JPS60258437A - electrical contact materials - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver-oxide contact material, in particular a contact material based on silver-bismuth tin oxide, and aims to improve the properties thereof.

Silver-cadmium oxide contacts are widely used as silver-oxide contact materials. Silver-cadvarum oxide contacts exhibit excellent properties on average in terms of contact resistance, welding resistance, abrasion resistance, etc. required of contact materials, and machinability is sufficient for practical use. Therefore, they are often used in load current ranges of several amperes or more, such as relays, no-fuse breakers, and power switches for household appliances. However, in recent years, as safety regulations have become stricter for various power switching devices, more and more characteristics are being required for contact materials. On the other hand, since the silver-cadmium oxide contact contains cadmium in its components, it is likely to become an unfavorable material in terms of manufacturing and general society. - An attempt is made to provide a new contact material that can replace oxidized cadaverum contacts, and basically proposes improvements in the properties of silver-bismuth tin oxide contact materials.

A contact material in which bismuth oxide is dispersed in a silver base is a contact material with low contact resistance and excellent welding resistance, as disclosed in JP-A-52-133669. The problem was found to be a large amount of wear and tear. The inventors conducted various studies to improve this point, and added tin oxide in addition to bismuth oxide to the silver base, and reacted these two oxides to form bismuth tin oxide ( Bi25n20.) and dispersed material (
(Japanese Patent Application No. 52-139309), and furthermore, in addition to tin oxide, oxides such as copper, zinc, and indium are added to improve machinability (Japanese Patent Application No. 1512-1982).
No. 84) (Patent Application No. 53-20073).

These materials show good properties in terms of welding resistance and abrasion resistance, and the latter material in particular has machinability and can be processed into various shapes, making it more practical. It can be said that it is a material. However, while the latter material has improved machinability, the addition of oxides such as copper and zinc may cause contact surfaces to become rough in opening/closing mechanisms subject to large impact forces, or ,
Mechanisms with slow opening/closing speeds tend to have disadvantages such as increased wear.

The object of the present invention is to improve such defects, and to further enhance contact characteristics without impairing machining performance.

The composition of the material of the present invention is a composite material in which at least bismuth tin oxide is dispersed in a silver base, and the constituent metal components are silver, bismuth, tin, indium,
In addition to one or more of the groups consisting of copper and zinc, we have newly added one or more of the groups consisting of magnesium/ium, aluminum, titanium, and rare earth metals (lanthanum, cerium, praseodymium, neodymium) K. Consists of one type. Therefore, the features of the configuration of the present invention are as follows:
The method consists of adding magnesium, aluminum, titanium, or one of rare earth metals to paulownia wood, which was previously developed by the inventors.

Next, the material of the present invention will be specifically explained.

The contact material according to the present invention is a composite contact material in which metal oxide particles are homogeneously dispersed in a silver base.The metal oxide, its effects, and characteristics are summarized as follows. Wax (1) Bismuth tin oxide (Bi2Sn20.) ・
Bismuth oxide (B 120 s ) and tin oxide (SnO, ) were mixed in a molar ratio of 1=2 to 700
By heating at a temperature in the range of 750 to 900'C, it is produced as an oxide with a yellow curb structure.It has a melting point of 1200'C or more and exhibits sublimation. . When this bismuth tin oxide is dispersed in the silver base, the FRR crystallinity is weakened and the degree of 1Φ becomes relatively high even after normal annealing.

This property shows that when used in a switching contact mechanism that has a strong impact force, surface deformation and wear of the contact point are small.

Shun) Indium oxide... It rarely reacts with other contained oxides and rarely inhibits the function of other oxides. In terms of contact properties, an improvement in arc wear resistance was observed, and in terms of dimensions and materials, there was relatively little deterioration in machinability due to addition. Compared to tin oxide, it is less effective in reducing arc consumption, but it has an advantage in machinability. Therefore, it can be used as a partial replacement for tin oxide when more workability is required. In the present invention, since hard oxides such as magnesium, which will be described later, are used, the hard oxides constitute components effective in reducing workability deterioration caused by these.

(3) Via, 7/(copper oxide (tatoe is CuB)
1204).

