly in the case of joining dissimilar metals, galvanic corrosion can reduce the joint strength. In particular, when using a brazing filler metal containing Ag as the main phase, Ag is a noble metal in terms of potential, and the potential difference becomes large, making galvanic corrosion more likely to occur. Furthermore, using Ag as the brazing filler metal can increase costs. Therefore, there is a demand for a joining technology that uses a brazing filler metal that does not contain Ag as the main phase.

[0004] Patent No. 5430655

[0005] However, a problem with brazing filler metals that do not have Ag as the main phase is that it is difficult to lower the melting point of the brazing filler metal by using an element that is difficult to evaporate instead of Ag. As a result, brazing filler metals that do not have Ag as the main phase do not melt at low heating temperatures, or even if they do melt, they may not be able to maintain high bonding strength of the bonded body.

[0006] An object of the present disclosure is to provide a technique for increasing the bonding strength of a bonded body.

[0007] According to one aspect of the present disclosure, there is provided a brazing filler metal for joining dissimilar or homogeneous metal members, the brazing filler metal comprising: Cu; Mg; and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, wherein Cu has the highest content among the elements constituting the brazing filler metal.

[0008] According to another aspect of the present disclosure, there is provided a brazing filler metal for joining a first member made of an oxide-based ceramic to a second member made of a metal or an oxide-based ceramic, the brazing filler metal comprising: Cu; Mg; and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, wherein Cu has the highest content among the elements constituting the brazing filler metal.

[0009] According to yet another aspect of the present disclosure, there is provided a joined body comprising: two metal members of the same or different types; and a joining layer formed on the joining surface of the two metal members, wherein the joining layer contains Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and Cu has the highest content among the elements constituting the joining layer.

[0010] According to yet another aspect of the present disclosure, there is provided a joined body comprising: a first member made of an oxide-based ceramic; a second member made of a metal or an oxide-based ceramic; and a joining layer formed on the joining surfaces of the first member and the second member, wherein the joining layer contains Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and Cu has the highest content among the elements constituting the joining layer.

[0011] 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 arranging two metal members of the same or different types so as to be stacked with a brazing filler metal interposed therebetween; and a heating step of heating a laminate in which the two metal members and the brazing filler metal are stacked while applying pressure in the stacking direction, to form and maintain a liquid phase in at least a portion of the brazing filler metal, wherein the brazing filler metal is made of a material containing Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and the Cu content is the highest among the elements constituting the brazing filler metal.

[0012] 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 arranging a first member made of an oxide-based ceramic and a second member made of a metal or an oxide-based ceramic so as to be stacked with a brazing filler metal interposed therebetween; and a heating step of heating a stack in which the first member, the brazing filler metal, and the second member are stacked while applying pressure in the stacking direction, to form and maintain a liquid phase in at least a portion of the brazing filler metal, wherein the brazing filler metal is made of a material containing Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and wherein Cu has the highest content among the elements constituting the brazing filler metal.

[0013] According to the present disclosure, the bonding strength of the bonded body can be increased.

[0014] 1A and 1B are enlarged partial cross-sectional views of a bonded body 100 according to one embodiment of the present disclosure; FIG. 1C is an enlarged partial cross-sectional photograph of the bonding layer of Sample 1; FIG. 1A is a diagram schematically illustrating shear stress applied to the bonding layer 30, and FIG. 1B is a diagram schematically illustrating tensile stress applied to the bonding layer 30; FIG. 1A is a diagram illustrating a state in which a first metal member 10 and a second metal member 20 are arranged via a brazing material 50; FIG. 1B is a diagram illustrating a state in which a laminate of the first metal member 10 and the second metal member 20 is heated while being pressurized; and FIG. 1C is a diagram illustrating the manufactured bonded body 100.

[0033] FIGS. 1A and 1B are diagrams schematically illustrating a state in which a shear strength test is performed.

[0015] <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 contains mainly Cu and is composed of copper (Cu) and magnesium (Mg), and which can significantly lower the melting point of Cu, as a brazing filler metal composition that satisfies these requirements.

[0016] However, in the Cu-Mg binary eutectic composition, the vapor pressure of Mg is high, and when Mg is contained in the brazing material as a simple substance, the vapor pressure is 600°C or higher. ２ It is known that when Mg is contained in the 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 720°C, the Cu-Mg eutectic point at which the liquid phase begins to form. On the other hand, from the viewpoint of increasing the wettability of the liquid phase, it is better to heat the brazing filler metal to a higher temperature. However, if the heating temperature is increased to increase the wettability, Mg becomes more likely to evaporate. Therefore, voids may be formed due to Mg evaporation before a strong bonding structure is formed, and bonding layers containing such voids tend to have low bonding strength. Furthermore, if excessive Mg is contained, bonding can be performed before the Mg evaporates, but if MgCu is used, bonding can be performed before the Mg evaporates. ２ and CuMg ２ However, a large amount of intermetallic compounds known for their brittleness is formed, making it difficult to maintain high joining strength. Although the Cu-Mg binary eutectic composition can significantly lower the melting temperature, it tends to be difficult to achieve both wettability and suppression of Mg evaporation.

[0017] The present inventors have investigated methods for suppressing Mg evaporation during heating of Cu-Mg eutectic compositions. They have devised the inclusion 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 an element that forms a eutectic with Cu and Mg in a ternary system. After extensive investigation into elements that can cause such eutectic reactions, they have found that Group 14 and Group 15 elements, which are solid at room temperature and atmospheric pressure, are suitable. Among these elements, silicon (Si), germanium (Ge), tin (Sn), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi) have been found to suppress Mg evaporation when incorporated into Cu-Mg brazing filler metals. In this specification, these elements are also referred to as Mg evaporation suppressing elements.

[0018] The present invention was made based on the above findings.

[0019] <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.

