103 results about "Ag alloy" patented technology

A metallic sealing tape has a metallic layer and a layer of a pressure-sensitive adhesive disposed on one side of the metallic layer. The metallic layer is comprised of a brazing alloy, and may, e.g., comprise a thin foil of the brazing alloy. The brazing alloy may be, e.g., a copper-phosphorus alloy or a copper-phosphorus-silver alloy. A method for using the metallic sealing tape includes sealing a joint between two pipes with the metallic sealing tape and brazing the joint without removing the metallic sealing tape. The brazing may include heating the metallic sealing tape and may also include adding additional filler metal to the joint.

The invention provides a metallographic corrosion method of a Ti-Ag alloy and the Ti-Ag alloy, and relates to the technical field of metallographic detection. The metallographic corrosion method comprises the following steps: machining Ti-Ag alloy so as to form a microscopic structure observation plane on the Ti-Ag alloy; the microscopic structure observation plane is ground on a metallographic phase pre-grinding machine, and the ground microscopic structure observation plane is placed on a polishing machine to be subjected to mechanical polishing; etching the mechanically polished microscopic structure observation plane by using an etchant solution to obtain a microscopic structure observation plane to be observed; wherein the corrosion solution comprises ammonium hydrogen fluoride, hydrofluoric acid and water, and the ratio of the ammonium hydrogen fluoride to the hydrofluoric acid to the water is (5-10) g: (10-20) mL: 100 mL. According to the method, the metallographic corrosion effect of the Ti-Ag alloy can be improved.

A fusible link element (10; 15; 25; 35) comprising a metal composite material in which a first fusible metal (11; 21; 31) and a second fusible metal (12; 22; 32) are layered on top of each other, wherein the second fusible metal (12; 22; 32) has a lower melting temperature than the first fusible metal (11; 21; 31), characterized by the fact that the first fusible metal (11; 21; 31) is a Sn-Ag alloy and the Sn-Ag alloy contains at least 20 wt% and at most 30 wt% Ag, and the second fusible metal (12; 22; 32) is a Sn-Bi alloy and the Sn-Bi alloy contains at least 40 wt% and at most 70 wt% Bi, wherein at a common working temperature at least part of a component of the second fusible metal (12; 22; 32) is melted and part of a component of the first fusible metal (11; 21; 31) is melted, and where, at the common working temperature, the difference between a liquidus temperature and a solidus temperature of the first fusible metal (11; 21; 31) and the second fusible metal (12; 22; 32) is reduced by a shift in the equilibrium of Sn between the first fusible metal (11; 21; 31) and the second fusible metal (12; 22; 32) and by a mutual diffusion of Ag and Bi between the first fusible metal (11; 21; 31) and the second fusible metal (12; 22; 32).

An aqueous composition including (a) metal ions including tin ions and silver ions and (b) at least one complexing agent of formula C11RC12-XC11-RC11   (C11)and their salts,whereXC11 is selected from(a) a divalent 5 or 6 membered aromatic N-heterocyclic group;(b) a divalent 6 membered aromatic carbocyclic group; and(c) a divalent 5 or 6 membered aliphatic N-heterocyclic group including one N atom and optionally a second heteroatom selected from N and O; all of which may be unsubstituted or substituted by one or more OH or one or more RC14;RC11 is selected from ; andRC12 is selected from RC11, XC11-RC11, H, OH, NRC142, C1 to C10 alkyl, and C1 to C10 alkoxy

The invention discloses a metal conductive film for EC, a method, an assembly and application, and the conductive film comprises a first hardening layer, a flexible substrate, a second hardening layer, a bottom sealing cover layer, a first silver function layer, an intermediate dielectric layer, a second silver function layer, a first top sealing cover layer and an external sealing cover layer which are sequentially arranged. The total thickness of the first silver functional layer and the second silver functional layer is 14-18nm, d2-d1 < = 4nm, d1 is the thickness of the first silver functional layer, and d2 is the thickness of the second silver functional layer. Through the optical design of the film layer, the high light transmittance of the product is kept, and the light transmittance of the visible light band is larger than or equal to 83%. Meanwhile, by means of the technological means, Ag alloy is used, special sealing cover layer gold is added, and the durability and reliability of the product can be greatly improved.

