JPS6320902B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a material used for electrical contacts such as an encapsulated magnetic switch and an encapsulated breaker, and a method for manufacturing the same. Conventionally, silver-cadmium oxide based materials, which have excellent welding and wear resistance, have been used as electrical contact materials for magnetic switches, breakers, etc.; The use of copper-cadmium oxide was considered. However, although copper-cadmium oxide has no problem in welding resistance, its abrasion resistance is significantly inferior to that of silver-cadmium oxide. This is because abnormal heat is generated locally at the time of contact. In other words, when contact begins, current is instantaneously concentrated and flows in the first contact area, causing abnormal heat generation. As a result, the copper crystal grains in that area become coarse.
This is because the copper base deteriorates, and frequent opening and closing causes the copper to flake off into fine flakes and wear out.
This kind of consumption becomes noticeable when used in the medium current range of 10 to 400A. The present invention has been made to solve this problem, and is an electrical contact material for encapsulation that has excellent welding resistance and abrasion resistance equivalent to the expensive electrical contact material for encapsulation made of silver-cadmium oxide. It is an object of the present invention to provide an electrical contact material for encapsulation that is an improved version of the electrical contact material for encapsulation made of copper-cadmium oxide, and a method for manufacturing the same. The electrical contact material for encapsulation of the present invention consists of 5 to 25 w/o of cadmium oxide, 0.01 to 1 w/o of at least one of iron, cobalt, and chromium, and the balance copper. In addition, the manufacturing method of the present invention for making this electrical contact material for encapsulation is to mix cadmium oxide powder and copper alloy powder with at least one of iron, cobalt, and chromium added to cadmium oxide powder and copper with 5 to 25 w/o of cadmium oxide, iron, and cobalt. , at least one kind of chromium is 0.01~1w/o,
It is mixed to a composition such that the remainder is copper, compressed and sintered in a vacuum or inert gas atmosphere, and then molded into the desired shape by repeating plastic processing and heat treatment in a vacuum or inert gas atmosphere. It is characterized by: The electrical contact material for encapsulation of the present invention is made by adding 0.01 to 1 w/o of at least one of iron, cobalt, and chromium to the conventional electrical contact material for encapsulation made of copper-cadmium oxide. amount added
The reason for limiting it to 0.01 to 1 w/o is to prevent the coarsening of crystal grains due to heat generation of the copper base in copper-cadmium oxide, improve the mechanical strength of the copper base, prevent deterioration, and prevent flakes from falling off. To prevent wear and tear caused by
This is because if it is less than 0.01 w/o, there is no effect, and if it exceeds 1 w/o, the workability becomes poor and the material becomes extremely brittle, causing abnormal wear. Furthermore, in the method for manufacturing the electrical contact material for encapsulation of the present invention, the reason why the copper alloy powder to which at least one of iron, cobalt, and chromium is added and the cadmium oxide powder are mixed, compressed, and sintered is as follows. Particles of at least one of iron, cobalt, and chromium are uniformly dispersed in the copper crystal grains, suppressing coarsening of the crystal grains at high temperatures, and then mixed with cadmium oxide powder and compressed and sintered. This is because the copper crystal grains will not grow even if the copper is heated. However, when copper and cadmium oxide powder is mixed with at least one of iron, cobalt, and chromium powder and sintered, the cadmium oxide dispersed in the copper inhibits the dispersion of iron, cobalt, and chromium, and the copper The crystal grains grow and the mechanical strength deteriorates. In order to clarify the effects of the electrical contact material for encapsulation of the present invention and the method for manufacturing the same, electrical contacts for encapsulation made from the electrical contact material for encapsulation of specific examples and the electrical contact material for encapsulation of the conventional example will be described below. This section describes the welding resistance and abrasion resistance of . Example 1 Add 0.58 w/o of Fe to Cu, melt it, spray this molten metal to make a Cu-Fe alloy powder, and then
Cu-Fe alloy powder and CdO powder 10.5w/o are mixed and compressed to make a 30mm□×150mm compacted powder, which is sintered at 830℃ in vacuum, followed by groove rolling and 830℃ in vacuum. Repeat the heat treatment, and when it becomes a 9mm square bar, heat treat it at 830℃ in vacuum, and repeat the swaging process and heat treatment at 830℃ in vacuum until it reaches 8.5mmφ, and make a 8.5mmφ Cu-CdO10.5w/o-Fe0.52w. /o. Example 2 Co0.26w/o and Cr0.65w/o are added to Cu and melted, this molten metal is sprayed to make a Cu-Co-Cr alloy powder, and then this Cu-Co-Cr alloy powder and CdO
Mix and compress powder 18.5w/o to 30mm□×150mm
A green compact is made and heated at 850℃ in a nitrogen gas atmosphere.
After repeated groove rolling and heat treatment at 850°C in a nitrogen gas atmosphere, the rod was made into a 9 mm square rod, which was then heat treated at 850°C in a nitrogen gas atmosphere.
Swaging process up to 8.5mmφ and in nitrogen gas atmosphere
After repeated heat treatment at 850℃, 8.5mmφ Cu−
A wire rod consisting of CdO18.5w/o-Co0.21w/o-Cr0.53w/o was made. Conventional example 1 Cu powder 88w/o and CdO powder 12w/o are mixed and compressed to make a 30mm x 150mm green compact, which is sintered at 830℃ in a nitrogen gas atmosphere, followed by trailing groove rolling. Repeated heat treatment at 830℃ in nitrogen gas atmosphere,
At the point where it becomes a 9mm square rod, it is placed in a nitrogen gas atmosphere.
Heat treated at 850℃, swaging process until 8.5mmφ and heat treatment at 830℃ in nitrogen gas atmosphere were repeated to obtain 8.5mm.
A wire rod made of Cu-CdO12w/o with a diameter of mmφ was made. Conventional example 2 Dissolving Cd11w/o and Zn1.6w/o in Ag
Ag-Cd-Zn alloy grains of 2.3 mmφ x 2.3 mm are made and internally oxidized in an oxygen gas atmosphere at 8 atm and 800°C to form Ag-CdO12w/o-ZnO2w/o grains. The grains are compressed, sintered, and extruded, then repeatedly subjected to wire drawing and heat treatment at 700℃ in the atmosphere.
A wire rod made of Ag-CdO12w/o-ZnO2w/o with a diameter of 8.5 mm was made. However, the wire rods of Examples 1 and 2 and Conventional Examples 1 and 2 were cut into lengths of 1.5 mm to obtain 1.2 wire rods made of Cu alloy.
An electric contact for encapsulation is made by brazing to a base material of mmt x 10mmw, and this is assembled into a magnetic switch and connected to a vacuum or an inert gas (N ₂ , Ar, N ₂ -H ₂
Several %, Ar−H ₂ , He, N ₂ −O ₂ several %, Ar−O ₂ ,
An opening/closing test was conducted under the following test conditions in a container filled with CO ₂ , N ₂ −CO ₂ , Ar−CO ₂ , CO ₂ −O ₂ ), in this example a container filled with Ar gas, and the number of welding times of the electrical contact for encapsulation was determined. , the amount of consumption was measured and the results shown in the table below were obtained. Test conditions Fixed contact 8.5mmφ×1.5mmt Movable contact 8.5mmφ×1.5mmt (with 30mmR) Voltage 200V Frequency 50Hz Load Inductive load Current 165A (0.1 seconds) when turned on 33A (1.1 seconds) when turned off Power factor 0.4 when turned on Opening/closing frequency 20 times/min Energization time 0.1 + 1.1 seconds = 1.2 seconds Rest time 1.8 seconds

