Preparation Method of Rapid Composite of Long Silver-graphite Electrical Contact Material and Solder Strip Material

Abstract

A preparation method of a rapid bonding of a long silver-graphite electrical contact material and a solder strip material includes the following steps: first step, making a silver-graphite spindle into a silver-graphite electrical contact sheet material by an extrusion process; second step, performing a sintering to composite a solder strip material with the silver-graphite electrical contact sheet material to obtain a composite blank; and third step, performing a rolling and a heat treatment on the composite blank for one or more times to complete the composite of the long silver-graphite electrical contact material and the solder strip material. The method is a method for preparing a silver-based electrical contact material and solder composite material.

Claims

1. A preparation method of a rapid composite of a long silver-graphite electrical contact material and a solder strip material, comprising the following steps: first step, making a silver-graphite spindle into a silver-graphite electrical contact sheet material by an extrusion process; second step, performing a sintering to composite a solder strip material with the silver-graphite electrical contact sheet material to obtain a composite blank; and third step, performing a rolling and a heat treatment on the composite blank for one or more times to complete the rapid composite of the long silver-graphite electrical contact material and the solder strip material; wherein in the first step, the extrusion process is a hot extrusion, a sintering temperature of the silver-graphite spindle is 600 C.-800 C., and a sintering time is 1-5 h; wherein in the first step, the silver-graphite electrical contact sheet material has a U-shaped structure with a stuck slot, and the stuck slot makes the long silver-graphite sheet material stuck with the solder strip material, so that surfaces of the long silver-graphite sheet material and the solder strip material contact with each other closely; and during the sintering in the second step, the solder strip material covers the stuck slot to form a good solder layer; wherein in the second step, a temperature of the sintering is 600 C.-800 C., and a protective atmosphere for the sintering is hydrogen; wherein in the third step, the rolling is a cold rolling, so that the silver-graphite sheet material and the solder strip material are bonded densely after being composited, and the composite silver-graphite is rolled to a desired thickness of a finished product: wherein the heat treatment is a diffusion annealing; a temperature of the diffusion annealing is 400 C.-600 C., and a time of the diffusion annealing is 0.5-3 h.

2. (canceled)

3. (canceled)

4. The preparation method of the rapid composite of the long silver-graphite electrical contact material and the solder strip material according to claim, wherein the silver-graphite electrical contact sheet material has a length of 5-50 m.

5. The preparation method of the rapid composite of the long silver-graphite electrical contact material and the solder strip material according to claim, wherein in the second step, the solder strip material is stuck in the stuck slot of the long silver-graphite sheet material for the sintering to achieve the rapid composite.

6. (canceled)

7. (canceled)

8. (canceled)

9. The preparation method of the rapid composite of the long silver-graphite electrical contact material and the solder strip material according to claim 1, wherein after the composite of the long silver-graphite electrical contact material and the solder strip material is completed, a punching is further performed to obtain an electrical contact material with a solder layer; and the punching is to punch the silver-graphite material rolled to a desired thickness of the finished product into a desired outer dimension.

10. An electrical contact material with a solder layer prepared by the preparation method according to claim 1.

11. (canceled)

12. (canceled)

13. The preparation method of the rapid composite of the long silver-graphite electrical contact material and the solder strip material according to claim 4, wherein after the composite of the long silver-graphite electrical contact material and the solder strip material is completed, a punching is further performed to obtain an electrical contact material with a solder layer; and the punching is to punch the silver-graphite material rolled to a desired thickness of the finished product into a desired outer dimension.

14. The preparation method of the rapid composite of the long silver-graphite electrical contact material and the solder strip material according to claim 5, wherein after the composite of the long silver-graphite electrical contact material and the solder strip material is completed, a punching is further performed to obtain an electrical contact material with a solder layer; and the punching is to punch the silver-graphite material rolled to a desired thickness of the finished product into a desired outer dimension.

15. (canceled)

16. (canceled)

17. (canceled)

18. The electrical contact material with the solder layer prepared by the preparation method according to claim 10, wherein in the second step, the solder strip material is stuck in the stuck slot of the long silver-graphite sheet material for the sintering to achieve the rapid composite.

19. (canceled)

20. The electrical contact material with the solder layer prepared by the preparation method according to claim 10, wherein the silver-graphite electrical contact sheet material has a length of 5-50 m.

