阅读说明：本技术 一种复合钎料及其制备方法 (Composite brazing filler metal and preparation method thereof ) 是由 纠永涛 董媛媛 路全彬 秦建 董宏伟 薛行雁 常云峰 刘晓芳 于 2021-09-22 设计创作，主要内容包括：本发明涉及一种复合钎料及其制备方法,属于钎焊技术领域。本发明的复合钎料包括钎料管、第一钎剂和第二钎剂；钎料管包括第一钎料层和第二钎料层,第二钎料层的内壁面与第一钎料层的外壁面贴合设置；第一钎料层为银基钎料层,第二钎料层含有锡元素、铟元素、镓元素中的任意一种或两种以上,第二钎料层的熔点低于第一钎料层；第一钎剂设于钎料管的管腔内,且与第一钎料层相匹配；第二钎剂设于钎料管外,且与第二钎料层相匹配。使用时,由于复合钎料的第二钎料层的熔点较低,流动性好,润湿铺展效果较好,而熔化的第二钎料层能溶解银基钎料层并与第二钎料层扩散合金化,从而大大降低银基钎料层的熔点,提高其流动性和润湿性,保证填缝效果。(The invention relates to a composite brazing filler metal and a preparation method thereof, and belongs to the technical field of brazing. The composite brazing filler metal comprises a brazing filler metal pipe, a first brazing flux and a second brazing flux; the brazing material pipe comprises a first brazing filler metal layer and a second brazing filler metal layer, and the inner wall surface of the second brazing filler metal layer is attached to the outer wall surface of the first brazing filler metal layer; the first brazing filler metal layer is a silver-based brazing filler metal layer, the second brazing filler metal layer contains any one or more of tin element, indium element and gallium element, and the melting point of the second brazing filler metal layer is lower than that of the first brazing filler metal layer; the first brazing flux is arranged in the tube cavity of the brazing material tube and matched with the first brazing material layer; the second brazing flux is arranged outside the brazing filler metal pipe and matched with the second brazing filler metal layer. When the brazing filler metal is used, the second brazing filler metal layer of the composite brazing filler metal is low in melting point, good in flowability and good in wetting and spreading effects, and the melted second brazing filler metal layer can dissolve the silver-based brazing filler metal layer and is in diffusion alloying with the second brazing filler metal layer, so that the melting point of the silver-based brazing filler metal layer is greatly reduced, the flowability and the wettability of the silver-based brazing filler metal layer are improved, and the joint filling effect is guaranteed.)

1. The composite brazing filler metal is characterized by comprising a brazing pipe, a first brazing flux and a second brazing flux;

the brazing material pipe comprises a first brazing filler metal layer and a second brazing filler metal layer, and the inner wall surface of the second brazing filler metal layer is attached to the outer wall surface of the first brazing filler metal layer;

the first brazing filler metal layer is a silver-based brazing filler metal layer, the second brazing filler metal layer is a brazing filler metal layer containing low-melting-point metal elements, the low-melting-point metal elements are selected from any one or more of tin elements, indium elements and gallium elements, and the melting point of the second brazing filler metal layer is lower than that of the first brazing filler metal layer;

the first brazing flux is arranged in the tube cavity of the brazing pipe and matched with the first brazing flux layer; the second brazing flux is arranged outside the brazing filler metal pipe, covers the outer wall surface of the brazing filler metal pipe and is matched with the second brazing filler metal layer.

2. The composite filler metal according to claim 1, wherein the total mass of the low-melting-point metal elements in the filler metal tube accounts for 3 to 19.8% of the mass of the filler metal tube.

3. The composite solder according to claim 1 or 2, characterized in that the silver-based solder layer consists essentially of Ag, Cu and Zn; in the brazing pipe, the mass percent of Ag is 9.6-43.6%, the mass percent of Cu is 24.1-51%, and the mass percent of Zn is 20-36.6%.

4. The composite solder according to claim 1 or 2, characterized in that the silver-based solder layer is a BAg10CuZn solder layer, a BAg20CuZn solder layer, a BAg25CuZn solder layer, a BAg30CuZn solder layer, a BAg40CuZn solder layer, a BAg45CuZn solder layer, a BAg50CuZn solder layer, a BAg15CuZnSn solder layer, a BAg18CuZnSn solder layer, a BAg25CuZnSn solder layer, a BAg30CuZnSn solder layer, a BAg40CuZnSn solder layer, a BAg45CuZnSn solder layer, a BAg55CuZnSn solder layer or a BAg30CuZnIn solder layer.

