Tape-shaped contact member and method for manufacturing same

Abstract

Provided is a tape-shaped contact member including a tape-shaped contact material. At least one wire-shaped brazing material is bonded to the tape-shaped contact material, at least one projection including the brazing material and protruding from a surface of the contact material is formed in a cross-sectional shape, a diffusion region containing a metal component forming the brazing material is formed along an interface with the brazing material inside the contact material, and the diffusion region has a thickness of 2 μm or more and 10 μm or less. A chip-shaped contact component can be obtained by cutting the tape-shaped contact member to an arbitrary length. The present contact component is useful as a constituent member for a switching electrical contact, and capable of adapting to height reduction of the electrical contact. The present invention can also contribute to reduction of occurrence of poor bonding.

Claims

1. A tape-shaped contact member comprising a tape-shaped contact material, wherein at least one wire-shaped brazing material is bonded to the tape-shaped contact material, at least one projection including the brazing material and protruding from a surface of the contact material is formed in a cross-sectional shape, a diffusion region containing a metal component forming the brazing material is formed along an interface with the brazing material inside the contact material, and the diffusion region has a thickness of 2 82 m or more and 10 μm or less.

2. A tape-shaped contact member comprising a tape-shaped contact material, wherein a tape-shaped intermediate metal layer and at least one wire-shaped brazing material is bonded to the tape-shaped contact material, at least one projection protruding from a surface of the contact material is formed from the brazing material in a cross-sectional shape, a diffusion region containing a metal component forming the brazing material is formed along an interface with the brazing material on the intermediate metal layer, and the diffusion region has a thickness of 2 μm or more and 10 μm or less.

3. The tape-shaped contact member according to claim 1, wherein a bonding width W between the tape-shaped contact material and the wire-shaped brazing material and a diameter (D.sub.1) of the wire-shaped brazing material satisfy a relationship of W≥0.5D.sub.1.

4. The tape-shaped contact member according to claim 1, wherein the brazing material incudes an Ag-Cu alloy.

5. The tape-shaped contact member according to claim 4, wherein the brazing material comprises an Ag-Cu alloy containing at least one of P, Sn, In, Ni, Si and Mn.

6. The tape-shaped contact member according to claim 1, wherein the contact material is an Ag-based contact material.

7. The tape-shaped contact member according to claim 6, wherein the contact material is an Ag-based contact material containing a metal of at least one of Cu, Ni, Zn, Sn and In.

8. The tape-shaped contact member according to claim 1, wherein the intermediate metal layer contains a metal of at least one of Ag, Ni and Cu.

9. A method for manufacturing the tape-shaped contact member according to claim 1, wherein the method comprises the steps of: pressure-bonding at least one wire-shaped brazing material to a tape-shaped contact material; and forming a diffusion region by performing heating at a temperature equal to or higher than 500° C. and equal to or lower than the melting point of the brazing material.

10. The method for manufacturing the tape-shaped contact member according to claim 9, wherein the tape-shaped contact material and a tape-shaped intermediate metal layer are bonded to each other, and at least one wire-shaped brazing material is then pressure-bonded to the tape-shaped intermediate metal layer.

11. The method for manufacturing the tape-shaped contact member according to claim 9, wherein the tape-shaped intermediate metal layer and at least one wire-shaped brazing material are pressure-bonded to the tape-shaped contact material.

12. The method for manufacturing the tape-shaped contact member according to claim 9, wherein when the wire-shaped brazing material is pressure-bonded to the tape-shaped contact material or tape-shaped intermediate metal layer, the wire-shaped brazing material is bonded by applying pressure until the bonding width W of the wire-shaped brazing material and the diameter D.sub.0 of the wire-shaped brazing material satisfy a relationship of W≥0.5D.sub.0.

13. A chip-shaped contact component obtained by cutting the tape-shaped contact member according to claim 1.

14. A method for manufacturing an electrical contact by use of the chip-shaped contact component as defined in claim 13, the method comprising the step of bonding the chip-shaped contact component to a terminal of the electrical contact, wherein in the bonding step, the chip-shaped contact component is pressed to the terminal, and simultaneously fed with electricity to melt the brazing material of the contact component, so that the contact component is bonded to the terminal.

15. A relay comprising the chip-shaped contact component as defined in claim 13.

16. The tape-shaped contact member according to claim 2, wherein a bonding width W between the tape-shaped contact material and the wire-shaped brazing material and a diameter (D.sub.1) of the wire-shaped brazing material satisfy a relationship of W≥0.5D.sub.1.