The application provides a superfine nanocrystalline silver alloy and a preparation method thereof, and belongs to the technical field of superfine crystal preparation.The superfine nanocrystalline silver alloy is prepared by the following steps: firstly, rolling the silver alloy; secondly, breaking the original grains in the silver alloy by rolling; thirdly, transforming the broken grains into equiaxed grains by annealing; fourthly, cross-extruding under ultralow temperature to inhibit recovery recrystallization; fifthly, breaking the equiaxed grains into superfine equiaxed grains by cross-extruding; sixthly, further refining the grains by ultralow-temperature rolling; and finally, recrystallizing the broken grains by annealing after rolling, so that the superfine nanocrystalline silver alloy with nanometer grain size is obtained; the superfine nanocrystalline silver alloy has uniform microstructure, obvious strength improvement, good conductivity and ductility, and the preparation method is simple, easy to popularize in large scale, and has wide application prospect in industry.

The present invention relates to the technical field of semiconductor devices, and disclosed are a semiconductor device structure, a preparation method therefor, and a corresponding chip. The semiconductor device structure comprises a gold-silver alloy bump and an UBM layer, the UBM layer being composed of a seed layer and an adhesion layer, a bottom portion of the gold-silver alloy bump being connected to the seed layer, the adhesion layer being connected to a chip electrode, and a difference in thermal expansion coefficients between the gold-silver alloy bump and the adhesion layer being below 9 ppm / K. The technical solution provided in the present invention can solve the technical problem that gold-silver alloy bumps and existing UBM layers cannot pass high-low temperature cycle reliability testing. The semiconductor device structure and the corresponding chip obtained by the technical solution of the present invention can pass various reliability tests, thus it is feasible to replace a pure gold bump with a gold-silver alloy, thereby greatly reducing production costs of a flip-chip.

The high-strength high-conductivity copper-silver alloy disclosed by the application has the following weight percentage composition: 0.5-12% of Ag, 0.1-1.5% of B, 0.1-2.0% of Mn, the balance of Cu and inevitable impurities. The application simultaneously adds Mn and B elements in the Cu-Ag alloy to form a high-melting-point B-Mn compound at high temperature, thereby improving the strength of the alloy, having little influence on the electrical conductivity, and due to the combined action of the dispersion strengthening of the high-melting-point hard B-Mn compound and the work hardening of the Ag fiber phase and Cu matrix, the alloy has excellent comprehensive properties such as thermal stability, tensile strength, hardness and electrical conductivity. The tensile strength of the alloy is above 600 MPa, the electrical conductivity is above 65% IACS, the Vickers hardness is above 200 HV, and after being kept at 180 DEG C for 24 hours, the reduction rate of the tensile strength is not more than 8%, and the alloy can be applied to the power, electronic, communication and electromagnetic conversion industries.

The invention relates to the technical field of new materials, in particular to an Al-Cu-Li-Mg-Ag-Zn-Mn-Zr series high-strength and high-heat-resistance aluminum lithium alloy and a preparation method thereof. According to the invention, Al-Cu-Li-Mg-Ag-Zn-Mn-Zr is used as an alloy system, a certain amount of Cu, Li, Mg and Ag alloy elements are added to obtain a core-shell structure strengthening phase T1-AgMg phase which is stable at a high temperature, a certain amount of Zn element is added to improve the intrinsic stability of the T1 phase, and a certain amount of Mn and Zr alloy elements are added to obtain strengthening phases of a T phase and an Al3Zr phase. The novel high-strength and high-heat-resistance aluminum-lithium alloy with excellent tensile property at room temperature, 250 DEG C and 300 DEG C is obtained by combining proper preparation processes such as casting, homogenization, thermal deformation, solid solution aging and the like.

An alloy consisting of 0.1 to 1 wt. %of copper (Cu), 0.1 to 5 wt. %of bismuth (Bi), 0.01 to 0.2 wt.%of nickel (Ni), 0.01 to 0.1 wt.%of chromium (Cr) and tin (Sn) as a remainder.

A method of manufacturing a metal structure for an optical semiconductor device, including a treatment step (1) of immersing in and / or applying the solution containing a polyallylamine polymer a base body, the base body including an outermost layer at a portion or entire surfaces of the base body, the outermost layer including a plating of at least one selected from the group consisting of gold, silver, a gold alloy, and a silver alloy, so as to manufacture the metal structure for an optical semiconductor device having an increased adhesion to a resin material.