5. The composite filler metal according to claim 1 or 2, wherein the first flux is filled in a tube cavity of the filler metal tube to form a flux core; the second brazing flux covers the whole outer wall of the brazing material pipe to form a brazing flux layer; the thickness of the brazing flux layer is 0.1-0.3 mm.

6. The composite filler metal according to claim 1 or 2, wherein the first brazing flux is a brazing flux; the second brazing flux is rosin soft solder.

7. The composite filler metal according to claim 1 or 2, wherein the thickness of the first solder layer is 0.05-0.3mm and the thickness of the second solder layer is 0.01-0.1 mm.

8. The composite filler metal according to claim 1 or 2, wherein the first solder layer has a circular cross section and an outer diameter of 0.5 to 3 mm.

9. A method for preparing a composite filler metal according to any one of claims 1 to 8, characterized by comprising the steps of: and (3) obtaining a silver-based brazing filler metal pipe, placing the first brazing flux into a pipe cavity of the silver-based brazing filler metal pipe, then dip-coating a second brazing filler metal layer outside the silver-based brazing filler metal pipe, and then coating the second brazing flux on the second brazing filler metal layer, thus obtaining the brazing filler metal pipe.

10. The method for preparing the composite filler metal according to claim 9, wherein the interposing comprises the steps of: and pumping the melt of the first brazing flux into the cavity of the silver-based brazing filler metal pipe, cooling or injecting the paste of the first brazing flux into the silver-based brazing filler metal pipe, and then drying.

Technical Field

The invention relates to a composite brazing filler metal and a preparation method thereof, and belongs to the technical field of brazing.

Background

The silver-based brazing filler metal has moderate melting point, superior brazing process performance, higher brazing strength, conductivity, corrosion resistance and the like, and is widely applied to the industries of aerospace, rail transit, electronic information, refrigeration household appliances, superhard tools and the like. The main alloy elements of the silver-based solder are Ag, Cu, Zn, Cd and the like, and In order to further reduce the melting temperature range of the solder and improve the fluidity and the joint filling capacity of the solder, Ga, In, Sn and the like are usually added to regulate the temperature of the solder. However, Ga, In, Sn, etc. have limited solubility In solder, and they are very likely to form brittle compounds with other alloying elements, which makes the rolling brittle and broken, and the drawing difficult to reduce, etc., and thus are difficult to form by conventional processing methods.

Disclosure of Invention

The invention aims to provide a composite solder, which can improve the fluidity and the joint filling capacity of the solder without increasing the preparation difficulty.

The invention also provides a preparation method of the composite solder.

In order to realize the purpose, the technical scheme adopted by the composite solder is as follows:

the composite brazing filler metal comprises a brazing filler metal pipe, a first brazing flux and a second brazing flux; the brazing material pipe comprises a first brazing filler metal layer and a second brazing filler metal layer, and the inner wall surface of the second brazing filler metal layer is attached to the outer wall surface of the first brazing filler metal layer; the first brazing filler metal layer is a silver-based brazing filler metal layer, the second brazing filler metal layer is a brazing filler metal layer containing low-melting-point metal elements, the low-melting-point metal elements are selected from any one or more of tin elements, indium elements and gallium elements, and the melting point of the second brazing filler metal layer is lower than that of the first brazing filler metal layer; the first brazing flux is arranged in the tube cavity of the brazing pipe and is matched with the first brazing flux layer; the second brazing flux is arranged outside the brazing filler metal pipe, covers the outer wall surface of the brazing filler metal pipe and is matched with the second brazing filler metal layer.

