EP3319753A1

EP3319753A1 - Alloys

Info

Publication number: EP3319753A1
Application number: EP16733604.9A
Authority: EP
Inventors: Gunther Wiehl; Steven THIEROLF-DOEPP; Inge Fallheier; Sebastian Starck; Daniel Schnee; Helmut Ries
Original assignee: Umicore Technical Materials AG and Co KG
Current assignee: Umicore Technical Materials AG and Co KG
Priority date: 2015-07-06
Filing date: 2016-07-01
Publication date: 2018-05-16
Also published as: WO2017005620A1; EP3115146A1; CN107735213A

Abstract

The invention relates to novel brazing alloys containing copper, silver, zinc, manganese and indium, and to methods for producing same and the use thereof.

Description

alloys

Brazing is an important process for joining components in mass production and prototype production. It is an economical method for joining metal components with a metal additive, the braze, which exposes the components only to low mechanical stresses. Optionally, flux and / or inert gases are often used. The melting temperature of the brazing alloy is lower than the melting temperature of the metal parts to be brazed. Both are wetted by the molten solder without melting themselves. Common brazing alloys for the

Melting range of 600-800 ° C are often Ag-Cu-Zn solders and are described in standards such. DIN EN ISO 17672 and AWS A5.8M / A5.8-2011 (Brazing Filing Metals) and US-A-2019984.

Such alloys can be used for many applications, but do not always meet all the requirements for their corrosion tendency and a melting range, which should be as low as possible with a defined silver content.

Modified Ag-Cu-Zn solder alloys with often higher silver content also contain nickel (Ni) and manganese (Mn) and are known from DE 19725956. Such solder alloys are often used in the tool industry. Nickel can be added to strengthen the solder joints and to improve wetting on tool steels. However, this increases the melting range of the alloys.

EP-A-1078711 shows Ag-Cu-Zn solder alloys containing small amounts of gallium, indium, tin or manganese. These alloys often lack good mechanical properties such as ductility and ductility and exhibit increased melting temperatures at low silver levels and thus the same disadvantages as materials with higher silver contents.

CN-A-102909489 shows brazing alloys suitable for brazing at above 850 ° C, but not at lower temperatures of, for example, 720 ° C or 730 ° C.

The task was to provide new solder alloys, which are easy to manufacture, despite significantly lowered silver content compared to Ag l25 can be processed at comparable soldering temperatures, when soldering copper, brass, stainless steels and structural steels, such as S235. Typical structural steels are, for example, S235JR + AR (new edition EN 10025-2: 2004-10, formerly S235JRG2, even earlier St 37-2, material n Ummer 1.0036 to 1.0038, earlier designation to EU 25-72 also Fe 360 B) or also S355J2 + N (new edition EN 10025-2: 2004-10, earlier

S355J2G3, even earlier St 52-3 N, material number 1.0577 or 1.0570, earlier designation to EU 25-72 also Fe 510 Dl). The structural steel grades are standardized in EN 10025.

Further, the solder alloys must be completely melted at a comparable temperature as Ag l25 and at the same time have good cold workability at room temperature (e.g., for cold rolling, wire drawing or wire rolling) and have sufficient ductility for solder joints and contain no cadmium to be ecologically safe. Alloys which have a minimum cold ductility of 10% after recrystallization of 10% (based on the diameter before and after deformation) in the wire form are advantageous.

It is known that the silver content of Ag-Cu-X alloys plays an important role in the alloy's liquidus temperature due to the eutectic behavior of the Ag-Cu system. Low melting at a certain silver content means that a certain silver content of z. B. 13% has significantly higher melting temperatures than an alloy with 25% silver, if no additional melting point lowering elements are added. In this case, the melting point-lowering elements must be skillfully combined and tuned with melting point-enhancing elements, so that the cold workability and the strength of the joint connection are not adversely affected.

The object is achieved by a solder alloy, which is free of alkali and alkaline earth metals, phosphorus and cadmium, with the exception of unavoidable impurities, containing 10 to 15 wt .-% silver, 20 to 35 wt .-% zinc, 5 wt .-% up to 15% by weight of manganese, from 0.1% by weight to 4% by weight of indium, ad 100% by weight of copper and unavoidable impurities, with the Furthermore, 0 wt .-% to 3 wt .-% of tin and / or gallium and 0 wt .-% to 1 wt .-% silicon, germanium, nickel may contain and the amounts of the ingredients to a total of 100 wt. % complete.