21. The electrical contact material with the solder layer prepared by the preparation method according to claim 10, wherein after the composite of the long silver-graphite electrical contact material and the solder strip material is completed, a punching is further performed to obtain an electrical contact material with a solder layer; and the punching is to punch the silver-graphite material rolled to a desired thickness of the finished product into a desired outer dimension.

22. The electrical contact material with the solder layer prepared by the preparation method according to claim 20, wherein after the composite of the long silver-graphite electrical contact material and the solder strip material is completed, a punching is further performed to obtain an electrical contact material with a solder layer; and the punching is to punch the silver-graphite material rolled to a desired thickness of the finished product into a desired outer dimension.

23. The electrical contact material with the solder layer prepared by the preparation method according to claim 18, wherein after the composite of the long silver-graphite electrical contact material and the solder strip material is completed, a punching is further performed to obtain an electrical contact material with a solder layer; and the punching is to punch the silver-graphite material rolled to a desired thickness of the finished product into a desired outer dimension.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features, objectives and advantages of the present invention will become more apparent by reading and referring to the below detailed description of drawings regarding the non-limiting embodiments.

[0035] FIG. 1 is a process flow diagram of a preparation method according to an embodiment of the present invention;

[0036] FIG. 2 is a schematic diagram showing a main structure of an AgC sheet material having a U-shaped structure with a stuck slot formed by a hot extrusion of an AgC spindle according to an embodiment of the present invention;

[0037] FIG. 3 shows a metallographic photograph (left) of a cross section of a long AgC3 sheet material composited with a solder strip material after a sintering according to an embodiment of the present invention, and a metallographic photograph (right) of a solder layer and a stuck slot portion with a magnification of 200; and

[0038] FIG. 4 is a metallographic photograph of a finished product of an AgC4 electrical contact material according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The present invention will be described in detail below with reference to specific embodiments. The following embodiments are intended to assist those skilled in the art to further understand the present invention, rather than to limit the present invention in any way. It should be noted that some variations and improvements may be made by those skilled in the art without departing from the inventive conception of the present invention. These variations and improvements are all within the protection scope of the present invention.

[0040] As shown in FIG. 1, the preparation method in the following embodiments of the present invention is implemented according to the process flow shown in FIG. 1.

Embodiment 1

[0041] The preparation of AgC4 electrical contact material is taken as an example, and the specific preparation includes the following steps:

[0042] (1) an AgC4 spindle with a diameter of 90 mm is prepared by a powder metallurgy technology; after sintering at 750 C. for 3 h, a hot extrusion is carried out to obtain a long continuous AgC4 sheet material with a stuck slot structure shown in FIG. 2; the sheet material has a thickness of 2.1 mm and a length of 35-45 m;

[0043] (2) a BCu88PAg solder stripe material is evenly stuck in the stuck slot of the AgC4 sheet material, and the sintering is performed to composite the AgC4 sheet material with the solder stripe material; a sintering temperature is 730 C., and a protective atmosphere is hydrogen, so that AgC4 sheet material is tightly bonded with the solder stripe material;

[0044] (3) the AgC4 sheet material composited with the solder stripe material is subjected to multiple times of cold rolling and annealing heat treatment, and then rolled to a desired thickness of a finished product;

[0045] in this step, a deformation amount of each time of cold rolling is 12%-16%, an annealing temperature is 500 C., an annealing time is 1 h, and the protective atmosphere is hydrogen; and

[0046] (4) after performing a punching, a finished product of AgC4 electrical contact material with a desired outer dimension is obtained.

Embodiment 2

[0047] The preparation of AgC3 electrical contact material is taken as an example, and the specific preparation includes the following steps:

[0048] (1) an AgC3 spindle with a diameter of 100 mm is prepared by a powder metallurgy technology; after sintering at 740 C. for 3.5 h, a hot extrusion is carried out to obtain a long AgC3 sheet material having a U-shaped structure with a stuck slot; the sheet material has a thickness of 3.3 mm and a length of 25-35 m;

[0049] (2) a BAg25CuZn solder stripe material is evenly and flatly stuck in the stuck slot for sintering to composite the AgC3 sheet material with the solder stripe material; a temperature is 740 C., and a protective atmosphere is hydrogen, so that AgC3 sheet material is tightly bonded with the solder stripe material;

[0050] (3) the AgC3 sheet material composited with the solder stripe material is subjected to multiple times of cold rolling and annealing heat treatment, and then rolled to a desired thickness of a finished product;

[0051] in this step, a deformation amount of each time of cold rolling is 15%-20%, an annealing temperature is 490 C., an annealing time is 1.5 h, and the protective atmosphere is hydrogen; and

[0052] (4) after performing a punching, a finished product of AgC3 electrical contact material with a desired specification, such as a round tip, is obtained.

