Patent Publication Number: US-2013233195-A1

Title: Pressure-enhancing Explosive Charge

Description:
The present patent application claims priority from German Patent Application Serial No. 10 2010 022 982.2, titled “Druckverstärkende Sprengladung”, and filed on Jun. 8, 2010, the entire contents of which are incorporated herein by reference. 
     The present invention relates to the use of metal carbonyls in highly explosive multi-shelled explosive charges, hereinafter also referred to as blast effect charges, as well as their use in guided or unguided release munitions or in guided weapons munitions. 
     The present invention relates to the use of metal carbonyls in shaped charges or shaped-charge-like explosive charges, wherein their application is not expressly restricted to the use in guided or unguided release munitions or guided weapons munitions. 
     Changes in operational scenarios have in past decades have led to the development of more diversified concepts using newer explosives and explosive formulations and/or newer construction to increase the blast effect. 
     A part of these developments focuses on the addition of inorganic fuels to explosive formulations. The performance-enhancing addition of fuels, such as aluminum powder to explosive formulations has for a long time been well-known. Besides the amount of fuel component of a mixture its blast performance can also be affected by the quality of the fuel (grain size, surface etc.) and/or the admixture of further aggregates such as inorganic oxidizing agents. 
     Various investigations have been directed toward the development of suitable blast effect charges using nanoscale powder characteristics of inorganic fuels or fuel mixtures with particle diameters smaller than 1 μm for accelerating the conversion. The problem of the conversion of inhibiting oxide coating of such powder (with boron and many light metals) as well as the prevention of the passivation of reactive metal surfaces makes the addition of suitable auxiliary materials into the respective mixtures, if necessary by suitable upstream coating process, generally necessary. Examples of such aggregates can be fluorine-substituted organic binder or ammonium perchlorate as an inorganic oxidizing agent. As well as functioning as binders fluorine-substituted polymers also act as coating agents and activators of the fuels, since in their conversion traces of hydrogen fluoride are formed, which decompose into a passivating oxide layer on the fuel powder. In the same way it is to be also accepted that ammonium perchlorate, which is often used oxidant (e.g. U.S. Pat. No. 5,996,501, U.S. Pat. No. 6,955,732 and U.S. Pat. No. 6,969,434), acts additionally during the conversion of released hydrogen chloride as activator. 
     To avoid the aforementioned problems, DE 10 2006 030 678 B4 proposes a blast effect explosive charge with very high pressure volume effect based on red phosphorus as inorganic fuel. 
     If the use of ever finer metallic powders—if necessary in connection with the above-mentioned aggregates—leads to explosive formulations with ever higher peak pressure performance (see FIG. 2 in WO 2009/145926 A1), then ultimately with an atomic-sized fuel distribution, corresponding maximum power should be attainable dependent on the respective fuel. 
     According to the present invention there is provided a multi-shell structured blast effect charge, wherein a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with an inorganic fuel is integrated in a closed container. 
     Further aspects of the invention are set forth as follows. 
     In another aspect the present invention provides a shaped charge or shaped-charge-like explosive charge, wherein a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with an inorganic fuel is integrated in a closed container. 
     The metal carbonyl contained therein may be one of the following compounds: Cr(CO) 6 , Mo(CO) 6 , W(CO) 6 , Fe(CO) 5 , Fe 2 (CO) 9 , or Fe 3 (CO) 12 , although other suitable compounds are not excluded. 
     The metal carbonyl as a pure substance may be present as a liquid depending on its chemical physical properties. 
     Alternatively, the metal carbonyl as a pure substance depending on its chemical physical properties may be present as a loose or compacted bulk powder or as a molten solid. 
     The integrated metal carbonyl may be present in the closed container as a compressible granulate consisting of a metal carbonyl and a suitable bonding agent in quantities up to a maximum of 10 percent by weight relative to the mixture. 
     The integrated metal carbonyl may be present in the closed container as a mixture with an inorganic fuel (up to 50 percent by weight relative to metal carbonyl), as a loose or compacted bulk powder or as a molten solid. 
     The integrated metal carbonyl is present as the mixture with the inorganic fuel as a compressible granulate consisting of a metal carbonyl, an inorganic fuel, and a suitable bonding agent in a quantity up to a maximum of 10 percent by weight relative to the mixture. 
     In the case of a two- or three-shelled structure, one or two shells comprise(s) one or two compressible, castable, or meltable explosive formulations and the remaining second or third shell contains a metal carbonyl in a closed container as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with an inorganic fuel. 
     In the case of a two-shelled structure for the total charge, the compressible, castable, or meltable explosive formulation of an existing shell serves as an initiation-charge. 
     The blast effect charge may be as a central core charge, which is surrounded with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel, or granulate of a mixture of an inorganic fuel filled in a container. 
     The container filled with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel, or granulate of a mixture with an inorganic fuel may be wholly or partially surrounded by a compressible, castable, or meltable explosive formulation. 
     In the case of the three-shelled structure, the container may be filled with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with an inorganic fuel is arranged as a central core charge or outer shell, whereby the corresponding arrangement of the remaining two, results from the compressible, castable, or meltable explosive formulations. 
     The container filled with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel, or granulate of a mixture with an inorganic fuel may be wholly or partially surrounded by shells containing compressible, castable, or meltable explosive formulations. 
     The proportion by weight of the metal carbonyls as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with an inorganic fuel relative to the total charge may be between 10 percent by weight and 70 percent by weight, preferably however 15 percent by weight to 45 percent by weight. 
