US2434775A

US2434775A - Process for making foamlike mass of metal

Info

Publication number: US2434775A
Application number: US486209A
Authority: US
Inventors: Sosnick Benjamin
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-05-08
Filing date: 1943-05-08
Publication date: 1948-01-20
Anticipated expiration: 1965-01-20

Description

Patented Jan. 20, 1948 .PROCESE .FQR MAKING FOAMLIKE MASS OF METAL Benjamin Sosnick, San Francisco, Calif.

No Drjawing. Application May s, 1943, Serial No. 486,209

r Glaims. (or. 75-20 1 This invention relates to'asponge metal and the process of making it.

The name, sponge metal/is used herein to designate a metal product in-any'desiredshape and form in which the metal-contains a plurality of closely adjacent spaces or voids-of partial vacuum or fluid. The metal structurally resembles a-solidified'foamy mass of metal.

One of the objects of'the invention isthe process of making the sponge metal from a'mixture of As a concrete example, assuming aluminum and -1nercury are used, these maybe mixed in the proportion of 90 parts .of aluminum to parts of mercury, and. are melted in a closed chamber or .under conditions preventing escape of the mercury vapor. The proportions are, of course,

' greatly (dependent uponithe capacity of the enclosure to produce-a desired vapor pressure, that metals, compounds, alloys,'elements, or minerals,

and the resultant product therefrom.

Another object is the product of my process of fmaking the sponge metal, and which product is a solidified, foamy'mass of metal having extreme lightness in proportion to the volumetric mass of 'the metal and being structurally resistant to "shock and strain proportional-to thenormal resistanoe of ordinary metal or the same kind, while possessing greater resiliency to impact not found where the mass of metal is solid.

v Briefly described, the sponge metal of this invention maybe cast, fashioned, processed; or out to the desired shape, such as blocks, sheets, plates, tubing, or in whatever formis desired. As the 'cells in the metal are not intercommunicating, it

possesses heat insulation properties and the metal may obviously be made resistant to oxidization, either by its inherent nature or by treatment of its exposed surface. Also the metal has sound and vibration absorbing properties.

In general, the process of making the metal comprises heating the desired metal, mixture of metals, compounds, alloys, or other'minerals, etc., to a temperature between the melting point thereof at atmospheric pressure and a temperature sufficient to produce a, vapor pressure of volatile material in the mixture, and under conditions where the volatile portion or portions are held in the molten mass against escape therefrom. The molten mass is then released into a lower pressure space resulting in'the formation of a froth or mass of metallic, gas filled bubbles, which, after cooling will constitute the sponge metal.

As examples of mixtures that are suitable for forming sponge metal, one or more of the following combinations may be used:

In carrying out this process, any conventional apparatus may be employed capable of withstanding the necessary heat and pressure, it being understood that the volatile portion of the material treated is prevented-from escape so as to'produce the desired vapor pressure.

foamy or sponge-like.

is, the less vapor pressure space the less mercury is required, and the greater the space the more is needed.

At atmospheric pressure, the aluminum should melt at about1658 .C. and as the boiling pointrof mercury is about 357 C. it will be seen that a vapor pressure due to the yolatilizing of the mercury may .be increased :to the point where the -mercury in themixture is stabilized or is not vaporized unless there isa reduction in pressure. When this condition is reached and the pressure is released, which may be "by withdrawing the molten mass from the high pressure chamberto 'alow pressure space, there willbe a volatiliaing of the mercury in the mass causing it ;to become Upon cooling a sponge metal will-result.

Where iron, aluminum and .zinc are used, the "relative rproportions'of aluminum-to iron m y be from about 1% iron-to aluminum by weight,

or from 90% to 10% aluminum, and from 1% to 20% of zinc relative to'the entire mass will sup- :ply the desired-amount .of zinc for supplying the vapor. A .higher temperature will normally re- "sult in less zinc being required.

In all instances in compositions of diiierent metals their melting points will vary from that of the respective metals, hence exact melting point temperatures cannot be given.

In zinc alloys the zinc in the alloy will be suftlcient to produce the necessary gas, and where mercury is used, from 1% to 10% by weight of the entire mass is generally adequate, and Where no amalgam is formed, there will be some free mercury in the cells in the sponge metal, but the empty spaces will nevertheless beformed.

Iron alone with 1% to 20% zinc, or magnesium and iron with 1 to 20% magnesium, or magnesium and zinc may be used to form the metal.

As an example of a mineral and a metal, gold and mercuric oxide melted together in aconfined space will produce sponge metal.

The pressure produced will vary in Proportion to temperature, composition andsolubility, but as a general principal in all instances the heating is to the point where vapor pressure of volatile material or materials is above the pressure of the space into which the molten material is to be released, or a relativelyrapid lowering of pressure in the space in which the material is melted is the equivalent if the molten material is not drawn from the space in which it is melted.