The utility model relates to the antiaging structure technical field of ceramic temperature controller, and disclose an antiaging structure of ceramic temperature controller, including base, the one side fixed connection of base has the antiaging component, the inside fixed connection of base has the damping seal component, the antiaging component includes the fixed connection in the seal pad of base one side, the inboard fixed connection of seal pad has the connecting block, the one side fixed connection of connecting block has silver alloy, the bottom fixed connection of silver alloy has graphite particle dispersion layer, the damping seal component includes the fixed connection in the damping gel of base inside, the top fixed connection of base has the rubber cover, the surface fixed connection of rubber cover has the spring. The antiaging structure of ceramic temperature controller, through the setting of antiaging component, reduced the water vapor permeation to the corrosion of junction and temperature controller internal structure, reduced the ablation of the junction because of arc energy high, improved the stability of product.

Embodiments of the present application provide an electroplating solution for a gold-silver alloy and a use thereof. The electroplating solution comprises a gold ion source, a silver ion source, a first complexing agent, and a second complexing agent, wherein the first complexing agent comprises a hydantoin-based substance, and the second complexing agent comprises an organic sulfonic acid or a salt thereof. By means of a synergistic effect of the two types of complexing agents, the electroplating solution exhibits relatively high stability and can specifically inhibit electrodeposition of silver without affecting deposition of gold, thereby reducing the influence of current density fluctuations on the gold content in an alloy coating. Thus, an alloy coating having a gold content stably maintained within a range of 30-50 wt% can be produced over a relatively wide current density range having an interval width of at least 0.3 ASD.

Described herein are indium-tin-silver alloys suitable for use as lead-free solders. The alloys can comprise indium primarily or tin primarily. The alloys can further comprise copper, nickel, and iron or copper, antimony, and zinc. The compositions can be used to solder electrical connectors (18, 30) to electrical contact surfaces (16) on glass assemblies (10). Also described herein are methods of forming the alloys.

The present application belongs to the technical field of aluminum alloy material structure manufacturing, and relates to a large high-strength heat-resistant aluminum alloy hub forge and a preparation method thereof. The method is suitable for preparing a large hub with a diameter (Φ500mm~Φ800mm) x depth (200mm~400mm) x outer wall thickness (20mm~50mm). Compared with a conventional hub, the present application obtains a preparation method suitable for Al-Cu-Mg-Ag alloy large hub forgings by optimizing alloy components, combining extrusion + forging compound breaking down, medium-temperature die forging, deep cryogenic treatment and other processes, so that the large hub forgings have excellent high-strength heat-resistant performance. The room temperature yield strength is higher than 450MPa, the tensile strength is higher than 500MPa, and the elongation is higher than 8%. The 150℃ high-temperature tensile yield strength is higher than 400MPa, the tensile strength is higher than 450MPa, and the elongation is higher than 10%. The 200℃ high-temperature tensile yield strength is higher than 350MPa, the tensile strength is higher than 400MPa, and the elongation is higher than 12%.

The invention discloses a copper-silver alloy high-strength continuous transposed conductor, and relates to the technical field of transposed conductors, the copper-silver alloy high-strength continuous transposed conductor comprises a copper-silver alloy wire core, the copper-silver alloy wire core is fixedly sleeved with a composite insulating layer, the composite insulating layer is fixedly sleeved with a flame-retardant layer, and the surface of the flame-retardant layer is provided with a groove. A reinforcing piece is fixedly connected to the corner of the inner wall of each groove, a reinforcing layer is fixedly connected to the outer portion of the flame-retardant layer in a sleeving mode, heat dissipation holes are formed in the two sides of the reinforcing layer, heat is fully conducted to the two sides through the grooves for heat dissipation, the structural strength is enhanced through the reinforcing pieces, collapse is avoided, and the heat dissipation effect is improved; the hot air circulation effect is further improved on the two sides of the flame-retardant layer, and the problems that due to the arrangement of supporting strips, the supporting area is small, the outer layer structure is likely to collapse, heat dissipation is hindered, due to the supporting strips, heat dissipation spaces are not communicated, heat of the top and the bottom is difficult to transmit to the two sides to be discharged, and local heat accumulation is likely to happen are solved.