When the composite brazing filler metal is used, the second brazing filler metal is melted and spread preferentially, then the second brazing filler metal layer is melted and spread, then the first brazing filler metal is melted and spread, and finally the high-melting-point silver-based brazing filler metal layer is melted and spread. The second brazing filler metal layer has a good wetting and spreading effect due to low melting point and good fluidity, and the melted second brazing filler metal layer can dissolve the silver-based brazing filler metal layer and is in diffusion alloying with the silver-based brazing filler metal of the first brazing filler metal layer, so that the melting point of the silver-based brazing filler metal layer is greatly reduced, the fluidity and the wettability of the silver-based brazing filler metal layer are improved, and the joint filling effect is ensured; secondly, when the second brazing filler metal layer contains one or more low-melting-point metal elements of tin element, indium element and gallium element, the addition of the low-melting-point metal elements in the silver-based brazing filler metal layer by a smelting method can be reduced or even avoided, so that the formation of brittle compounds by the low-melting-point metal elements and other alloy elements is reduced or avoided, the processing performance of the silver-based brazing filler metal layer is further ensured, and the silver-based brazing filler metal layer is easy to process and form, so that the composite brazing filler metal disclosed by the invention can improve the content of the low-melting-point elements such as tin, gallium and indium, and the like, and can ensure the easy processing performance of the brazing filler metal; in addition, the second brazing filler metal layer with the low melting point is coated outside the silver-based brazing filler metal layer, so that the second brazing filler metal layer can better absorb heat, the second brazing filler metal layer is further melted more quickly, and the brazing efficiency is improved; finally, the second brazing flux is matched with the second brazing flux layer, the melting point of the second brazing flux is lower than that of the second brazing flux layer, so that the second brazing flux layer can be melted before the second brazing flux layer is melted, not only can the oxide on the surface of the base metal be removed, but also the melted second brazing flux layer can be protected, wetting and spreading of the second brazing flux layer are promoted, the second brazing flux gradually loses efficacy along with the proceeding of the brazing process and the rising of the temperature, and the first brazing flux layer is melted before the melting of the silver-based brazing flux layer, so that the oxide on the surface of the base metal is further removed, the melted second brazing flux layer and the subsequently melted silver-based brazing flux layer are protected, namely, and good film removing and protecting effects can be achieved through the matching of the second brazing flux and the first brazing flux.

The composite brazing filler metal integrates the brazing filler metal and the brazing flux, and can solve the problems of complex process operation, high experience dependence, more brazing flux residues after welding and the like when the traditional brazing filler metal and the traditional brazing flux are respectively added, so that the stability of brazing connection and the use reliability of workpieces are improved; meanwhile, the problems that the brazing flux is easy to disorder, loss at low temperature, time delay failure and the like when being added independently can be solved, and the excessive brazing flux is prevented from generating a large amount of smoke dust, so that the environment is seriously polluted, the health of operating personnel is harmed, occupational diseases are caused, and the potential safety hazard is reduced.

Preferably, the total mass of the low-melting-point metal elements in the brazing filler metal pipe accounts for 3-19.8% of the mass of the brazing filler metal pipe.

The composition of the silver-based brazing filler metal layer is not limited and can be the same as that of any existing silver-based brazing filler metal. The silver-based brazing filler metal layer mainly comprises Ag, Cu and Zn. For example, the silver-based solder layer is an Ag-Cu-Zn-based solder layer or an Ag-Cu-Zn-X-based solder layer, and X is one or more of Sn, Ga, and In. Preferably, in the brazing pipe, the mass percent of Ag is 9.6-43.6%, the mass percent of Cu is 24.1-51%, and the mass percent of Zn is 20-36.6%.

Preferably, when the silver-based brazing filler metal layer is an Ag-Cu-Zn-X system brazing filler metal layer, the mass percentage of the X element in the silver-based brazing filler metal layer is not more than 2%. Preferably, the silver-based solder layer is a BAg10CuZn solder layer, a BAg20CuZn solder layer, a BAg25CuZn solder layer, a BAg30CuZn solder layer, a BAg40CuZn solder layer, a BAg45CuZn solder layer, a BAg50CuZn solder layer, a BAg15CuZnSn solder layer, a BAg18CuZnSn solder layer, a BAg25CuZnSn solder layer, a BAg30CuZnSn solder layer, a BAg40CuZnSn solder layer, a BAg45CuZnSn solder layer, a BAg55CuZnSn solder layer or a BAg30CuZnIn solder layer.

Preferably, the inner wall surface and/or the outer wall surface of the first brazing filler metal layer is/are a rough surface. This may facilitate retention of the first braze in the core, with the second braze layer being dip coated over the first braze layer. The rough surface may be an oriented rough surface or a random rough surface, the oriented rough surface has obvious grooves in the same direction, and the random rough surface has grooves with random directions or randomly distributed pits. Preferably, the roughness of the rough surface is in the range of Ra < 3.2 μm < 25 μm.

Preferably, the first brazing flux is filled in a tube cavity of the brazing pipe to form a brazing flux core. The second brazing flux covers the whole outer wall of the brazing material pipe to form a brazing flux layer. The thickness of the brazing flux layer is 0.1-0.3mm, preferably 0.1-0.2 mm.

