Explosive and thermic compositions or charges – Metal or alloy or metalloid – each in particulate form – with... – Inorganic oxygen-halogen salt
Reexamination Certificate
2002-03-12
2003-12-16
Carone, Michael J. (Department: 3641)
Explosive and thermic compositions or charges
Metal or alloy or metalloid, each in particulate form, with...
Inorganic oxygen-halogen salt
Reexamination Certificate
active
06663731
ABSTRACT:
STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to the field of lead-free pyrotechnic compositions. More particularly, the invention pertains to non-toxic pyrotechnic compositions to replace lead-based pyrotechnic compositions that use substances such as lead styphnate or lead azide. The present invention may be used, for example, in ignition devices, to provide solid formulations for illumination devices such as flares or fireworks, or in warhead applications for military uses.
2. Brief Description of the Prior Art
For many years, primer compositions have included two sensitive explosive constituents together with oxidizers, binders/friction agents, and fuels. The most commonly used explosive constituents are lead styphnate coupled with tetracene. The most commonly used fuel is antimony sulphide. These constituents are used despite the fact that the by-products of firing such a composition result in highly toxic materials being released into the atmosphere such as lead and antimony. Such elements produce a potential health hazard, particularly within enclosed areas such as firing ranges where such elements can accumulate over time.
Because of the health problems associated with using such primer compositions, many compositions have been developed over the past twenty years attempting to produce a non-toxic alternative that still provides a non-corrosive material that functions as well as the lead-based primer compositions. Examples of such compositions can be found in U.S. Pat. Nos. 5,993,577; 5,610,367; 5,538,569; 5,684,268; 5,353,707; and a number of others. These patents disclose compositions that replace lead styphnate as the primary explosive with materials such as dinitrobenzofuroxan, diazodinitrophenol, or cupric azide. However, either due to the high production costs associated with these non-toxic compositions or problems associated with their performance as primers, none of these compositions have been commercially used as a substitute for the lead-based primers discussed above.
Based upon the problems described above, it would be desirable to provide a lead-free pyrotechnic composition to replace lead-based primers that is similar or lower in cost to such primers and provides similar or better performance. To provide a cost competitive replacement, it would be desirable to provide a lead-free pyrotechnic composition that could be used for pyrotechnic applications other than as a primer. Examples would be for illumination such as flares or fireworks or in warhead applications for military uses.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide a lead-free pyrotechnic composition that can be used as a substitute for lead-based primer compositions.
It is a further object of this invention to provide a lead-free pyrotechnic composition that is cost-competitive with lead-based primer compositions.
It is yet a further object of this invention to provide a lead-free pyrotechnic composition that may be used for pyrotechnic applications other than as a primer.
This invention accomplishes these objectives and other needs related to lead-free pyrotechnic compositions by providing a composition comprising from about 60 percent by weight to about 80 percent by weight iodine pentoxide and from about 15 percent by weight to about 35 percent by weight of a solid-powder fuel. The solid-powder fuel may normally be selected from aluminum, magnesium, or a combination thereof. Depending upon the potential use for the lead-free pyrotechnic composition of the present invention, the composition may also include from about 4 to 10 percent by weight of a stabilizer that neutralizes any iodic acid formed by the iodine pentoxide, from about 3 to 5 percent by weight of a binder, or from about 5 to 15 percent by weight of a coloring agent. In a preferred embodiment of the invention, the aluminum will comprise aluminum flake having a size ranging from about 20 nanometers to about 100 nanometers.
The present invention may be used for many applications including use in warheads, as a percussion primer, or for use as a pyrotechnic flare or other illumination device. The composition may be specifically designed for such uses as discussed below by one skilled in the art. Therefore, the versatility of the present invention should help to improve its cost-competitiveness versus currently used lead-based pyrotechnics.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention comprises a versatile, lead-free pyrotechnic composition that may be used for many pyrotechnic applications. While this invention can provide a lead-free replacement for lead styphnate based percussion primers, which has been the basis of much research as discussed above, the invention can also be used for such things as warhead applications and in illumination devices. This versatility helps make the present invention extremely attractive from a commercial use/manufacturing standpoint.
The invention comprises from about 60 percent by weight to about 80 percent by weight iodine pentoxide and from about 15 percent by weight to about 35 percent by weight of a solid-powder fuel. Therefore, the reaction products will be non-toxic. In this most general embodiment of the present invention, the composition may be used as an explosive in warheads for military applications. A preferred solid-powder fuel for warhead applications would be aluminum. In a preferred embodiment of the invention, the aluminum would be aluminum flake having a size of from about 20 nanometers to about 100 nanometers. One preferred embodiment of the invention for warhead applications comprises approximately 80 percent by weight iodine pentoxide and approximately 20 percent by weight of aluminum flake. In this embodiment, the iodine pentoxide would be about 20 to 200 mesh size and the aluminum flake would be about 20 to 40 nanometers in size. Preparation of the composition would be accomplished using normal warhead explosive mixing procedures that are known by those skilled in the art. Several hundred kilograms of the composition would be required for a normal sized warhead.
The present invention may also include from about 4 to about 10 percent by weight of a stabilizer to nuetralize iodic acid formed from any contact with water from the ambient surroundings. With the addition of the stabilizer, the composition may easily be used for either warhead applications or for percussion primer applications. The stabilizer may be any chemical capable of nuetralizing the iodic acid that will not interfere with the reaction of the oxidizer and fuel and may be selected by one skilled in the art. Preferred stabilizers include calcium carbonate, strontium carbonate and barium carbonate with the most preferred being calcium carbonate.
For warhead applications, one preferred embodiment of the invention that includes the stabilizer would be where the iodine pentoxide comprises approximately 75.2 percent by weight, the aluminum comprises approximately 20 percent by weight aluminum flake, and the stabilizer comprises approximately 4.8 percent by weight calcium carbonate.
For percussion primer applications, the preferred size of the iodine pentoxide comprises from about 20 microns or less. The preferred size of the aluminum flake size would still range from about 20 to 100 nanometers. For percussion primer applications, it would be preferred to include from about 3 to 5 percent by weight of a binder. Particular binders may be selected by one skilled in the art. Examples of such binders include gum arabic, Fluorel, Viton, or other high temperature stable polymers with gum arabic being the most preferred binder. One preferred embodiment of a percussion primer composition would be where the iodine pentoxide comprises approximately 71.5 percent by weight, the aluminum flake comprises approxim
Elstrodt Douglas
Puszynski Jan A.
Rose James E.
Carone Michael J.
Felton Aileen B.
Homer Mark
The United States of America as represented by the Secretary of
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