JPS6365740B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a sintered silver-oxide electrical contact material. As is well known, electrical contact materials are desired to have excellent adhesion resistance, dielectric strength and low contact resistance. Conventionally, the main contact materials used have been silver-oxide alloys manufactured by internal oxidation. In some cases, silver-oxide alloys produced by non-powder metallurgy are also used. Silver-oxide based alloys produced by internal oxidation methods include silver-cadmium oxide, silver-zinc oxide, silver-tin oxide, etc., but all of these alloys have different shapes of dispersed oxides due to added elements. The performance has been improved by controlling the oxidation rate and changing the oxide structure. However, in the case of the internal oxidation method, it is assumed that internal oxidation is possible as an added element, and there are restrictions on the structure and amount of the oxide to be dispersed, which naturally limits performance improvement. Another disadvantage is that the size of the dispersed oxide particles differs between the surface and the inside, resulting in a thin oxide part inside, resulting in deterioration of performance. On the other hand, silver-oxide alloys produced by powder metallurgy have the advantage of being able to freely control the amount, shape, type, and degree of dispersion of dispersed oxides, but materials with superior performance have yet to be discovered. Not yet. The present inventors have investigated various reasons why the performance of silver-oxide alloys improved by the internal oxidation method, and have discovered that the structure of dispersed oxide particles greatly contributes to the performance, and have arrived at the present invention. It is ivy. To give an example, the internal oxidation contacts of Ag-15cd-1Sn alloy, as shown in Figure 1, undergo internal oxidation during internal oxidation.
CD ₂ SnO ₄ is formed, the thermal stability of the oxide is improved, and the welding resistance and abrasion resistance are several times better than that of Ag-15CD internal oxidation contacts. The present invention is characterized in that oxide particles containing a composite oxide produced in advance and silver powder are mixed, molded, and sintered to form the same alloy as produced by an internal oxidation method. Furthermore, according to the present invention, the structure of the composite oxide can be changed in many ways, and its amount can be controlled freely, and it is also possible to uniformly disperse the oxide, which cannot be done with internal oxidation, making it easy to improve performance. I discovered that it can be measured. The alloy according to the present invention is (1) a silver-oxide based alloy produced by a powder metallurgy method, and is an electrical contact material in which composite oxide particles made of two types of metal elements are dispersed; (2) An electrical contact, which is a silver-oxide alloy manufactured by powder metallurgy and has composite oxide particles made of two of cadmium, tin, zinc, indium, manganese, and antimony dispersed therein. Materials provided. The composite oxide according to the present invention includes crystalline (including solid solution) and amorphous oxides composed of two types of metal elements. The composition of the composite oxide is preferably such that its main constituent elements are cadmium, tin, zinc, indium, manganese, and ammothine. These composite oxides decompose and scatter appropriately when the current is switched on and off, so the temperature rise is kept relatively low, and
This is because it functions to maintain sufficient heat resistance and improve welding resistance. These composite oxide particles have the effect of fundamentally improving welding resistance and insulation resistance. Its composition range is
It is necessary to contain 1 to 20 wt%. This is because if it is less than 1wt%, the dispersion strengthening effect will be small and the welding resistance as a contact will be significantly reduced, and the behavior will be equivalent to that of pure silver.On the other hand, if it is less than 20wt%, the welding resistance will improve but the specific resistance of the contact will decrease. This is because the temperature rises significantly and becomes unsuitable as an electrical contact. In the present invention, it is essential that a composite oxide is contained, but a normal oxide may be dispersed in addition to this. Next, the manufacturing method of this material will be explained. Composite oxide particles can be produced by known methods, namely, a method of mixing oxide powders and heat treatment, a method of incubating a mixture of nitrates, sulfates, carbonates, and chlorides;
It is manufactured by spraying a solution of nitrates, sulfates, carbonates, and chlorides by coprecipitation and then calcination, or by oxidizing an alloy powder. The composite oxide produced by any of these methods is pulverized using a ball mill, an atrider, or a vibration mill to obtain a particle size of -325 mesh. After mixing this powder and silver powder in a predetermined ratio, ball mill,
Mixed by atrider or vibrating mill,
The material of the present invention in which the composite oxide is dispersed in the silver base can be obtained by molding and sintering this mixed powder and then processing it into a desired shape by extrusion, molding, or rolling. Next, the present invention will be explained in more detail with reference to Examples. Example 1 Oxide powder and salt were mixed in the proportions shown in Table 1, mixed in a ball mill for 20 hours, and then heat treated under the conditions shown in Table 1 to obtain a mixed powder. After pulverizing these powders in a ball mill for 20 hours, X-ray diffraction analysis of the powders revealed that a composite oxide was formed as shown in Table 1. Representative X-ray diffraction results are shown in FIGS. 2 and 3. Example 2 The powder obtained in Example 1 and -325mesh electrolytic powder were mixed in the proportions shown in Table 2, and then mixed in a vibrating mill for 20 hours. The obtained mixed powder was molded at 2 tons/cm ² and then sintered at 700° C. in air for 20 hours. This sintered body is extruded into 84. Extrusion conditions are 700℃, extrusion speed 20
mm/sec. The results of X-ray diffraction of this extruded body are shown in Figures 4, 5, 6, 7, and 8.
As shown in the figure. This extruded rod was drawn to a diameter of 2.4φ, and a rivet contact of 5φ×1.4×2.5φ×2.5×30R was obtained by header processing. Example 3 The riveted contact obtained in Example 2 was assembled into a commercially available safety breaker, and under the conditions shown in Table 3, a temperature rise after overload-durability test and an overload-short circuit test were conducted to determine dielectric strength and welding. The number of times until The results are shown in Table 4. Also, for comparison, Ag-10% by internal oxidation method
Contacts made under the same conditions as Example 2 using cdo and simple oxide powder were added. The composition of the comparative material is as shown in Table 2. These results show that the contact of the present invention in which a composite oxide is dispersed in silver using a powder metallurgy method is different from the contact in which each oxide is simply dispersed, or the Ag- It is clear that it has a good balance of welding resistance, insulation resistance, and low contact resistance characteristics compared to 10% CDO. Thus, the material of the present invention exhibits excellent performance, especially as an electrical contact material for medium currents, and has great industrial value.

[Table] (Note) Number 6 is a missing number.

[Table] Table 3 Temperature rise Overload test AC220V, 150A, power factor 0.8 Test Opening and closing times 50 times Endurance test AC220V, 20A, opening and closing times 5000 times After the above test, measure the temperature rise Short circuit test After overload test, AC220V , 1500A, power factor 0.75, 1 pole 0 → CO ⇒ 2 poles 0 - CO ⇒
Repeat until the 2-electrode CO is welded.

【table】 [Brief explanation of drawings]

Figures 1, 2, 3, 4, 5, 6, 7, and 8 are all charts showing X-ray diffraction results for explaining the present invention.

Claims (1)

[Claims] 1 A silver-based dispersed alloy containing composite oxide particles of 1 wt% or more and 20 wt% or less consisting of two types of metal elements, uniformly dispersed, and containing cadmium, tin, zinc, indium, or manganese. ,
A sintered electrical contact material characterized by being a composite oxide consisting of two types of antimony.