Preferably, the first brazing flux is a brazing flux. The brazing flux consists of the following components in percentage by mass: 84.4% of borate, 9.9% of active agent and 5.7% of finished paste.

It will be appreciated that the second solder layer is a metal layer. Preferably, the second solder layer is a tin metal layer, an indium metal layer, a gallium metal layer, a tin-based alloy layer, an indium-based alloy layer, or a gallium-based alloy layer. Further, the second solder layer is a tin metal layer, an indium metal layer, a gallium metal layer, a tin-indium alloy layer, a tin-gallium alloy layer, an indium-gallium alloy layer or a tin-indium-gallium alloy layer.

Preferably, the second brazing flux is a rosin brazing flux.

Preferably, the thickness of the first solder layer is 0.05 to 0.3mm, and more preferably 0.2 to 0.3 mm.

Preferably, the thickness of the second solder layer is 0.01 to 0.1mm, more preferably 0.01 to 0.03 mm.

The cross section of the brazing pipe can be various regular or irregular shapes, such as a circular ring. Preferably, the cross section of the first brazing filler metal layer is a circular ring, and the outer diameter of the first brazing filler metal layer is 0.5-3mm, and more preferably 1-3 mm.

The preparation method of the composite solder adopts the technical scheme that:

the preparation method of the composite solder comprises the following steps: and (3) obtaining a silver-based brazing filler metal pipe, placing the first brazing flux into a pipe cavity of the silver-based brazing filler metal pipe, then dip-coating a second brazing filler metal layer outside the silver-based brazing filler metal pipe, and then coating the second brazing flux on the second brazing filler metal layer, thus obtaining the brazing filler metal pipe.

The preparation method of the composite solder is simple in process and convenient to popularize and apply.

The silver-based brazing material pipe can be a seamless silver-based brazing material pipe, can also be a butt joint silver-based brazing material pipe, and can also be a lap joint silver-based brazing material pipe. The inner wall surface and/or the outer wall surface of the silver-based brazing material pipe are rough surfaces. The roughness of the rough surface is preferably in the range of Ra of 3.2 [ mu ] m or less and 25 [ mu ] m or less. When the silver-based brazing filler metal pipe is a seamless silver-based brazing filler metal pipe prepared by extruding and drawing an ingot, an extruding and drawing die meeting the roughness requirement can be used. The roughness of the surface of the extrusion die core can be controlled during extrusion, so that the inner surface of the first brazing filler metal layer meets the requirement of the roughness, and the roughness of the drawing hole wall can be controlled during drawing, so that the outer surface of the first brazing filler metal layer meets the requirement of the roughness.

The silver-based brazing filler metal pipe can be formed according to the existing preparation method of the flux-cored brazing filler metal, and the first brazing flux is placed in a pipe cavity of the silver-based brazing filler metal pipe. Preferably, the preparation method of the silver-based solder pipe comprises the following steps: melting the components according to the formula amount according to the composition of the silver-based brazing filler metal pipe, and then casting to obtain a cast ingot; then extruding the cast ingot into a seamless tube, and drawing the seamless tube to a preset size.

In order to reduce splashing during the use of the composite filler metal, the embedding preferably comprises the following steps: and pumping the molten first brazing flux into the pipe cavity of the silver-based brazing material pipe and cooling. In addition, in order to facilitate the preparation of the composite solder at normal temperature, the embedding comprises the following steps: and injecting the paste of the first brazing flux into the silver-based brazing filler metal tube and then drying.

Preferably, the dip coating is to dip the silver-based brazing filler metal pipe filled with the first brazing filler metal into the melt of the second brazing filler metal layer, and to coat the second brazing filler metal layer outside the silver-based brazing filler metal pipe after the silver-based brazing filler metal pipe is taken out. Compared with an electroplating method or an electroforming method and the like in the prior art, the method has the advantages that the low-melting-point element is coated on the silver-based brazing material pipe by the dip coating method, the implementation is easier, the process is simpler, the production efficiency is improved, and the production cost is saved.

Drawings

Fig. 1 is a schematic view showing the structure of a composite filler metal according to example 1 of the present invention, wherein 1 is a flux core, 2 is a first flux layer, 3 is a second flux layer, 4 is a flux layer, and 5 is a flux tube.

Detailed Description

The technical solution of the present invention will be further described with reference to the following embodiments.