[0020] (1) Brazing Filler Metal The brazing filler metal of this embodiment can be used to join metal members of the same or different types. Specifically, the brazing filler metal is a Cu-Mg brazing filler metal containing Cu as a primary component. Specifically, the brazing filler metal contains Cu, Mg, and at least one Mg evaporation inhibitor selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi. The brazing filler metal of this embodiment has the highest Cu content (at %) among the elements constituting the brazing filler metal, and may contain other elements within a range that does not interfere with (does not inhibit) the eutectic reaction between Cu, Mg, and the Mg evaporation inhibitor. The brazing filler metal may contain Mg, the Mg evaporation inhibitor, and inevitable impurities, with the remainder being Cu. Since the brazing filler metal of this embodiment is intended for joining metal members, it does not necessarily need to be substantially free of the active metal elements (e.g., at least one metal element selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), and tungsten (W)) that are contained in brazing filler metals for joining ceramic and metal members. The inevitable impurities are 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. The term "substantially free of active metal elements" means, for example, that the total content of the active metal elements described above is lower (at% basis) than any of the Cu, Mg, and at least one Mg evaporation inhibitor element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi that constitute the brazing filler metal of this embodiment, or that the total content is less than 0.1 at%.

[0021] Cu is an element that mainly constitutes the bonding layer when the brazing filler metal is heated and forms a solid solution with Mg and the Mg evaporation suppressing element, and also contributes to the ductility and malleability of the solid solution.

[0022] Mg lowers the melting point of the solid solution more than Cu, thereby lowering the joining temperature of the brazing filler metal, and also increases the wettability of the brazing filler metal with the metal members and removes oxides from the surfaces of the metal members.

[0023] 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 molten components such as Mg are less likely to evaporate. 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, thereby improving the strength of the joining layer. The Mg evaporation inhibitor can be at least one element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi.

[0024] The brazing filler metal of this embodiment primarily contains Cu, and the contents of other elements are not particularly limited. Here, "primarily containing Cu" means that Cu has the highest content among the elements constituting the brazing filler metal, or that the Cu content is 40 at% or more (preferably 50 at% or more). The contents of each element preferably fall within the following ranges. Specifically, the Cu content is preferably 40 to 80 at%, more preferably 50 at% to 80 at%. The Mg content is preferably 1 at% to 15 at%, more preferably 3 at% to 12 at%. The total content of the Mg evaporation inhibitor elements is preferably 1 at% to 20 at%, more preferably 3 at% to 15 at%. Furthermore, when the Mg content is X at% and the total content of the Mg evaporation inhibitor elements is Y at%, it is preferable that X-5≦Y≦X+5. By containing each element at such a content, the bonding temperature of the brazing filler metal can be reduced while still achieving a predetermined bonding strength in the bonding layer.

[0025] The brazing filler metal of this embodiment may further contain at least one element (referred to as a melting point depressant) selected from the group consisting of silver (Ag), indium (In), and manganese (Mn). 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. The melting point depressant exists in solid solution with Cu or diffused into the joined materials. Ag may exist as a single phase in the joining layer. The total content of the melting point depressant is preferably 50 at% or less (less than 40 at% for each element alone). More preferably, the total content is 35 at% or less, and even more preferably, the total content is 20 at% or less.

[0026] The form of the brazing filler metal is not particularly limited, and may be, for example, a paste, foil, or wire. Among these, a paste is preferable from the viewpoint of obtaining a uniform phase structure described later in the bonding layer. The paste brazing filler metal contains powder 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 simple powder or as a compound powder containing each element. The form of inclusion of each element will be described below.

[0028] Mg can be, for example, a simple substance (Mg), a solid solution in which part of Mg in the Mg crystal is replaced with another element, or an intermetallic compound with Cu (for example, MgCu ２ and Mg ２Preferably, the brazing filler metal contains at least one of a powder containing an intermetallic compound with an Mg evaporation inhibiting element, such as Mg, Cu, or an intermetallic compound with an Mg evaporation inhibiting element (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 inhibiting element, i.e., an alloy powder formed from Mg and an intermetallic compound containing an Mg evaporation inhibiting element. For example, the Mg may contain only an alloy powder formed from Mg and an intermetallic compound containing an Mg evaporation inhibiting element, or the alloy powder may be mixed with at least one of an Mg metal powder, an Mg oxide powder, an Mg-Cu intermetallic compound powder, or the like. By previously converting at least a portion of the Mg into an intermetallic compound with an Mg evaporation inhibiting element, evaporation of Mg can be more reliably suppressed when the brazing filler metal is heated.

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

[0030] The alloy powder may be prepared by mixing and melting Mg, a Mg evaporation suppressing element, and optionally Cu, 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 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 oxide powder, an Mg-Cu intermetallic compound powder, etc., it is recommended to adjust the content of the alloy powder 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. The content of the alloy powder containing Mg and an Mg evaporation inhibiting element may be set so that it is 100% of the total amount of Mg contained in the brazing filler metal, that is, the alloy powder alone may be included as the Mg source. By setting such a content rate, Mg evaporation can be more stably suppressed.

[0032] Cu can be, for example, a simple substance (Cu), a solid solution in which part of Cu in the Cu crystal is replaced with other elements, or an intermetallic compound with Mg (for example, MgCu ２ etc.), intermetallic compounds with Mg evaporation inhibitor elements (e.g., Cu ３ Sn, etc.), or in the form of powder containing at least one of Cu alone, a solid solution, and an alloy containing an intermetallic compound.

[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 in which a part of the crystal is substituted with another element, an intermetallic compound formed with at least one of Mg and Cu, or an alloy containing the simple substance, solid solution, and intermetallic compound of the Mg evaporation inhibiting element.

[0034] The content of the powder containing each element is not particularly limited, and may be adjusted appropriately depending on the content of each element in the powder used. For example, the brazing filler metal may contain each powder so that the contents of the elements derived from the powder used are, specifically, 50 at% to 80 at% for Cu, 1 at% to 15 at% for Mg, and 1 at% to 20 at% for the Mg evaporation inhibitor. By setting the contents 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.

