JPS61284540A - Production of contact point material for vacuum circuit breaker - Google Patents

Abstract

PURPOSE:To produce a contact point material having excellent dielectric strength performance and breaking performance by infiltrating copper at the temp. above the m.p. in a non-oxidizing atmosphere to a porous body obtd. by pressing metallic powder having a high m.p. under the prescribed pressure. CONSTITUTION:The single or plural metallic powders or intermetallic powders having the m.p. of copper are mixed and thereafter the mixture is pressed under the prescribed pressure to obtain a green compact consisting of the porous body. Copper is then infiltrated into the porous body at the temp. above the m.p. of copper and below the temp. at which the sintering of the porous body does not relatively progress in the non-oxidizing atmosphere or reducing atmosphere. The porous body consisting of W alone or consisting essentially of Cr, contg. a slight ratio of Cu as an additive, if necessary, and contg. >=1 kinds among Ti, Zr, Al and Si as the other additives is adequately used for the above- mentioned porous body. The contact point material for the vacuum circuit breaker having the excellent breaking performance and dielectric strength performance, a long electrical life and low welding tripping force is obtd. by the above-mentioned method.

Description

[Detailed Description of the Invention] [Industrial Application Field] This F! A relates to a contact material for a vacuum breaker that has excellent breaking performance and withstand voltage performance, has a long electrical life, and has low welding and pulling force.

[Conventional technology]

Vacuum breakers are rapidly expanding their range of applications because they require no maintenance, are non-polluting, and have excellent breaking performance and withstand voltage performance. Along with this, there is a tendency for the voltage and current at which vacuum breakers are used to increase, resulting in higher withstand voltages and
OtaniRequirements for quantification are becoming more stringent. on the other hand,
The most important factor that affects the performance of a vacuum breaker is the contact material, and the number of excellent contact materials that can be developed will directly lead to the development of an excellent vacuum breaker.

The Cu-W contact materials currently used in gas circuit breakers, oil circuit breakers, and vacuum circuit breakers were initially used in air, and their scope has gradually expanded to oil and gas. Therefore, due to the atmosphere in which it is used, efforts have been made to obtain a very strong porous body in order to prevent the wear and tear of the contact material and micro-destruction. For example, special public Sho 5l-409
The contact material made of Cu-WC-Co described in 4 (18) is pre-sintered at 1400°C in vacuum to obtain this porous body. Regarding the Cu-Cr contact material described in No. 30761, the importance of sintering the compacted powder body (porous body) is also mentioned, and this sintering improves the strength, hardness, toughness, etc. of the contact material. In addition, in Japanese Patent Publication No. Sho 57-2122, a permeable composite metal as a contact material for a vacuum chest occluder and a method for manufacturing the same, Cr-Zr, Cr-Ni, Cr as a porous body is used. -Ti, Zr-
Ni, Zr-Mn at 1500°C, Cr-Mn, T
i -Fe, 'l''i -Ni, Ti-Mn is 1
It is stated that Zr-Ti is sintered at 400°C and sintered at 1650°C.

Also, on the other hand, the metal f! that is infiltrated into the porous body! As an example of using an alloy for i, Cu
-Ti, Cu-Ta%Cu-Zr are mentioned.

[Problem that the invention seeks to solve]

As mentioned above, conventional contact materials for vacuum circuit breakers are manufactured using the conventional powder metallurgy method, which improves properties such as the strength and toughness of the porous body. Among the components constituting the contact, those with lower melting points are selectively melted and evaporated and scattered, leaving a strong porous body, resulting in a decrease in voltage resistance. Furthermore, when additives are added, there is a problem in that the blocking performance is reduced.

This invention was made to solve the above-mentioned problems, and aims to provide a contact material for a vacuum breaker that has excellent voltage resistance and breaking performance when additives are added.

[Means for Solving the Problems] The contact material for a vacuum breaker according to the present invention includes a single or multiple metal powder or intermetallic compound powder having a melting point higher than the melting point of copper in a desired composition ratio of a porous body. A porous body is obtained by weighing and mixing them, filling them into a mold, and pressing at a predetermined pressure. Copper is added to this porous body at a temperature above the melting point of copper and below a temperature at which sintering of the porous body does not progress relatively. It can be obtained by infiltrating it with water.