Example 1

The composite brazing filler metal of the embodiment, as shown in fig. 1, includes a brazing flux core 1, a brazing filler metal pipe 5, and a brazing flux layer 4; the brazing filler metal pipe 5 comprises a first brazing filler metal layer 2 and a second brazing filler metal layer 3, the outer wall surface of the first brazing filler metal layer 2 is completely attached to the inner wall surface of the second brazing filler metal layer 3, a brazing filler metal core 1 is filled in the cavity of the brazing filler metal pipe 5, and the brazing filler metal layer 4 is coated on the outer wall surface of the brazing filler metal pipe 5.

The brazing flux core 1 comprises the following components in percentage by mass: 84.4% of borate, 9.9% of active agent and 5.7% of ointment.

The first brazing filler metal layer is a BAg25CuZn silver-based brazing filler metal layer and specifically comprises the following components in percentage by mass: 25% of silver, 40% of copper and 35% of zinc; the thickness of the first brazing filler metal layer is 0.2mm, the cross section of the first brazing filler metal layer is a circular ring, and the outer diameter of the first brazing filler metal layer is 2 mm. The roughness Ra of the inner wall surface and the outer wall surface of the first brazing filler metal layer are both 6.3 mu m.

The second solder layer is a tin metal layer with the thickness of 0.01 mm.

The soldering flux layer is a rosin soldering flux layer, and the thickness of the soldering flux layer is 0.1 mm.

In the composite solder of the embodiment, the mass of tin accounts for 4.5% of the mass of the solder pipe, the mass of silver accounts for 23.9% of the mass of the solder pipe, the mass of copper accounts for 38.2% of the mass of the solder pipe, and the mass of zinc accounts for 33.4% of the mass of the solder pipe.

Example 2

The composite filler metal of the present example is different from the composite filler metal of example 1 only in that:

in the composite solder of the embodiment, the thickness of the tin metal layer is 0.02 mm;

in the composite solder of the embodiment, the mass of tin accounts for 8.8% of the mass of the solder pipe, the mass of silver accounts for 22.8% of the mass of the solder pipe, the mass of copper accounts for 36.5% of the mass of the solder pipe, and the mass of zinc accounts for 31.9% of the mass of the solder pipe.

Example 3

The composite filler metal of the present example is different from the composite filler metal of example 1 only in that:

in the composite solder of the embodiment, the thickness of the tin metal layer is 0.04 mm;

in the composite solder of the embodiment, the mass of tin accounts for 16.3% of the mass of the solder pipe, the mass of silver accounts for 20.9% of the mass of the solder pipe, the mass of copper accounts for 33.5% of the mass of the solder pipe, and the mass of zinc accounts for 29.3% of the mass of the solder pipe.

Example 4

The composite filler metal of the present example is different from the composite filler metal of example 1 only in that:

in the composite solder of the embodiment, the thickness of the tin metal layer is 0.05 mm;

in the composite solder of the embodiment, the mass of tin accounts for 19.6% of the mass of the solder pipe, the mass of silver accounts for 20.1% of the mass of the solder pipe, the mass of copper accounts for 32.2% of the mass of the solder pipe, and the mass of zinc accounts for 28.1% of the mass of the solder pipe.

Example 5

The composite filler metal of the present example is different from the composite filler metal of example 1 only in that:

in the composite solder of the embodiment, the first solder layer is a BAg10CuZn silver-based solder layer, and specifically comprises the following components in percentage by mass: 10% silver, 53% copper, 37% zinc; the thickness of the first brazing filler metal layer is 0.25mm, and the outer diameter is 2.5 mm; the thickness of the second brazing filler metal layer is 0.01mm, and the thickness of the brazing filler metal layer is 0.1 mm.

In the composite solder of the embodiment, the mass of tin accounts for 3.8% of the mass of the solder pipe, the mass of silver accounts for 9.6% of the mass of the solder pipe, the mass of copper accounts for 51% of the mass of the solder pipe, and the mass of zinc accounts for 35.6% of the mass of the solder pipe.

Example 6

The composite filler metal of the present example is different from the composite filler metal of example 1 only in that:

in the composite solder of the embodiment, the first solder layer is a BAg45CuZn silver-based solder layer, and specifically comprises the following components in percentage by mass: 45% of silver, 30% of copper and 25% of zinc; the thickness of the first brazing filler metal layer is 0.3mm, and the outer diameter is 3 mm; the thickness of the second brazing filler metal layer is 0.02mm, and the thickness of the brazing filler metal layer is 0.2 mm. The roughness Ra of the inner wall surface and the outer wall surface of the first brazing filler metal layer is 3.2 mu m and 25 mu m respectively.