     The proportion by weight of the compressible, castable, or meltable explosive formulations relative to the total charge by a two-shelled total structure may be between 30 percent by weight and 90 percent by weight, preferably between 55 percent by weight and 85 percent by weight. 
     The proportion by weight of the compressible, castable, or meltable explosive formulations relative to the total charge of a three-shelled total charge structure may be between 30 percent by weight and 90 percent by weight, preferably between 55 percent by weight and 85 percent by weight. 
     The explosive formulations may contain an admixture of inorganic fuels and/or inorganic oxidizing agents in quantities up to 70 percent by weight relative to the respective explosive formulations themselves. 
     The container filled with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with inorganic fuel may be formed in a pointed or frusto-conical shape. 
     The container filled with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with an inorganic fuel may have any one of the forms defined herein. 
     The container filled with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with inorganic fuel may be formed with areas of different wall thicknesses. 
     The amount of the metal carbonyl in the inset container as a pure substance, granulate, mixture with an inorganic fuel or as a granulate of a mixture with an inorganic fuel may be between 5 percent by weight and 95 percent by weight, relative to the total mass of the container and integrated metal carbonyl. 
     The inset container may be formed from copper or another suitable material. 
     The explosive formulations can contain an admixture of inorganic fuels and/or inorganic oxidizing agents in quantities up to 70 percent by weight relative to the respective explosive formulations themselves. 
     The invention also extends to a munition in the form of guided or unguided release munition or in guided weapons munition, comprising a multi-shell structured blast effect charge or shaped charge or shaped-charge-like explosive charge as defined herein. 
     The invention also extends to a munition in the form of guided or unguided rocket or rocket weapons munition, comprising a multi-shell structured blast effect charge or shaped charge or shaped-charge-like explosive charge as defined herein. 
     The invention further extends to a munition in the form of mortar or grenade launcher, comprising a multi-shell structured blast effect charge or shaped charge or shaped-charge-like explosive charge. 
     The invention still further extends to a munition in the form of shoulder-fired charges, comprising a multi-shell structured blast effect charge or shaped charge or shaped-charge-like explosive charge as defined herein. 
     The invention further extends to a munition in which multi-shelled blast-effect or shaped-charge effect or shaped-charge like explosive charges are integrated into submunitions or partial charges. 
     The invention still further extends to a modular structured munition, which through retrofit/assembly of a closed container filled with a metal carbonyl as a pure substance, granulate, mixture with an inorganic fuel, an inorganic fuel or as a granulate of a mixture with an inorganic fuel forms a munition as defined herein. 
     The present invention is based on the idea of generating multi-shelled blast explosive charges using metal carbonyls as fuel. For this, primarily the lower temperature-stable metal carbonyls, especially iron pentacarbonyl, will be suitable. The pressure-enhancing effect should stem from the fact that these compounds should be disintegrated by detonative excitation into respective atomically finely distributed elementary metal and the corresponding equivalent carbon monoxide. 
     With particle diameters from 50 nm to 1 μm, nanoscale fuel powders contain, depending on the respective atomic diameter, several hundred to several thousand atoms per particle, which may also still be surrounded by a passivating oxide coating. In contrast, thereto atomically finely distributed fuel should be generated from the metal carbonyls by detonative excitation in situ, so that a corresponding increase mass conversion should lead to a clearly enhancing blast effect. 
     In addition to the necessary finer fuel distribution, when using metal carbonyls with nanoscale fuel or fuel mixtures the latent problem of the passivating oxide coating is avoided. 
     The detonative excitation of the metal carbonyls is associated with the simultaneous release of atomically finely distributed metal together with a corresponding number of gas-forming carbon monoxide equivalents, which should deliver a suitable contribution to the pressure volume performance of the multi-shelled blast effect charges. Depending upon the construction and composition of the explosive-containing shells of the herein suggested multi-shelled explosive charges (inter alia depending on the oxygen balance and the type of the ingredients and reaction products), it is also conceivable that the suddenly released carbon monoxide itself explodes with the primary detonation. 
     As a function of the chemical physical properties of each of the metal carbonyls under consideration different conversion mechanisms are also conceivable. Irrespective of the respective conversion mechanism, in each case a blast effect with increased energy release is to be expected. 
     Of the well-known metal carbonyls, those of iron, especially iron pentacarbonyl, come into question as potentially suitable metal carbonyls. The main advantage in using iron pentacarbonyl might consist of the fact that these compounds due to their use inter alia in the area of metal organic catalysts in suitable quantities are commercially available. Beside diiron nonacarbonyl and triiron dodecacarbonyl, chromium hexacarbonyl may in particular, inter alia due to its temperature stability, be of interest. The use of all further existing, proven not only in matrix isolation experiments, metal carbonyls, in particular those of molybdenum, tungsten, manganese and cobalt are here however not excluded. 
     Proposed are multi-shelled, two- or three-shelled, structured blast effect charges as well as shaped charges or shaped-charge-like explosive charges, in which metal carbonyls in the form of pure substances, granulates, mixtures with inorganic fuels or as granulates of mixtures with inorganic fuels are integrated in suitable closed containers. The metal carbonyls serve in the form proposed herein as fuel, which during the intended conversion of the total charge exhibit an undirected (multi-shell structured blast effect charges) or at least a partially directed (shaped charges or shaped-charge-like explosive charges) pressure enhancing effect. 
    