Bismuth zinc oxide (for example, ZnB1,07)
・Pinomas oxide (B1203) and copper oxide (Cub
) or zinc oxide (ZnO) is produced when heated above 600'C, and is usually bismuth oxide (B1205).
It has a melting point lower than the melting point of 826°C. When these oxides are present, the bismuth tin oxide tends to disperse into the silver matrix and impart recrystallization to the state where the recrystallization has weakened, thereby significantly improving workability. However, the oxide particles become enlarged, and as a result, arc wear resistance decreases, and surface roughness and deformation are more likely to occur in the above-mentioned strong impact contact opening/closing mechanism.

(4) 18 of magnesium, aluminum, titanium and rare earth metals! oxides・These oxides are
By adding it, the effect of improving the welding resistance as a contact material is recognized. -! In addition, it has the effect of making the particles of bismuth copper oxide or bismuth zinc oxide in (2) finer, and tends to reduce the roughness and deformation of the contact surface described above. However, when bismuth copper or bismuth zinc oxides are not added, the workability deteriorates when these oxides are added, for example, cold wire drawing, H-rolling, header processing, etc. It becomes difficult. Therefore, the processing method is hot extrusion, cutting, etc. On the other hand, this difficult-to-process material is characterized by high hardness and less wear and deformation.

(6) In the material of the present invention, in addition to the above-mentioned oxides, depending on the composition ratio, it may not react as a composite oxide, but may be
For example, bismuth oxide (Bi203).

It may exist as tin oxide (SnO2), copper oxide (Cub), or zinc oxide (ZnO). When tin oxide and zinc oxide can exist alone among these oxides, sometimes these oxides react to form 5nZn2o4 with a spinel structure, and silver-oxide The hardness of the material composite material may increase, impeding workability and abnormally increasing contact resistance. When bismuth oxide is present alone among the oxides, the welding resistance is improved, but the amount of wear is increased. On the other hand, when tin oxide is present alone, the opposite tendency is exhibited. Crushed tin oxide has a strong tendency to reduce machinability, even when it exists alone or when it reacts with bismuth oxide, zinc oxide, etc. to form a composite oxide. It is an oxide. Therefore, in order to further improve processability, a portion of tin oxide is replaced with indium oxide to increase the amount of indium oxide. However, in this case, it must be noted that there is a tendency for the surface wearability to be slightly inferior.

As explained above, in the material of the present invention, several types of oxides are finely and homogeneously dispersed in the silver matrix, and in addition to the properties of these oxides alone, several composite oxides are also present. Excellent contact characteristics are obtained through a synergistic effect.

The effective composition range for the material of the present invention is as follows.

When trying to obtain the electrical contact material of the present invention, it is possible to manufacture it by an internal oxidation method as described below.
．． 5-6.0% by weight bismuth, 0.5-4.0% by weight
of tin, 1.0-6.0% by weight indium.

Q.One of the groups consisting of 0.05-1.0% by weight of copper or zinc, and of the group consisting of 0.01-0.5% of magnesium, aluminum, titanium, and rare earth metals. The composition range before internal oxidation is a silver alloy composed of at least one kind and the balance being silver.

In these composition ranges, the respective minimum values indicate the lower limits at which the above-mentioned effects of addition as an oxide are observed. -1 Regarding each maximum value, as the amount of bismuth added increases, the welding resistance improves, but it becomes easier to segregate within the silver alloy.
This is because bismuth oxide exists alone and tends to cause coarse particles, which increases the amount of consumption and makes it impossible to expect desired results. The biggest problem with increasing the addition of tin is that it deteriorates mechanical workability, and if the manufacturing method described below is to be used with emphasis on mechanical workability, the composition must be kept below the above-mentioned composition υ. . Indium is used as a substitute for tin and is added to improve wear resistance and processability, but addition of too much tends to have an adverse effect on both of these properties. The purpose of adding copper and zinc is to impart workability, and they should be limited to the minimum necessary amount. Adding too much may unnecessarily increase arc wear, and cause contact surface roughness and deformation. It only invites

In addition, zinc oxide has disadvantages such as inhibiting processability and increasing contact resistance, as described above, due to the amount of tin oxide. magnesium,
Aluminum, titanium, and rare earth metals make the bismuth and zinc or copper oxides finer, reduce roughness and deformation of the contact surface, and have the effect of improving welding resistance and arc wear resistance. Since these metal oxides are thermally stable and hard, they have the property of causing adverse effects such as increasing contact resistance and reducing machinability, so adding too much is not desirable. For these reasons, the upper limit of each composition is set. Next, a method for producing the material of the present invention will be explained.