[0035] In the brazing filler metal, the particle size of each powder containing Cu, Mg, a Mg evaporation suppressing element, etc. can be appropriately changed depending on the size of the joined material and the thickness of the joining layer. For example, in the case of a macrostructure such as a heat exchanger or a hermetically sealed body, the particle size may be large, and a median diameter D50 of 45 μm or more and 150 μm or less is preferable. On the other hand, while there is no particular restriction on the lower limit of the median diameter D50, a median diameter D50 of 5 μm or more is preferable from the viewpoint of suppressing the influence of surface oxidation of the powder. The median diameter D50 is measured, for example, using a laser diffraction particle size distribution analyzer, and indicates the particle size at 50% of the volume-based cumulative distribution curve.

[0036] In addition to the powder, the brazing material may contain binders, solvents, surfactants, plasticizers, dispersants, etc. as needed. 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.

[0037] The method for preparing the brazing material is not particularly limited, and any conventionally known method may be used.

[0038] (2) Bonded Body Next, the bonded body will be described with reference to Fig. 1. Fig. 1 is an enlarged partial cross-sectional view of a bonded body according to one embodiment of the present disclosure.

[0039] As shown in Figure 1, the joined body 100 comprises a first metal member 10, a second metal member 20 joined to the first metal member 10, and a joining layer 30 formed on the joining surface between the first metal member 10 and the second metal member 20.

[0040] (Metal Members) The first metal member 10 and the second metal member 20 are composed of the same or different metals. Examples of metals that constitute these metal members include pure copper, copper alloys, pure nickel, nickel alloys, titanium alloys, stainless steel (SUS), and chromium-based alloys. 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 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).

[0041] There are no particular limitations on the shapes and dimensions of the first metal member 10 and the second metal member 20. The shapes and dimensions of the first metal member 10 and the second metal member 20 may be adjusted appropriately depending on the configuration of the electronic component.

[0042] (Bonding Layer) A bonding layer 30 is formed between the first metal member 10 and the second metal member 20 along their bonding surfaces 10s, 20s. The bonding layer 30 is formed from the brazing material described above and contains Cu, Mg, and a Mg evaporation suppressing element. The bonding layer 30 may further contain at least one element (melting point lowering element) selected from the group consisting of Ag, In, and Mn. Of the elements constituting the bonding layer 30, it is preferable that Cu have the highest content.

[0043] The bonding layer 30 has a solid solution phase in which at least one of Mg and an Mg evaporation inhibiting element is solid-solved in Cu, and a compound phase containing a ternary intermetallic compound containing Cu, Mg, and an Mg evaporation inhibiting element. The thickness of the bonding layer 30 may be, for example, 1 μm to 2000 μm.

[0044] The bonding layer 30 has a phase structure as shown in Fig. 2. Fig. 2 is an enlarged partial cross-sectional photograph of the first metal member 10, the second metal member 20, and the bonding layer 30 of Sample 1, and shows a cross-sectional photograph (SEM image) of the bonding layer 30 containing Sb as an element inhibiting Mg evaporation, as will be described later.

[0045] As shown in FIG. 2, the bonding layer 30 includes a solid solution phase 30A and a compound phase 30B.

[0046] The solid solution phase 30A is mainly composed of a solid solution of Cu with at least one of Mg and a Mg evaporation inhibiting element. The solid solution phase 30A may also contain metal elements constituting the first metal member 10 and the second metal member 20. The solid solution of each element in the solid solution phase 30A can improve the strength of the solid solution phase 30A through solid solution strengthening.

[0047] The solid-solution state of Mg and the Mg evaporation inhibiting element in the solid-solution phase 30A may vary depending on the type of Mg evaporation inhibiting element. Specifically, when the Mg evaporation inhibiting element is Si, at least Si may be solid-solubilized in the solid-solution phase 30A, but Mg may not be solid-solubilized. When the Mg evaporation inhibiting element is Ge, Mg and Ge may be solid-solubilized in the solid-solution phase 30A. When the Mg evaporation inhibiting element is Sn, Mg and Sn may be solid-solubilized in the solid-solution phase 30A. When the Mg evaporation inhibiting element is P, Mg and P may be solid-solubilized in the solid-solution phase 30A. When the Mg evaporation inhibiting element is As, at least As may be solid-solubilized in the solid-solution phase 30A, but Mg may not be solid-solubilized. When the Mg evaporation inhibiting element is Sb, at least Sb may be solid-solubilized in the solid-solution phase 30A, but Mg may not be solid-solubilized. When the Mg evaporation inhibiting element is Bi, at least Mg may be dissolved in the solid solution phase 30A, but Bi may not be dissolved.

[0048] In the solid solution phase 30A, 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. The amount of dissolved Mg is preferably 5 at% or less. The amount of dissolved Mg evaporation inhibiting element is preferably 10 at% or less. The amount of dissolved Mg can be measured, for example, by energy dispersive X-ray analysis (EDX) of the solid solution phase 30A.

[0049] The compound phase 30B contains an intermetallic compound containing any of Cu, Mg, and an Mg evaporation inhibiting element, and may be made of a ternary intermetallic compound consisting of Cu, Mg, and an Mg evaporation inhibiting element. The compound phase 30B is formed, for example, by precipitation of an intermetallic compound. The compound phase 30B contains an intermetallic compound according to the type of Mg evaporation inhibiting element. Specifically, when the Mg evaporation inhibiting element is Si, Cu ３ Mg ２ Si and Cu １６ Mg ６ Si ７ When the Mg evaporation inhibitor element is Ge, CuMgGe is included. When the Mg evaporation inhibitor element is Sn, Cu ４ The compound phase 30B includes MgSn. When the Mg evaporation inhibiting element is P, the compound phase 30B includes CuMgP. When the Mg evaporation inhibiting element is As, the compound phase 30B includes CuMgAs. When the Mg evaporation inhibiting element is Sb, the intermetallic compound includes CuMgSb. When the Mg evaporation inhibiting element is Bi, the intermetallic compound includes CuMgBi. When two or more Mg evaporation inhibiting elements are present, the intermetallic compound is in a partially substituted form. Note that the compound phase 30B includes at least a ternary intermetallic compound, but Cu, Mg, and the Mg evaporation inhibiting element may also be present as compounds in other forms. Examples include binary intermetallic compounds composed of two of Cu, Mg, and the Mg evaporation inhibiting element, and simple metals of each element. The compound phase 30B may also include intermetallic compounds formed from Cu, Mg, or the Mg evaporation inhibiting element and a metal element diffused from the first metal member 10 or the second metal member 20. For example, when the first metal member 10 is made of Ti or SUS304, TiCu ４ Ya Ni ２ In this case, MgSn is rarely formed with the first metal member 10 or the second metal member 20 to form a brittle compound, and high strength can be maintained.