[Effect]

In the present invention, although a porous body is obtained, it is not sintered at a high temperature, so the porous body is not formed very strongly, so when the current is cut off, the copper and pond components evaporate at the same time. As a result, there is little change in the metal components on the surface of the contact, and less electron emission occurs, resulting in improved withstand voltage performance.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described while comparing them with conventional examples.

(Example 1) W powder with an average particle size of 2.5 μm and Cu with a particle size of 25 μm or less
The powders were weighed at a weight ratio of 95:5 and mixed for 2 hours. Next, fill the mold with a predetermined amount of this mixed powder,
A load of 1 to 4 tons per unit area was applied to obtain a disc-shaped powder compact. This green compact is mixed with oxygen-free copper and 1250 ml of oxygen in a hydrogen atmosphere.
C. to obtain a Cu-W contact material. The final component ratios of the resulting contact material were Cu-69% by weight, WW Cu-76% by weight, Cu-84% by weight, and Cu-90% by weight.
Using four types of W, the amount of pores into which copper penetrates into the green compact was adjusted by changing the load applied when making the green compact.

Thereafter, the contact material was machined into an electrode with a diameter of 2υn, assembled into a vacuum breaker, and electrically tested.

(Conventional example 1) W powder with an average particle size of 2.5 μm and Cu with a particle size of 25 μm or less
Powder? (2) They were weighed at a ratio of 95:5 and mixed for 2 hours. Next, a predetermined amount of this mixed powder was filled into a mold, and a load of 1 to 4 tons per unit area was applied to obtain a disc-shaped green compact. This green compact was sintered in vacuum at 1500°C for 2 hours,
Thereafter, oxygen-free copper was immersed in a hydrogen atmosphere at 1250° C. to obtain a CuW contact material.

The final component ratio of the obtained contact material was Cu-70%W by weight;
There were three types: Cu-76% by weight W and Cu-84% by weight. These contact materials have a diameter of 20 mm as in Example 1.
It was processed into an electrode of m and was incorporated into a vacuum breaker.

A point of consideration between Example 1 of the present invention and Conventional Example 1 is that in the conventional example, the green compact is sintered in a vacuum at 1500°C, whereas in the Example of the present invention, it is not sintered. .

The results of electrical tests on vacuum circuit breakers incorporating these contact materials are shown below. Figure 1 shows the #voltage performance of the Cu-W contact material, where the horizontal axis is the wt% of W and the vertical axis is when the withstand voltage performance of Cu-69wt%W of Conventional Example 1 is taken as 1. Indicates voltage resistance performance. 1 in the figure represents the withstand voltage performance of the contact material of the present invention shown in Example 1, and 2 in the figure represents the withstand voltage performance of the Cu-W contact material shown in Conventional Example 1.

It can be seen from FIG. 1 that the withstand voltage performance of the contact material of the present invention is two to three times better than that of the conventional contact material.

The method for measuring withstand voltage performance is to apply a predetermined voltage with the electrodes separated after switching the load once and check for the presence or absence of discharge, which is repeated several thousand to tens of thousands of times. We used a method to measure the probability of occurrence. The withstand voltage performance of the female example shown in F below was also measured in the same manner. Furthermore, when we measured the voltage resistance performance of these contact materials using a conventional voltage resistance test method called conditioning, we found that there was almost no difference between the conventional example and the example. From this, the method of measuring withstand voltage performance used this time is effective in determining a value close to the withstand voltage performance of circuit breakers actually used.

Figure 2 shows the electrical life of the same Cu-70wt%W of Example 1 and Cu-69wt%W of Conventional Example 1, and shows the relationship between the current interrupting performance and the number of load switching times. There is. The vertical axis shows the breaking performance when the initial breaking performance of Cu-69wt%W of Conventional Example 1 is set to 1, and the horizontal axis shows the number of load switching times.

3 in the figure indicates the electrical life of the contact material of the present invention, and 4t in the figure
/i Shows the electrical life of the conventional example. From FIG. 2, it can be seen that the contact material of the present invention has a lifespan 1.3 times longer than that of the conventional material.

