JPS6120090B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an Ag--Ni electrical contact material. Conventionally, Ag-Ni electrical contact materials have been used for relay contacts that can be opened and closed several tens of thousands of times, and are known as contact materials that have better welding resistance than Ag or Ag alloys. There was a drawback that initial welding of less than 10 times was likely to occur. In order to eliminate this cause, we observed a large number of initial welds and found that initial welds differed depending on the distribution and oxidation state of Ni in the surface layer. In other words, comparatively large Ni particles were scattered in the surface layer of the contact material that had undergone initial welding, and the Ag particles in the matrix were welded together, whereas relatively small Ni particles were dispersed in the material that did not undergo initial welding. Was. The present invention was completed as a result of intensive research based on the above knowledge, and its purpose is to reduce initial welding by uniformly dispersing fine metal particles that do not dissolve in Ag in the surface layer. An object of the present invention is to provide a method for manufacturing a Ni-based electrical contact material. The method for producing an Ag-Ni electrical contact material according to the present invention is to apply a composite precipitated particle layer of 1 to 100 μm consisting of Ag and a metal that does not dissolve in Ag to the Ag-Ni electrical contact material.
The adhesion process and the adhering composite precipitated particle layer
This process consists of a step of self-diffusing Ag through heat treatment. In the manufacturing method of the present invention, only Ni, Fe, Co, Mo, and W are used as metals that do not dissolve in Ag. In addition, the composite precipitated particle layer is
A layer in which metals that do not dissolve in Ag are uniformly and finely dispersed. As a method for attaching the composite precipitated particle layer, any one of a wet plating method, a dry plating method, and a thermal spraying method is used. According to these methods,
Since the precipitated particles are fine, Ag and particles that do not dissolve in Ag coexist to form a composite layer. However, in this state, the underlying Ag matrix and the precipitated Ag particles are not integrated, so they self-diffuse through heat treatment, and the Ag precipitated particles are integrated into the Ag matrix. If this self-diffusion process is insufficient,
This is because during use as an electrical contact, it may peel off from the composite layer interface, or precipitated particles that are not dissolved in Ag may aggregate and become coarse, making it impossible to suppress the occurrence of initial welding. The preferred temperature range for heat treatment is 500°C to 900°C. In addition, Ni, Fe,
Metals other than Cr, Mo and W are unfavorable in terms of contact performance. The Ag alloy of the adhesion layer to which these metals were added had excellent welding resistance in the accelerated test described below. The typical structure of the Ag-Ni electrical contact material manufactured through the above process is as shown in Figure 1, starting from the surface.
There are no Ni particles 3 in the Ag matrix 1 up to a depth of 100μ, and the metal particles 2 do not dissolve in Ag.
exhibits a finely dispersed structure. On the other hand, traditional
As shown in FIG. 2, the structure of the Ag--Ni electrical contact material exhibits a structure in which Ni particles 3 are sparsely present in the surface layer. However, in the manufacturing method of the present invention, the thickness of the adhesion layer is set to 1 to 100 .mu.m, because if it is less than 1 .mu.m, it is not effective in reducing the initial welding, and if it exceeds 100 .mu.m, it takes time and effort to manufacture. Next, an example of a specific manufacturing method of the present invention will be described. Example 1 Ag and Ni were simultaneously vacuum-deposited at 3 μ, 10 μ, and 80 μ on the contact surface of an electrical contact material of Ag-20 wt% Ni, and then maintained at 900°C for 24 hours in an N ₂ atmosphere to remove the deposited layer. Ag was sufficiently self-diffused. Example 2 Ag and Fe were vacuum-deposited at 1 μ, 10 μ, and 80 μ at the same time on the contact surface of Ag-10 wt% Ni electrical contact material, and then held at 600°C in a vacuum of 5 × 10 ^-3 mmHg for 12 hours. Ag in the adhesion layer was sufficiently self-diffused. Example 3 After spraying 3μ, 10μ, and 80μ of Ag-5wt% Mo onto the contact surface of an electrical contact material made of Ag-20wt% Ni, the adhesive layer was maintained at 800°C for 6 hours in an Ar atmosphere. Ag was sufficiently self-diffused. Example 4 Ag and Cr were vacuum-deposited at 3 μ, 10 μ, and 80 μ at the same time on the contact surface of an electrical contact material of Ag-10 wt% Ni, and then held at 500°C in the atmosphere for 1 hour to remove the Ag in the deposited layer. Enough self-diffusion. Example 5 Ag and Co were vacuum-deposited at 3 μ, 50 μ, and 100 μ at the same time on the contact surface of an Ag-10 wt% Ni electrical contact material, and then held at 800°C for 6 hours in an Ar atmosphere to remove the Ag in the deposited layer. self-spread. Example 6 Ag and W were vacuum-deposited at 3 μ, 50 μ, and 80 μ at the same time on the contact surface of an Ag-10 wt% Ni electrical contact material, and then held in the atmosphere at 700°C for 30 minutes to remove the Ag in the deposited layer. Self-spread. Comparative Examples 1 to 7 Corresponding to each example, Ag-10wt%Ni or
After vacuum-depositing composite precipitated particle layers of 0.5μ and 200μ of each example on the contact surface of Ag-20wt%Ni electrical contact material, the layers were held at 800°C for 6 hours in an Ar atmosphere to remove the Ag in the deposited layer. Comparative Examples 1 to 7 were prepared by self-diffusion. However, in order to clarify the effects of the method for producing Ag-Ni-based electrical contact materials according to the present invention, each electrical contact material made from the electrical contact materials of Examples 1 to 6 and the electrical contact materials of Comparative Examples was tested. An accelerated test was conducted on 72 units under the test conditions below, and the results for the number of units in which initial welding occurred after opening and closing less than 10,000 times were as shown in the table below. The table below also shows the test results of electrical contacts made of Ag-10 wt% Ni and Ag-20 wt% Ni as conventional examples.

【table】

[Table] Here, the number of times of opening and closing refers to the number of times the product was opened and closed before welding. If welding occurred, the number of times was displayed and the process ended. If welding did not occur even after 10,000 times, "10,001~" was displayed. As is clear from the table above, the Ag-Ni electrical contact material obtained by the manufacturing method of the present invention has an initial welding resistance that is several orders of magnitude better than that of conventional Ag-Ni electrical contact materials. This shows that the method for manufacturing the Ag--Ni electrical contact material according to the present invention is extremely meaningful and therefore exists.

[Brief explanation of the drawing]

Figure 1 is obtained by the manufacturing method of the present invention.
FIG. 2 is a cross-sectional view showing the main part of the structure of an Ag--Ni electrical contact material, and FIG. 2 is a cross-sectional view of a conventional example. 1...Ag matrix, 2...Fine metal particles that are uniformly dispersed and do not dissolve in Ag, 3...Ni particles.

Claims (1)

[Claims] 1 A process of attaching a composite precipitated particle layer of 1 to 100 μm consisting of Ag and a metal that does not dissolve in Ag to the Ag-Ni electrical contact material, and self-diffusion of Ag in this adhered composite precipitate particle layer by heat treatment. A method for producing an Ag--Ni electrical contact material, comprising the steps of: