JPS6029439A - Electrical contact point material - Google Patents

Abstract

PURPOSE:To provide a sintered material for a contact point which is improved in resistance to welding, has approximately the same contact point performance as that of an AgCdO material and is inexpensive by incorporating a specific amt. of Cu and C in an AgNi sintered material. CONSTITUTION:A sintered material for an electrical contact point consists of 10-30% Ni, 1.7-10% Cu, 0.1-0.5% C and the balance Ag. The material is considerably improved in resistance to welding as compared to the conventional sintered AgNi material and exhibits approximately the same resistance to welding as that of a sintered AgCdO material. The contact resistance thereof increases if Ni is added to Ag but the contact resistance can be made smaller than that of the AgCdO material by adding Cu and C in combination and sintering the material while allowing both of Cu and C to coexist. The resistance to consumption is slightly inferior to that of the AgCdO material but the difference is too small to be of a problem in practical use. The material relating to this invention permits a reduction in the content of costly Ag as compared to the AgCdO material and does not contain harmful Cd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrical contact materials, and in particular to a sintered material for electrical contacts that has excellent welding resistance and is harmless.

Conventionally, AgCd0-based sintered materials, which have been widely used as electrical contact materials in the medium load range, have excellent contact performance, but because they are made from harmful CCl, they contain CCl during the manufacturing process and during use. There is a risk that it will turn into dust and cause pollution, and it also has the disadvantage of being high in cost due to the high Ag content.

In the north, 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 AgCd0-based materials.

The object of the present invention is to improve the welding resistance, which is a drawback of conventional AgNi-based sintered materials, and to provide an inexpensive single-gas contact material that has almost the same contact performance as AgCd0-based electrical contact materials. is U-like.

The essence of the present invention is Ni1O-30%, Cu1.7-10
%, C1), 1 to 0.5%, with the remainder essentially consisting of Ag and unavoidable impurities.

To explain the reason for limiting the composition of the sintered material for electrical contacts according to the present invention as described above, Ni is added to improve wear resistance, but if Ni is less than 10%, Since this effect cannot be obtained and the contact resistance increases if it exceeds 30%, it is set at 10 to 30%. Cu is added to improve contact resistance and Ni dispersibility; if the amount added is less than 1.7%, no improvement in Ni dispersibility is seen, and if it exceeds 10%, welding resistance deteriorates. So 1
It was set at 7 to 10%. In addition, C is added to improve welding resistance, and if the added amount ζ() is less than 1%, the effect of addition will not be fully achieved, and if it exceeds 0.5%, the processability will deteriorate. Therefore, it was set to O, 1 to 0°5%.

The sintered material for electrical contacts according to the present invention having the above-mentioned composition has greatly improved adhesion resistance compared to conventional AgNi-based sintered materials, and has almost the same resistance as AgCdO-based sintered materials. In addition, regarding the contact resistance, adding N1 to AB increases the contact resistance, or by adding CL1 and C together and sintering them while coexisting, A g Cd
It can be made smaller than the O type. Furthermore, in terms of abrasion resistance, although it is slightly inferior to that of the A3Cd○ series, the difference is not so great as to cause a practical problem. Moreover, the sintered material for electrical contacts according to the present invention can be produced at a low cost because it can reduce the A8 content compared to the A gCd O-based sintered H material, and it does not contain harmful Ccl, which is a cause of pollution. It will never happen.

The sintered material for electrical contacts uses A? :, N1,
Using fine powders of Cu and C, these were blended in a predetermined ratio, and after pressure molding, 700~80% (
It is manufactured by a method of sintering at 1'C for 1 to 20 hours.

Further, after sintering, it is preferable that the sintered body is subjected to reprocessing such as zaining or coining.

As the raw material powder, powders having a particle size of 0.1 to 103μ, preferably 0.5 to 20μ can be used, but commercially available powders can be used as they are.

Examples of the present invention will be described below.

The raw material powder of the example was A8 powder (average particle size: ], f, ) 8 μ)
70 times overheating, Ni powder (average particle size: 2.2μ) 19.
7% by weight, Cu powder (average particle size: 5μ) 10% by weight,
C powder (average particle size: 5μ) (mixed at a ratio of 1.3% by weight and mixed uniformly in a ball mill, and the mixed powder was
diameter 2 (l bun, length 30
tn+. The obtained molded body was heated and sintered at 75° C. in an inert gas atmosphere for 2 hours to obtain a sintered body for an electrical contact. This sintered body is 7 (10 to 5 (1 (1
After heating the product to 1000 m and forming it into a rod-shaped body with a diameter of 6 nm using an extruder, it was processed using a wire drawing header to incorporate an eyebrow contact as a relay, and a test product was obtained.

Comparative Example 1 Using powders of Ag and C (10) used in Examples as raw materials, a sintered body of Ag-12%CdOH- was obtained in the same manner as in Examples, used as a contact, and incorporated into a relay. This was used as a sample.

Comparative Example 2 Using the Ag 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 AgNi-based sintered body was obtained in the same manner as in the examples to be used as a contact. This was incorporated into a relay and used as a test product.

The contact resistance, abrasion resistance, and welding characteristics of the relays obtained in the Examples and Comparative Examples were measured under the following conditions.The results are shown in the table. The table is based on the number of relays whose contact force was 5 g or less when the relays were opened and closed several times.

[Test conditions] Sample: 5 relays (2C) each Voltage: ACIIIOV Current near A Load: Resistance load contact crab Initial 20-3 () 8 Opening/closing degree: 30 times/min 1 Table 11 Contact resistance Wear resistance Welded life (IIIΩ) (pcs) (distance) Example 32 3 42 Comparative example 136 0 45 Comparative example 2 67 1 34 As is clear from the results shown in Table 1, the electrical contact material according to the present invention has the following properties: Compared to Comparative Example 2, the smear resistance was improved in terms of strength, and the properties were almost the same as those of Comparative Example 1. Further, regarding the contact resistance, it exhibited superior characteristics compared to Comparative Examples 1 and 2.

Furthermore, regarding wear resistance, Comparative Example 1 and Comparative Example 2
It can be seen that although the difference is slightly inferior to that of

Procedural amendment (voluntary) 1 Indication of case Patent application No. 139143 filed in 1982 Relationship with case 3 Person making the amendment Patent applicant Address 10 Hanazono Tsuchido-cho, Ukyo-ku, Kyoto-shi, Kyoto Representative Takao Tateishi 4 Agent ``One person, one military spirit, one instruction book material,'' said the five old men and one sword.

Claims (1)

[Claims] (1) Ni 10-30%, Cu 1.7-10%,
A sintered material for electrical contacts consisting of CO, 1 to 0.5%, the remainder substantially Ag and unavoidable impurities.