A method for producing a Cu-Ag alloy wire material, which sequentially comprises the following steps, and a Cu-Ag alloy wire material produced by the production method. Step 1: A metal rod is obtained by dissolving a metal raw material blended so as to have a composition containing 10.0-30.0 wt% of Ag, excluding unavoidable impurities, with the balance being Cu. Step 2 to step 4: while gradually increasing the cross-section reduction rate before and after processing, the cold wire drawing processing and the heat treatment are repeated three times. Step 5 to step 7: repeating the three times of cold wire drawing processing and heat treatment so that the cross-section reduction rate before and after processing is greater than that of step 2 to step 4. And a step (8) in which a Cu-Ag alloy wire material having a diameter of 0.1 mm or less is obtained by performing a cold wire drawing treatment so that the reduction rate of the cross section relative to the metal rod is 99.0-99.9999%.

The application discloses a silver alloy sheet-shaped electric contact piece corrosion inhibition treatment failure detection method and a regulation and control system, and comprises the following steps: S1: obtaining the thickness d of an organic protective film on the surface of the electric contact piece in real time through an ellipsometric spectrum org and the thickness d of an oxide film ox ; S2: inputting the thickness d of the organic protective film org or the thickness d of the oxide film ox into a preset film thickness-contact resistance correlation model to obtain a predicted contact resistance value R c ; S3: when the predicted contact resistance R c is less than or equal to 25 mΩ, the electric contact piece is determined to be qualified, and when the predicted contact resistance R c is greater than 25 mΩ, the electric contact piece is determined to be failed, a back-end processing flow is triggered, and a front-end cleaning process is returned. The application utilizes the dynamic change effect of the predicted contact resistance value R c to determine the failure of the electric contact piece in the front-end cleaning process, to timely investigate the causes of the failure of the cleaning tank, and to improve the timeliness and reliability of the electric contact piece failure detection.

There is provided a novel Ag alloy bonding wire for semiconductor devices which provides an excellent bonded ball shape during ball bonding, which is required for high-density packaging. The Ag alloy bonding wire for semiconductor devices is made of an Ag alloy that contains one or more elements selected from the group consisting of Te, Bi and Sb and that satisfies at least one of the following conditions (1) to (3):(1) a concentration of Te is 5 to 500 at. ppm;(2) a concentration of Bi is 5 to 500 at. ppm; and(3) a concentration of Sb is 5 to 1,500 at. ppm.

This invention discloses a chiral gold-silver-platinum alloy nanomaterial, its preparation method, and its applications, relating to the field of metal nanomaterials technology. The invention includes: a substrate, wherein the substrate is chiral helical gold-silver alloy nanoparticles, and the substrate has a left-handed or right-handed helical morphology; and platinum nanoparticles, wherein the platinum nanoparticles are selectively deposited on the helical edges of the substrate by photodeposition, and the chiral helical morphology of the substrate is preserved after deposition. The photodeposition method is a photodeposition reaction performed under circularly polarized light irradiation with a specific helical direction. This invention provides more active sites for catalytic reactions and effectively avoids the displacement etching of the gold-silver alloy shell by platinum in traditional deposition methods, preserving the complete helical chiral structure.

The utility model belongs to cable field provides a kind of photoelectric composite cable applied to tethered unmanned aerial vehicle, comprising: conductor;Insulating layer and sheath layer, insulating layer is two layers in turn cladded in conductor;Sheath layer is extruded in the outer wall of insulating layer;Shielding reinforcing layer, close to sheath layer, shielding reinforcing layer is extruded in sheath layer outside with metal-plated ultrahigh molecular weight polyethylene and kevlar aramid fiber double-layer mixed, with copper nickel silver alloy on the surface of metal-plated ultrahigh molecular weight polyethylene and kevlar aramid fiber outer layer, to realize corrosion and electromagnetic shielding. Compared with prior art, the utility model has the advantages that shielding reinforcing layer is adopted, which is integrated with tensile resistance and shielding, simplifies the structure, effectively reduces the volume and weight of the cable, improves the application efficiency;In combination with the modified flexible TPU outer sheath reinforced by silicon dioxide, the cable performs well in extreme temperature difference and harsh environments such as sand and dust, prolongs the service life and reduces the maintenance cost.