[0050] Furthermore, at the interface between the first metal member 10 and the second metal member 20 in the bonding layer 30, interdiffusion of elements may occur between each metal member and the bonding layer 30. As a result, a metal diffusion layer containing metal elements originating from each metal member and elements originating from the bonding layer 30 may be formed. For example, in FIG. 2, a metal diffusion layer 30C is formed on the interface side of the first metal member 10 with the bonding layer 30. While FIG. 2 shows the case where the metal diffusion layer 30C is formed on a portion of the interface, it may be formed over the entire interface. When an intermetallic compound is not segregated at the interface, the formation of the metal diffusion layer 30C due to interdiffusion facilitates high strength. In this embodiment, Mg can reduce surface oxides in the first metal member 10 and the second metal member 20, causing interdiffusion on the surfaces of each member, facilitating the formation of a uniform metal diffusion layer 30C and further increasing strength.

[0051] (Phase Structure) Here, the phase structure of the bonding layer 30 will be specifically described.

[0052] In the bonding layer 30, it is preferable that the solid solution phase 30A, which has excellent malleability and ductility, is configured as a continuous phase. For example, as shown in FIG. 2, the bonding layer 30 preferably has a sea-island structure in which a compound phase 31B is dispersed in a solid solution phase 31A. The compound phase 30B containing an intermetallic compound is more brittle than the solid solution phase 30A containing a solid solution, and this can be a factor that hinders improvement of the bonding strength of the bonding layer 30. For example, if this compound phase 30B is continuous in a layered structure throughout the entire bonding layer 30 and is formed in a region corresponding to a stress concentration point, crack propagation cannot be stopped when a stress load is applied to the compound phase 30B, and there is a risk of significantly reducing the bonding strength. In this regard, by having the bonding layer 30 have a sea-island structure as shown in FIG. 2, it is possible to maintain high bonding strength.

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

[0054] Furthermore, in the bonding layer 30, the solid solution phase 30A is preferably configured as a continuous phase connecting the first metal member 10 and the second metal member 20. In other words, the bonding layer 30 preferably has a path formed by the solid solution phase 30A connecting the first metal member 10 and the second metal member 20. The solid solution phase 30A is primarily formed of a solid solution containing Cu and has excellent malleability and ductility. When the solid solution phase 30A is configured without being interrupted by the compound phase 30B, in other words, when the solid solution phase 30A is configured to continuously connect the first metal member 10 and the second metal member 20, the first metal member 10 and the second metal member 20 can be firmly bonded together, thereby improving the bonding strength. To form the continuous phase, it is preferable to form the compound phase 30B 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 30A 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 30A 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 first metal member 10 and the second metal member 20 are bonded using a brazing filler metal containing Mg, there is a concern that the evaporation of Mg contained in the brazing filler metal may cause voids or pinholes (hereinafter, collectively referred to as voids) to occur in the bonding layer 30. The presence of such voids can reduce the bonding strength of the bonded body 100. In this regard, in this embodiment, by including an Mg evaporation suppressing element in the brazing filler metal, the evaporation of Mg can be suppressed, thereby reducing the occurrence of voids in the bonding layer 30.

[0056] Specifically, when observed in a cross section perpendicular to the bonding surfaces 10s and 20s, the bonding layer 30 has a thickness of 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, when the bonding layer 30 is observed in a cross section perpendicular to the bonding surfaces 10s and 20s, even if voids are observed, the circular equivalent diameter of the voids is preferably less than 8 μm, for example, more preferably less than 4 μm, and even more preferably less than 1 μm.

[0057] (Bonding strength) In this embodiment, the bonding layer 30 is formed from the brazing filler metal, thereby providing a high bonding strength between the first metal member 10 and the second metal 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.

[0058] The shear strength of the bonding layer 30 herein refers to the magnitude of shear load per unit area required to fracture the bonding layer 30 (shear fracture) when stress (shear stress) is applied to the bonding layer 30 so as to displace the first metal member 10 and the second metal 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 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 first metal member 10 and the second metal member 20 apart in a direction perpendicular to the bonding surfaces 10s and 20s, as shown in Fig. 3(b).

[0059] (3) Method for Manufacturing the Bonded Body Next, a method for manufacturing the bonded body 100 will be described with reference to FIGS. 4(a) to 4(c).

[0060] First, as shown in FIG. 4A, the first metal member 10 and the second metal member 20 are arranged so as to be stacked with the brazing material 50 interposed therebetween.

[0061] 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, and 1 to 20 at% Mg evaporation inhibitor. In the brazing filler metal 50, Cu, Mg, the Mg evaporation inhibitor, 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 and an alloy powder formed from an intermetallic compound containing at least Mg and the Mg evaporation inhibitor may be appropriately mixed so that the respective elements have predetermined content ratios.

[0062] Methods for placing the brazing material 50 on the intended joining surfaces 10s', 20s' of the first metal member 10 and the second metal member 20 include known techniques such as screen printing, transfer, dispensing, inkjet, spray coating, sputtering, and vapor deposition.

[0063] 4(b), the laminate 100' of the first metal member 10 and the second metal member 20 arranged with the brazing filler material 50 interposed therebetween is heated in a predetermined atmosphere while being pressurized in the lamination direction, and the brazing filler material 50 is melted while maintaining a state in which 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.

