US2136549A - Copper-uranium alloys - Google Patents

Description

Patented Nov. 15, 1938 UNITED STATES I 2,136,549 COPPER-URANIUM ALLOYS Franz R. Hensei and Earl I. Larsen, Indianapolis, Ind., assignors to P. R. Mallory & 00., Inc., Indianapolis, Ind., a corporation of Delaware lilo Drawing.

4 Claims.

This invention relates to alloys, and more particularly to copper alloys of improved characteristics.

An object of thepinvention is to produce a 6 copper alloy of high electrical and heat conductivity, combined with suitable hardness.

Another object of the invention is to provide an alloy which, in the form of a casting, will have a very high electrical conductivity.

10 Further objects are to improve the cold working and crystallizing characteristics of the alloy.

Other objects of the invention will be apparent from the following description, taken in connection with the appended claims.

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

While the 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.

The invention relates to alloys consisting basically of copper and uranium. to which third elements'are added to further improve the characteristics. While these alloys may vary in their physical characteristics, according to the specific compositions, they will generally be characterized by high conductivity and improved hardness. The alloys are further characterized by desirable electrical properties, such as being a material of low work function, which might be useful for special contacting purposes, or applications, such as neon sign electrodes, and similar applications where high electrode emissivity is required.

It is contemplated that alloys may be produced according to the invention, having the ingredients combined in the following range of proportions:

It has also been possible to add small percentages of any one of the following ingredients without changing materially the characteristics Application September 15, 1937, Serial No. 164,035

of our new alloy: aluminum, silicon, phosphorus, manganese, iron, cobalt, nickel and tin.

In alloys consisting predominantly of copper and uranium, it is found that additions of uranium to copper have very little effect on lowering 5 the electrical conductivity. Alloys consisting of uranium and copper have an extremely high electrical conductivity. The addition of .1% of uranium will produce an alloy with 98% electrical conductivity, while .2-.3% uranium will decrease 10 the conductivity to 94-95% and of uranium will still produce an alloy above 92% conductivity.

We have found that alloys of copper and uranium apparently show what is generally known as an eutectic structure. With higher percent- 15 ages of uranium present, such as 10-20%, a microscopic analysis shows a definite copper-uranium compound similar in structure to that noted in copper-uranium alloys of lower uranium content. This compound is one constituent of the eutectic. 20

It appears that it is due to the formation of this eutectic and the small amount of uranium, taken up in solid solution by the copper, which is responsible for the high electrical conductivity values. It is remarkable, however, to find that 25 even with high uranium contents, the alloys remain easily workable-and can be hot and cold worked.

The additions of elements taken from the second group 0f.the periodic system and particularly so the element cadmium, tend to improve considerably the cold worked characteristics of the copper-uranium alloy. By adding both cadmium and uranium to our improved copper alloy, it is possible to produce a material for electrical pur- 35 poses, of outstanding merit. Similar results are obtained by adding the other materials contained in this group, such as magnesium or zinc. By adding a high enough amount of beryllium, alloys can be made susceptible to heat treatment, gen- 40 erally known as age hardening, and characterized by the fact that the heat treatment consists in two steps; namely, the quenching operation, followed by the aging operation, with or without cold working.

In carrying out the present invention, an alloy of copper and an element taken from the second group of the periodic system may be made according to the conventional alloy making procedure of the prior art, and then uranium may be added in any convenient form, such as cuprouranium, pure uranium, or any other uranium alloy or compound. We have found it even possible to use ferro-uranium; provided that impurities of iron are not objectionable for the specific application under consideration. 7

The great deoxidizing power of uranium can be judged'irom the heat of formation of the oxide. This heat amounts to 304,000 calories per gram atomicweigh'tot metal. By comparing this with another material, which is generally known as a good deoxidizer, such as manganese, superiority is clearly shown. The heat of formation of the manganese oxide is only 91,000 calories per gram atomic weight of metal. This high heat 01 formation of oxides also points to the fact that it alloys of copper and uranium are to be made which contain appreciable quantities of uranium, the molten bath must be free of oxides, particularly of copper oxides; otherwise a certain quantity of the uranium will be lost in reducing the copper oxide to pure copper with the resulting formation of uranium oxide.

The presence in the alloy of small proportions of other ingredients which do not substantially alter its characteristics is contemplated as within the purview of the invention.

While the present invention as to its objects and advantages has been described herein as carried out in specific embodiments thereof, it is not desired to be limited thereby, but it is intended to cover within the spirit and scope of the appended claims.

' What is claimed is:

1. An alloy consisting oi copper and from- 0.005% to 10% uranium, to which an element has been added, taken from the second group of the periodic system, the latter elements being present in quantities from more thanitraces up to 30%.

2. An alloy composed of 0.005% to 20% uranium, from the least useful amount up to 30% of a material selected from the group consisting of cadmium. zinc, beryllium, magnesium, calcium, strontium and barium, and the balance copper.

3. An electric current conducting member iormed of an alloy composed of 0.005% to 20% uranium, from the least useful amount up to 30% ot a material selected from the group consisting of cadmium, zinc, beryllium, magnesium, calcium, strontium and barium, and the balance copper. 4. An electrical contacting member of the type comprising resistance welding electrodes and the like formed or an alloy composed of 0.005% to 20% uranium, from the least useful amount up'to 30% of a material selected from the group consisting of cadmium, zinc, beryllium, magnesium, calcium, strontium and barium, and the balance copper.

FRANZ R. HENSEL. EARL I. LARSEN.