The material of the present invention can be manufactured by the same method as that of general silver-metal oxide contact materials.

i.e. silver, bismuth, tin, indium, magnesium, aluminum, titanium, rare earth metals.

It can be manufactured by internally oxidizing an alloy of metal components selected according to the composition of the present invention from metal elements such as copper and zinc. When using the internal oxidation method, the oxidation rate of alloy metal elements is different, and tin is particularly difficult to oxidize, so the heating temperature, oxidizing atmosphere, and heating time must be set to sufficient conditions so that a composite oxide with bismuth oxide is formed. Must be set. Roughly appropriate conditions are: when the oxidizing atmosphere is air, the temperature is 70°C.
The temperature is 0 to 900°C for 20 to 200 hours. The temperature is desirably 750°C or lower when an oxide with a low melting point is produced.

EXAMPLES In order to concretely demonstrate the material of the present invention, examples will be given and explained.

[Example 1] Silver, bismuth, tin, indium, magnene, um, aluminum, titanium according to the composition of the invention.

Metal components selected from rare earth metals, copper, and zinc were melted to produce an ingot containing silver-bismuth-tin as the main component. The amount of melting was 2007, using an aluminum crucible and melting using high frequency E in an argon atmosphere. Regarding some additive metals, aluminum-copper, titanium-copper, minosu metal (lanthanum, cerium, neodymium,
(containing 93% by weight or more of rare earth metals such as praseodymium) was used as the base metal and gold. The molten metal is 16×3
It was cast into a mold of 0x70111M'. The ingot made in this way is immediately rolled to a thickness of 0.2~
Q, 5 M: After crushing into scale-like chips of I, 20
It was loaded into a cylindrical mold with a diameter of 1+1ff and molded at a pressure of 2 tons/Cm2. Next, this molded body was placed in an oxygen stream for 700 minutes.
'C for 20-60 hours to sinter.

At the same time, internal oxidation of the chip was performed. Further, this sintered body was compression molded at a pressure of 8 tons/Cll12, and then sintered in air at 830°C for 5 hours.

This sintered body was subsequently hot extruded at 550'C for 10
It was processed into a cylindrical rod with the same diameter. Thereafter, wire drawing and annealing were repeated to produce a wire rod with a diameter of 6 wires. Finally, the radius of curvature is 7
This was processed into a spherical contact stud and annealed at 700°C for 1 hour. The contact studs thus produced were subjected to a contact opening/closing test described below.

[Example 2] In Example 1 above, the hot extruded cylindrical rod with a diameter of I10 was further hot extruded again into a wire rod with a diameter of 5 mm, and then formed into a spherical contact stud with a radius of curvature of 7 mm. Machined. It was annealed at 7oo'C for 1 hour. Then, it was subjected to the same opening and closing test as in Example 1.

The contact characteristics were evaluated by the number of times of welding during opening/closing 2×10 times and the amount of wear after opening/closing 2×10′ times under the following conditions.

The results are summarized in Table 1.

Opening/closing test conditions (by ASTM type testing machine) Voltage ACl
oQV Current 60A (power factor CO8ψ=1) Contact force 30p Separation force 40f Number of samples 6 pairs Table 1 shows the minimum and maximum values of each characteristic value. Until now, silver-cadmium oxide (
The test results for the internal oxidation method are also shown.

(Left below) As shown in the table, the material of the present invention exhibits superior performance to silver-cadmium oxide contacts in both welding resistance and abrasion resistance, and is likely to have extremely high practical value.

Claims (1)

[Claims] A silver-oxide composite material in which a metal oxide is dispersed in a tin matrix, the metal oxide contained in this material includes at least bismuth-tin oxide, and the composition of the metal components contained is , bismuth 1.5 in metal equivalent value
-6.0% by weight, 0.5-4.0% by weight of tin, 1.0-6.0% by weight of indium, and 0.05-1.0% of one of the group consisting of copper or zinc. weight%,
At least 1f of the group consisting of magnesium, aluminum, titanium, and rare earth metals is 0.
．． An electrical contact material comprising: 0.01 to 0.5% by weight, and the balance being silver.