In the composite solder of the embodiment, the mass of tin accounts for 5.7% of the mass of the solder pipe, the mass of silver accounts for 42.4% of the mass of the solder pipe, the mass of copper accounts for 28.3% of the mass of the solder pipe, and the mass of zinc accounts for 23.6% of the mass of the solder pipe.

Example 7

The composite filler metal of the present example is different from the composite filler metal of example 6 only in that:

in the composite solder of the embodiment, the thickness of the tin metal layer is 0.04 mm;

in the composite solder of the embodiment, the mass of tin accounts for 10.9% of the mass of the solder pipe, the mass of silver accounts for 40.1% of the mass of the solder pipe, the mass of copper accounts for 26.7% of the mass of the solder pipe, and the mass of zinc accounts for 22.3% of the mass of the solder pipe.

Example 8

The composite filler metal of the present example is different from the composite filler metal of example 6 only in that:

in the composite solder of the embodiment, the thickness of the tin metal layer is 0.05 mm;

in the composite solder of the present example, the mass of tin was 13.3% of the mass of the solder tube, the mass of silver was 39% of the mass of the solder tube, the mass of copper was 26% of the mass of the solder tube, and the mass of zinc was 21.7% of the mass of the solder tube.

Example 9

The composite filler metal of the present example is different from the composite filler metal of example 6 only in that:

in the composite solder of the embodiment, the thickness of the tin metal layer is 0.08 mm;

in the composite solder of the embodiment, the mass of tin accounts for 19.8% of the mass of the solder pipe, the mass of silver accounts for 36.1% of the mass of the solder pipe, the mass of copper accounts for 24.1% of the mass of the solder pipe, and the mass of zinc accounts for 20% of the mass of the solder pipe.

Example 10

The composite filler metal of the present example is different from the composite filler metal of example 6 only in that:

in the composite brazing filler metal of the embodiment, the thickness of the first brazing filler metal layer is 0.3mm, and the outer diameter is 2.5 mm; the thickness of the tin metal layer is 0.01 mm;

in the composite solder of the embodiment, the mass of tin accounts for 3% of the mass of the solder pipe, the mass of silver accounts for 43.6% of the mass of the solder pipe, the mass of copper accounts for 29.1% of the mass of the solder pipe, and the mass of zinc accounts for 24.3% of the mass of the solder pipe.

Example 11

The composite filler metal of the present example is different from the composite filler metal of example 1 only in that:

in the composite solder of the embodiment, the first solder layer is a BAg25CuZnSn silver-based solder layer and is composed of the following components in percentage by mass: 25% of silver, 40% of copper, 33% of zinc and 2% of tin; the thickness of the first brazing filler metal layer is 0.3mm, and the outer diameter is 3 mm; the second brazing filler metal layer is an indium metal layer, and the thickness of the second brazing filler metal layer is 0.02 mm; the thickness of the flux layer is 0.2 mm. The roughness Ra of the inner wall surface and the roughness Ra of the outer wall surface of the first brazing filler metal layer are respectively 20 micrometers and 4 micrometers.

In the composite solder of the embodiment, the mass of indium accounts for 6% of the mass of the solder pipe, the mass of tin accounts for 1.9% of the mass of the solder pipe, the mass of silver accounts for 23.5% of the mass of the solder pipe, the mass of copper accounts for 37.6% of the mass of the solder pipe, and the mass of zinc accounts for 31% of the mass of the solder pipe.

Example 12

The composite filler metal of the present example is different from the composite filler metal of example 11 only in that:

in the composite solder of the embodiment, the thickness of the indium metal layer is 0.05 mm;

in the composite solder of the embodiment, the mass of indium accounts for 14% of the mass of the solder pipe, the mass of tin accounts for 1.7% of the mass of the solder pipe, the mass of silver accounts for 21.5% of the mass of the solder pipe, the mass of copper accounts for 34.4% of the mass of the solder pipe, and the mass of zinc accounts for 28.4% of the mass of the solder pipe.

Example 13

The composite filler metal of the present example is different from the composite filler metal of example 11 only in that:

in the composite solder of the embodiment, the thickness of the indium metal layer is 0.06 mm;

in the composite solder of the embodiment, the mass of indium accounts for 16.3% of the mass of the solder pipe, the mass of tin accounts for 1.7% of the mass of the solder pipe, the mass of silver accounts for 20.9% of the mass of the solder pipe, the mass of copper accounts for 33.5% of the mass of the solder pipe, and the mass of zinc accounts for 27.6% of the mass of the solder pipe.