A specific embodiment relates to a solder alloy containing 11 to 14 wt .-% silver, 20 to 30 wt .-% zinc, 8 wt .-% to 12 wt .-% manganese, 1 wt .-% to 3 wt .-% indium , ad 100% by weight of copper and unavoidable impurities and wherein the amounts of the constituents add up to a total of 100% by weight; or a solder alloy containing 12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight to 2.5% by weight Indium, ad 100 wt .-% copper and unavoidable impurities and wherein the amounts of the ingredients to complete a total of 100 wt .-%.

These embodiments are also free of alkali and alkaline earth metals, phosphorus and cadmium, with the exception of unavoidable impurities.

Optionally, the above embodiments may contain 0.1 to 2.0 wt%, in particular 0.5 to 1.5 wt% tin. These can be added to control the melting point, in particular its reduction, but lead to embrittlement at too high levels. Optionally, the above embodiments may further contain from 0.1 to 0.8% by weight, more preferably from 0.3% to 0.7% by weight of gallium, optionally together with the aforementioned addition of tin.

Optionally, the above embodiments may contain 0.1 to 0.6 wt%, especially 0.2 to 0.5 wt% germanium, optionally together with the above-mentioned addition of tin, gallium or combinations thereof. Similar to tin and gallium germanium can be added to fine tune the melting point, but also leads to embrittlement on addition of too large amounts.

Optionally, the above embodiments may contain 0.1 to 0.5 wt .-%, in particular 0.2 to 0.4 wt .-% silicon, optionally together with the above-mentioned addition of tin, gallium, germanium or combinations thereof. These can be added to control the melting point and the flowability of the solder, but at too high levels lead to embrittlement of the joint zone when brazing iron alloys. Optionally, the above embodiments may contain 0.2 to 1.0 wt%, more preferably 0.3 to 0.7 wt% nickel, optionally together with the above-mentioned addition of tin, gallium, germanium, silicon or combinations thereof , These can lead to control of the wetting ability of iron and copper alloys, but at too high levels lead to increasing melting ranges.

Because of its high toxicity, cadmium should be avoided; alkali and alkaline earth metals (ie lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium and radium) are too sensitive to oxidation. Phosphorus (P) must not be used because of the formation of brittle intermetallic phases in solder joints with iron or ferrous alloys.

Alkali and alkaline earth metals, phosphorus and cadmium may be present only in amounts of unavoidable impurities, as well as certain other metals. The content of unavoidable impurities together may not be higher than 0.5% by weight, preferably 0.3% by weight.

Aluminum may be present as an impurity in amounts of up to 0.001% by weight. Phosphorus, magnesium or calcium, as well as the other alkali and alkaline earth metals listed above, can be present as an impurity in amounts of up to 0.008% by weight each. Cadmium, selenium, tellurium, tin, antimony, bismuth and arsenic may be present as impurities in amounts of up to 0.01% by weight each. Lead may be present as an impurity in amounts of up to 0.025% by weight. Sulfur can be present as an impurity in amounts of up to 0.03 wt%. Iron may also be present as an impurity in amounts of up to 0.15% by weight. Impurities can be added in amounts of up to 0.5% by weight or 0.3% by weight. % or 0.15 wt .-% total. Free of cadmium and phosphorus means as a cadmium content of up to 0.01% by weight and phosphorus content of up to 0.008% by weight.

Cobalt may only be present as an unavoidable impurity in amounts of up to 0.05% by weight, in particular only 0.01% by weight, since cobalt leads to a strong increase in the liquidus temperature.

To avoid misunderstandings, it is pointed out that the solder alloy of the invention must contain copper. The copper content is usually 26 to 64.9 wt .-%. In this embodiment, therefore, the alloys other than unavoidable impurities are free of alkali and alkaline earth metals, phosphorus and cadmium

10 to 15% by weight, 10 to 13.5% by weight, or 10 to 13% by weight of silver;

20 to 35% by weight, 15 to 25.5% by weight, or 20 to 25% by weight of zinc;

5 to 15% by weight, 8 to 12% by weight or 9 to 11% by weight of manganese;

0.1 to 4 wt .-%, 1 to 2.5 wt .-% or 1.7 to 2.3 wt .-% indium;