(Example 2) Cr powder with a particle size of 325 mesh or less and Cu powder with a particle size of 25 μm or less were weighed at a weight ratio of 88:12 and mixed for 2 hours. Next, a predetermined amount of this mixed powder was filled into a mold, and a load of 1 to 4 tons per unit area was applied to obtain a disc-shaped green compact. Oxygen-free copper is added to this green compact in a hydrogen atmosphere.
A Cu-Cr contact material was obtained by infiltration at 250°C. The final component ratio of the obtained contact material was Cu-44% by weight Cr% Cu
-65% by weight and Cr.

The contact material was then machined into a 20 m diameter electrode, assembled into a vacuum breaker, and electrically tested.

(Conventional Example 2) Cr powder with a particle size of 325 mesh or less and Cu powder with a particle size of 25 μm or less were weighed in a weight ratio of 88:12 and mixed for 2 hours. Next, a predetermined amount of this mixed powder was filled into a mold, and a load of 1 to 4 tons per unit area was applied to obtain a disc-shaped powder compact. This compact was sintered in vacuum at 1'500°C for 2 hours, and then oxygen-free copper was sintered at 1250°C in a hydrogen atmosphere.
to obtain a CuCr contact material. The final component ratios of the contact materials obtained were two types: Cu-44% by weight and Cu-65% by weight Cr. The diameter of these contact materials is 20
After being machined into m electrodes, it is assembled into a vacuum breaker,
I went to electric test) k.

(Example 3) Cr powder with a particle size of 325 mash or less and a particle size of 350 mes
A Ti powder having a particle size of 25 μm or less and a Cr powder having a particle size of 25 μm or less were weighed at a weight ratio of 88:1:11, and mixed for 2 hours. Next, a predetermined amount of this mixed powder was filled into a mold, and a load of 1 to 4 tons per unit area was applied to form a disc-shaped green compact. Oxygen-free copper was infiltrated into this green compact at 1250°C in a hydrogen atmosphere to obtain a CuCr-Ti contact material.

The final component ratio of the resulting contact material was 10% by weight of Cu-44 and 5% by weight of T1. In addition, by using the same method and changing the initial blending ratio, Cu-44 wt% Cr 0.1
wt% T1, Cu-44 wt% Cr-1 wt% 1, C
u-44% by weight Cr-2% by weight T1, Cu 44% by weight
Cr-3% by weight Ti, Cu-44% by weight Cr-5% by weight
Ti, Cu - 65% by weight Cr - 0.1% by weight Ti, C
u-65 wt% Cr-0.5 wt% Ti.

Cu-65% by weight Cr-1% by weight Ti, Cu-65% by weight Cr-2% by weight T1, Cu-65% by weight Cr-3
A contact material with weight% Ti, Cu-65wt%-5wt% T1 was obtained.

(Conventional Example 3) Or powder with a particle size of 325 mesh or less and Cu powder with a particle size of 25 μm or less were weighed at a ratio of 88:12 and mixed for 2 hours. Next, a predetermined amount of this mixed powder was filled into a mold, and a load of 1 to 4 tons per unit area was applied to obtain a disc-shaped green compact. This green compact was sintered in vacuum at 1500°C for 2 hours. On the other hand, a Cu-Ti alloy was manufactured by a melting method as an alloy to be infiltrated. Prepared Cu-Ti alloy tfiC
u0.2 wt% T1, Cu-1 wt% T1, Cu-2 wt% Ti, Cu-4 wt% T1, Cu-6 wt% T1,
It was Cu-10% by weight T1. These alloys were infiltrated into the previously prepared sintered body at 1250° C. in a hydrogen atmosphere to obtain a contact material. The final component ratio of the contact material obtained was Cu-4
4% by weight Cr-0, 1% by weight T1, Cu-44% by weight C
r-0.5 wt% 1, Cu-44 wt% Cr-1 wt% T1, Cu-44 wt% Cr-2 wt% T1, Cu
-44 wt% Cr-3 wt% T1, Cu-44 wt% C
r-57X amount %T1.

