JP2013048095A - Electric contact member not containing silver base material-cadmium composite material having arc consumption resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric contact member not containing a silver base material-cadmium composite material having arc consumption resistance.SOLUTION: An Ag-Cu oxide (oxide) where the occupation ratio of Cu oxide (oxide) in the components is 15-25% is used. Under conditions that the Vickers hardness (Hv) of an electric contact member is 100-150, the measurement current is 1-5 A, and the voltage is 10-20 V, when an electric contact member having a contact resistance of 5-60 mohm (milliohm) and an arc consumption resistance reaching 210-1010times is formed on the metal base material of an electric connector, two electric contacts satisfy the requirement of low contact resistance while maintaining a high hardness, and can maintain the antiwear effect due to arc consumption effectively.

Description

  The present invention relates to the field of electrical contact members, and in particular, an electrical contact not including a silver base material-cadmium composite material having a low contact resistance characteristic and a better arc wear resistance while having a kind of high hardness and wear resistance. It relates to members.

  Electrical contact members are currently used in fields that require operation by various electrical contacts. For example, transmission of communications, system or power supply output control, connection of electronic instruments and peripherals of computers (computers), etc., usually at the moment of operation of an electrical connector or relay switch, before the two electrode contacts are contacted or disconnected In an environment where the distance is small and a high electric field distribution is maintained, current discharge is caused between the two electrodes, and the physical phenomenon of “arc discharge” is caused.

  In general, in the process of arc consumption, a mass transition is caused in a member between two electrodes, and protrusions or depressions are formed on the surface of the electrical contact. Or the surface melts the metal due to arc consumption and solidifies again, forming a rough surface, causing contamination or destruction phenomenon, losing the flatness of the electrical contact surface, increasing the contact resistance, It affects the operation effect of the contact.

In terms of practical operation, traders used platinum early, but platinum is replaced by copper because it is expensive.
However, although copper has advantages such as high conductivity, high heat conductivity, and low cost, a silver base material having the same advantages as copper has been proposed because an oxide is easily formed on the surface of copper.
However, although silver is resistant to oxidation, it is not suitable for a long-time electrical contact member because of its low strength, poor wear resistance, and high arc consumption.
Later, a more economical CdO / Ag contact member was developed by a contractor, which can conduct high electrical conductivity, high heat conductivity, corrosion resistance, and conduct a larger current, and can cope with use of a switch or relay having a large load.
However, Cd has strong toxicity, and the European Union has passed WEEE and RoHS, and the use of electronic products containing highly toxic substances such as Cd and Pb is prohibited.

  FIG. 1A and FIG. 1B show external surface views (No. 1) and (No. 2) of a connector after an arc wear test of a known AuCo electric contact member 500 times, respectively. As is apparent from the figure, the electric contact member of the known technology has a severe damage phenomenon on the surface of the member after the arc wear test is performed 500 times and the product life is deteriorated.

  Based on the above-mentioned limitations and requirements, it was an issue to be improved to propose an electrical contact member that has improved high current, better corrosion resistance, contact member hardness, and meets international non-toxic member regulations.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electric contact member having arc wear resistance having low contact resistance characteristics while having a kind of high hardness and high wear resistance. There is to do.

In order to realize the above-described object, the present invention is designed to have a contact resistance value of 5 to 60 mohm (milliohm) under conditions of Bickus hardness (Hv) of 100 to 150, a test current of 1 to 5 amperes, and 10 to 20 volts. ), The arc wear capacity reaches 2 ^* 10 ³ to 10 ^* 10 ³ times, and when the electrical contact member is used on the surface of the metal base material of the electrical connector, the two electrode contacts have low contact resistance arc wear. Provided is an electrical contact member which does not include a silver base material-cadmium composite material having arc wear resistance with features.

  Among them, the electrical contact member may be a combination of Ag-Cu oxide (oxide) composite material. Furthermore, among them, the ratio of the Ag-Cu oxide (oxide) composite material to the Cu oxide (oxide) component is 15 to 25%.

  The effect of the present invention conforms to the European Union (EC) waste electrical appliance (WEEE) and RoHS regulations, and the contact member is cleared of the requirements of high current conduction, better corrosion resistance and high contact hardness, arc wear It is possible to provide an electrical contact member that does not include a silver base material-cadmium composite material that can effectively reduce the effect, achieve the purpose of low contact resistance, and greatly improve the product life and has a kind of arc wear resistance. .

FIG. 5 is an external surface view (No. 1) of a connector after a 500 times arc wear test of a known AuCo electrical contact member. FIG. 5 is a second external view of the connector after the arc wear test of 500 times by a known AuCo electrical contact member. FIG. 2 is a surface view (No. 1) of an external appearance of a connector of a known art CuCu electrical contact member after 2000 times of arc wear test. FIG. 4 is a surface view (No. 2) of an external appearance of a connector after a 2000 times arc wear test of a known art AgCu electrical contact member. It is a SEM micrograph of the electrical contact member of this invention.

  In order to further understand the content of the present invention, the following description will be described in detail in combination with an experimental table.