The invention provides an electrical contact assembly. The electrical contact assembly comprises an electrical contact, a laminated soldering lug and a supporting piece, the laminated soldering lug is arranged between the electric contact and the supporting piece and is connected with the electric contact and the supporting piece in a welding manner; one side face of the laminated soldering lug is a first soldering face, the other side face opposite to the first soldering face is a second soldering face, the first soldering face is welded to the electrical contact, and the second soldering face is welded to the supporting piece; the laminated soldering lug is made of a layered composite material and comprises 2N + 1 material layers, the (2N + 1) th material layer in the laminated soldering lug is made of silver alloy, the 2Nth material layer in the laminated soldering lug is made of copper or copper alloy, and N is a positive integer greater than 0. According to the invention, through the technical means of setting the laminated soldering lug of the solder layer as the multilayer material layer, the temperature rise of the electrical contact assembly is reduced, and the problem of slippage failure of the electrical contact caused by resistance heat of the solder layer is avoided, so that the overload tolerance capability of a switching electric appliance product is improved, and the service life of the switching electric appliance product is prolonged.

The present invention belongs to the technical field of semiconductor device preparation. Disclosed are a gold-silver alloy structure for a semiconductor device and a preparation method therefor. The main body of the gold-silver alloy structure is a gold-silver alloy bump, and a porous gold layer is provided on the surface of the gold-silver alloy bump. After the gold-silver alloy bump is prepared by electroplating, reverse electroplating is performed by using the same electroplating solution, or by using an etching solution (the main difference between the etching solution and the electroplating solution lies in the absence of gold salt and silver salt), silver on the surface of the gold-silver alloy bump is etched, and a porous gold layer is formed on the surface of the gold-silver alloy bump, thereby solving the technical problem that the silver in the gold-silver alloy bump is easily oxidized or sulfidized, and achieving use of a gold-silver alloy instead of pure gold for a semiconductor device. The present invention does not require adding new electroplating equipment or chemical plating equipment, and the process is simple and easy to implement.

The invention relates to the field of advanced packaging semiconductor driving chips, and discloses a gold etching solution, application thereof and a method for electroplating gold-silver alloy on an etched wafer. The gold etching liquid comprises a complexing agent, an oxidizing agent, an aluminum protective agent and a solvent; wherein the complexing agent comprises a main complexing agent and an auxiliary complexing agent; the main complexing agent is selected from thiourea and / or thiourea derivatives; the auxiliary complexing agent is selected from at least one of butyl xanthate, isoamyl xanthate, thionocarbamate and diethyl phosphonate; the weight ratio of the complexing agent to the oxidizing agent to the aluminum protective agent to the solvent is 1: (0.2-1.5): (0.2-1.5): (20-30). The gold etching liquid has mild oxidability, can selectively etch a PVD gold seed layer, avoids etching a gold-silver alloy bump, does not cause serious deformation of the gold-silver alloy bump, avoids damage of etching to an aluminum circuit in a wafer, and is mild in etching condition and adjustable in gold etching rate.

The invention relates to the technical field of tension testing, and discloses a tensile testing device for silver-plated alloy wire production, the tensile testing device comprises a left-right through test board, a control panel and a camera, the control panel and the camera are mounted at the right end and the top of the test board, a plurality of wire positioning columns are linearly arrayed on the front side of the upper end of the test board, and positioning plates are intermittently arranged between every two wire positioning columns. The upper wall of the test bench is rotatably connected with a pressing plate corresponding to the positioning plate, and the rear side of the upper wall of the test bench is slidably clamped with a U-shaped elastic sliding frame. The silver-plated alloy wire is wound between the plurality of movable wire columns and the fixed wire column in a snakelike manner, and the front and back multi-point fixation of the silver-plated alloy wire is realized by matching the pressing plate with the positioning plate and the positioning column, so that different parts of the same silver-plated alloy wire are subjected to tensile test at the same time, the test is convenient and rapid, and mutual interference is avoided; uniformity detection of wire materials is achieved, the elastic sliding frame is driven to move backwards in different forms in cooperation with the pressure applying assembly, and the testing requirements are diversified and comprehensive.