Example 14

The composite filler metal of the present example is different from the composite filler metal of example 1 only in that:

in the composite solder of the embodiment, the first solder layer is a BAg18CuZnSn silver-based solder layer, and specifically comprises the following components in percentage by mass: 18% of silver, 42% of copper, 2% of tin and the balance of zinc; the thickness of the first brazing filler metal layer is 0.16mm, and the outer diameter is 1.8 mm; the thickness of the second brazing filler metal layer is 0.01mm, and the thickness of the brazing filler metal layer is 0.1 mm.

In the composite solder of the embodiment, the mass of tin accounts for 7.6% of the mass of the solder pipe, the mass of silver accounts for 17% of the mass of the solder pipe, the mass of copper accounts for 39.6% of the mass of the solder pipe, and the mass of zinc accounts for 35.8% of the mass of the solder pipe.

Example 15

The composite filler metal of the present example differs from the composite filler metal of example 13 only in that:

in the composite filler metal of the present example, the thickness of the first filler metal layer was 0.24mm, and the outer diameter was 2.2 mm.

In the composite solder of the embodiment, the mass of tin accounts for 5.9% of the mass of the solder pipe, the mass of silver accounts for 17.3% of the mass of the solder pipe, the mass of copper accounts for 40.3% of the mass of the solder pipe, and the mass of zinc accounts for 36.5% of the mass of the solder pipe.

Example 16

The composite filler metal of the present example differs from the composite filler metal of example 13 only in that:

in the composite brazing filler metal of the embodiment, the thickness of the first brazing filler metal layer is 0.2mm, and the outer diameter is 2 mm; the second brazing filler metal layer is a gallium metal layer, the thickness of the second brazing filler metal layer is 0.01mm, and the thickness of the brazing filler metal layer is 0.1 mm.

In the composite solder of the embodiment, the mass of gallium accounts for 3.8% of the mass of the solder pipe, the mass of tin accounts for 1.9% of the mass of the solder pipe, the mass of silver accounts for 17.3% of the mass of the solder pipe, the mass of copper accounts for 40.4% of the mass of the solder pipe, and the mass of zinc accounts for 36.6% of the mass of the solder pipe.

Examples of the preparation method of composite brazing filler Metal

Example 17

The preparation method of the composite filler metal of the embodiment is the preparation method of the composite filler metal of the embodiment 1, and comprises the following steps:

1) taking silver, copper and zinc according to the formula amount according to the composition of the first brazing filler metal layer, melting and casting into an ingot, cutting off a dead head, and turning the ingot to remove oxide skin for later use;

2) preheating the cast ingot, extruding the cast ingot by using an extruding device to form a seamless hollow circular tube, and drawing the seamless hollow circular tube until the outer diameter of the hollow circular tube is 2mm and the wall thickness is 0.2mm to obtain a silver-based brazing material tube with the roughness Ra of the inner surface and the outer surface of the silver-based brazing material tube being 6.3 mu m;

3) mixing borate, an active agent and a paste according to the formula amount to obtain a first soldering flux, heating the first soldering flux to 560-580 ℃ to melt the first soldering flux into a liquid state to obtain a first soldering flux melt;

4) pumping the first brazing flux solution into a pipe cavity of the silver-based brazing filler metal pipe by using a pumping device, filling the pipe cavity with the first brazing flux solution, and cooling and solidifying the first brazing flux solution in the pipe cavity to obtain an intermediate product;

5) heating tin metal to a molten state, immersing the obtained intermediate product into molten tin metal for a period of time, and taking out the intermediate product, so that a tin metal layer with the thickness of 0.01mm is formed on the outer wall surface of the silver-based brazing material pipe after the intermediate product is coated by the tin metal;

6) and mixing alcohol and rosin to obtain a second soldering flux, coating the second soldering flux on the surface of the tin metal layer, and drying to form a soldering flux layer with the thickness of 0.1mm on the tin metal layer to obtain the soldering flux.

In the preparation of the composite filler metal of examples 2 to 5, the outer diameter and wall thickness of the filler metal tube, the metal layer (second solder layer) and the thickness of the solder layer were adjusted as necessary with reference to the preparation method of the composite filler metal of example 17 above.