At the moment when the electrical contact is disconnected, the current flows from the electrical contact that is conducted a little, but at this time, an arc discharge is caused on the conducted small area, and the density of the flowing current is 5 ^* 10 ⁴ A. / Cm ² . For this reason, the temperature of a contact location rises rapidly, a strong magnetic field is caused, the movement of an electron or a positive / negative ion moves, and it may become a severe arc consumption effect.
Therefore, in order to avoid the occurrence of such a breakdown phenomenon, the electrical contact member has a high conductivity coefficient, reduces the generation of thermal energy due to the passage of current, and prevents softening due to high temperature, thereby affecting the strength of the member. If the contact member has a good heat transfer capability, the heat amount of the electrical contact can be effectively conducted and dispersed, damage due to overheating of the member can be avoided, and the influence of arc discharge can be reduced.
Furthermore, since the electrical contact member is always exposed to various corrosive atmospheres, the electrical contact member is one of the characteristics that require corrosion resistance or oxidation resistance.
This prevents the contact resistance from increasing due to the formation of a non-conductive compound or oxide on the surface of the member, thereby shortening the useful life of the member.
On the other hand, mechanical wear that occurs at the moment of contact or disconnection of an electrical contact may cause damage to the surface of the contact member over time. Therefore, the use of a hard and wear-resistant electrical contact member is one of the requirements.

  However, the physical properties of a member satisfying the above-mentioned requirements for high hardness or wear resistance are accompanied by a high contact resistance value. Accordingly, an object of the present invention is to provide an electrical contact member having the above-mentioned requirements and characteristics that can be effectively applied in various fields by traders. The difference between the physical properties and arc wear resistance of the two types of members of the present invention and the known electric contact members will be described with reference to the following table.

From the previous table, it can be seen that the electrical contact member that does not contain the silver base material-cadmium composite material having arc wear resistance of the present invention does not contain harmful substances and has features that meet internationally recognized standards.
Furthermore, the use of silver as a base material can achieve the above-described demand for a high conductivity coefficient or better heat transfer capability. At the same time, the Vix (registered trademark) hardness value (Hv) of the electric contact member reaches 100 to 150, and the requirement for wear resistance can be effectively realized.
In addition to this, the electrical contact member of the present invention improves the contact resistance associated with good hardness of known members. As described above, the member of the present invention has a low contact resistance value of 5 to 60 mohm (milliohm) at high hardness.
For example, in the case of an Ag—Cu oxide (oxide) composite material, the ratio of Cu oxide to the component is 15 to 25%.
For example, an AuCo alloy is used as an example of a conventional electrical contact member, but the hardness is high, but the cost is high, and the contact resistance value is also high at 50-100 mohm (milliohm). Therefore, the consumption of the member by arc discharge is large.
Furthermore, the experimental operation of the Bix hardness value here can be measured by the following relational expression: Hv = 1.484 ^* P (Kg) / d ² (mm ² ). Of these, the P value is obtained from the load. The d value is obtained by multiplying the load by the load speed.

The arc wear resistance of the member reaches 2 ^* 10 ³ to 10 ^* 10 ³ times, and the service life of the product is greatly improved compared to the arc wear resistance of only 500 times of the known technology.
Therefore, even if the electrical contact member is formed on the surface of the electrical connector, it still has a low contact resistance value and the arc wear resistance is effectively maintained.
Further, the arc wear resistance test experiment shown here is based on a single arc wear test at a constant distance or multiple arc wear tests.
Among them, arc consumption at a constant distance is different from arc consumption many times. The latter is close to a simulation test of damage caused by electrical contact operation that is more practical.
For example, the multiple arc wear test includes continuous arc wear and repeated impact testing of electrical contacts, and the former provides a simpler and faster method of studying arc wear conditions and processes. For example, the cathode and the anode are attached at a fixed distance, and the surface of the member is consumed by a discharge method in which the energy is considerably concentrated, and at the same time, mechanical contact wear is avoided.

FIGS. 2A and 2B are external surface views (No. 1) and (No. 2) of an electrical connector after the arc wear test of 2000 times for the AgCu electrical contact member of the present invention.
As is clear from these figures, after the arc wear test, the surface of the electrical contact member of the present invention still maintains extremely good flatness, integrity and hardness, and is protected from the destruction of the member due to arc wear. Yes.
Next, the SEM micrograph of the electrical contact member of the present invention in FIG. 3 will be described.
In particular, when the cross section is observed with an electron microscope, the member characteristics of the additive of the present invention are uniformly dispersed in the silver base material, the sprayability is strong, and the mechanical wear resistance effect is enhanced.

  The effect of the present invention conforms to the European Union (EC) waste electrical appliance (WEEE) and RoHS regulations, and the contact member is cleared of the requirements of high current conduction, better corrosion resistance and high contact hardness, arc wear Does not contain silver matrix-cadmium composite with a kind of arc wear resistance, which can effectively reduce the effect, achieve the purpose of low contact resistance value, and greatly improve the life of products using various electrical contacts An electrical contact member can be provided.

  What has been described above is a preferred embodiment of the present invention and does not limit the scope of the present invention. Accordingly, any equivalent changes and modifications within the spirit and scope of the present invention by those skilled in the art are also included in the present invention.

Claims (2)

The electrical contact member combined from the Ag-Cu oxide (oxide) composite material has a Bix (registered trademark) hardness value (Hv) of 100 to 150, a measurement current of 1 to 5 amps, and a contact resistance value of 10 to 20 volts. 5 to 60 mohm (milliohm), arc wear resistance reaches 2 * 10 ³ to 10 * 10 ³ times, and this is formed into an electrical contact member,
When formed on the surface of a metal base material of an electrical connector, the two electrical contacts maintain a low contact resistance value while effectively maintaining the arc consumption resistance. An electrical contact member that does not contain a material-cadmium composite material.   2. The silver base material-cadmium composite having arc wear resistance according to claim 1, wherein a ratio of the Ag-Cu oxide composite material to a Cu oxide component is 15 to 25%. Electrical contact member that does not contain materials.