[0064] The heating temperature during joining 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 points of the first metal member 10 and the second metal member 20. The heating temperature is preferably equal to or lower than 115% of the melting point (K) 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 (K) of the brazing filler metal 50. 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 higher than 720°C and equal to or lower than 900°C. Note that known furnaces such as a stationary batch furnace, a multi-chamber furnace, and a belt conveyor furnace can be used as the heat treatment furnace used for joining.

[0065] Other conditions for bonding are exemplified as follows: Oxygen concentration: 1000 ppm or less, or 100 ppm or less Pressure: 0.5 kPa or more Holding time: Not particularly limited, but for example, 3 minutes to 120 minutes

[0066] During heating, it is necessary for a liquid phase to be formed in at least a portion of the brazing filler metal 50. This state can be achieved by setting the heating temperature to 720°C or higher. However, if the heating temperature is too high, the effect of the Mg evaporation suppression element may be exceeded and Mg may evaporate, which may make it difficult to form a liquid phase or may cause voids in the resulting bonding layer 30. Setting the heating temperature to 1000°C or lower (more preferably 900°C or lower) can avoid these problems. By applying a pressure of 0.5 kPa or higher, the first metal member 10 and the second metal member 20 can be maintained in close contact with each other via the brazing filler metal 50, thereby increasing the bonding strength between the first metal member 10 and the second metal member 20. There is no particular upper limit to the pressure, but it can be set to, for example, approximately 20 kPa.

[0067] Thereafter, the heated laminate 100' is cooled, resulting in the bonded body 100 shown in FIG.

[0068] The joined body 100 in this embodiment can be used, for example, as a heat sink, a metal housing, or a component part of a power generating machine.

[0069] (4) Effects According to this aspect, one or more of the following effects can be obtained.

[0070] (a) The brazing filler metal of this embodiment contains Cu, Mg, and at least one Mg evaporation inhibitor selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi. Since Cu has the highest Cu content among the elements constituting the brazing filler metal, when the brazing filler metal is heated and joined while lowering its melting point, the Mg evaporation inhibitor reacts with Mg to inhibit Mg evaporation. Furthermore, at least Cu, Mg, and the Mg evaporation inhibitor can be bonded to form an intermetallic compound. This intermetallic compound is characterized by being easily melted at the joining temperature due to the eutectic reaction with Cu, and by being bonded to the Mg evaporation inhibitor, preventing 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 the melting and solidification of the components contained in the brazing filler metal. This inhibits Mg evaporation. As a result, in the bonding layer 30 obtained by heating the brazing material, the generation of voids due to evaporation of Mg can be reduced, a dense phase structure can be formed, and high bonding strength can be achieved.

[0071] (b) Furthermore, according to the brazing filler metal of this embodiment, the inclusion of Mg can lower the melting point of Cu, thereby achieving high bonding strength at a low heating temperature, for example, in the range of 720°C to 1000°C (more preferably 720°C to 900°C). Furthermore, the inclusion of Mg can remove oxides on the surfaces of the first metal member 10 and the second metal member 20, and can increase the wettability of the first metal member 10 and the second metal member 20.

[0072] (c) The brazing filler metal contains 1 at% to 15 at% Mg, 1 at% to 20 at% Mg evaporation inhibitor, X at% Mg content, and Y at% Mg evaporation inhibitor total content, so that X-5≦Y≦X+5 holds. By including each element at such a content, the effect (a) can be more stably achieved.

[0073] (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.

[0074] (e) The brazing filler metal preferably contains alloy powder such 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, thereby more reliably achieving the effect of (d) above.

[0075] (f) When the brazing filler metal of this embodiment is used to join the first metal member 10 and the second metal member 20, Mg evaporation can be suppressed in the joining layer 30, thereby reducing voids caused by Mg evaporation. Furthermore, the joining layer 30 can be configured to have a solid solution phase 30A formed by solid-solving at least one of Mg and an Mg evaporation inhibitor in Cu, and a compound phase 30B containing an intermetallic compound containing Cu, Mg, and the Mg evaporation inhibitor. The solid solution phase 30A has excellent malleability and ductility due to the inclusion of Cu. The compound phase 30B contains an intermetallic compound further containing an Mg evaporation inhibitor, resulting in higher strength than when the compound phase 30B does not contain an Mg evaporation inhibitor. A joining layer 30 having such a phase structure can firmly join the first metal member 10 and the second metal member 20, achieving high joining strength.

[0076] (g) By suppressing the generation of voids in the bonding layer 30, when the bonding layer 30 is observed in a cross section perpendicular to the bonding surface, the voids are 10,000 μm ２ No voids having a circular equivalent diameter of 8 μm or more are observed within any field of view.

[0077] (h) The bonding layer 30 preferably has a sea-island structure in which the compound phase 31B is dispersed in the solid solution phase 31A. In the sea-island structure of the bonding layer 30, the solid solution phase 30A forms a continuous sea-like phase, and the compound phase 30B has a dispersed island-like phase structure. If the compound phase 30B is present in a layered form, for example, it is prone to breakage when a load is applied to that portion. However, by dispersing the compound phase 30B, breakage due to a load can be suppressed, and the bonding strength can be more reliably increased.

[0078] (i) When any region of the bonding layer 30 is extracted in units of 10 μm in thickness and the area ratio of the compound phase 30B in the any region is measured, it is preferable that all area ratios are 40% or less. When the area ratio of the compound phase 30B falls within the predetermined range, the compound phase 30B is finely dispersed in the solid-solution phase 30A, and the effect of (h) described above can be more reliably obtained.

[0079] (j) It is preferable that the bonding layer 30 is configured such that the solid solution phase 30A is a continuous phase that connects the first metal member 10 and the second metal member 20. This allows the bonding layer 30 to have paths made of the solid solution phase 30A, which can more reliably increase the bonding strength.

[0080] (k) When the bonding layer 30 has any one of the phase structures (f) to (j) above, it is possible to make the shear strength of the bonding layer 30 20 MPa or more. The tensile strength of the bonding layer 30 can be calculated from the shear strength using the von Mises equation, and the tensile strength is approximately 1.73 times the shear strength, so it is possible to make the tensile strength of the bonding layer 30 34.6 MPa or more.