The abcve principle being understood, it is, of

8 course, obvious that the invention is not restricted to exact metals disclosed, but to any metallic mixture, compound, alloy, etc., in which a metal or mineral is incorporated therein that has a relatively lower boiling point than the main body of the mass so as to produce the vapor pressure in the molten mass suificient to create the conditions in which a release of the vapor pressure will result in subsequent volatilizing of the said metal or mineral in the mass to produce the cellular structure when the mass is cooled in the low pressure space or area.

While earlier herein the statement was made that the cells in the sponge metal were not intercommunicating, this statement is to be taken generally, since some intercommunication between certain cells cannot be avoided.

Having described my invention, I claim:

1. The process of making a metal containing substantially throughout its body completely enclosed voids that comprises melting the metal below its boiling point at atmospheric pressure out of contact with the atmosphere in the presence of material relatively volatile with respect to the treated metal at a temperature above the boiling point of the latter at atmospheric pressure, and under pressure sufiicient to substantially raise the boiling point of the said latter material, thereafter reducing the said latter pressure to below the boiling point pressure of said latter material, and thereafter cooling to produce the solidified metal containing the enclosed voids.

2. The process of making a metal containing substantially throughout its body completely enclosed spaces that comprises melting the metal below its boiling point at atmospheric pressure out of contact with the atmosphere in the presence of material relatively volatile with respect to the treated metal at a temperature above the boiling point of the latter at atmospheric pressure, and under pressure sufficient to prevent the escape of the relatively volatile material therefrom, thereafter reducing the said latter pressure to below the boiling point pressure of said relatively volatile material, and thereafter cooling to produce the solidified metal containing the enclosed spaces.

3. The process of making a metal containing substantially throughout its body closely adjacent completely enclosed spaces that comprises ;melting the metal below its boiling point at atmospheric pressure out of contact with the at- .mosphere in the presence of material relatively volatile with respect to the treated metal at a temperature above the boiling point of the latter at atmospheric pressure, and under pressure sufiicient to substantially raise the boiling point of the said relatively volatile material, thereafter reducing the said latter pressure to below the boiling point pressure of said relatively volatile material, and thereafter cooling to produce the solidified metal containing the enclosed spaces.

4. The process of making a metal containing substantially throughout its body closely adjacent completely enclosed non-communicating spaces that comprises melting the metal below its boiling point at atmospheric pressure out of contact with the atmosphere in the presence of another metal relatively volatile with respect to the treated metal at a temperature above the boiling point of the latter at atmospheric pressure, and under pressure sufficient to substantially raise the boiling point of the said relatively volatile metal, thereafter reducing the said latter pressure to below the boiling point pressure of said relatively volatile metal, and thereafter cooling to produce the solidified metal containing the enclosed spaces.

5. The process of making a solidified foamlike mass of metal containing substantially throughout its body closely adjacent completely enclosed non-communicating spaces that comprises melting the metal below its boiling point at atmospheric pressure out of contact with the atmosphere in the presence of another metal relatively volatile with respect to the treated metal at a temperature above the boiling point of the latter at atmospheric pressure, and under pressure sufficient to substantially raise the boiling point of the said relatively volatile metal, thereafter releasing into a lower pressure space the molten metal to form a foam-like mass of metal, and thereafter cooling said mass to produce the solidified metallic mass containing the enclosed spaces.

6. The process of making a solidified foamlike mass of metal containing substantially throughout its body closely adjacent non-communicating completely enclosed spaces which comprises mixing molten metal at a temperature below its boiling point at atmospheric pressure out of contact with the atmosphere with another metal relatively volatile with respect to the treated metal, and under pressure sufficient to substantially raise the boiling point of the said relatively volatile metal, thereafter releasing into a lower pressure space the molten metal to form a foam-like mass of metal. and thereafter cooling said mass to produce the solidified foam-like metallic mass.

'7. The process of making a solidified foam-like mass of metal containing substantially throughout its body closely adjacent non-communicating completely enclosed spaces which comprises mixing molten metal at a temperature below its boiling point at atmospheric pressure out of contact with the atmosphere with another material relatively volatile with respect to the treated metal, and under pressure sufficient to substantially raise the boiling point of the said relatively volatile material, thereafter releasing into a lower pressure space the molten metal to form a foamlike mass of metal, and thereafter cooling said mass to produce the solidified foam-like metallic mass.

BENJAMIN SOSNICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Principles of Powder Metallurgy, by W. D. Jones, published by Edward Arnold & Co., London, 1937, pages 133, 134 and 135.

The Making, Shaping and Treating of Steel, by Camp and Francis, published by the Carnegie Illinois Steel Co. of Pittsburgh, Pa., pages 65% and 655.