JPS5884938A - Electrical contact material - Google Patents

Abstract

PURPOSE:To enhance the welding resistance and hardly dissipative property of the resulting titled material, to control the temp. rise, and to reduce the contact resistance and cost by dispersing the carbide and boride of a IVa, Va or VIa group metal in an iron group metal and silver. CONSTITUTION:This electrical contact material has a composition consisting of, by weight, 5-70% carbide of a IVa, Va or VIa group metal, 0.1-30% boride of a IVa, Va or VIa group metal, 2-60% iron group metal, and the balance silver. Said carbide and boride are solubilized in the iron group metal when the starting materials are sintered, and they are dispersed in the iron group metal and silver.

Description

[Detailed description of the invention] It relates to gas contact materials.

In particular, the present invention is aimed at improving the characteristics of Ag-Ni-carbide alloy contact materials. Conventional SAg-WO alloys have been widely used as contacts in devices such as air circuit breakers and switches due to their excellent arc resistance and welding resistance. However, in recent years, electromagnetic switch single contactors have been trending toward smaller size and higher performance, and as a result, the load on contact materials has become severer, and there is a strong demand for improved contact performance. or,
Due to the miniaturization of devices, there is a trend toward smaller contact dimensions and lower contact pressure, which reduces the wear and tear that occurs when switching current.
Problems have arisen such as increased scattering, welding of contacts, and temperature rise when switching at the rated current. In order to meet the demand for improved characteristics, a contact made of Ag--No alloy with nickel added has been developed. This contact has the effect of reducing wear due to arc heat generated during opening and closing. However, there was a drawback that the temperature rise due to oxidation of Wa was high.

For this reason, the range of use of small, high-performance electromagnetic switches and contactors + is fixed.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a contact alloy that has both welding resistance and abrasion resistance, has low temperature rise, and is excellent in practical use. Furthermore, the alloy of the present invention provides an inexpensive contact alloy that can be used as a contact even when the amount of expensive silver is considerably reduced.

The alloy according to the present invention combines iron group metals and silver with ■a1■a, ■a
This is an electrical contact material containing dispersed carbides of group metals and borides of group metals.

The characteristics of the alloy according to the present invention will be explained below.

The inventors conducted various studies on alloys made by adding iron group metals and various carbides to silver, and found that alloys in which carbides are dispersed in iron group metals are consumed by the arc heat generated when the current is switched on and off. It was reconfirmed that the effect was extremely low in scattering.

However, although iron group metals and carbides have poor oxidation resistance, they are oxidized by the arc heat generated during opening and closing, forming oxides at the contact point am, increasing contact resistance and increasing the concentration of the metal. 〇When borides are added to the above contact alloy, carbides and borides are solidly dissolved in the iron group metal during sintering, and these dispersions make the alloy highly hard and improve its resistance to corrosion. It was found that the iron-nickel carbide exhibits low contact resistance and excellent abrasion resistance that could not be expected.

Solid solution reactions between iron group metals, carbides, and borides occur only at high temperatures, but when silver is present, the silver becomes a liquid phase during baking, and the reaction is accelerated through this liquid phase. It was found that the iron group metals are 1, Oo, Nil, and 2 to 40 weight S
``''C, preferably 20~sO weight ≦ is appropriate. Below the weight range, iron group metals are dispersed in the chain, forming carbides,
Solid solution of boride does not occur and wear resistance does not improve, t40
Above the weight resistance, even if boride is added, the contact resistance does not decrease and there is no effect on temperature rise characteristics.

Borides include li, Mo, Ta5Nb, Ti, and Or.

A boride of a SV&, VIIL group metal such as Zr5V is effective, and the amount thereof is preferably 017 to 30% by weight, and particularly 3 to 7% by weight has good properties. Boride is 0
．． If it is less than 1% by weight, the amount of boride in the chain is too small and the effect of improving contact properties is insufficient, and if it is more than 30% by weight, wear resistance is poor due to the balance with carbide.

The amount is preferably 3 to 70% by weight, particularly 20 to 70% by weight.
Good properties of O weight %. This is because if it is less than 3% by weight, the effect of improving wear resistance is small, and if it is more than 70% by weight, the contact resistance does not decrease even if boride is added.

Note that about 0.1% by weight of jkl does not impair the purpose of the present invention.
, Si, So, To, Bi, Zn, Od, In,
Sn.

There is no problem even if metal elements such as Oa and 111 are included.

Next, the characteristics of the contact alloy according to the present invention will be specifically explained using examples.

Example 1 Each powder was blended in the proportions shown in Table 1, Table 1, Table 3, and Table 9, and after mixing, a molded body was made, and the molded body was sintered at a temperature of /10OC in a hydrogen atmosphere. The sintered body was re-pressed to produce an alloy with almost zero porosity. The alloys in the table are conventional alloys for comparison.

Chapter/Table Unit double amount % Soukoji example, Examples! From the alloy created by A-k, B/ Soko and Hiso #cal, the movable contact /I X /j f
- After cutting to the dimensions of ■, it was joined to the base metal with a resistor bell, and this was assembled into an electromagnetic switch of JoQm rating.The contact performance was evaluated under the test conditions shown below, and as a result, Table 6 was obtained. .

Test conditions: Voltage □ov1 Current l. θA1 power rate. ,λ
jj2Fil open/close.

As shown in Table 6, Table 84, it can be seen that the alloy of the present invention has low wear and contact resistance, and has high performance contact characteristics.

The alloy of the present invention not only has excellent contact performance as described above, but also contains large amounts of iron group metals, carbides, and borides, and the amount of expensive silver can be significantly reduced, so it is of high industrial value. .

Claims (1)

[Claims] (1) IVa, Va, VI of the periodic table of elements
Carbide of group a metal is S ~ 0% by weight -■a-%Va1■
Borides of group a metals 007-30% by weight, iron group metals 2-6
An electrical contact material characterized in that the balance is silver, and carbides and borides are dispersed in iron group metals and chains. (A Carbide is tungsten, molybdenum, tantalum,
The electrical contact material according to claim (1), characterized in that it is a carbide of at least one of niobium, titanium, and chromium. (The borides are tungsten, molybdenum, tantalum,
The electrical contact material according to claim (1), characterized in that it is at least seven borides selected from diopter, titanium, chromium, zirconium, and vanadium. () The electrical contact material according to claim 3, wherein the iron group metal is at least one of nickel, iron, and cobalt.