JPS614115A - Electric contact material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inexpensive and high-performance electrical contact material that can replace noble metal-coated electrical contact materials used in electrical and electronic equipment and their parts. .

[Conventional technology]

Generally, electrical/electronic equipment and its parts switches, relays,
Electrical connections such as connectors and IC sockets are made of Au.
, Pd, Pt, Ag and their alloys, such as AU-Ag, ALI-AQ-Pd-GelAg
7Pd, Pd-Ir, A.

(7) Alloys such as Cd O, Ag WC, and AQ Ni are selected and used depending on the electric circuit conditions and usage conditions. For example, high to medium current switching applications that involve arc discharge wear and tear require high melting points and high temperatures, while microcurrent switching and connections require conductivity and corrosion resistance to achieve contact resistance and stability. In order to satisfy these requirements, the above-mentioned noble metal is deposited on a conductive substrate to form an electrical contact material.

In recent years, with the development of electronics, applications such as key switches for connecting weak currents and inputting ON-OFF signals have expanded, and the demand for negative metals, particularly Au, has expanded. Although Au is known to be effective in switching and connecting the weak current, it is an expensive precious metal and therefore poses an economic burden. Therefore, by making the film as thin as possible,
It is desired to use it in a localized manner.

[Problem that the invention seeks to solve]

However, the film formation causes exposure corrosion of base metals such as Cu due to unavoidable pinholes and mechanical wear, which deteriorates electrical connectivity. In addition, localization is caused by miniaturization of the contact portion as much as possible, and corrosion products of the base metal substrate exposed around the Au surface creep, causing poor contact. A for history
This is a cause of deterioration of electrical connectivity due to heat diffusion between the base metal and the base metal. Instead of A I+ (relatively inexpensive noble metals A(l) and Pd may be used, but these tend to form insulating films such as polymers and sulfides, making the contact resistance low and unstable. There are drawbacks.

Recently, inexpensive conductive rubber with stable contact resistance has come to be used for inputting the ON-OF signals and digital signals. This is because stability is required rather than the level of contact resistance.

However, while the contact resistance between gold and gold is several rLΩC, the contact resistance of conductive rubber is extremely large, on the order of 100Ω. Therefore, there is a strong desire to develop an inexpensive contact material that has low contact resistance and can replace All-coated contact materials.

[Means for Solving the Problems] In view of this, the present invention has developed an inexpensive and high-performance electrical contact material that can replace noble metal-coated electrical contact materials by using metal silicide, as a result of various studies. Something,
It is characterized in that metal silicide is deposited on at least the contact portions on the conductive substrate.

That is, the present invention provides Pdz on at least the contact portion or the entire surface of a conductive substrate such as Cu, Cu alloy, Fe alloy, Ni alloy, etc.
Si, PtSi, N15iz, Co51z, WSiz,
Mo5iz, Ta5iz, Nb5iz, 1-iSiz.

It is coated with metal silicide such as Zr5iz, l-1fsiz, VSiz, etc. The metal silicide can be easily deposited using a PVD method such as sputtering or vapor deposition, or a CVD method applying a gas phase chemical reaction. Alternatively, metal and silicon can be sputtered simultaneously, or metal and silicon can be deposited in two layers and then heated and diffused to form metal silinide. Furthermore, it is also possible to sinter the metal silicide powder and apply it onto the substrate by brazing or the like.

[For production]

The above-mentioned metal silicide has a high melting point of 1200 to 2300°C, is chemically stable, hard, and has high conductivity. By coating at least the contact portion on one substrate, it is possible to obtain an electrical contact material having low contact resistance and stable electrical connectivity that can replace a contact material coated with a noble metal. In other words, the specific resistance of metal silicide increases by about 10 to 100 μΩ・α.
2.4μΩ・α or graphite (for aIIllh) No. 1
00 to 200 μΩ・1, which is much smaller than the 10 to 103 μΩ・0 of conductive rubber used in some weak current key switches and connectors.

For example, TiSi z is 10 to 20 μΩ・α, which is smaller than the 55μ0・cm of Ti, and metal silicide has electrical conductivity comparable to that of metal, is thermally and chemically stable, is harder than metal, and is wear resistant. It also has excellent characteristics. Furthermore, metal silicide is much cheaper than noble metals and can reduce the cost of electrical contact materials.

〔Example〕

(1) PdzSi with a thickness of about 0.2μ was deposited on a Cu-9,3%Ni-2,5%3N alloy substrate by sputtering.
and pt3i were deposited to form a contact material of the present invention. A for this! + Probe (tip radius 2.5#+II+>
using a load m' of 1.70 g and a current of 1001 rLA
Contact resistance was measured under these conditions. These results are shown in Table 1 in comparison with a conventional contact material plated with AU and Pd to a thickness of 0.5 μm by electroplating.

Table 1 [ (2) WSiz and Nb5iz chips (
1111, 5111#l, length 1.5M, thickness 0,3.
) and convert it into Fe -42% for reed relays.
A C1 non-inventive contact material was formed on an N1 alloy substrate by brazing. Based on this, I made one movable contact at each °C and set two fixed contacts between them to assemble the relay. Regarding this (voltage 30V, current 1A, frequency 1
A contact life test was conducted under the conditions of 1-lz, and the number of vibrations until welding or malfunction occurred was measured. These results were compared with those of a conventional contact material plated with A Ll and Rh to a thickness of 2.5 μm by electroplating (see Table 2).

Table 2 - As is clear from the above examples, the contact material of the present invention has lower contact resistance than conventional contact materials, and it can be seen that the contact life can be significantly improved.

As described above, according to the present invention, it is possible to provide an electrical contact hole which has superior electrical connectivity and is inexpensive compared to the conventional contact material coated with a noble metal, and has C of b, which has an industrially significant effect.

Claims (1)

[Claims] An electrical contact material characterized in that metal silicide is deposited on at least a contact portion on a conductive substrate.