26 to 64.9% by weight, 31 to 64.9% by weight, 46.5 to 66% by weight or 48.7 to 59.3% by weight of copper;

optionally 0.1 to 3% by weight, 0.1 to 1.5% by weight or 0.6 to 1.4% by weight of tin;

optionally 0.1 to 3 wt%, 0.1 to 0.8 wt% or 0.4 to 0.7 wt% gallium;

optionally 0.1 to 1% by weight, 0.1 to 0.5% by weight or 0.2 to 0.5% by weight of silicon;

optionally 0.1 to 1% by weight, 0.1 to 0.5% by weight or 0.2 to 0.5% by weight of nickel;

optionally 0.1 to 1% by weight, 0.1 to 0.5% by weight or 0.2 to 0.5% by weight of germanium and unavoidable impurities, the amounts of the constituents being in total 100% by weight. -% complete. A solder alloy which is free of alkali and alkaline earth metals, phosphorus and cadmium, except for unavoidable impurities, is therefore made From 12 to 14% by weight of silver,

From 22 to 28% by weight of zinc,

9% by weight to 11% by weight of manganese,

1.5% to 2.5% indium by weight,

0.5 wt .-% to 1.5 wt .-% tin and

ad 100% by weight of copper and unavoidable impurities, the amounts of the constituents adding up to a total of 100% by weight.

In a specific embodiment, the solder alloy therefore contains

12 to 14% by weight of silver,

From 22 to 28% by weight of zinc,

9% by weight to 11% by weight of manganese,

1.5% to 2.5% indium by weight,

From 0.5% to 1.5% by weight of tin,

0.2 wt .-% to 0.4 wt .-% silicon and

ad 100 wt .-% copper and unavoidable impurities, wherein the

Supplement amounts of the ingredients to a total of 100% by weight; or in a further embodiment 12 to 14 wt .-% silver,

From 22 to 28% by weight of zinc,

9% by weight to 11% by weight of manganese,

1.5% to 2.5% indium by weight,

From 0.5% to 1.5% by weight of tin,

From 0.2% to 0.4% by weight of silicon,

0.3 wt .-% to 0.7 wt .-% gallium and

ad 100% by weight of copper and unavoidable impurities and wherein the amounts of the constituents add up to a total of 100% by weight; or in a further embodiment

From 12 to 14% by weight of silver,

From 22 to 28% by weight of zinc,

9% by weight to 11% by weight of manganese,

1.5% to 2.5% indium by weight,

From 0.5% to 1.5% by weight of tin, From 0.2% to 0.4% by weight of silicon,

0.3 wt.% To 0.7 wt.% Gallium,

0.3 wt .-% to 0.7 wt .-% nickel and

ad 100% by weight of copper and unavoidable impurities and wherein the amounts of the constituents add up to a total of 100% by weight.

The indications of unavoidable impurities above are also applicable to these embodiments.

In a specific embodiment, the solder alloy is made

12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight to 2.5% by weight of indium, 0, 5% by weight to 1.5% by weight of tin and ad 100% by weight of copper and unavoidable impurities, and wherein the amounts of the constituents add up to a total of 100% by weight; or in a further embodiment

12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight to 2.5% by weight of indium, 0, 5 wt .-% to 1.5 wt .-% tin, 0.2 wt .-% to 0.4 wt .-% silicon and ad 100 wt .-% copper and unavoidable impurities and wherein the amounts of the components to total add 100 wt .-%; or in a further embodiment, 12 to 14 wt .-% silver, 22 to 28 wt .-% zinc, 9 wt .-% to 11 wt .-% manganese, 1.5 wt .-% to 2.5 wt. % Indium, 0.5 wt% to 1.5 wt% tin, 0.2 wt% to 0.4 wt% silicon, 0.3 wt% to 0.7 wt%. -% gallium and ad 100% by weight of copper and unavoidable impurities and wherein the amounts of the constituents add up to a total of 100% by weight; or in a further embodiment

12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight to 2.5% by weight of indium, 0, 5% by weight to 1.5% by weight Tin, 0.2 wt.% To 0.4 wt.% Silicon, 0.3 wt.% To 0.7 wt.% Gallium, 0.3 wt.% To 0.7 wt. % Nickel and ad 100% by weight of copper and unavoidable impurities, and wherein the amounts of the constituents add up to a total of 100% by weight;

