JPS61246337A - Contact material - Google Patents

Abstract

PURPOSE:To obtain a contact material having much superior melt sticking resistance and contg. no harmful element by dispersing prescribed percentages of Li and Sb in Ag in the form of metallic oxides by an internal oxidation method. CONSTITUTION:Li oxide and Sb oxide are formed in Ag by an internal oxidation method and dispersed in the Ag to obtain a contact material. At this time, it is necessary to regulate the Li oxide content to 0.1-3 wt% (expressed in terms of Li) and the Sb oxide content to 0.01-2 wt% (expressed in terms of Sb). It is preferable that at least one kind of transition metal selected among Fe, Ni and Co is further added to the Ag and oxidized by the internal oxidation method so as to make the grains of the matrix of the contact material fine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a contact material in which a metal oxide produced by an internal oxidation method is dispersed in Ag.

[Background technology]

Various contact materials are used in electromagnetic contactors, relays, breakers, etc. These contact materials have low wear and tear;
Characteristics such as << for welding and low contact resistance are required. However, in reality, it is difficult to find a material that simultaneously satisfies these three properties.

Conventionally, Ag-Cd0. Ag-Nt, Ag
-3n02 is often used. Ag-Cd0 has welding resistance properties, AgNi has contact resistance properties, and Ag
5n02 is known as a material with good wear resistance.

By the way, recently, relays have been widely used to control the input and output of circuits or devices. When used to control input, the purpose is to control capacitive loads; when used to control output, the purpose is to control motors, lamps, etc. As a result, a rush current flows through the contacts of the relay, causing problems such as welding of the contacts. In view of these factors, there is currently an increasing demand for contact materials with good welding resistance.

From this point of view, among the above contact materials, Ag-C
Although d0 is excellent, since it uses cadmium, it is undesirable in terms of its toxicity and pollution, and its use tends to be avoided. Therefore, a contact material that does not contain harmful elements and is an alternative to Ag-Cd0 has been desired.

[Purpose of the invention]

In view of the above, an object of the present invention is to provide a method for manufacturing a contact material that can obtain a contact material that has even better welding resistance and does not contain harmful elements.

[Disclosure of the invention]

The inventors have previously described alloys in which small amounts of Li and Ni are added to Ag, i.e. preferably 0, 1
~3 wt% (7) Li and 0.05-1 wt%
A method for manufacturing a contact material was developed in which an alloy with a composition of Ni and the balance being Ag is heat treated in an oxidizing atmosphere to obtain a contact material in which Li and Ni are dispersed in Ag in the form of oxides. In this specification, the process of heat-treating the metal in Ag in an oxidizing atmosphere to form a metal oxide is referred to as an "internal oxidation method". The obtained contact material contained no harmful elements and had good welding resistance. However, compared to those in which Sn oxide is dispersed in Ag, the Li oxide in Ag is thicker (tends to precipitate), so the welding resistance is still not fully satisfactory. It wasn't something.

Therefore, in order to improve the welding resistance of this contact material,
The inventors have repeatedly devised various ideas. They also discovered that if a small amount of Sb (antimony) is included together with Li and both are dispersed in the form of oxides in Ag using an internal oxidation method, Li oxides will become finer and precipitate. With this knowledge, this invention was completed.

Therefore, the present invention provides a contact material in which a metal oxide produced by an internal oxidation method is dispersed in Ag, wherein the metal elements of the metal oxide are Li and Sb,
The metal oxide has Li of 0.1 in terms of metal element.
The gist of the present invention is a contact material characterized in that Sb is contained in an amount of 0.01 to 2 wt%. This will be explained in detail below.

In this invention, the reason why the content of the metal oxide contained in the contact material is defined as described above will be described based on the relationship between the characteristics of the contact material. The content is calculated by converting the metal oxides in all contact materials into metal elements, and adding A
Each amount is calculated as weight % based on the addition of the amount of element g.