This application provides a graphene-bonded silver alloy wire and its preparation process, belonging to the field of bonding wire technology for packaging. The preparation process of this graphene-bonded silver alloy wire comprises the following components by weight percentage: graphene content 1000-4500 ppm; Pd content 10000-20000 ppm; the balance being Ag and impurities. With the addition of low gold and palladium content, the graphene-bonded silver alloy wire effectively improves the susceptibility of bonded silver alloy wire to moisture and sulfur / chlorine corrosion, thus migrating silver ions. It achieves the corrosion resistance and silver ion migration inhibition effects of traditional bonded silver alloy wires, significantly reducing material costs and possessing significant scientific research value and application prospects. Furthermore, the circular limiting ring seat, positioning groove, and conical pressure block of the high-tension wire drawing machine in the preparation process enable the high-tension wire drawing machine to quickly fix the I-beam and the wire, greatly improving production efficiency.

Provided is a semiconductor laser element (100) comprising a substrate (101), a semiconductor laminate (100S) disposed above the substrate (101), and a p-side electrode (113) disposed above the semiconductor laminate (100S) and in contact with the semiconductor laminate (100S), wherein the semiconductor laminate (100S) includes: an n-type cladding layer (102) that is a nitride semiconductor layer containing Al; an n-side guide layer (104) disposed above the n-type cladding layer (102); an active layer (105) disposed above the n-side guide layer (104); and a p-type cladding layer (110) that is disposed above the active layer (105) and is a nitride semiconductor layer containing Al, the composition ratio of Al in the n-type cladding layer (102) is greater than the composition ratio of Al in the p-type cladding layer (110), and the p-side electrode (113) is made of at least one of Ag, an Ag alloy, Al, or a translucent conductive film.

The invention belongs to the technical field of preparation of medical degradable metal-based composite materials, and relates to a biodegradable composite material and a preparation and application method thereof. The preparation method comprises the following steps: 1, taking graphene oxide, silver nitrate and ferric nitrate as raw materials, and enabling Ag and Fe2O3 nanoparticles to grow on the surface of the graphene oxide together in situ through a hydrothermal method, so as to form (Ag + Fe2O3) coated GO; 2, (Ag + Fe2O3) coated GO is uniformly dispersed in Zn powder through wet ball milling, and (Ag + Fe2O3) coated GO / Zn mixed powder is obtained; and 3, the mixed powder is subjected to sintering and plastic processing, and the ZnO-coated GO / Zn-Fe-Ag alloy-based composite material is prepared. And reinforcing the zinc matrix by using an in-situ alloying reaction between the Ag nanoparticles and the zinc matrix, and endowing the zinc matrix with an antibacterial characteristic, so as to finally obtain the biodegradable ZnO (at) GO / Zn-Fe-Ag biological composite material with good comprehensive performance.

The invention discloses a preparation method of a bismuth-based high-temperature superconducting multi-core wire strip containing a two-stage pre-oxidation process, which comprises the following process steps of: 1, filling a silver or silver alloy tube with bismuth-based high-temperature superconducting precursor powder, and drawing and forming after seal welding; 2, filling a silver alloy sheath with a plurality of single-core wires, and carrying out bundling drawing or rolling; 3, implementing two-section type gradient pre-oxidation treatment under the set oxygen concentration; and 4, performing staged heat treatment to obtain the bismuth-based high-temperature superconducting multi-core wire or strip. By designing a multi-parameter synergistic pre-oxidation process comprising oxygen partial pressure regulation and control, temperature gradient and aging control and dispersion strengthening precipitation of alloy elements, abnormal grain growth of the silver alloy sheath in the high-temperature heat treatment process is effectively inhibited, formation of a uniform fine grain structure with preferred orientation is promoted, and the quality of the silver alloy sheath is improved. And meanwhile, oxygen permeation uniformity caused by oxidation in the heat treatment process is avoided, so that a more stable and high-content superconducting phase can be formed in the subsequent heat treatment process.

Disclosed are a ceramic substrate unit for a power module and a method for manufacturing the ceramic substrate unit for a power module. The disclosed ceramic substrate unit for a power module comprises: a ceramic substrate having an upper metal layer and a lower metal layer formed respectively on the upper surface and the lower surface of a ceramic base material; first filler layers disposed respectively between the ceramic base material and the upper metal layer and between the ceramic base material and the lower metal layer; a reinforcing substrate bonded to the lower metal layer of the ceramic substrate; and a second filler layer disposed between the lower metal layer and the reinforcing substrate, wherein the first filler layers and the second filler layer are composed of Ag-containing alloys, and the alloy for the first filler layers and the alloy for the second filler layer have different compositional ratios.