Suitable examples of alloys consist of 49% by weight copper, 13% by weight silver, 25% by weight zinc, 10% by weight manganese, 2% by weight indium and 1% by weight tin, or 48 , 7% by weight copper, 13% by weight silver, 25% by weight zinc, 10% by weight manganese, 2% by weight indium, 1% by weight tin and 0.3% by weight Silicon, or 48.2% by weight copper, 13% by weight silver, 25% by weight zinc, 10% by weight manganese, 2% by weight indium, 1% by weight tin, 0.3 % By weight silicon and 0.5% by weight gallium, or 47.7% by weight copper, 13% by weight silver, 25% by weight zinc, 10% by weight manganese, 2% by weight % Indium, 1 wt% tin, 0.3 wt% silicon, 0.5 wt% gallium and 0.5 wt% nickel. The solder alloy can be obtained by mechanical alloying or liquid phase alloying. A common way is melting. The solder alloy of the invention can be easily obtained by co-melting the respective amounts of the alloy components. It is also possible to use alloys as starting materials, ie z. B. to supplement an alloy consisting of silver, copper and zinc with the appropriate amounts of manganese and indium or an alloy thereof and to melt this combination.

The melting can be carried out in inert gas, such as argon or nitrogen, or in air. Gas, electric and induction furnaces are, among other things, suitable devices for this purpose.

The molten alloy may be poured into a mold, atomized or granulated so as to obtain powders or granules. The atomized powder can z. B. be used for solder pastes. Both these powders and granules can be used for pressing and extruding, as described below. In this way, powders and granules can be used for the production of stampings, wires or rods. Melting can thus be used in production methods such as ingot casting, continuous casting, melt spinning, alloy granulation or atomization. Ingots and bolts can also be used to extrude or extrude the braze alloy and place it in the form of a wire or ribbon. The alloy can be produced and used as a solid solder, ie in the form of, for example, rod, wire, wire ring, foil, sheet metal or punched parts made of foil or sheet metal. Advantageous thicknesses for films or sheets used in this way are from 0.1 mm to 0.5 mm, wires and rods may generally have diameters between 0.5 mm and 2.5 mm, in particular 1 mm to 2 mm typically.

The geometry of such semi-finished products can be adapted to customer requirements by pressing, forging, wire drawing, hot or cold rolling, wire rolling, smoothing, cutting, punching or their combinations. Continuous casting is another option for making wires, ribbons or bars. In addition, it is possible to bring the solder alloy into the desired shape by rolling sheets, producing shaped articles such as rings or stamping punched parts. The solder can also be provided with flux, in particular in the form of rods, wires and wire rings, and may be completely or partially sheathed in this case.

The solder alloy is particularly suitable for brazing copper, brass, stainless steels and structural steels, such as S235, as joining partners.

The solder alloy is also suitable for brazing steel against steel. Suitable steels are u.A. described in the standards EN 10025-2 and DIN EN 10027-2 and for example 1.6582, 1.2003, 1.2235, 1.8159, S235 or S355.

In general, for the solder alloys of the invention known flux can be used in the form of pastes, paints, powders, coatings of the solder alloy, the z. B. in the form of rods, rods, ribbons or wires may be present.

Also, sintered shaped parts of the solder alloy and flux can be used. For this purpose, powdered solder and powdered flux are mixed, pressed (eg by cold isostatic pressing) and a Subjected to heat treatment, such as. B. sintered to obtain sufficient strength.

Suitable fluxes are, for example, FHIO and FH 12, which are described in the standard DIN EN 1045. BrazeTech h 280, (FH IO), BrazeTech h 285 (FH12), BrazeTech 80 (FHIO) and BrazeTech h Spezial (FH 12) or BrazeTec CoMet (FH IO).

Therefore, the invention also relates to molded articles of any of the solder alloys of the invention in combination with fluxes. The solder alloys may in particular be in the form of wires, wire rings or rods and be coated with a flux. In particular, rods or wires of the solder alloy of the invention may be coated with a flux selected from FH IO and FH 12 described in standard DIN EN 1045.

The brazing with the brazing alloys of the invention can be carried out as in the following method of joining metal parts by brazing with the steps

- providing a base material;

Providing a part to be bonded to the base material;

Arranging base material and part in contact with each other in a for

Soldering suitable way;

Arranging a solder alloy according to the invention or its combination with a flux in contact with the base material, the part or both in a manner suitable for soldering;

- Heat treatment of the thus obtained arrangement with a sufficient

Temperature to effect the brazing and so obtain a bonded part;

- cooling the connected part.

