JPS6029404A - Manufacture of electrical contact material - Google Patents

Abstract

PURPOSE:To improve the welding resistance by sintering a molded body of powder consisting of prescribed percentages of Ni, Cu oxide, C and Ag in a neutral or reducing atmosphere. CONSTITUTION:A powdery mixture consisting of 10-30% Ni, 1.7-10% (expressed in terms of Cu) Cu oxide, 0.1-0.5% C and the balance Ag is press-molded. The molded body is sintered in a neutral or reducing atmosphere. At least a part of the Cu oxide is reduced during the sintering, and it forms a solid solution in the Ag and Ni in the form of metal. Thus, the welding resistance of the resulting electrical contact material is improved.

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing an electrical contact material, and more particularly, to a method for manufacturing a harmless sintered material for electrical contacts with excellent welding resistance. Conventionally, it has been widely used as an electrical contact material in the medium load range! XgCdO-based sintered materials have excellent contact performance, but since they are made from harmful CD, there is a risk that they will generate dust containing CCl during the manufacturing process and use, causing pollution. It also had the disadvantage of being expensive due to its high content. On the other hand, Ag is used as a harmless electrical contact material that does not contain Cd.
Although Ni-based sintered materials have been put into practical use, this AgNi-based sintered material has a problem in that it is inferior in welding resistance compared to Ag Cd O-based materials. The present invention improves the welding resistance, which is a drawback of conventional AgNi-based sintered materials, and makes it possible to manufacture inexpensive electrical contact materials that have contact performance equivalent to or better than ABCClO-based electrical contact abrasives. The purpose is to The gist of the present invention is that Ni1O~30%, Cu oxide CL
After pressure-molding a mixed powder consisting of 167-10% IFA, 1-0.5% C, and the remainder substantially Ag, it is sintered in a neutral or reducing atmosphere, and the oxides are A method for producing an electrical contact material, characterized in that at least a portion of the material is reduced to form a solid solution in 88 and Ni in the form of a metal. To explain the reason why the composition of the sintered material for electrical contacts according to the present invention is limited as described above, N1 is added to improve wear resistance, but if Ni is less than 10%, this effect is not achieved. 30 again
If the content exceeds 10%, the processability deteriorates, so the content was set at 10 to 30%. Cu oxide is added to improve the contact resistance and the dispersibility of Ni, and if the amount added is less than 1.7% in terms of metal Cu, no improvement in the dispersibility of N1 is observed.
If it exceeds 10%, the welding resistance will deteriorate, so it should be 1.7 to 10.
%. In addition, C is added to improve welding resistance, and if the amount added is less than 0.1%, the effect of addition will not be fully achieved, and if it exceeds 0.5%, processability will deteriorate. Therefore, it was set at 1 to 0.5%. The electrical contact material according to the method of the present invention having the above-mentioned composition has greatly improved welding resistance compared to conventional AgNi-based sintered materials, and exhibits welding properties equal to or higher than that of AgCd0-based sintered materials. Regarding the contact resistance, adding Ni to Ag increases the contact resistance, but by adding Cu oxide and C together and sintering them while coexisting, it can be made smaller than that of the A g Cd O type. be able to. Furthermore, in terms of wear resistance, although it is slightly inferior to that of the AgCd0 series, the difference is not so great as to cause a practical problem. Moreover, the electrical contact material according to the method of the present invention has a
Because it can be produced cheaply by reducing the g content,
Since it does not contain harmful Cd, it does not cause pollution. According to the present invention, the electrical contact material contains Ag as a raw material.
, Ni, Cu oxide, and C fine powders are mixed in a predetermined ratio, and after pressure molding, decomposed ammonia gas (
It is produced by a method of sintering at 700-800°C for 1-20 hours in a reducing atmosphere such as N2 + 82). This is because at least a portion of the oxide is reduced and solid-solved in Ni, and the Ni alloy is refined, so that finer N1 alloy particles can be dispersed in the Ag matrix. . Further, after sintering, it is preferable that the obtained sintered body is subjected to reprocessing such as scissoring and finning. As the raw material powder, powders having a particle size of 0.1 to 103 μm, preferably 0.5 to 20 μm can be used, but commercially available powders may be used as they are. Examples of the present invention will be described below. Example raw material powder was Ag (average particle size: 1.08μ) 70% by weight
, Ni (average particle size: 2.2μ) 19.7% by weight, Cu2
0 (average particle size: 5μ) 10% by weight (Cu conversion), C (
Average particle size: 5μ) 0.3% by weight was mixed uniformly in a ball mill, and the mixed powder was molded under a pressure of 4t/Cm2 to a diameter of 20IOI11 and a length of 30+n+n. The body is placed in a reducing gas atmosphere (N 2 +
82) for 2 hours at 750°C to obtain a sintered body for electrical contacts. This sintered body was heated to 700-800°C and formed into a rod-shaped body with a diameter of 6 + n + 0 using an extruder, and then processed with a wire drawing header and the resulting contacts were assembled into a relay and used as a test product. . Comparative Example 1 Using the powders of Ag and CdO used in the examples as raw materials, a sintered body made of Ag-12%CdO was obtained in the same manner as in the examples and used as a contact, and this was incorporated into a relay to make a sample. And so. Comparative Example 2 Using the AgB and Ni powders used in the examples as raw materials, they were mixed at a weight ratio of 70% Ag and 30% Ni, and an ABNi-based sintered body was obtained in the same manner as in the examples to form a contact. This was incorporated into a relay and used as a test product. Comparative Example 3 Raw material powder A used in the example and N1 were combined with metal CLI and C 70%, Ni 19.7%, Cu metal powder (average particle size: 5μ) 10%, C (average particle size :5μ
) A sintered body was obtained as a contact point in the same manner as in the example, and this was incorporated into a relay as a sample. The contact resistance, abrasion resistance, and welding properties of the specimens obtained in each of the Examples and Comparative Examples described above were measured under the following conditions. The results are shown in the table. The wear resistance is expressed as the number of relays whose contact force was 5 g or less after 350,000 opening and closing operations. [Test conditions] Sample: 5 relays (2C) each Voltage: AC220V Current: 4A Load: Resistance load contact crab Initial 20-30g Opening/closing frequency: 30 times/min

[Table 1] Contact resistance Wear resistance Welding life (IIIΩ) (units) (distance) Example 32 2 47 Comparative example 1 41) 1 4.5 Comparative example 2 70 2 38 Comparative example 3 50 2 43 In Table 1 As is clear from the results shown, the electrical contact material according to the present invention has significantly improved adhesion resistance compared to those of Comparative Example 2 and Comparative Example 3, and exhibits properties equivalent to or better than those of Comparative Example 1. There is. Furthermore, it can be seen that the contact resistance is superior to all comparative examples. However, the wear resistance is equivalent to Comparative Example 2 and Comparative Example 3, and compared to Comparative Example 1.
It can be seen that, although it is slightly inferior to that of Patent applicant Tateishi Electric Co., Ltd.

Claims (1)

[Claims] (1) Ni 10-30%, Cu oxide 1 in terms of Cu
．． 7-10%, C0.1-0.5%, remainder substantially Ag
After press-molding a mixed powder consisting of the following, it is sintered in a neutral or reducing atmosphere, and at least a portion of the oxide is reduced to form a solid solution in Ag and Nl in the form of a metal. A method for producing a featured electrical contact material.