The results of electrical tests on vacuum breakers incorporating the contact materials of Examples 2 and 3 and Conventional Examples 2 and 3 are shown below. Third
The figure shows the breaking performance of the Cu-Cr-Ti contact material, where the horizontal axis shows the amount of T1 added in weight%, and the vertical axis shows the breaking performance of Cu 44% by weight Cr shown in Conventional Example 2. The figure shows the breaking performance of the contact material of the present invention. 5 in the figure indicates Example 3 fl Cu-44 wt% Cr
-'l'' represents the breaking performance of the i contact material, and the T1 addition amount of 0% represents the point on the Cu-44 weight % meter shown in Example 2. 6 in the figure is the same (as shown in Example 3). Cu-65
fi amount% represents the breaking performance of Cr-Ti contact material, T
1 addition amount of 0% represents the point of Cu-65 weight % shown in Example 2. In addition, 7 in the figure is Cu shown in conventional example 3.
-44% by weight Cr--I'i contact material is shown, and the T1 addition amount of 0% represents the point where Cu is 44% by weight as shown in Conventional Example 2. Note that 8 in the figure is a point indicating the breaking property it of Cu-65% by weight Cr shown in Conventional Example 2.

From FIG. 3, it can be seen that firstly, the contact material of the present invention has better breaking performance than the conventional one, and when the Cr content is 44% by weight, the breaking performance is improved by adding T1 to 0.5% by weight. It shows a peak, and shows better breaking performance than the conventional Cu-44 wt% Cr when the Ti amount is in the range of 0 to 5 wt%. Also, when the Cr content is 65% by weight, the T11l addition is 0.5
The blocking performance peaks near the weight % range, and the blocking performance is better than the conventional Cu-65 weight % Cr when the Ti amount is in the range of O to 3 weight %.

Moreover, from FIG. 3, Cu-44 weight %C shown in Conventional Example 3
The breaking performance of r-Ti contact material does not show a sharp peak unlike the contact material of the present invention, and as the amount of T1 added increases, K,
It can be seen that it is decreasing.

(Other Examples) By the same method as Example 3, Cu-Cr-Zr%Cu
-0r-AI, Cu-Cr-8i and CuCr
- A Ti-8i contact material was manufactured, assembled into a vacuum breaker, and tested.

The same powders as in Example 3 were used for Cu and Cr, 7i- had a particle size of 200 mesh or less, AI had a particle size of 350 mesh or less,
The Si used had a particle size of 200 mesh or less.

Figure 4 shows the breaking performance of Cu-Cr-, which is one of the contact materials of the present invention, where the horizontal axis represents the amount of additive, and the vertical axis represents the weight of Cu-44 of conventional example 2. % Breaking performance of contact material? Breaking property Fi! of the contact material of the present invention when used as a standard! , is shown. 9 in the figure represents the breaking performance of the contact material for Cu-44 wt% Cr -, which is one of the contact materials of the present invention, and 10 in the figure represents the same (Cu-65 wt% C
It represents the breaking performance of r-Zr contact material.

From FIG. 4, it is clear that the contact material of the present invention has a better breaking performance than the conventional one, and when the sugar content is 44% by weight, the breaking performance peaks at around 0.1% by weight. , 2Srfi is in the range of 0 to 1.6% by weight, showing better breaking performance than the conventional Cu-44% by weight Cr. Also, when the amount of Cr is 65% by weight, the blocking performance peaks when the amount added is around 0.1% by weight, and when the amount is 0 or ♂r
It shows better breaking performance than the conventional Cu-65% by weight range of Cr.

Figure 5 also shows one of the contact materials of the present invention -Cr-
Shows the breaking performance of AI contact material, horizontal axis td
The amount of At added is represented, and the vertical axis represents the breaking performance of the contact material of the present invention based on the breaking performance of the 44 wt % Cr contact material of Conventional Example 2.

12 in the figure represents the breaking performance of Cu-44wt% Cr-Al contact material, which is one of the contact materials of the present invention, and 13 in the figure
represents the breaking performance of the same <Cu-65 wt% Cr-Al contact material.

From FIG. 5, it is clear that the contact material of the present invention has better breaking performance than the conventional one, and when the contact material is 44% by weight, the breaking performance peaks when the amount of AI added is around 0.3% by weight. , conventional Cu-4 with an M amount in the range of 0 to 2% by weight.
It shows better breaking performance than 4% by weight. Also, Cr
Even when the amount of Al is 65% by weight, the breaking performance peaks when the amount of Al added is around 0.3% by weight, and when the amount of Al is 2% by weight from O
In the range of 65 wt % Cr, it shows better breaking performance than the conventional 65% Cr.