The base material and the part may be selected as described above, in particular from copper, brass, structural steel or stainless steel. The part and base material may be made of the same or different material. The present application also relates to bonded parts obtained by this process.

Both the part and the base material may have different compositions, shapes and dimensions and may be the same or different with respect to these parameters.

It is also possible to connect a plurality of parts to the base material so that several parts, such as e.g. several steel parts, with one

Base material, such as a copper or brass material, or vice versa.

These are arranged in mutual contact in such a way that they can be connected together by soldering. A solder material according to the invention, optionally in combination with a flux, is then placed on the part, the base material or both. This can also be done before arranging part and base material on each other, for. B. by coating with a solder paste containing a solder alloy according to the invention, and then arranging or by a continuous feed during the heat treatment, or the solder alloy can be used as a molded part such. B. be applied as a solder ring. The flux may be applied before or simultaneously with the solder alloy. A plumb rod with a coating or a core of flux is one way to apply the flux simultaneously with the solder, but the part, the base material, or both can also themselves be fluxed, e.g. B. by applying a flux-containing liquid.

The heat treatment can be done by flame brazing, by induction brazing, but also in an oven (furnace brazing) or otherwise. Inert gas such as argon, nitrogen or hydrogen, or mixtures thereof, or soot-doped atmospheres can be used as well as brazing in air or in vacuum. The temperature of the heat treatment must be sufficient to melt the solder and allow it to flow and wet. The soldering operation can also be performed with additional ultrasonic excitation to achieve improved seam strength, avoidance of gas pores or flux inclusions. However, the temperature must be below the melting temperatures of the base material or part. After the heat treatment, the connected part is allowed to cool.

For this purpose, soldering temperatures in the range of at least 680 ° C, better at least 775 ° C, especially 680 ° C to 950 ° C or 775 ° C to 790 ° C are well suited. In the alloys, it is advantageous that soldering temperatures of 775 ° C to 790 ° C, in particular with silver contents of only 12 wt .-% lead to 14 wt .-% to good results.

This results in a soldering process with the steps

- providing a base material;

Providing a part to be bonded to the base material;

Arranging base material and part in contact with each other in a for

Soldering suitable way;

- heat treatment of the assembly so obtained to a temperature of at least 680 ° C to effect the brazing and so to obtain a connected part;

- cooling the connected part.

Examples

The alloys were obtained by melting the appropriate amounts of the alloying ingredients in a crucible in an induction furnace and casting into a graphite mold. These samples were used for the investigation of the alloys. The compositions in the table contain data in weight percent (wt.%).

The cold workability (Table: K) was evaluated by repeated cold rolling. Several cold rolling operations were carried out with a thickness reduction of 1 mm each without intermediate annealing until tearing of the sample occurred. The result is listed in the table.

The judgments have the following meanings:

+ easily reshapeable, o restrictedly deformable, - poorly deformable. Liquidus temperatures were reported in relation to the standardized brazing alloy AG125 in DIN EN ISO 17672. TL is the liquidus temperature of the respective alloy in the specified composition in the Examples and Comparative Examples. The symbols used mean:

~ Liquidus temperature maximum 15 ° C to higher or lower than the liquidus temperature of the brazing alloy AG125 according to DIN EN ISO 17672 ab.

<Liquidus temperature is more than 15 ° C lower than the liquidus temperature of the brazing alloy AG125 according to DIN EN ISO 17672.

> Liquidus temperature is more than 15 ° C higher than the liquidus temperature of the brazing alloy AG125 according to DIN EN ISO 17672.

Claims

claims

Solder alloy which is free of alkali and alkaline earth metals, phosphorus and cadmium, with the exception of unavoidable impurities containing 10 to 15% by weight of silver, 20 to 35% by weight of zinc, 5% by weight to 15% by weight Manganese, 0.1 wt .-% to 4 wt .-% indium, ad 100 wt .-% copper and unavoidable impurities, wherein the alloy also 0 wt .-% to 3 wt .-% tin and / or gallium and in each case 0 wt .-% to 1 wt .-% silicon, germanium, nickel may contain and supplement the amounts of the ingredients to a total of 100 wt .-%.

