US2175236A - Method of preparing an alloy having artificial radio activity - Google Patents

Description

Patented 0a.. B0, 1939 METHOD or PREPARING AN ALLOY HAVING ARTIFICIAL RADIO ACTIVETY Oleg Yadofi, Issy-les-Moulineaux, France No Drawing. Original application December 28,

1936, Serial No. 117,976. Divided and this application November 26, 1937, Serial No.

In France December 27, .1935

1 2 Claims.

The present invention concerns a method of producing artificial radio-active bodies.

The object of the present invention is to produce a metallic alloy of this kind capable of spontaneously emitting radiations similar to alpha rays and the activity of which remains practically constant after a long time.

According to an essential feature of the present invention, the alloy, which is obtained from a mixture, in the molten state, of aluminium and magnesium and, advantageously silicon, lead, tin and manganese, is treated in an intense electric field, that is to say a field corresponding to a voltage of at least 100 volts per centimeter of distance between the electrodes.

According to another feature of the present invention, copper is added to the alloy so as to improve the cohesion and the mechanical properties of the alloy finally obtained.

According to still another feature of the present invention mercury is introduced into the mixture of molten bodies and allowed to evaporateat least partly. This treatment purifies the composition of the alloy finally produced.

Other features of the present invention will result from the following detailed description of a. specific embodiment of said invention.

According to this method, I proceed in the following manner:

The alloy is prepared in a suitable furnace.

I first pour, in the cold state, a certain amount of mercury on the bottom of the furnace. I cover this layer of mercury with tin and lead.

, I place thereabove copper and aluminium previously mixed together, for instance in the form of an alloy such as commonly used for the manufacture of automobile engine pistons. The percentage ofaluminium lacking in this alloy for obtaining the desired composition is introduced in the pure state. Then the furnace is heated until the whole of these elements is molten. A part of the mercury evaporates and purifies the composition of the alloy. Then manganese is introduced, by quickly immersing it into the molten bathin such manner as to avoid oxidation thereof. About five minutes after complete melting, once mercury has evaporated, magnesium is introduced into the furnace in the pure state.

I have found that the amounts of" the bodies above mentioned should preferably'be such as to correspond to the following composition Per cent Aluminium 68 to-74 'Magnesium 4.2 to 8.4 Silicon 1.5 to 3.5 Copper 5 to 12 Tin 4 to 6.5 Lead 2.4. to 5 Manganese 1.89 to 2 Mercury 0.5 to 1 In a more specific manner, the following composition has proved highly satisfactory:

The alloy thus molten in the bath is stirred. Then two electrodes provided in the furnace and immersed in the molten alloy are connected to a source of high tension direct current.

As above stated, it is necessary, according to the present invention, to have an electric field of high intensity, that is to say corresponding to a voltage of at least volts per centimeter of distance between the electrodes.

To be more specific, I have found that very satisfactory results can be obtained by making use of the electric field corresponding to a voltage of 3000 volts for a thickness of ten centimeters of the alloy in the molten state.

The alloy is subjected to the action of the electric field of high intensity for about ten minutes. Then the tension between the terminals is reduced in a gradual manner so as to pass from the full value above mentioned down to zero in a period of time of about two minutes. After this, I operate in substantially the same manner as. in the case of ordinary alloys.

As a rule, the alloy according to the invention should not be subjected to violent shocks nor to sudden variations of temperature.

The present application is a division of my oo- 2 r pending application Ber. No. 117,976, flled Decamber 28, 1936.

ciple oi the invention as comprehended within the scope of the accompa ying claims.

What I claim is:-

1. A method of preparing an' alloy having artificial radio-activity, which comprises placing on the bottom of a furnace, in the cold state, from 0.5 to l per cent of mercury, adding from 4 to 6.5 per cent oi tin and from 2.4 to 5 per cent of lead, adding from 5 to 12 per cent of copper, and from,68 to 74 per cent of aluminium, melting these metals, introducing from 1.89 to 2 per cent of manganese into the molten bath, heating to melt the whole of the above mmtioned bodies, evaporating mercury, adding from 4.2 to 8.4 of magnesium in a substantially pure state, stirring the whole, and subjecting the molten mixture thus finally obtained to the action of an electric field of high intensity corresponding to a tension of at least 100 volts per centimeter of thickness of molten alloy thus treated.

2. A method of preparing an alloy having artificial radio-activity, which comprises placing on the bottom of a furnace, in the cold state,

0.15 percent of mercury, adding 5.1 per cent of tin, and 2.4 per cent of lead, adding 7.5 per cent -01 copper, and 73 per cent of aluminium, melting these metals, introducing 1.89 per cent of manganese, into the molten bath, heating to melt the whole 01' the above mentioned bodies, evaporating mercury, adding 6.4 per cent of magnesium in a substantially pure state, stirring the whole and subjecting the molten mixture I thus finally obtained to the action of an electric field of high intensity corresponding to a tension of at least 100 volts per centimeter of thickness 20 oi. molten alloy thus treated.

OLEG YADOFF.