17. The tape-shaped contact member according to claim 2, wherein the brazing material incudes an Ag-Cu alloy.

18. The tape-shaped contact member according to claim 2, wherein the contact material is an Ag-based contact material.

19. The tape-shaped contact member according to claim 2, wherein the intermediate metal layer contains a metal of at least one of Ag, Ni and Cu.

20. A chip-shaped contact component obtained by cutting the tape-shaped contact member according to claim 2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1A and 1B illustrate a cross-sectional shape for one example of a tape-shaped contact of the present invention.

(2) FIG. 2 illustrates a position at which a projection is formed in the tape-shaped contact of the present invention.

(3) FIG. 3 illustrates a thickness (t) and a bonding width (W) of a diffusion region in the tape-shaped contact of the present invention.

(4) FIG. 4 illustrates a process for manufacturing a tape-shaped contact in an embodiment.

(5) FIG. 5 shows photographs of cross-sections of tape-shaped contact members manufactured in an embodiment.

(6) FIG. 6 shows results of EPMA analysis in the vicinity of a brazing material (projection) of a tape-shaped contact in Example 1.

(7) FIG. 7 shows photographs of cross-sections of terminals after durability tests in Examples 1 and 4 and a conventional example.

(8) FIG. 8 illustrates a structure of a general relay that is a type of switching contact.

(9) FIG. 9 illustrates a structure of a relay of flexure type.

(10) FIG. 10 illustrates a configuration of a contact component to which a conventional welding material with a projection is applied.

(11) FIG. 11 illustrates a configuration of a contact component including conventional back solder.

DESCRIPTION OF EMBODIMENTS

(12) Hereinafter, preferred examples of the present invention will be described.

First Embodiment

(13) In this embodiment, a tape-shaped contact member was manufactured by application of a tape-shaped oxide dispersive Ag-based alloy as a contact material and copper-based phosphorus copper solder as a wire-shaped brazing material for forming a projection.

(14) In this embodiment, a plurality of contact members different in the number and wire diameter of wire-shaped brazing materials. Ag was applied as an intermediate metal layer.

(15) Contact members in which a tape-shaped intermediate metal layer and one wire-shaped brazing material (wire diameter: 0.16 mm or 0.26 mm) are bonded to a tape-shaped contact material, and thus one projection is formed (Examples 1 and 2 and Comparative Examples 1 and 2)

(16) Contact members in which a tape-shaped intermediate metal layer and two wire-shaped brazing materials (wire diameter: 0.16 mm or 0.26 mm) are bonded to a tape-shaped contact material, and thus two projections are formed (Examples 3, 4 and 5)

(17) FIG. 4 shows a process for manufacturing a contact member in which a tape-shaped intermediate metal layer and two wire-shaped brazing materials are bonded to a tape-shaped contact material (Examples 3, 4 and 5). A process for manufacturing various tape-shaped contact members in this embodiment will be described with reference to this drawing.

(18) As the contact material, a tape member of an oxide dispersive Ag-based alloy (parent phase: Ag (85.5 wt %), dispersion phase: SnO.sub.2+In.sub.2O.sub.3, trade name: SIE-21 DK (manufactured by Tanaka Kikinzoku Kogyo)) was prepared. In addition, a tape member of pure Ag (purity: 99.9 wt %) was prepared as the intermediate metal layer in FIG. 4. These tape members were superposed on each other, and pressure was applied to manufacture a tape member having two-layer structure of contact material/intermediate metal layer (dimensions=width: 2.48 mm, contact material thickness: 0.315 mm, intermediate metal layer thickness: 0.05 mm).

(19) For the two-layer tape-shaped contact material prepared as described above, a wire-shaped brazing material of phosphorus copper solder (Ag (15 wt %)-P (5 wt %)-Cu (balance) (BCuP-5)) was prepared as a brazing material. In this embodiment, two wire-shaped brazing materials having different wire diameters (0.16 mm and 0.26 mm) were prepared, and a contact member was manufactured with each of the brazing materials. These wire-shaped brazing materials were each positioned on and press-bonded to a surface of a tape-shaped contact material.

(20) The bonded tape member and wire-shaped brazing material were subjected to heat treatment in an atmospheric furnace to form a diffusion region, so that a tape-shaped contact member was manufactured. As conditions for the heat treatment, the heat treatment was performed at 600° C. for 0.5 hours (Examples 1 to 4), at 600° C. for 1 hour (Example 5), at 300° C. for 0.5 hours (Comparative Example 1) and at 700° C. for 0.5 hours (Comparative Example 2).

