JPS5985833A - Contact material - Google Patents

Abstract

PURPOSE:To obtain a contact material with improved arc shielding characteristics, welding resistance and consumption resistance by adding specified amounts of oxide of zinc, tin or indium, lithium oxide, and iron, cobalt or nickel to a silver matrix. CONSTITUTION:This contact material is obtd. by adding 1-7wt% (expressed in terms of metal) >=1 kind selected from zinc oxide, tin oxide and indium oxide (A), <=1.5wt% lithium oxide (B), and 0.1-1.0wt% >=1 kind selected from iron, cobalt and nickel (C) to a silver matrix. In the contact material having said composition, the metals (C) are more effective in improving the welding resistance and consumption resistance when combined with the metallic oxides (A).

Description

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

Conventionally, Ag-Ca2 contact materials, Ag-3nO□ contact materials, and Ag-Ni contact materials have been used in various electrical devices such as electromagnetic contactors. Among these contact materials, A
The g-Ca2 contact material and the Ag=Snug contact material have excellent welding resistance and abrasion resistance, and the Ag-Ni contact material has excellent abrasion resistance and processability. However, when these contact materials are used in no-fuse breakers, the large current that flows during a short circuit generates an arc, and this arc does not break sufficiently, resulting in poor short-circuit breaking performance. .

As a result of repeated research to eliminate these drawbacks, the inventors discovered that lithium oxide has the effect of improving arc interrupting performance, and created a contact material by incorporating it into a silver base.

As a result of further research, it was found that along with a predetermined amount of lithium oxide, a predetermined amount of at least one of zinc oxide, tin oxide, and indium oxide, and a predetermined amount of at least one of iron, cobalt, and nickel. The present invention was completed based on the discovery that if this is done, deterioration in wear resistance and welding resistance due to the inclusion of lithium oxide can be avoided.

That is, this invention provides the following metal oxide (
A) is 1 to 7% by weight based on the metal, metal oxide (B) is 1.5% by weight or less based on the metal, and metal (C) is 0.1 to 7% by weight.
The gist thereof is a contact material characterized in that it contains 1.0% by weight.

(A) At least one metal oxide selected from the group consisting of zinc oxide, tin oxide, and indium oxide.

(B) Lithium oxide.

(C) At least one metal selected from the group consisting of iron, cobalt and nickel.

The metal oxide (B), that is, lithium oxide, has a large effect of improving arc interrupting performance, so its content is calculated as lithium (metal standard) of 1.5.
ili amount % (hereinafter abbreviated as 1%) or less. Preferably, o, o o s ~ 1.0 based on lithium
%, most preferably from 0.01 to 0.01% based on lithium.
It is 0.03%. If the content exceeds 1.5%, the electrical conductivity of the contact material will be low, and the welding resistance and wear resistance will be significantly low.

Note that when the content is less than 0.001%, the effect becomes considerably smaller.

Further, the metal oxide (A), that is, at least one of zinc oxide, tin oxide, and indium oxide, exhibits the effect of improving welding resistance and wear resistance when coexisting with lithium oxide, and its content is , singly or in total 1
Selected by ~7%. - That is, if the content is less than 1%, the effect of improving welding resistance and wear resistance will be small, and if it exceeds 7%, the arc characteristics will deteriorate. In addition, when only tin oxide is used as the metal oxide (A), it is most preferable to select the content in the range of 1 to 5% based on tin in terms of effectiveness.

Furthermore, at least one of the metals (C), namely iron, cobalt, and nickel, has the same effect of improving welding resistance and wear resistance as the metal oxide (A), and the metal oxide (
By using it in combination with A), the effect of improving welding resistance and abrasion resistance becomes even greater. The content thereof is selected to be 0.1 to 1.0% individually or in total. In other words, if it is less than 0.1%, the effect is extremely small;
This is because if it exceeds this, the electrical type of the contact material will deteriorate once, and the welding resistance and abrasion resistance will worsen.