[0081] (l) By forming the bonding layer 30 using a brazing material that does not contain Ag as a main component, migration due to a high Ag content can be suppressed. In other words, high migration resistance can be achieved in the bonding layer 30.

[0082] 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.

[0083] For example, while the above-described embodiments have described brazing filler metals for joining dissimilar or homogeneous metal members and their joined bodies, the present disclosure can also be applied to brazing filler metals for joining a first member made of oxide-based ceramics to a second member made of metal or oxide-based ceramics, and their joined bodies. Even in this case, the brazing filler metal may be composed of a material containing the same metal elements as in the above-described embodiments, such as Cu, Mg, and at least one Mg evaporation inhibitor selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, with the highest Cu content among the elements constituting the brazing filler metal. Furthermore, when the Mg content is X at % and the total content of the Mg evaporation inhibitor is Y at %, it is preferable that 1≦X≦15, 1≦Y≦20, and X−5≦Y≦X+5.

[0084] Normally, brazing filler metals used to join ceramic members need to contain active metal elements such as Ti. However, the brazing filler metal of the present disclosure is capable of joining oxide-based ceramics even when it does not substantially contain active metal elements (for example, at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W). This is thought to be because a part of the oxide-based ceramic reacts with a part of the Mg contained in the brazing filler metal, forming an interfacial reaction layer containing MgO at the interface between the oxide-based ceramic and the joining layer. Note that examples of oxide-based ceramics that can be joined include alumina (Al ２ O ３ ), silica (SiO ２ ), zirconia (ZrO ２) and the like. The bonded body preferably 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 an intermetallic compound containing Cu, Mg, and an Mg evaporation inhibitor. The bonding layer can improve bonding strength by having a path formed by the solid solution phase connecting the two members. 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 oxide-based ceramic or metal members to be bonded. The heating temperature is preferably equal to or lower than 115% of the melting point (K) 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 (K) of the brazing filler metal 50. 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 higher than 720°C and equal to or lower than 900°C.

[0085] Example 1 In this example, two metal members were joined together using the prepared brazing filler metal, and the joining strength of the resulting joined body was evaluated.

[0086] (1) Preparation As 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 5.0 mm, and a steel material (SUS304) having a thickness of 5.0 mm were prepared.

[0087] Furthermore, powders containing Cu, Mg, and an Mg evaporation inhibiting element were prepared as powders for preparing brazing filler metals. Specifically, a Cu simple metal powder was prepared as a powder containing Cu. As a powder containing Mg and an Mg evaporation inhibiting element, Cu ４ Alloy powders formed from MgSn and Cu, alloy powders formed from CuMgSb and Cu, alloy powders formed from CuMgP and Cu, Cu １６ Mg ６ Si ７ Four types of alloy powders composed of Cu and Mg were prepared. Mg simple metal powder was also prepared as the Mg-containing powder. The median diameter D50 of each powder was 45 μm or less. The alloy powders were produced by atomization.

[0088] (2) Preparation of Brazing Filler Metals First, the above-mentioned powders were mixed so that the contents of Cu, Mg, Mg evaporation inhibiting element, etc. were as shown in Table 1, and the mixture was made into a paste to prepare the brazing filler metals of Samples 1 to 6. When making the paste, polyethylene glycol and diethylene glycol monobutyl ether having a molecular weight of 400 or less were used as solvents, and the ratio of the solvent in the paste was 9 mass %. In preparing each brazing filler metal, the amount of alloy powder containing Mg and the Mg evaporation inhibiting element was adjusted so that the Mg content derived from the alloy powder was 40% or more of the total amount of Mg contained in the brazing filler metal.

[0089] (3) Fabrication of Joint Next, for Samples 1 to 6, the prepared paste brazing material was applied by screen printing onto the intended joining surface of the first metal member shown in Table 1. Next, the second metal member shown in Table 1 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 Bonded bodies of Samples 1 to 6 were fabricated by carrying out a heat treatment under the conditions shown in Table 1 in a vacuum atmosphere of 100 Pa or less.

[0090]

[0091] (4) Evaluation The phase structure and bonding strength of the bonding layer of the produced bonded bodies were evaluated by the following methods.

[0092] The cross section of the bonding layer of the bonded body was observed to evaluate the phase structure of the bonding layer. Specifically, the bonding 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 an island-in-sea structure, (2) paths (continuous phases) consisting of the solid solution phase connecting the metal members were secured in the bonding 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 bonding layer within the field of view.

[0093] The amount of elements dissolved in the solution phase in the bonding layer was also determined by measuring the content of the elements dissolved in the solution phase using an energy dispersive X-ray analyzer (EDX).

[0094] The bond strength of the bonded structure was evaluated by a shear strength test. Specifically, as shown in FIG. 5 , the second metal member of the bonded structure 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 first metal member was exposed to prepare a test specimen. Then, with the first metal member of the test specimen fixed, the cylindrical second metal member was pressed using a displacement jig in a direction parallel to the bonding surface. The magnitude of the stress at which 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 first metal member, and the displacement axis movement speed was set at 100 μm / s.

[0095] 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.

[0096] The results are shown in Table 1.

[0097] (5) Evaluation Results: Cross-sectional observation of the bonding layer of Sample 1 confirmed the phase structure shown in FIG. 2 . FIG. 2 is a partial cross-sectional enlarged photograph of the bonding layer 30 of Sample 1, corresponding to a partial enlargement of the dashed-line area A in FIG. 1 . As shown in FIG. 2 , the bonding layer 30 was confirmed to have a sea-island structure in which island-like compound phases 30B are dispersed in a sea-like solid solution phase 30A. Furthermore, it was confirmed that the solid solution phase 30A was configured to have paths (continuous phases) connecting the first metal member 10 and the second metal member 20. The compound phase 30B, shown in white in FIG. 2 , was confirmed to be finely dispersed in the solid solution phase 30A. Furthermore, it was confirmed that a metal diffusion layer 30C formed by interdiffusion between the bonding layer 30 and the first metal member 10 was present at the interface between the bonding layer 30 and the first metal member 10. It was also confirmed that the bonding layer 30 did not have any voids with a circle-equivalent diameter of 1 μm or greater.

[0098] Furthermore, EDX measurement confirmed that in the solid solution phase 30A, Sb was dissolved in Cu, but Mg was not dissolved. The amount of Sb dissolved was 1.6 at %. On the other hand, the compound phase 30B was composed of CuMgSb and FeNiSb.２ It was also confirmed that the solid solution phase 30A contained precipitates containing elements that were not dissolved in the solid solution phase 30A or elements that did not constitute the compound phase 30B (black areas in FIG. 2). These were found to be Fe and MgO. In addition, the FeNiSb in the solid solution phase 30A ２ The Fe and Ni constituting the alloy are considered to be metal elements diffused from the steel material (SUS304).

[0099] Furthermore, as shown in Table 1, it was confirmed that Sample 1 had a shear strength of 168.6 MPa, and the converted tensile strength was 292 MPa. In other words, it was confirmed that high bonding strength could be achieved at a low heating temperature of 760°C to 800°C.

[0100] In Samples 2 to 6, as shown in Table 1, the type and content of the Mg evaporation inhibitor element 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 achieved. Furthermore, in all samples, like Sample 1, it was confirmed that the solid solution phase 30A was composed of Cu solid-solubilized with Mg and at least one of the Mg evaporation inhibitor element, and the compound phase 30B was composed of Cu, Mg, and an intermetallic compound containing the Mg evaporation inhibitor element. The amount of solid solution of Mg was 3 at% or less, and the amount of solid solution of the Mg evaporation inhibitor element was 5 at% or less. It was also confirmed that all samples had a shear strength of 20 MPa or more, and a tensile strength converted based on this was 34.6 MPa or more.

[0101] In this example, two members (a first member made of an oxide-based ceramic and a second member made of a metal) were joined using the prepared brazing filler metal, and the joining strength of the resulting joined body was evaluated. Specifically, the procedure is as follows.

[0102] (1) Preparation: An alumina plate having a thickness of 0.3 mm was prepared as the first member, and Kovar (registered trademark) having a thickness of 2.0 mm was prepared as the second member. Powder for preparing the brazing filler metal was prepared in the same manner as in Example 1.

[0103] The brazing filler metals of Samples 7 to 12 were prepared by mixing the elements in the ratios shown in Table 2 in the same manner as in Example 1, and then forming them into a paste. When forming the paste, terpineol was used as the solvent and polyisobutyl methacrylate was used as the binder, and the total amount of the solvent and binder in the paste was 17 mass %. When the brazing filler metal contained Ti (Samples 11 and 12), titanium hydride (TiH ２ ) was added as a powder.

[0104] (2) Fabrication of a Joint The prepared brazing filler metal paste was applied to the joining surface of the first member (alumina plate) by screen printing. Then, the second member (Kovar) was placed directly on the applied paste film and pressed with a force of 8 kPa along the stacking direction. －２ The bonded bodies of Samples 7 to 12 were fabricated by carrying out a heat treatment under the conditions shown in Table 2 in a vacuum atmosphere of 100 Pa or less.

[0105]

[0106] (3) The phase structures of the joined bodies of evaluation samples 7 to 12 were evaluated in the same manner as in Example 1.

[0107] The cross-sectional observation of the bonding layer of the bonded bodies of Samples 7 to 12 revealed 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 two components were secured in the bonding layer, and (3) the bonding layer had a thickness of approximately 10,000 μm. ２ It was confirmed that no voids with a circular equivalent diameter of 8 μm or more were observed in the bonding layer within the field of view. For samples in which the above (1) to (3) were confirmed, a "Good" was entered in the "Cross-section evaluation results" column in Table 2.

[0108] It was also confirmed that the bonded structure would not peel off even when peeled off by hand.

[0109] From the above, it was confirmed that the brazing filler metal of the present disclosure can also be applied to joining oxide-based ceramics.

[0110] <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.

[0111] (Appendix 1) A brazing filler metal for joining dissimilar or homogeneous metal members, comprising: Cu; Mg; and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, wherein Cu has the highest content among the elements constituting the brazing filler metal.

[0112] (Supplementary Note 2) In Supplementary Note 1, preferably, when the content of the Mg is X at % and the content of the Mg evaporation inhibiting element is Y at %, 1≦X≦15, 1≦Y≦20, and X−5≦Y≦X+5.

[0113] (Appendix 3) The brazing filler metal according to appendix 1 or 2, comprising Cu powder containing Cu, and alloy powder formed from an intermetallic compound containing at least Mg and the Mg evaporation inhibiting element.

[0114] (Appendix 4) The brazing material according to Appendix 3, which is configured in a paste form.

[0115] (Appendix 5) A brazing filler metal for joining a first member made of an oxide-based ceramic to a second member made of a metal or an oxide-based ceramic, the brazing filler metal containing Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, wherein Cu has the highest content among the elements constituting the brazing filler metal.

[0116] (Appendix 6) The brazing filler metal according to Appendix 5, wherein, when the content of the Mg is X at % and the content of the Mg evaporation inhibiting element is Y at %, 1≦X≦15, 1≦Y≦20, and X−5≦Y≦X+5.

[0117] (Appendix 7) A bonded body comprising: two metal members of the same or different types; and a bonding layer formed on a bonding surface of the two metal members, wherein the bonding layer contains Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and Cu has the highest content among the elements constituting the bonding layer.

[0118] (Supplementary Note 8) The joined body according to Supplementary Note 7, wherein the joining layer has a solid solution phase in which Mg and at least one of the Mg evaporation inhibiting elements are solid-solved in Cu, and a compound phase including an intermetallic compound containing Cu, Mg, and the Mg evaporation inhibiting element.

[0119] (Supplementary Note 9) The joined body according to Supplementary Note 7 or Supplementary Note 8, wherein the joining layer has a path made of the solid solution phase connecting the two metal members.