(21) FIG. 5 shows photographs of cross-sections of tape-shaped contact members in Examples 1 to 4. In these examples, the contact materials have the same width and thickness, and the intermediate metal layers have the same width and thickness. In all of these examples, the cross-sectional shape of the wire-shaped brazing material was deformed by pressure-bonding of the brazing material to the contact material, and turned into a circular shape collapsed on the upper side (at the interface with the contact material).

(22) In this embodiment, a photograph of a cross-section as in FIG. 5 was taken in each example, and the bonding width (W) and the diameter (D.sub.1) of the wire-shaped brazing material were measured on the basis of the photograph of the cross-section. For example, in the contact member in FIG. 5, the bonding width (W) was 0.2 mm (Example 1 and example using a wire having a diameter of 0.16 mm) and 0.3 mm (Examples 2 and 4 using a wire having a diameter of 0.26 mm). In addition, in this embodiment, the length of the outer periphery of the cross-section of the brazing material was equal to the length of the outer periphery of the wire-shaped brazing material before pressure-bonding, and therefore D.sub.1 was equal to D.sub.0. Accordingly, in Examples 1 and 3, the bonding width W was 1.25D.sub.1. In Examples 2 and 4, the bonding width W was 1.15D.sub.1. Similarly, the bonding width (W) and the diameter (D.sub.1) of the brazing material in each of other examples and comparative examples were measured.

(23) The diffusion regions of the tape-shaped contact members in examples and comparative examples were examined. FIG. 6 shows results of analysis by EPMA (electron beam microprobe) in the vicinity of the brazing material of the contact member in Example 1. In this embodiment, the intermediate metal layer (silver layer) was applied, and a diffusion region in which Cu as a component of the brazing material was diffused was formed inside the silver layer. The content of Cu in the diffusion region was inclined. The thickness of the diffusion region was measured on the basis of the line of the Cu concentration in the EPMA analysis in FIG. 6. In this measurement, a center line was drawn to a Cu line inside the brazing material, and a tangent line to an inclined Cu line inside the diffusion region (line extending rightward and downward from the line inside the brazing material) was then drawn. A part at which these lines crossed each other was defined as one end (start point) of the diffusion region. A center line was drawn to a line of Cu in a region free from Cu (region having a Cu intensity close to zero) inside the intermediate metal layer, and a part at which this line crossed a tangent line to a Cu line extending leftward and upward to the inside of the diffusion region was defined as the other end (end point). The thickness of the diffusion region was measured after the start point and the end point of the diffusion region were defined as described above, the results showed that a diffusion region of 5.0 μm was formed. In this embodiment, the thickness of the diffusion region in each of other examples and comparative examples was measured in the same manner as in Example 1.

(24) The results of measuring the bonding width (W), the diameter (D.sub.1) of the brazing material and the thickness of the diffusion region in examples and comparative examples are shown in Table 1. For contact members in which two projections are formed, average values are shown in Table 1.

(25) TABLE-US-00001 TABLE 1 Wire-shaped brazing material Heat treatment Thickness Contact Intermediate D.sub.0 Temperature Time W D.sub.1 of diffusion material metal layer Type (mm) Number (° C.) (hr) (mm) (mm) W/D.sub.1 region (μm) Example 1 Ag/ Ag Ag—Cu—P 0.16 1 600 0.5 0.20 0.16 1.25 5.0 Example 2 (SnO.sub.2 + In.sub.2O.sub.3) 0.26 0.20 0.26 0.77 6.0 Example 3 0.16 2 0.30 0.16 1.25 4.0 Example 4 0.26 0.30 0.26 1.15 5.0 Example 5 0.26 1 0.35 0.26 1.35 8.0 Comparative Ag 0.26 1 300 0.5 0.11 0.26 0.42 1.2 Example 1 Comparative 0.16 700 1 0.24 0.16 1.50 11.0 Example 2

(26) Next, the tape-shaped contact member in each example was cut to manufacture a chip-shaped contact component, and the durability of the chip-shaped contact component bonded to a terminal was evaluated. In this test, the chip-shaped contact component was bonded to a 0.15% Cu—Sn plate cut to a length of 2.48 mm and used to simulate a terminal of an electrical contact. The contact component was set in a relay (DC 14 V, 30 A, and a durability test was conducted.