Embodiment 3

[0053] The preparation of AgC5 electrical contact material is taken as an example, and the specific preparation includes the following steps:

[0054] (1) an AgC5 spindle with a diameter of 100 mm is prepared by a powder metallurgy technology; after sintering at 760 C. for 3 h, a hot extrusion is carried out to obtain a long AgC5 sheet material having a U-shaped structure with a stuck slot; the sheet material has a thickness of 3.4 mm and a length of 25-35 m;

[0055] (2) a BAg30CuZnSn solder stripe material is evenly and flatly stuck in the stuck slot of the AgC5 sheet material for sintering to composite the AgC5 sheet material with the solder stripe material; a temperature is 770 C., and a protective atmosphere is hydrogen, so that the AgC5 sheet material is tightly bonded with the solder stripe material;

[0056] (3) the AgC5 sheet material composited with the solder stripe material is subjected to multiple times of cold rolling and annealing heat treatment, and then rolled to a desired thickness of a finished product;

[0057] in this step, a deformation amount of each time of cold rolling is 15%-20%, an annealing temperature is 495 C., an annealing time is 2 h, and the protective atmosphere is hydrogen; and

[0058] (4) after performing a punching, a finished product of AgC5 electrical contact material with a desired specification is obtained.

[0059] Referring to FIG. 2, a silver-graphite sheet material after a hot extrusion according to an embodiment of the present invention is shown. The sheet material is U-shaped and has a stuck slot structure. The height of the stuck slot depends on the thickness of the solder strip material. In one embodiment, the height of the stuck slot can be 0.02 to 0.04 mm larger than the thickness of the solder strip material, so as to ensure that the solder strip material is stuck tightly, thus making the interfaces of the silver-graphite and the solder strip material bonded tightly when performing the sintering to composite the silver-graphite and the solder strip material. In the present invention, the stuck slot can make the long silver-graphite sheet material stuck with the solder strip material, so that the surfaces of the long silver-graphite sheet material and the solder strip material contact with each other closely, and the solder strip material can cover the stuck slot to form a good solder layer during the sintering. Moreover, the extruded silver-graphite sheet material of the present invention is relatively long, and the silver-graphite is soft. After the solder strip material is stuck in the stuck slot, the silver-graphite sheet material can be rolled into bundles for sintering to achieve the composite, thereby improving the production efficiency of the long silver-graphite. In addition, the stuck slot can prevent the solder from falling off.

[0060] In the present invention, after the long silver-graphite sheet material is sintered and composited with solder, the thickness of the solder layer can be made uniform by rolling, and the thickness can be controlled. That is, the finished product is obtained by the steps of extrusion for preparing sheet material, compositing solder, and punching.

[0061] Referring to FIG. 3, and according to the above embodiments, in the silver-graphite electrical contact sheet material after sintered and composited with solder strip material prepared by the present invention, the interfaces of the silver-graphite sheet material and the solder strip material are bonded tightly, and the middle portion is a porous structure formed by sintering of the solder strip material. Subsequent rolling can make the solder strip material compact.

[0062] Referring to FIG. 4, a metallographic photograph of a finished product of AgC4 electrical contact material according to the embodiment of the present invention is shown. The interface is densely bonded, and the thickness of the solder layer is uniform.

[0063] In the above embodiments of the present invention, the steps of extrusion, sintering, cold rolling and heat treatment are used for preparation, which is beneficial for shortening the cycle, improving the production efficiency and saving the production cost.

[0064] According to the present invention, a good dense silver-graphite sheet material can be obtained by extruding a pure silver-graphite spindle. After the good dense silver-graphite sheet material is sintered and composited with a solder strip material, a desired silver-graphite material can be obtained by rolling and heat treatment. Compared with the prior art (including Chinese Patent ZL200910153565.2), the method of the present invention has the advantages of simple operation, simplified process, and high yield.

[0065] According to the present invention, a highly efficient and continuous composite of a long silver-graphite electric contact sheet material and a solder strip material is realized, products with good interface bonding quality and high dimensional accuracy are produced, the thickness of solder layer has high consistency, and continuity and short process is realized, which facilitates the realization of soldering automation, with significant economic benefits.

[0066] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and various modifications and variations may be made by those skilled in the art within the scope of the pending claims, which do not affect the essential contents of the present invention.