[0120] (Appendix 10) A bonded body comprising: a first member made of an oxide-based ceramic; a second member made of a metal or an oxide-based ceramic; and a bonding layer formed on a bonding surface between the first member and the second member, wherein the bonding layer contains Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and Cu has the highest content among the elements constituting the bonding layer.

[0121] (Appendix 11) A method for manufacturing a joined body, comprising: an arrangement step of arranging two metal members of the same or different types so as to be stacked with a brazing filler metal interposed therebetween; and a heating step of heating a laminate in which the two metal members and the brazing filler metal are stacked while applying pressure in the stacking direction, to form and maintain a liquid phase in at least a part of the brazing filler metal, wherein the brazing filler metal is made of a material containing Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and wherein Cu has the highest content among the elements constituting the brazing filler metal.

[0122] (Appendix 12) The method for producing a joined body according to Appendix 11, wherein the brazing filler metal contains Cu powder containing Cu and alloy powder formed from an intermetallic compound containing at least Mg and the Mg evaporation inhibiting element.

[0123] (Appendix 13) The method for manufacturing a joined body according to Appendix 12, wherein the brazing material is in a paste form.

[0124] (Appendix 14) A method for manufacturing a joined body, comprising: an arrangement step of arranging a first member made of oxide-based ceramics and a second member made of metal or oxide-based ceramics so as to be stacked with a brazing filler metal interposed therebetween; and a heating step of heating a stack in which the first member, the brazing filler metal, and the second member are stacked while applying pressure in the stacking direction, to form and maintain a liquid phase in at least a part of the brazing filler metal, wherein the brazing filler metal is made of a material containing Cu, Mg, and at least one Mg evaporation inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, and wherein Cu has the highest content among the elements constituting the brazing filler metal.

[0125] REFERENCE SIGNS LIST 100 Bonded body 100' Laminated body 10 First metal member 10s Bonding surface 20 Second metal member 20s Bonding surface 30 Bonding layer 30A Solid solution phase 30B Compound phase 30C Metal diffusion layer 50 Brazing filler metal

Claims

1. A brazing material for joining dissimilar or identical metal components, Cu and, Mg and, It comprises at least one Mg evaporation-inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, Among the elements constituting the aforementioned brazing material, Cu has the highest content. A brazing material having a Mg content of X at%, a Mg evaporation-inhibiting element content of Ya at%, where 1 ≤ X ≤ 15, 1 ≤ Y ≤ 20, and X - 5 ≤ Y ≤ X + 5.

2. The alloy powder contains Cu powder and an intermetallic compound containing at least Mg and an element that inhibits the evaporation of the Mg. The brazing material according to claim 1.

3. It is made up in a paste-like form. The brazing material according to claim 2.

4. A brazing material for joining a first member made of oxide ceramics and a second member made of metal or oxide ceramics, Cu and, Mg and, It comprises at least one Mg evaporation-inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, Among the elements constituting the aforementioned brazing material, Cu has the highest content. A brazing material having a Mg content of X at%, a Mg evaporation-inhibiting element content of Ya at%, where 1 ≤ X ≤ 15, 1 ≤ Y ≤ 20, and X - 5 ≤ Y ≤ X + 5.

5. A powder comprising Cu powder containing Cu and an alloy powder formed from an intermetallic compound containing at least Mg and an element that inhibits the evaporation of the Mg, The brazing material according to claim 4.

6. Two metal components of different or the same type, A bonding layer formed on the joining surface of the two metal members, The aforementioned bonding layer is Cu and, Mg and, It comprises at least one Mg evaporation-inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, Among the elements constituting the aforementioned bonding layer, Cu has the highest content. The bonding layer comprises a solid solution phase in which Cu is solidly dissolved with Mg and at least one of the Mg evaporation-inhibiting elements, and a compound phase containing an intermetallic compound containing Cu, Mg, and the Mg evaporation-inhibiting element.

7. The bonding layer has a path made of the solid solution phase connecting the two metal members. The joint according to claim 6.

8. A first component made of oxide ceramics, A second member made of metal or oxide ceramics and A bonding layer formed on the joining surface of the first member and the second member, The aforementioned bonding layer is Cu and, Mg and, It comprises at least one Mg evaporation-inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi, Among the elements constituting the aforementioned bonding layer, Cu has the highest content. The bonding layer comprises a solid solution phase in which Cu is solidly dissolved with Mg and at least one of the Mg evaporation-inhibiting elements, and a compound phase containing an intermetallic compound containing Cu, Mg, and the Mg evaporation-inhibiting element.

9. The bonding layer has a path made of the solid solution phase connecting the two metal members, The joint according to claim 8.

10. A placement step involves arranging two metal members of different or the same type so as to be laminated with a brazing material in between, The process includes a heating step in which a laminate formed by stacking the two metal members and the brazing material is heated while applying pressure in the stacking direction to form and hold a liquid phase in at least a portion of the brazing material. As the brazing material, a material is used that includes Cu, Mg, and at least one Mg evaporation-inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi. A method for manufacturing a bonded body, wherein the Cu content is the highest among the elements constituting the brazing material.

11. The brazing material contains Cu powder containing Cu and alloy powder formed from an intermetallic compound containing at least Mg and an element that inhibits the evaporation of the Mg. A method for manufacturing a joint according to claim 10.

12. The aforementioned brazing material is in paste form. A method for manufacturing a joint according to claim 11.

13. Arrangement step: Arrange a first member made of oxide ceramics and a second member made of metal or oxide ceramics so as to be laminated with a brazing material in between. The process includes a heating step of heating a laminate formed by stacking the first member, the brazing material, and the second member while applying pressure in the stacking direction to form and hold a liquid phase in at least a portion of the brazing material, As the brazing material, a material is used that includes Cu, Mg, and at least one Mg evaporation-inhibiting element selected from the group consisting of Si, Ge, Sn, P, As, Sb, and Bi. A method for manufacturing a bonded body, wherein the Cu content is the highest among the elements constituting the brazing material.