(27) In the durability test, the switching frequency was set to ON for 0.3 seconds and OFF for 4.5 seconds, and switching was performed 120,000 times, followed by examining whether or not deposition occurred. In addition, the cross-section of the terminal after the test was observed to examine the bonding state of the contact component and the consumption of the contact material. The contact component was rated acceptable “Good” when the contact material was confirmed to remain and there was no change in contact state between the contact component and the terminal in the observation of the cross-section. On the other hand, the contact component was rated unacceptable “Bad” when the contact material was noticeably worn, or peeling occurred at the bonding interface between the contact component and the terminal.

(28) The durability test in this embodiment was also conducted for a contact component having a welding material provided with a projection of a conventional art. The conventional example is a contact member in which the same contact material as in this embodiment is bonded to a welding material formed of a Cu-30% Ni alloy and integrated with a projection as in FIG. 10. In the conventional example used in this embodiment, a welding material and a contact material are bonded to each other with a pure Ag intermediate metal interposed between the welding material and the contact material. Results of durability tests conducted for examples, comparative examples and the conventional example are shown in Table 2.

(29) TABLE-US-00002 TABLE 2 Brazing material Thickness Result of Contact Intermediate D.sub.0 W D.sub.1 of diffusion durability material metal layer Type (mm) Number (mm) (mm) W/D.sub.1 region (μm) test Example 1 Ag/ Ag Ag—Cu—P 0.16 1 0.20 0.16 1.25 5.0 “Good” Example 2 (SnO.sub.2 + In.sub.2O.sub.3) 0.26 0.20 0.26 0.77 6.0 “Good” Example 3 0.16 2 0.30 0.16 1.25 4.0 “Good” Example 4 0.26 0.30 0.26 1.15 5.0 “Good” Example 5 0.26 0.35 0.26 1.35 8.0 “Good” Comparative Ag 0.26 1 0.11 0.26 0.42 1.2 “Bad”*.sup.1 Example 1 Comparative 0.16 0.24 0.16 1.50 11.0 “Bad”*.sup.1 Example 2 Conventional Ag Ag—Ni — — — — — “Bad”*.sup.2 Example *.sup.1Unacceptable because contact member is peeled off *.sup.2Unacceptable because the wear amount of contact member is excessively large

(30) In the durability test in this embodiment, switching operation was performed 120,000 times, and deposition did not occur in any of the contact component. However, observation of the cross-section in the vicinity of the contact member after the test showed that there was a difference between the test results in examples and the test results of comparative examples and the conventional example.

(31) FIG. 7 shows photographs of cross-sections of terminals after durability tests in Examples 1 and 4 and a conventional example. FIG. 7 indicates that in the contact component in the conventional example, the contact material was mostly worn, and a base (Ag forming the intermediate metal layer) was exposed. Thus, the contact component in the conventional example was unacceptable for the result of the durability test. This result suggests that when the contact member in the conventional example is applied, a long-term load causes a failure. On the other hand, the contact components in Examples 1 and 4 were rated acceptable because the contact material remained sufficiently, and the bonding state between the contact member and the terminal was favorable. The same durability test results as in Examples 1 and 4 were obtained for the contact components in Examples 2 to 5.

(32) A difference in consumption of the contact material as shown from comparison of examples with comparative examples is ascribable to a difference in bonding area between the contact member and the terminal. As described above, in the present invention, the bonding area can be increased as compared to the contact member of the conventional example in which a welding member provided with a projection is applied. It is considered that due to the increase in bonding area, the heat dissipation amount to the terminal from the contact material increased, resulting in reduction of a load on the contact material. It can be said that wear of the contact material was suppressed as a result of the load reduction.

(33) On the other hand, the reason why the contact members in Comparative Examples 1 and 2 were rated unacceptable in durability test results is that peeling was observed at the bonding interface between the contact member and the terminal in observation of the cross-section. In these comparative examples, the thickness of the diffusion region was less than 2 μm (Comparative Example 1) or more than 10 μm (Comparative Example 2). The insufficient thickness of the diffusion region may be a direct factor of peeling due to poor bonding of the contact member. In addition, it is considered that when the thickness of the diffusion region was excessively large, a variation in composition of the brazing material increased, leading to deterioration of bondability of the brazing material. Thus, the excess or insufficient thickness of the diffusion region may be a factor of peeling of the contact member. In this durability test, the contact member was not peeled off and scattered during the test, but it was shown to be necessary that the diffusion region have an appropriate thickness because peeling may occur during use depending on a load on the electrical contact.