Figure 6 also shows -Cr- which is one of the contact materials of the present invention.
This shows the breaking performance of 8i contact material, and the horizontal axis is Sl
The vertical axis represents the breaking performance of the contact material of the present invention based on the breaking performance of the contact material of Conventional Example 2 containing 44% by weight.

14 in the figure represents the breaking performance of Cu-44wt% Cr-81 contact material, which is one of the contact materials of the present invention, and 15 in the figure
are the same (representing the breaking performance of Cu-65 wt% Cr-81 contact material).

From FIG. 6, it can be seen that the contact material of the present invention has a better breaking performance than the conventional one, and when the Cr content is 44% by weight, the breaking performance shows a gentle peak around 0.5% by weight when the 5iiK addition is 0.5% by weight. It shows better breaking performance than the conventional Cu-44 weight % Si content in the range from 0 to nearly 5 weight %. In addition, when the ω amount is 65% by weight, the 5ill addition is 0.5]1 (the breaking performance shows a gentle peak around the amount %, and the S1 amount produced in this experiment is 5% by weight). It showed better breaking performance than the conventional Cu-65 wt% Cr.

Figure 7 shows Cu-Cr, which is also one of the contact materials of the present invention.
-It shows the breaking performance of Ti-Si contact material, and since the components are four elements, it is expressed in the form of adding 81 to Cu-Cr-'I''i.The horizontal axis shows the amount of Sl added. The vertical axis shows the breaking performance of the contact material of the present invention based on the breaking performance of the Cu-44][amount% needle contact material of Conventional Example 2. In the figure, 16 indicates the breaking performance of the contact material of the present invention. 17 represents the breaking performance of the Cu-44wt% Cr-0.1wt% Ti-Si contact material, and 17 in the figure also shows the breaking performance of the Cu-44wt%Cr-0.1wt%Ti-Si contact material.
Weight % Cr -0.5 weight % Ti-Si represents the breaking performance of the contact material, 18 in the figure is Cu-44 weight % Cr-1
% by weight represents the breaking performance of the Ti-8L contact material.

From FIG. 7, it can be seen that the contact material of the present invention has better breaking performance than the conventional one, and when the Ti amount is within the range of 1% by weight and the 81 amount is within the range of O to 5% by weight, It can be seen that it exhibits better properties than the conventional Cu-44 weight % □□□ contact material.

Further, as the electrical performance of the contact materials of the present invention in Example 2 and below, the withstand voltage performance was also measured in the same manner as the Cu-W contact material of Example 1. An example of the eighth factor is Cu-Cr-S
The withstand voltage performance of the i-contact material is shown. The horizontal axis represents the addition amount 2 of risi, and the vertical axis represents the conventional example Cu-44 wt%CC
It shows the withstand voltage performance of the contact material of the present invention based on the withstand voltage performance of the contact material.

In the figure, 19 represents the withstand voltage performance of the Cu-44 wt% Cr-Si contact material, and 20 in the figure represents the Cu-65 wt% Cr-
It represents the voltage resistance performance of Si contact material.

From FIG. 8, it can be seen that the contact material of the present invention has superior voltage resistance performance than the conventional one, and the performance increases up to 2% by weight with the addition of Sl, and thereafter the performance decreases. However, in this experiment, the amount of I/iSi added was up to 5% by weight, and within this range, the performance exceeded that of conventional products. In addition, the withstand voltage performance was also measured for the contact materials shown in the examples, such as Ti and Zr%A/. As a result, it was found that the withstand voltage performance of all contact materials was improved by adding T1, etc. (7
) However, similar to the Cu-Cr-8i contact shown in Fig. 8, the one that showed performance around 1.5 times was the Cu-Cr-
Only for the Ti-8i contact material, the other materials were about 1.2 times as large.

A possible reason for the improved breaking performance of the contact material of the present invention compared to conventional materials is that additives such as T1 are added at the time of powder mixing, this mixed powder is compression molded, and then the successor is infiltrated. As a result, by not using a copper alloy as an immersion material as in the past, all additives do not dissolve into the copper in the finished contact material, suppressing a decrease in the electrical conductivity of the contact material. It has become. It is currently unknown what effect additives such as T1 have on the barrier performance, but similar experiments conducted by the inventors have shown that Co
, Fe, Ni, AjF, etc., had no effect on the breaking performance.

