JPS6383242A - Arc-resistant conductive material - Google Patents

Abstract

PURPOSE:To improve consumption resistance, low contact resistance, electrical conductivity, and machinability, by adding specific amounts of rare earth elements of oxides of rare earth elements to an arc-resistant conductive material composed of W-base or WC-base alloy. CONSTITUTION:In the arc-resistant conductive material composed of W- or WC-base alloy, 0.1-10wt%, of rare earth elements and/or oxides of rare earth elements are incorporated so as to improve various characteristics of the above material and to enable the prolongation of the service lives of electric contacts, electrodes for electric discharge machining, etc. It is preferable that one or more elements among Y, La, and Ce and one or more kinds among the oxides of the above elements are used as the above rare earth elements and the oxides of them, respectively. It is also preferable to use Ag-WC alloys containing 30-70% Ag as the above WC-base alloy and, as the W-base alloy, it is preferable to use Ag-W alloys containing 20-60% Ag and further Cu-W alloys containing 20-60% Cu can also be used. Moreover, it is preferable that wettability to Ag is improved by incorporating <=2% of iron group elements and/or Cu to the above arc-resistant conductive material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an arc-resistant conductive material used for electrical contacts, electrical discharge machining electrodes, and the like.

<Prior art> Various W-based or WC-based alloys have been known as arc-resistant conductive materials used for electrical contacts or electrodes for electrical discharge machining, especially kg-WC, Ag-W, Cu-W. Sintered alloys are preferred.

In these alloys, Ag; Cu has high electrical conductivity and thermal conductivity, and W and WC have high hardness and high melting points. By combining these, they have good heat resistance and conductivity, and have low wear and tear. This results in a material with low contact resistance and good welding resistance.

In addition, when comparing AH and Cu in these alloys, AH has a small affinity for oxygen, and Ag oxide is very unstable and easily decomposed, so Ag-containing W
The base sintered alloy is suitable for electrical contacts used in air and electrodes for electrical discharge machining.

Compared to Ag, Cu has a greater affinity for oxygen, so it is not preferable to use in air, but since it has a high melting point and is inexpensive, Cu-containing W-based sintered alloys have no oxidation problems. It is currently widely used as a contact for gas switches.

Comparing W and WC, WC is stable with high corrosion resistance and has a low oxidation rate, so even if arcing occurs, the contact resistance increases little. Furthermore, WC has a high melting point, low vapor pressure, and low consumption.

For these reasons, WC is better as a contact material, but its high hardness results in poor machinability, making it undesirable as an electrode for electrical discharge machining.

(Problems to be Solved by the Invention) As described above, W-based or WC-based alloys are preferable as arc-resistant conductive materials, but conventional materials are still not fully satisfactory.

In other words, in terms of arc resistance, it is unavoidable that this type of material is subject to wear and deformation due to arc discharge, but it is a superior material with better conductivity, less wear and tear, and a longer service life. is requested to be provided.

For electrical discharge machining electrodes, in order to shorten machining time and extend the life of the electrode, there has been a demand for the development of a material that has a high machining speed and a low electrode wear ratio.

(Means for Solving the Problems) The present invention has been made in view of the above, and is suitable for electrical contacts or electrodes for electric discharge machining, which have improved arc wear resistance, low contact resistance, and excellent conductivity. It provides the alloy material used.

That is, the present invention provides an arc-resistant conductive material made of a W base or a WC base alloy, which contains 0.1 to 10% by weight of a rare earth element and/or a rare earth element oxide. It is the material.

Here, the rare earth element is preferably one or more selected from Y, La, and Ce, and the rare earth element oxide is preferably selected from oxides of Y, La, and Ce. It is preferable that one kind or two or more kinds are used.

In this case, if the added content is less than 0.1% by weight,
If the addition effect does not appear, and the amount exceeds 10% by weight, sinterability is inhibited, cavities are generated in the product material, and both mechanical properties and arc wear resistance are deteriorated.

W-based alloys are commonly used as this type of conductive material, an example of which is Ag-W, with an Ag content of 20 to 60% by weight.
The other side is Cu-W with a Cu content of 20 to 60% by weight.

An example of a WC-based alloy is Ag-W (:, with an Ag content of 3
It is 0 to 70% by weight.

