CN1022424C

CN1022424C - Spindle alloy of tungsten-copper-silver-nickel by powder metallurgy

Info

Publication number: CN1022424C
Application number: CN 90106491
Authority: CN
Inventors: 林炳; 刘海珊
Original assignee: Central South University
Current assignee: Central South University
Priority date: 1990-12-28
Filing date: 1990-12-28
Publication date: 1993-10-13
Anticipated expiration: 2005-12-28
Also published as: CN1062928A

Abstract

The present invention relates to a switch contact for high current electrical apparatuses, particularly to a W-Cu-Ag-Ni powder metallurgy contact alloy used under closed environment (called AW-[50] for short), which is characterized in that a binary solid solution quaternary alloy is designed according to a metallographic principle; silver powders are proportionally added to W-Cu-Ag-Ni composite powders as skeleton inducing metal by means of powder metallurgy technique and optimum technological parameters; the present invention is made up via impregnation and sintering. The present invention has the advantages of high oxidation resistance, low temperature rise, favorable arc extinguishing effect, strong direct current breaking capacity (up to 80KA/440V), short arcing time (generally up to 1/2 to 1/3 of that of Ag-W-[40]) and long electrical durability (which is 4 to 7 times longer than that of the Ag-W-[40]), and silver consumption is 12% to 20% less than that of the Ag-W-[40]).

Description

Spindle alloy of tungsten-copper-silver-nickel by powder metallurgy

The present invention relates to a kind of powder metallurgy contact alloy that is used for the high-current electrical equipment switch.

At present, be used for the contact material of the big electric current of conduct on the electric installation, Agcdo (Ag-CdO) series and silver-colored tungsten (Ag-W) series are generally arranged.The decomposition of Ag-CdO series CdO pollutes the environment, and is unwell in enclosed environment and uses; That employing is maximum in the Ag-W series is Ag-W ₄₀, its direct current breaking capacity has only 40KA/440V, can not satisfy the needs of big electric current, and the tungsten oxidation causes contact resistance to increase the electrical equipment poor work stability.

In order to overcome above deficiency, make the electric installation switch contact not only be applicable to enclosed environment, but also have high direct current breaking capacity, special the present invention proposed.

Alloy composition of the present invention is (weight percentage): W:49～51%, Ag:42～44%, Cu:4～5.5%, Ni:0.5～1.5%.

Produce the metallurgical contact alloy of tungsten-copper-silver-nickel by powder and (be called for short AW ₅₀Alloy), the present invention adopts powder metallurgy process to prepare the W-Cu-Ni composite powder, be dispensed into silver powder and induce metal by alloy model, one-tenth as skeleton, with mold pressing or isostatic pressing, make the W-Cu-Ag-Ni skeleton pressed compact that obtains to have certain porosity, the skeleton pressed compact is at 1050～1250 ℃ of infiltration silver, homogenizing thermal treatment subsequently, promptly can be made into have high direct current breaking capacity, oxidation resistant W-Cu-Ag-Ni quaternary system alloy.

The invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is technological process of production figure of the present invention.

Fig. 2 is sintering dress boat mode.

Fig. 3: AW50 is through three contact surface metallographs of D.C80KA/500V break-make.Amplify 1 times.

Fig. 4: Ag-W40 is through D.C60KA/500V break-make one-time contact surface metallograph.Amplify 1 times.

Alloy production technological process of the present invention is as follows:

1.W-Cu-Ni producing of composite powder

W powder (hydrogen reduction method is produced, the r pine: 2.8～3.4, meet the CEMENTED CARBIDE PRODUCTION technical qualification) is mixed with nickel nitrate aqueous solution, be heated to 70～100 ℃ of oven dry, the pyrolysis reduction is 1～1.5 hour in 800～850 ℃ of hydrogen atmospheres, the W-Ni composite powder; W-Ni composite powder and copper chloride solution are mixed into pasty state, heating, drying, the pyrolysis reduction is 1～1.5 hour in 460～500 ℃ of hydrogen, gets the W-Ni-Cu composite powder, crosses 100 orders (0.15mm) sieve.

2. the preparation of skeleton material

Add in the W-Cu-Ni composite powder after crossing 100 orders (0.15mm) 21～24% induce silver (particle diameter is less than 75um) as skeleton material (skeleton material account for finished product gross weight 75～81%), add 0.5% stearic acid again, in V-type blender or other mixing equipment, mixed 2～8 hours, obtain the skeleton compound.To the compression moulding of skeleton compound, the size and the substance of control briquetting guarantee that matrix porosity is 17～20% in the pressing process by hydropress.

3. infiltration sintering

The infiltration sintering of skeleton pressed compact and infiltration silver bullion (adopting 99.5% silver powder grain or bits sheet) carries out in molybdenum wire furnace (10～15KW, 1100～1500 ℃).Fig. 2 is sintering dress boat mode, wherein, and 1-infiltration silver bullion, 2-skeleton pressed compact, 3-Al ₂O ₃Filler.Infiltration silver bullion 1 also can be placed on the below of skeleton briquetting 2.Infiltration sintering hydrogen or cracked ammonium are as protective atmosphere, and the infiltration sintering temperature is 1050～1250 ℃, and soaking time is 45～60 minutes.Insulation is 30～45 minutes when being cooled to 990～1010 ℃, its objective is to make the thick Ag layer of the uniform one deck 0.2～0.5mm of alloy surface, and welding is carried out easily, improves use properties.

4. homogenizing thermal treatment

The goods that infiltration sinters are put into box temperature automatically controlled stove, heat in air, temperature is 380～400 ℃, and the time is 12～24 hours.

With AW ₅₀And Ag-W ₄₀Alloy is installed in respectively on the DW-440V series heavy DC switch (isolating switch), and connection 10KA/500V, 20KA/500V, 40KA/500V, 60KA/500V, 80KA/500V grade experimentize.AW ₅₀Alloy is smoothly by all rank test (each break-make three times), and test back contact is smooth, as Fig. 3 (amplifying 1 times).Ag-W ₄₀Only by 40KA/500V, when entering 60KA/600V, break and once promptly can't connect, the contact surface serious burn is as Fig. 4.

AW ₅₀Alloy and Ag-W ₄₀The alloy physics performance is compared as follows:

Alloy designations composition process characteristic density hardness resistivity

kg/mm ²10 ^-6Ωcm

Ag-W40 40%W, 60%Ag Ag powder+W powder, machinery mixes 12.51 90 0.25

Close compacting, sintering, the multiple pressure

AW50 50%W, 43%Ag, preparation W-Ni-Cu compound 13.00 115 0.27

The 7%Cu+Ni powder, the infiltration sintering

Ag-W series is a kind of immiscible pseudoalloy, but Ni, Cu and W at high temperature have certain solubility.After in the Ag-W alloy, adding Cu, Ni, can improve Ag, form Cu, Ni phase Solid solution coating W particle simultaneously, around the W particle, form the quad alloy tissue, help W particle antioxidant property W particulate wettability.Adopt leaching technology, improved the density and the compactness of alloy, thereby improved the electrical and thermal conductivity performance of alloy, reduced contact temperature rise.Oxide treatment in adopting, the arc quenching effect of enhancing contact alloy.With Ag-W ₄₀Relatively, the present invention (AW ₅₀Alloy) have following characteristics: the direct current breaking current is 80KA/440V, is Ag-W ₄₀Two times, and do not produce objectionable impurities during disjunction, be suitable in enclosed environment, using; The face contact resistance is stable, and temperature rise is low, and the erosion of the anti-ocean of energy humid weather does not have the three wastes, pollution-free, nuisanceless in process of production, has both satisfied the particular requirement of using in enclosed environment, can replace Ag-W yet ₄₀Use on other electric switch, performance is more excellent; Arc time is short, saves cost, than Ag-W ₄₀Joint silver 12～20%.

Claims

1, a kind of powder metallurgy contact alloy is characterized in that consisting of (weight): W: 49～51%, and Ag: 42～44%, Ni: 0.5～1.5%, Cu: 4.0～5.5%.

2, the method for the described alloy of a kind of production claim 1, it is characterized in that, in the W-Ni-Cu composite powder of median size, add 21～24% particle diameter silver powder less than 75um less than 0.15mm, be mixed together evenly with 0.5% stearic acid after, compression moulding gets the skeleton forming pressed compact; The infiltration silver bullion of skeleton forming pressed compact and 99.5% is stacked together, and infiltration sintering in hydrogen or cracked ammonium atmosphere carries out homogenizing thermal treatment behind the sintering, wherein:

A〉composite powder skeleton forming pressed compact porosity is 17～20%;

B〉the infiltration sintering temperature is 1050～1250 ℃, and soaking time is 45～60 minutes, and when sintering was cooled to 990～1010 ℃, soaking time was 30～45 minutes;

C〉the homogenizing heat-treat condition is to heat in air, and temperature is 380～400 ℃, and soaking time is 12～24 hours.

3, method according to claim 2, it is characterized in that, employed W-Cu-Ni composite powder is to adopt powder metallurgy process to produce, its concrete grammar is: the W powder is mixed with nickel nitrate aqueous solution, be heated to 70～100 ℃ of oven dry, the pyrolysis reduction is 1～1.5 hour in 800～850 ℃ of hydrogen atmospheres, gets the W-Ni composite powder; W-Ni composite powder and copper chloride solution are mixed into pasty state, heating, drying, the pyrolysis reduction is 1～1.5 hour in 460～500 ℃ of hydrogen, gets the W-Ni-Cu composite powder.

4, method according to claim 2 is characterized in that, the infiltration silver bullion can be placed on the below of skeleton forming pressed compact during the infiltration sintering, also can be placed on the top of skeleton forming pressed compact.