On the other hand, the reason why the contact material of the present invention exhibits excellent withstand voltage performance is due to the sintering of the green compact, which has been conventionally said.
It was believed that improving the strength of the sintered body was necessary to improve the strength and other performance of the completed contact material, but when used as an actual vacuum breaker to handle electric current, the porous body became strong. Therefore, the material with a relatively low melting point selectively evaporates and scatters, and the surface of the contact material becomes rich in porous components, making it easier to emit thermoelectrons. It does not form a porous body, and as a result, when the current is turned on and off, the peaks and other components are scattered together, so there is little change in the composition on the surface of the contact material, and the proportion of thermionic emission is lower than that of conventional products. is possible.

In addition, since the porous body is not strongly formed, even if welding occurs, the porous body easily separates.This also has the advantage that the welding force is reduced to about the same strength as the conventional one. Also confirmed.

On the other hand, in terms of manufacturing, the sintering process is omitted, significantly reducing manufacturing time and costs. In addition, there is almost no change in the dimensions of the porous body during green compact molding and after iIn infiltration, and unlike conventional products, the porous body shrinks during the sintering process, resulting in a change in porosity. It also has the advantage of eliminating the difficulty of understanding conditions.

〔Effect of the invention〕

As described above, according to the present invention, a contact material for a vacuum breaker is prepared by weighing one or more metal powders or intermetallic compound powders having a melting point higher than the melting point of copper in accordance with the desired component ratio of the porous body. After mixing, a porous body was obtained by filling a mold and pressing at a predetermined pressure so that the desired porosity was obtained, and by infiltrating copper into this porous body. This has the effect of providing a contact material for a vacuum breaker with excellent performance and withstand voltage performance.

[Brief explanation of drawings]

Fig. 1 is a graph showing the withstand voltage performance of the he-W contact material manufactured according to one embodiment of the present invention, wjZ diagram is a graph similarly showing the electrical life, and Fig. 3 is a graph showing the electrical lifespan of the he-W contact material manufactured according to another embodiment of the present invention. Figure 4 is a graph showing the breaking performance of the Cu-Ti contact material made according to another embodiment of the present invention.
A graph showing the breaking performance of u-Cr-Zr contact material, FIG.
- A graph showing the breaking performance of AI contact material, Figure 6 shows the Cu-CrSi fabricated according to the embodiment of the present invention.
A graph showing the breaking performance of the contact material, FIG. 7 is a graph showing the breaking performance of the Cu-Cr-Ti Si contact material manufactured according to the embodiment of the pond of the present invention, and FIG. 8 is a graph showing the breaking performance of the Cu-Cr-Ti Si contact material shown in FIG. 6. It is a graph showing the withstand voltage performance of -81 contact material.

Claims (1)

[Claims] 1) A step of mixing one or more metal powders or intermetallic compound powders having a melting point higher than the melting point of copper and then pressing at a predetermined pressure to obtain a porous body; A method for producing a contact material for a vacuum shield or disconnector, comprising the step of infiltrating copper in an oxidizing or reducing atmosphere at a temperature above the melting point of copper and below a temperature at which sintering of a porous body is relatively slow. 2) The method for manufacturing a contact material for a vacuum shield or disconnector according to claim 1, characterized in that tungsten is used as a component of the porous body. 3) A contact for a vacuum shield breaker according to claim 1, wherein the porous body contains chromium as a main component and at least one of titanium, zirconium, aluminum, and silicon as an additive. Material manufacturing method 4) The porous body is characterized in that it contains chromium as a main component, a small amount of copper as an additive, and at least one of titanium, zirconium, aluminum, and silicon as other additives. A method for manufacturing a contact material for a vacuum shield breaker according to claim 1. 5) The vacuum chamber according to claim 1, item 3 or 4, characterized in that the contact material contains titanium, zirconium, aluminum, and silicon in an amount of 5% by weight or less each. Method for manufacturing dexterous contact material 6) Any one of claims 1, 3, 4 or 5, characterized in that the contact material contains 44% by weight or more and 65% by weight or less of chromium. A method for producing a contact material for a vacuum shield and disconnector as described in .