In this case, the Ag or Cu content is determined according to the equipment (capacity) in which the arc-resistant conductive material of the present invention is used. In other words, for medium current use, select a high content range.
In addition, for large current applications, a smaller amount is used.

Regarding the numerical range of the Ag or Cu content, if the upper limit is exceeded, the alloy will not have sufficient heat resistance, the hardness will decrease, and the welding resistance and arc wear resistance will deteriorate. Also,
When it is less than the lower limit, the conductivity of the alloy decreases, which is not preferable.

Further, the arc-resistant conductive material made of the W-based or WC-based alloy of the present invention preferably contains 2% by weight or less of iron group elements and/or Cu.

(Examples) The present invention will be specifically explained below using some examples.

Example 1: This example concerns an A g-W C type product.

By containing 0.1 to 10% by weight of at least one rare earth element or rare earth element oxide in the Ag-WC alloy, arc resistance in particular could be effectively improved.

Rare earth elements that can be added include Y, La, Ce, Pr, Nd, Pm, Sm, IF
, u.

G d , T b , D y , Ho , E
There are r, Tm, Yb, Lu, etc., which meet the purpose of the present invention, but some of these have limitations due to difficulty in obtaining them, economic efficiency, etc.

Therefore, Y is easy to handle and can be obtained at a relatively low price with a certain quality.

La and Ce can be advantageously selectively used.

As the rare earth element oxide, for the same reason as above, Y,
Oxides of La, Ce (Y2O2, La2O3, Ce20
3) is advantageously used selectively.

A g -W C alloy is manufactured by powder metallurgy, and generally contains 30-70% by weight of Ag and 70-3% of WC.
A composition consisting of 0% by weight is used.

In the embodiment of the present invention, 0.1 to 10% by weight of a rare earth element or a rare earth element oxide is further contained in this.
~3 types may be added and contained at the same time.

By the way, WC and rare earth element oxides have poor wettability with Ag, and therefore easily form cavities.

In order to improve this wettability, iron group elements (F
It is good to add e, Ni, Co) and/or copper,
As a result, the arc resistance of a high-quality WC-based alloy without cavities can be obtained.

In this case, the added content of the iron group element or copper is preferably 2% by weight or less, and if it exceeds 2% by weight, there will be a problem that the conductivity of the product material will be reduced to an unacceptable level.

Next, we will explain the specific test results.

Each raw material was blended so that the final composition would be as shown in Table 1, and thoroughly mixed in a wet vibrating ball mill.

Each raw material powder used was a fine powder with an average particle size of several microns.

□ Put this mixture into a mold and molding pressure 3 ton/cm2
After pressing to obtain a molded body, the molded body was heated at 1250° C. for 2 hours in a hydrogen atmosphere to create a sintered body.

A test piece of 16 x 16 x 4 mm was cut out from this sintered body, silver-brazed onto a tough pitch copper base metal, and an electrical contact opening/closing test was performed.

The test conditions were as follows, and the results were as shown in Table 2.

= The above test piece was tested under the following conditions using an electromagnetic switch.

(Conditions) Voltage, AC220V Current: 480A Power factor: O, 35 Contact pressure + 3kg Opening/closing frequency + 1200 times/hour Number of openings/closing: 50, OOO Table 2 *Consumption amount: Contacts including platinum before and after the test The weight was measured and the difference was taken as the amount of contact wear.

It is shown as the total amount of wear of 3 fixed side contacts and 3 movable side contacts.

*Contact resistance: After closing both fixed side and movable side contacts with a contact pressure of 3 kg, a current of 30 A was applied, and the voltage drop between both contacts was measured and determined.

Contact resistance is shown as an average value of three phases.

As is clear from the results in Table 2, compared to the conventional comparative materials, the inventive example materials containing rare earth elements or their oxides had considerably less wear in all cases. In particular, those containing rare earth oxides have significantly reduced consumption.

Furthermore, regarding contact resistance, the materials of the examples of the present invention showed lower numerical values than the comparative materials, and it can be seen that they have excellent conductivity when opened and closed many times.

Example 2: This example is an example of an Ag-W type material.

An arc-resistant conductive material suitable as an electrical contact or an electrode for electric discharge machining was manufactured by containing 0.1 to 10% by weight of at least one rare earth element or rare earth element oxide in an Ag-W alloy. .