The reason for setting the Li content to 0.1 to 3 wt% is as follows. If it is less than 0.1 wt%, not only the desired welding resistance cannot be obtained, but also the wear resistance deteriorates. Even if Ll is contained in excess of 3-t%, Li oxide will precipitate as coarse particles, making it impossible to obtain the desired welding resistance.

The reason why the Sb content is set to 0.01 to 2 wt% is as follows. If 0.01 wt% or more of Sb is contained, Li oxide can be made fine and precipitated. If it is less than 0.01 wt%, there is no effect of making it finer.

If it exceeds 2 wt%, the welding resistance will be impaired. S
Also from the viewpoint of the harmfulness of Sb, it is not preferable for the contact material to contain more than 2 wt% of Sb.

In order to refine the crystal grains of the contact base (matrix), it is desirable to further contain at least one kind of transition metal such as Fe, Ni, or Co, and simultaneously oxidize it by an internal oxidation method.

This is because the presence of the transition metal prevents the growth of crystal grains during internal oxidation, which is thought to contribute to improving the welding resistance and wear resistance.

The content of this transition metal oxide is 0.01 to 1&4t%
is preferred. If it is less than 0.01%vt%, there is no effect of refining the crystal grains of the contact base. If the content is 1 wt% or more, the transition metal oxides will aggregate and the welding resistance will be impaired.

Next, examples and comparative examples will be shown. However, the contact material according to the present invention is not limited to the following examples.

(Examples 1 to 6) Elements such as Ag, Li, Sb, Fe, Ni, and Co were appropriately selected and weighed. It was melted using a high frequency furnace in an argon gas atmosphere, and cast into a mold to produce the following products as shown in Table 1.
6N type alloy ingots with different compositions were obtained. These ingots were annealed by heating in a nitrogen atmosphere. After this ingot is further formed into a plate through a rolling process,
Through a punching process and a molding process, the fixed contact had a shape of φ5, and the movable contact had a shape of φ5×12R. These were heat-treated at 700° C. for 100 hours in an oxygen atmosphere to cause internal oxidation to obtain six types of contact samples.

A for the three pairs of contact samples on each side obtained as above.
An opening/closing test was conducted using an STM type contact testing machine. The test conditions were as follows.

Voltage: AC 100V Current: Rush: 118A, steady state: 2OA Contact force: 100g Breaking force: 150g Number of openings and closings: 10,000 times According to this test method, the welding resistance was evaluated by the number of times welded. In other words, the smaller the number of times of welding, the better the welding resistance. The results of measuring the number of times of welding of the contact samples are shown in Table 1 by taking the average value of three pairs of each example.

As shown in Table 1, it can be seen that all of Examples 1 to 6 using the contact material of the present invention have improved welding resistance compared to Comparative Example 1.

Furthermore, it can be seen that Examples 4 to 6 containing transition metal oxides have better adhesion resistance than Examples 1 to 3 which do not contain transition metal oxides.

Table 1 [Effects of the invention] As detailed above, the contact material according to the present invention has A
Lf oxide and Sb oxide are generated in g by an internal oxidation method, and the content of these oxides is 0.1 to 3 wt% Li and 0.01 to 2 wt% Sb in terms of metal elements.
This is a contact material having the following structure, and by configuring it in this way, it was possible to improve the welding resistance of the contact. Furthermore, since it does not contain harmful Cd, there is no need to worry about contamination during production or use.

Claims (2)

[Claims] (1) In a contact material in which a metal oxide produced by an internal oxidation method is dispersed in Ag, the metal elements of the metal oxide are Li and Sb, and the metal oxide is
A contact material characterized by containing 0.1 to 3 wt% of Li and 0.01 to 2 wt% of Sb in terms of metal elements. (2) As a metal oxide, the metal element is Ni, Co, Fe.
A metal oxide, which is at least one selected from the group consisting of
% of the contact material according to claim 1.