A contact material having such a composition is usually manufactured as follows. That is, Ag, at least one of zinc, tin, and indium, lithium, iron, cobalt,
Adding a predetermined amount of at least one of nickel and
This is melted in an inert gas atmosphere to create an alloy. Next, this alloy is internally oxidized to selectively oxidize at least one of zinc, tin, and indium, and lithium. In this case, since lithium exhibits the effect of making the metal oxide finer, the metal oxide becomes finer and the welding resistance and abrasion resistance of the contact material improve. Furthermore, since lithium also exhibits an oxidation promoting effect, the internal oxidation time is shortened. In addition, in this case, iron, cobalt, and nickel (iron group elements) also have the effect of making metal oxides finer, so in combination with the effect of lithium, the melting resistance and wear resistance of the contact material are further improved. It becomes.

Although it is possible to produce a contact material having the above-mentioned composition using the sintering method, the internal oxidation method is preferable from the viewpoint of uniform dispersion of lithium oxide.

Since the contact material of the present invention has the above-mentioned composition, it has excellent arc interrupting performance and is also rich in welding resistance and wear resistance.

Next, examples will be described together with comparative examples.

[Example, comparative example]

Zn, S, n or In and Li are contained in the amounts shown in the following table, and Ni is contained in an amount of 0.2%.
Zn, Sn, or In, Li, and Ni were added to Ag, and the mixture was melted and alloyed in an argon atmosphere. next,
This was put into a mold and cast into a rod shape, and then annealed at 750° C. for 8 hours in a N2 atmosphere. Next, an Ag plate was crimped onto this, and then rolled to form a plate with a thickness of 1 mm.
Internal oxidation occurred in that state. Internal oxidation was performed at 720° C. for 100 hours in an 02 atmosphere. Next, this was punched and brazed to make a sample. Then, the obtained sample was assembled into a no-fuse breaker to examine its short-circuit breaking performance, and the abrasion resistance and welding resistance were examined by ASTM tests, and the results are shown in the following table. As is clear from the table, the examples have good short-circuit breaking performance (arc breakage time), wear resistance (wear M), and welding resistance (number of f6 deposits). On the other hand, the comparative examples lack one or the other, and are therefore of little practical use.

(Left below) Short-circuit breaking performance test and A37M test 11 were conducted as follows.

(Short-circuit breaking performance test) As described above, the sample was assembled into a no-fuse breaker, a short-circuit test was conducted, and the arc breakage time was measured. This arc duration is the time during which the arc generated between a pair of contacts stays as it is, and the longer this time, the longer the time that the pair of contacts are connected by the arc, and eventually the contact This will lead to thermal damage. Therefore, the shorter the arc activation time, the better the short circuit breaking performance. Note that the short circuit current is 5.2 KA.

(ASTM test) The samples were run on an ASTM test machine and tested under the following conditions.

Load: AC single phase 100V 40A contact crab 20
0g Opening crab 340g Contact shape: Movable φri XI
2R ball fixed φ5 flat Final number of opening/closing times: 100,000 times Number of pieces: 3 The amount of wear is shown as the average value of 3 pieces, and the welding amount is shown as the total number of weldings of 3 pieces.

Agent: Patent Attorney Takehiko Matsumoto

Claims (1)

[Claims] +11 The following metal oxide (A) is added to the silver base in an amount of 1 to 7% by weight on a metal basis, and the metal oxide (B) is added as 1 to 7% by weight on a metal basis.
．． 5% by weight or less and metal (C) 0.1-1゜0% by weight
A contact material characterized by containing: (A) At least one metal oxide selected from the group consisting of zinc oxide, tin oxide, and indium oxide. (B) Lithium oxide. (C) At least one metal selected from the group consisting of iron, cobalt and nickel. (2) When the silver base contains zinc oxide, lithium oxide, and nickel, the content of lithium oxide is selected to be less than 0.2% by weight based on lithium. Contact material.