A solder alloy as claimed in claim 1, containing 11 to 14% by weight of silver, 20 to 30% by weight of zinc, 8% by weight to 12% by weight of manganese, 1% by weight to 3% by weight of indium, ad 100% by weight of copper and unavoidable impurities and wherein the amounts of the constituents add up to a total of 100% by weight.

Solder alloy according to claim 1 or 2, containing 12 to 14 wt .-% silver, 22 to 28 wt .-% zinc, 9 wt .-% to 11 wt .-% manganese, 1.5 wt .-% to 2.5 Wt .-% indium, ad 100 wt .-% copper and unavoidable impurities and wherein the amounts of the ingredients to 100 wt .-% complete.

Solder alloy according to one or more of claims 1 to 3, containing an element selected from the group consisting of tin, gallium, silicon, nickel or combinations thereof.

Solder alloy according to one or more of claims 1 to 4, containing 0.1 to 2.0 wt .-%, in particular 0.5 to 1.5 wt .-% tin, and / or 0.1 to 0.8 wt, %, in particular from 0.3% by weight to 0.7% by weight of gallium and / or from 0.1 to 0.5% by weight, in particular from 0.2 to 0.4% by weight, of silicon and / or 0.2 to 1.0 wt .-%, in particular 0.3 to 0.7 wt .-% nickel and / or 0.1 to 0.6 wt .-%, in particular 0.2 to 0.5 wt .-% germanium. Solder alloy according to one or more of claims 1 to 5, consisting of 12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight. % to 2.5 wt .-% indium, 0.5 wt .-% to 1.5 wt .-% tin and 100 wt .-% copper and unavoidable impurities and wherein the amounts of the ingredients to a total of 100 wt. -% complete.

Solder alloy according to one or more of claims 1 to 5, consisting of 12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight. % to 2.5 wt.% indium, 0.5 wt.% to 1.5 wt.% tin, 0.2 wt.% to 0.4 wt.% silicon and ad 100 wt. % Copper and unavoidable impurities, and wherein the amounts of the components add up to a total of 100% by weight.

Solder alloy according to one or more of claims 1 to 5, consisting of 12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight. % to 2.5 wt .-% indium, 0.5 wt .-% to 1.5 wt .-% tin, 0.2 wt .-% to 0.4 wt .-% silicon, 0.3 wt. -% to 0.7 wt .-% gallium and ad 100 wt .-% copper and unavoidable impurities and wherein the amounts of the components to complete a total of 100 wt .-%.

Solder alloy according to one or more of claims 1 to 5, consisting of 12 to 14% by weight of silver, 22 to 28% by weight of zinc, 9% by weight to 11% by weight of manganese, 1.5% by weight. % to 2.5 wt .-% indium, 0.5 wt .-% to 1.5 wt .-% tin, 0.2 wt .-% to 0.4 wt .-% silicon, 0.3 wt. -% to 0.7 wt .-% gallium, 0.3 wt .-% to 0.7 wt .-% nickel and ad 100 wt .-% copper and unavoidable impurities and wherein the amounts of the components to a total of 100 wt .-% complete.

Solder alloy of composition CuAg l3Zn25MnlOIn2Snl, CuAg l3Zn25MnlOIn2SnlSiO, 3, CuAg l3Zn25Mnl0In2SnlSi0.3Ga0.5 or CuAgl3Zn25Mnl0In2SnlSi0.3Ga0.5Ni0.5. Solder alloy according to one or more of claims 1 to 10, containing 26 wt .-% to 64.9 wt .-% copper.

Combination of a solder alloy according to one or more of the preceding claims with a flux.

A method of joining metal parts comprising the steps

- providing a base material;

Providing a part to be bonded to the base material;

Arranging base material and part in contact with each other in a manner suitable for soldering;

Arranging a solder alloy according to one or more of claims 1 to 11 or a combination according to claim 12 in contact with the base material, the part or both in a manner suitable for soldering;

- heat treatment of the thus obtained assembly at a temperature sufficient to effect the brazing and to obtain a bonded part;

- cooling the connected part.

The method of claim 13, wherein the sufficient temperature to effect the brazing is at least 680 ° C, at least 775 ° C, especially 680 ° C to 950 ° C, or 775 ° C to 790 ° C.

The method of claim 13 or 12, wherein the base material and / or the part is copper, brass, a steel alloy such as S235.

16. Soldered article obtainable by a method according to any one of claims 13 to 15.