[Table] As is clear from the table above, the electrical contacts for encapsulation of Examples 1 and 2 are different from those of the conventional example in the medium current range of 165A.
The number of welding is as low as that of the encapsulated electrical contacts, and the amount of wear and tear is even lower. In addition, it has fewer welding times and less wear and tear than the expensive electrical contacts in the conventional magnetic switch, and has excellent welding resistance.
It can be seen that it has excellent wear resistance. As detailed above, the electrical contact material for encapsulation of the present invention is obtained by adding at least one of iron, cobalt, and chromium at 0.01 to 1 w/o to the conventional electrical contact material for encapsulation made of copper-cadmium oxide. Although it is an inexpensive material, it has excellent welding and abrasion resistance equivalent to expensive encapsulating electrical contact materials made of silver-cadmium oxide, so it is an innovative product that can replace it. It can be said to be an electrical contact material for encapsulation. Further, according to the method for producing an electrical contact material for encapsulation of the present invention, there is an advantage that the electrical contact material for encapsulation having excellent welding resistance and wear resistance as described above can be easily produced.

Claims (1)

[Claims] 1. Cadmium oxide in an amount of 5 to 25 w/o and at least one of iron, cobalt, and chromium in an amount of 0.01 to 1 w/o,
Electrical contact material for encapsulation, the remainder of which is copper. 2 Copper alloy powder made by adding at least one of iron, cobalt, and chromium to cadmium oxide powder and copper, with 5 to 25 w/o of cadmium oxide, 0.01 to 1 w/o of at least one of iron, cobalt, and chromium, and the remainder. It is mixed into a composition that becomes copper, compressed and sintered in a vacuum or inert gas atmosphere, and then molded into the desired shape by repeating plastic processing and heat treatment in a vacuum or inert gas atmosphere. A method for manufacturing an electrical contact material for encapsulation, characterized by: