US2197380A - Electric contact element - Google Patents

Description

15 product thereof, brought out Patented Apr. 16, 1940 Franz R.

Indianapolis, Ind.,

00., Inc., Indianapolis,

Delaware Reuse] and Kenneth L. Emmert, assignors to P. R. Mallory &

Ind.,' a corporation of No Drawing. Application June 2, 1939,

Serial No. 277,016

2 Claims. (01. 200-166) This invention relates to improvements in electric contact elements.

It is an object of the invention to provide a contact which possesses superior physical proper- 5 ties such as high specific gravity and satisfac tory strength. I

It is a further object of the invention to provide a contact of high melting point and high recrystallization temperature.

from the following description, taken in connection with the appended claims.

The present invention comprises a combination of elements, methods of manufacture and the and exemplified in the disclosure hereinafter set forth, the scope of the invention being indicated in the appended claims.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the combination of elements without departing from the spirit of the invention.

proved contact is contemplated, formed of an alloy having the following ingredients present in substantially the ranges of proportion given below: Y

Uranium- Refractory metal of the tungsten-molybdenum group Balance Part of the refractory metal can be replaced by rhenium. We have found that it is possible .to produce tungsten base materials containing up to of uranium, part of which is taken up by tungsten in solid solution and part of which exists as a free constituent, the bonded alloys showing increased hardness and considerable resistance to abrasion. Uranium is, suitable as an alloy element for tungsten because it has a melting point of 1700 to 1800 degrees C. Uranium and tungsten can be sintered by heating to a temperature above 1200 degrees C. in a non-oxidizing atmosphere, such as in vacuum.

a We have also found that such elements as carbon, boron, or silicon, may be added. Our experiments have shown that uranium will form compounds with these elements and when added to our improved tungsten-uranium alloys double compounds may be formed. We have found that alloys of the following composition show considerable advantages- Other objects of the invention will be apparent According to the present invention, an im- Per cent shapes then may Per cent Tungsten 99.50 Uranium .50 B. Tungsten 95.00

Uranium 5.00 5 C. Tungsten- Molybdenum -l 10 Rhenium 10 Uranium 5 10 D. Tungsten 65 Uranium 35 E. Tungsten "l5 Uranium 25 H F. Tungsten 35 Molybdenum Uranium 30 In our experiments we have found that alloys with low uranium contents can be manufactured 20.

by 'mixing the powders, subjecting same to a high pressure to form an ingot. The ingot or special be sintered and forged or swaged, rolled or drawn to a convenient shape from which the various parts can be manufac- 25 tured, for which this alloy is particularly suitable. Binary alloys of high uranium content are diflicult to swage and must be mamii'actured by a sintering process only. v

This swaging difliculty, however',can, in cer- 30 tain cases, be overcome if other elements of the tungsten group are added, such as molybdenum or rhenium. Tests conducted on the use of the alloys described for electrical make and break contacts indicated that the material has good 35 properties both as far as contact resistance and material transfer are concerned. This is the case, both if the materials are operated against each other or against a contact of this composition 'or under polarized conditions.

We have found that the desirable characteris-. tics described above will not be disturbed- 1! small proportions of other ingredients are present from the iron group materials, such as iron, cobalt and nickel, or small percentages of tantalum, columbium, chromium and manganese.

We have also found that we can use our new alloying composition as a refractory base for a material composition consisting of high melting point materials taken from the group molyb- 50 denum, tungsten, rhenium and containing substantial quantities of uranium impregnated with low melting point materials taken from the group copper, silver, gold, platinum and palladium and their alloys.

Since certain changes in producing the above alloy and certain modifications in the composiinvention, which as a matter of-lan be said to fall therebetween.

What is claimed is:

1. An electric contact element formed of an alloy of .1 to 35% uranium and the balance substantially all tungsten.

2. An electric contact element formed of a metal composition containing at least 65% tungsten and .1 to 35% uranium.

R. HENSEL.

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