The rare earth elements and rare earth element oxides that can be added or selectively used are the same as those in Example 1.

Ag-W alloys are manufactured by powder metallurgy, and generally contain Ag2O ~ 60% by weight and WC 80 ~ 40% by weight.
A composition consisting of is used.

In the examples of the present invention, 0.4 to 10% by weight of rare earth elements or rare earth element oxides, preferably 0.3 to 10% by weight,
Although the content is 5% by weight, one kind or two or three kinds of rare earth elements or their oxides may be added and contained at the same time.

In this case, if the added content is less than 0.1% by weight,
If the addition effect does not appear, and the amount exceeds 10% by weight, sinterability is inhibited, cavities are generated in the product material, and both mechanical properties and arc wear resistance are deteriorated.

By the way, W and rare earth element oxides have poor wettability with Ag, and therefore easily form cavities.

In order to improve this wettability, iron group elements (F
It is good to add e, Ni, Co) and/or copper,
As a result, arc resistance made of a high-quality W-based alloy without cavities can be obtained.

In this case, the added content of iron group elements and/or copper is preferably 2% by weight or less, and if it exceeds 2% by weight, there will be a problem that the conductivity of the product material will be reduced to an unacceptable level.

Next, we will explain the specific test results.

1 of Example 2 = Ag, W, rare earth elements or their oxides, iron group elements, and copper were blended in predetermined amounts and thoroughly mixed in a wet vibrating ball mill. Note that each raw material powder used was a fine powder with an average particle size of several microns.

After further adding and mixing a binder, this mixture was placed in a mold and pressed at a molding pressure of 3 ton/cm2 to obtain a molded body. Next, after removing the binder from the molded body at 700°C, silver infiltration material was placed on top and infiltration was carried out at 1250°C for 2 hours in a hydrogen gas atmosphere so as to achieve the desired compositions shown in Table 3. I went there and got an alloy body. From this alloy body,
A test piece of 16 x 16 x 4 mm was cut out, silver-brazed onto platinum tough pitch copper, and an electrical contact opening/closing test was performed.

The test conditions were as follows, and the results were as shown in Table 4.

The above test piece was tested under the following conditions using a 5F6 (sulfur hexafluoride) gas-filled electromagnetic switch.

(Conditions) Voltage: AC220V Current: 480A Power factor: 0.35 Contact pressure crab 3kg Opening/closing frequency: 1200 times/hour Number of openings and closings + 50,000 times Atmosphere gas = 6 sulfur fluoride (SFs) gas Gas-filled pressure crab 1.5 kg/cn+2 (gauge pressure)
4 Table *Amount of wear: The weight of the contact including the base metal before and after the test was measured, and the difference was taken as the amount of wear of the contact.

It is shown as the total amount of wear of 3 fixed side contacts and 3 movable side contacts.

*Contact resistance: After closing both fixed side and movable side contacts with SF and gas filling at a contact pressure of 3 kg, a current of 30 A was applied, and the voltage drop between both contacts was measured and determined. Contact resistance is 3
Shown as the average value of the phases.

As is clear from the results in Table 4, compared to the conventional comparative materials, the inventive example materials containing rare earth elements or their oxides had considerably less wear in all cases. In particular, those containing rare earth oxides have significantly reduced consumption.

Furthermore, regarding the contact resistance, the materials of the examples of the present invention showed lower values than the comparative materials, indicating that they have excellent conductivity when opened and closed many times.

Example 2-2: An alloy body having the composition shown in Table 5 was prepared in the same manner as in Example 2-1 using Ag, W, yttrium oxide (Y2O2), and nickel powder.

From approximately the center of this alloy body, the diameter is 11 mm and the height is 91 mm.
Cut out a cylindrical test piece with a diameter of 8II1m,
An electrode for electric discharge machining was prepared by soldering silver to the upper surface of a cylindrical brass shank having a height of 60 mm+. Then, put two sheets of cemented carbide G on the workpiece (workpiece) with a thickness of 10 mm and a pilot hole diameter of 2 m.
An electric discharge machining test was conducted using m).

The electric discharge machine and electric discharge machining conditions used are shown below, and the results are shown in Table 6.