Example 18

The preparation method of the composite filler metal of the embodiment is the preparation method of the composite filler metal of the embodiment 6, and comprises the following steps:

1) taking silver, copper and zinc according to the formula amount according to the composition of the first brazing filler metal layer, melting, casting into an ingot, cutting off a dead head, and turning the ingot to remove oxide skin for later use;

2) preheating the cast ingot, extruding the cast ingot by using an extruding device to form a seamless hollow round pipe shape, and drawing until the outer diameter of the hollow round pipe is 3mm and the wall thickness is 0.3mm to obtain a silver-based brazing pipe with the inner surface roughness Ra of 3.2 mu m and the outer surface roughness Ra of 25 mu m;

3) mixing borate, an active agent and a paste according to the formula amount to obtain a first soldering flux, heating the first soldering flux to 560-580 ℃ to melt the first soldering flux into a liquid state to obtain a first soldering flux melt;

4) pumping the first brazing flux solution into a pipe cavity of the silver-based brazing filler metal pipe by using a pumping device, filling the pipe cavity with the first brazing flux solution, and cooling and solidifying the first brazing flux solution in the pipe cavity to obtain an intermediate product;

5) heating tin metal to a molten state, immersing the obtained intermediate product into molten tin metal for a period of time, and taking out the intermediate product, so that a tin metal layer with the thickness of 0.02mm is formed on the outer wall surface of the silver-based brazing material pipe after the intermediate product is coated by the tin metal;

6) and uniformly mixing alcohol and rosin to obtain a second soldering flux, and coating the second soldering flux on the second tin metal layer to form a soldering flux layer with the thickness of 0.2 mm.

In the preparation of the composite filler metal of examples 7 to 10, the outer diameter and wall thickness of the filler metal tube, the metal layer (second solder layer) and the thickness of the solder layer were adjusted as necessary with reference to the preparation method of the composite filler metal of example 18 above.

Example 19

The preparation method of the composite filler metal of the embodiment is the preparation method of the composite filler metal of the embodiment 11, and includes the following steps:

1) taking silver, copper, zinc and tin according to the formula amount according to the composition of the first brazing filler metal layer, casting into an ingot after melting, cutting off a dead head, and turning the ingot to remove oxide skin for later use;

2) preheating the cast ingot, extruding the cast ingot by using an extruding device to form a seamless hollow circular tube, and drawing until the outer diameter of the hollow circular tube is 3mm and the wall thickness is 0.3mm to obtain a silver-based brazing material tube with the inner surface roughness Ra of 20 mu m and the outer surface roughness Ra of 4 mu m;

3) mixing borate, an active agent and a paste according to the formula amount to obtain a first soldering flux, heating the first soldering flux to 560-580 ℃ to melt the first soldering flux into a liquid state to obtain a first soldering flux melt;

4) pumping the first brazing flux solution into a pipe cavity of the silver-based brazing filler metal pipe by using a pumping device, filling the pipe cavity with the first brazing flux solution, and cooling and solidifying the first brazing flux solution in the pipe cavity to obtain an intermediate product;

5) heating indium metal to a molten state, immersing the obtained intermediate product into the indium metal melt for a period of time, and taking out the intermediate product, so that an indium metal layer with the thickness of 0.02mm is formed on the outer wall surface of the silver-based brazing material pipe after the intermediate product is coated by the indium metal;

6) and uniformly mixing alcohol and rosin to obtain a second soldering flux, and coating the second soldering flux on the surface of the indium metal layer to form a soldering flux layer with the thickness of 0.2mm to obtain the soldering flux.

In the preparation of the composite solders of examples 12 to 16, the outer diameter and wall thickness of the solder tube, the metal layer (second solder layer), and the thickness of the solder layer were adjusted as necessary with reference to the preparation method of the composite solder of example 19 above. In addition, in the preparation of the composite solders of examples 14 to 15, the intermediate product needs to be immersed in the tin metal solution for a certain period of time and then taken out to form the tin metal layer on the outer wall of the silver-based solder tube, and in the preparation of the composite solder of example 16, the intermediate product needs to be immersed in the gallium metal solution for a certain period of time and then taken out to form the gallium metal layer on the outer wall of the silver-based solder tube.

In other embodiments of the composite solder of the present invention, the second solder layer in any embodiment of embodiments 1 to 16 may be replaced by an alloy layer composed of two or more of tin, indium and gallium, and in the preparation of the composite solder of these embodiments, it is necessary to replace a single molten metal in step 5) in the above-mentioned embodiment of the preparation method with an alloy molten liquid with a corresponding composition.