(34) The thickness of the diffusion region after the durability test was measured for each of the contact members in Examples 1 and 2, and the result showed that the thickness was substantially identical to that before the durability test (state after manufacturing). The contact member may undergo thermal influences associated with heat treatment in bonding of the contact member to the terminal during manufacturing of the electrical contact, heat generation resulting from a load during drive of the electrical contact, and so on. The contact component of the present invention is considered to suffer from little change in configuration due to these thermal influences. Accordingly, the contact component of the present invention is supposed to suffer from little change in configuration, and stably act even when incorporated in the terminal of the electrical contact, etc.

Second Embodiment

(35) In this embodiment, a plurality of wire-shaped brazing materials were bonded to a tape-shaped contact materials to manufacture a tape-shaped contact member, and the bonding force of the tape-shaped contact member was examined. Here, an Ag—Cu alloy brazing material having an Ag—Cu alloy as a base and containing some additive metals was formed into a wire (wire diameter: 0.16 mm), bonded to a tape member of the same contact material as in Example 3 in the first embodiment and a tape member of an Ag intermediate metal layer, and subjected to heat treatment to manufacture a contact member (Examples 6 to 10 and Comparative Examples 3 to 5). The number and dimensions of projections were the same as in Example 3. In the contact member of each example which was manufactured in this embodiment, the thickness of a diffusion region at a brazing material interface was confirmed to fall within a range of 2 μm or more and 10 μm or less.

(36) For the manufactured tape-shaped contact member, a twisting test was conducted for examining the bonding force of the brazing material (projection). In the twisting test, a 300 mm tape-shaped contact member was prepared, and twisting was performed in 4 seconds in which the contact member was rotated to the right 24 times, and rotated to the left 24 times with the twisting angle set to 360° (one rotation). After the twisting, the appearance was observed to examine whether or not the brazing material (projection) was peeled off. Results of the test are shown in

(37) TABLE-US-00003 TABLE 3 Twisting Brazing material components (wt %) test Ag Cu P Sn Zn In Ni Mn Si result Example 3 15 80 5 — — — — — — “Good” Example 6 67 29 — 4 — — — — — “Good” Example 7 72 28 — — — — — — — “Good” Example 8 85 15 — — — — — — — “Good” Example 9 50 34 — — 16 — — — — “Fair” Example 10 56 22 — 5 17 — — — — “Fair” Comparative 45 26 — — 21 5 3   — — “Bad” Example 3 Comparative 5 55 — — 39.8 — — — 0.2 “Bad” Example 4 Comparative 49 16 — — 23 — 4.5 7.5 — “Bad” Example 5 “Good”: peeling is not observed at any part “Fair”: peeling partially occurs (less than half the sample length) “Bad”: peeling occurs (half or more to whole of the sample length)

(38) It can be said from the twisting test that when an Ag—Cu alloy (Examples 7 and 8) or an alloy with P or Sn added to an Ag—Cu alloy (Examples 3 and 6) is bonded, a favorable bonding force is obtained. The tape-shaped contact member free from Zn may have no risk of peeling of a brazing material even at the time of cutting the contact member to an arbitrary length according to a use purpose. On the other hand, Examples 11 and 12 and Comparative Examples 3 to 5 are examples in which a brazing material formed of an Ag—Cu alloy containing Zn is applied. In Comparative Examples 3 to 5, an Ag—Cu alloy containing 20% by mass or more of Zn is used, and the brazing material is peeled off in the twisting test, so that caution is needed for handling in cutting etc. In addition, in Examples 9 and 10, an Ag—Cu alloy containing Zn in an amount of more than 15% by mass, and peeling partially occurred. For the brazing material having a Zn content of more than 15% and not more than 20%, it is considered that by handling the brazing material with caution paid to occurrence of peeling, a contact component having contact performance can be manufactured without causing poor bonding.

INDUSTRIAL APPLICABILITY

(39) According to the present invention, a chip-shaped contact component to be used as a constituent material for a switching electrical contact can be efficiently manufactured. The contact component does not require a welding member unlike a contact component provided with a welding material with a projection, which is a conventional art. Thus, the height of the contact member can be reduced. In addition, the contact member is excellent in bondability and durability. The present invention can suitably contribute to manufacturing of switching electrical contacts for switches, relays and the like. Particularly, in an on-vehicle relay, downsizing is required, and therefore the present invention is suitable for this use purpose.