, LL Milk 2 1 Main body: Jabax DH-150A Power supply: UF105C ``L Koyu J'' processing set: CuW-WC (MWS), RI (MC3
)MA switch=3. Machining voltage without jump: 5~28■ (center value) Liquid pressure: Jet 0, 2~0, 25kg/c+s2 (gauge pressure) Selector: Unused Polarity: Electrode (-), Workpiece (10) Pressurized liquid; Daphne H135 Electric discharge machining time = 30 minutes 00 seconds However, (1) Machining speed is Machining time (2) Weight consumption ratio is (3) End face consumption ratio As is clear from the results in Table 6, Compared to conventional comparative materials, the electrode materials for electrical discharge machining of the examples of the present invention containing rare earth elements or their oxides have a significantly reduced amount of electrode wear and a considerably improved machining speed. In particular, the improvement in wear resistance means that the life of the electrode for electrical discharge machining can be extended, which is of high industrial value.

Example 3; This example is an example of a Cu-W type material.

By including 0.1 to 10% by weight of at least one clay element or rare earth element oxide in the Cu-W alloy, arc resistance in particular could be effectively improved.

The rare earth elements and rare earth element oxides that can be added or selectively used are shown in Example 1. Same as later.

Cu-W alloys are manufactured by powder metallurgy, and generally have a composition of 60% by weight of Cu2O and 80-40% by weight of W.

In the examples of the present invention, a rare earth element or a rare earth element oxide is further added in an amount of 0.1 to 10% by weight, preferably 0.3 to 10% by weight.
5 weight electrolytic corrosion, one kind or two or three kinds of rare earth elements or their oxides may be added and contained at the same time.

In this case, if the added content is less than 0.1% by weight,
If the addition effect does not appear, and the amount exceeds 10% by weight, sinterability is inhibited, cavities are generated in the product material, and both mechanical properties and arc wear resistance are deteriorated.

By the way, W and rare earth element oxides have poor wettability with Cu, and therefore easily form cavities.

In order to improve this wettability, iron group elements (F
As a result, the arc resistance of a high-quality W-based alloy without cavities can be obtained.

In this case, the added content of the iron group element is preferably 2% by weight or less, and if it exceeds 2% by weight, there will be a problem that the conductivity of the product material will be unacceptably lowered.

Next, we will explain the specific test results.

1 of Example 3 = Predetermined amounts of Ag, W, rare earth elements or their oxides, and iron group elements were blended and thoroughly joined using a wet vibrating ball mill. Note that each raw material powder used was a fine powder with an average particle size of several microns.

After further adding and mixing a binder, this mixture was placed in a mold and pressurized at a molding pressure of 3 ton/0 m2 to obtain a molded body. Next, after removing the binder from the molded body at 700°C, silver infiltration material was placed on top and infiltrated for about 2 hours at 1250°C in a hydrogen gas atmosphere so that each desired composition in Table 7 was obtained. An alloy body was obtained. From this alloy body,
A test piece of 16 x 16 x 4 mm was cut out, silver-brazed onto a tough pitch copper base metal, and an electrical contact opening/closing test was performed.

The test conditions were as follows, and the results were as shown in Table 8.

--Experiment The above test piece was tested under the following conditions using a 5F6 (sulfur hexafluoride) gas-filled electromagnetic switch.

(Conditions) Voltage: AC220V Current: 48OA Power factor: 0.35 Contact pressure Crab 3kg Opening/closing frequency: 1200 times/hour Opening/closing frequency: 50,000 times Atmosphere gas: Sulfur hexafluoride (SFs) gas Gas filling pressure Crab 1, 5 kg/cm2 (gauge pressure) Measures - 11 Impressions - 1 *Amount of wear: The weight of the contact including the base metal before and after the test was measured, and the difference was taken as the amount of wear of the contact.

It is shown as the total amount of wear of 3 fixed side contacts and 3 movable side contacts.

*Contact resistance: After closing both the fixed side and movable side contacts at a contact pressure of 3 kg while SF gas was being filled, a current of 30 A was applied, and the voltage drop between both contacts was measured. Contact resistance is shown as an average value of three phases.

As is clear from the results in Table 8, compared to the conventional comparative material, the material of the present invention containing a rare earth element or its oxide exhibits considerably less wear in all cases. In particular, those containing rare earth oxides have significantly reduced consumption.

Furthermore, regarding the contact resistance, the materials of the examples of the present invention showed lower values than the comparative materials, indicating that they have excellent conductivity when opened and closed many times.

Example 3-2: In the same manner as in Example 3-1 using Cu, W, yttrium oxide (Y2O2), and nickel powder,
An alloy body having a final composition as shown in Table 9 was obtained. A cylindrical test piece with a diameter of 11 cm and a height of 9 cm was cut out from approximately the center of this alloy body, and this was
The upper surface of the cylindrical brass shank of I was soldered with silver to form an electrode for electric discharge machining.

Then, the workpiece (workpiece) is 02 pieces of cemented carbide (thickness 10
An electric discharge machining test was conducted using a diameter of 2 mm and a prepared hole diameter of 2 mm. The electric discharge machine and electric discharge machining conditions used were as follows, and the results were as shown in Table 10.

Main body: JAVAX DH-150A Power supply: UF105C [L-Kyu]1 processing set: CuW-WC (MWS), RI (MC8
)MA switch 23. Machining voltage without jump: 5 to 28 ■ (center value) Fluid pressure: Jet flow 0.2 to 0, 25 kg/ Cm2 (gauge pressure) Selector 2 unused polarity: Electrode (-), workpiece (→-) Pressure Fluid: Daphne HL35 Electrical discharge machining time: 30 minutes OO seconds However, (1) machining speed, (2) weight consumption ratio, (3) end face consumption ratio are as follows.As is clear from the results in Table 10, conventional materials is C
By incorporating yttrium oxide (Y2O2) into the u-W alloy, the electrical discharge machining performance was greatly improved.

In particular, the electrode consumption ratio of conventional Cu-27= -It was less than 1/3 compared to W alloy.

As described above, the material of the present invention, which contains a rare earth element or its oxide in a Cu-W alloy, has the following characteristics compared to conventional materials:
For electrical contacts, it greatly reduces the amount of wear and tear when opening and closing multiple times, and has low contact resistance and excellent conductivity.For electrical discharge machining electrodes, it also greatly reduces the amount of wear and tear on the electrodes and increases machining speed. I was able to do that. In particular, improving wear resistance will extend the life of electrical contacts and electrodes for electrical discharge machining, and has high industrial value.

<Effects of the Invention> As explained in detail above, the present invention provides an arc-resistant conductive material made of W-based or WC-based alloy containing 0.1 to 10% by weight of rare earth elements and/or rare earth element oxides. Compared to conventional materials, the amount of wear when opening and closing electrical contacts many times is reduced by a factor of 11, and the contact resistance is low and the conductivity is excellent. It can greatly reduce wear and tear and improve machining speed. In particular, due to improved wear resistance, electrical contacts,
-28= It is possible to achieve a longer lifespan of the electrode for electrical discharge machining, which is of high industrial value.

Claims (8)

[Claims] (1) In arc-resistant conductive materials made of W-based or WC-based alloys, rare earth elements and/or rare earth element oxides are
．． An arc-resistant conductive material containing 1 to 10% by weight. (2) The arc-resistant conductive material according to claim 1, wherein the rare earth element is one or more selected from Y, La, and Ce. (3) The arc-resistant conductive material according to claim 1, wherein the rare earth element oxide is one or more selected from oxides of Y, La, and Ce. . (4) The WC-based alloy is Ag-WC, and the Ag content is 3
The arc-resistant conductive material according to any one of claims 1 to 3, characterized in that the content is 0 to 70% by weight. (5) The W-based alloy is Ag-W, and the Ag content is from 20 to
Claim 1 characterized in that the amount is 60% by weight.
The arc-resistant conductive material according to any one of items 1 to 3. (6) Claims 4 or 5, characterized in that the arc-resistant conductive material made of W-based or WC-based alloy contains 2% by weight or less of iron group elements and/or Cu. The arc-resistant conductive material described. (7) The W-based alloy is Cu-W, and the Cu content is from 20 to
Claim 1 characterized in that the amount is 60% by weight.
The arc-resistant conductive material according to any one of items 1 to 3. (8) The arc-resistant conductive material according to claim 7, wherein the arc-resistant conductive material made of a W-based alloy contains 2% by weight or less of iron group elements.