    
     
       Illustrated embodiments of the invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic sectional drawing of a two-shell structured explosive charge with a container filled with metal carbonyl on the outside or inside; and 
         FIG. 2  is a schematic sectional view of a three-shelled structured explosive charge with a container filled with metal carbonyl on the outside or inside. 
     
    
    
     In  FIGS. 1 and 2 , explosive charge  10 ,  10 ′ has a high explosive disintegrating- and initiation-charge  1 . This is surrounded by metal carbonyl, metal carbonyl granulate, or metal carbonyl-containing mixture or granulate  2 ,  4 . These are in turn enclosed by a container wall  3 . 
     With a two-shell structure for the total charge ( FIG. 1 ) a compressible, castable or meltable explosive formulation serves as shell as initiation-charge. This can be formed as a central core charge  1  and is surrounded by one container  3  filled with metal carbonyl  2 . Alternatively container  3  filled with a carbonyl  2  ( FIG. 1 , on the right) can also be totally or partly coated with an compressible, castable, or meltable explosive formulation  1 . 
     With a three-shelled structure of the total charge ( FIG. 2 ) a container  3  filled with metal carbonyl can be arranged as central core charge ( FIG. 2 , on the right) or outer shell ( FIG. 2 , on the left). From this a suitable arrangement of the remaining two follows, compressing, casting or melting the existing explosive formulation into the shells  1 ,  5 . 
     For the herein-proposed multi-shelled explosive charges next to the metal carbonyls it is possible to use compressible, castable, or meltable explosive formulations from established munition compositions. There are no constraints regarding the explosive or explosive mixtures to be used, the presence of any binder matrices as well as any additives such as stabilizers, catalysts or auxiliary materials. Furthermore, the explosive formulations can contain additions of inorganic fuel and/or inorganic oxidizing agents up to 70 percent by weight, relative to the respective explosive formulation, themselves. With a three-shelled structure for the total charge there exists the possibility, in the two explosive-containing shells, to use different explosive formulations e.g. to obtain gradated gradients regarding the fuel component or the oxygen balance, relative to the total charge. 
     The metal carbonyls, integrated in the proposed multi-shelled explosive charges in the form of closed containers, can be present, depending on their chemical physical properties as fluid in a pressure container (e.g. when using iron pentacarbonyl) or in a suitable container as loose or compacted bulk powder (e.g. when using diiron nonacarbonyl and triiron dodecacarbonyl) or from one of a bulk powder in an appropriate container in a molten state (e.g. when using chromium hexacarbonyl). Furthermore, depending on the chemical physical properties of each of the metal carbonyls under consideration, use of, if necessary mechanically compressible or pressable metal carbonyl granulate, consisting of a metal carbonyl and a suitable bonding agent in quantities up to a maximum of 10 percent by weight is possible. Furthermore it is, depending on the chemical physical properties of the respective metal carbonyls, conceivable, in order to control the power of the total charge, to mix this with up to 50 percent by weight of a metallic powder in the form of a loose or compacted bulk powder or in connection with a suitable bonding agent (up to a maximum of 10 percent by weight) as a compressible granulate. 
     The proportion by weight of the metal carbonyls or if necessary the metal carbonyl-containing fuel mixture in one the herein described two to three-shelled explosive charges consists of 10 percent by weight to 70 percent by weight, preferably however 15 percent by weight to 45 percent by weight relative to the total charge. The proportion by weight of the conventional explosive formulations is accordingly between 30 percent by weight and 90 percent by weight, preferably however between 55 percent by weight and 85 percent by weight. 
     With regard to the use of the suggested blast effect charges in modular constructed release ammunition or in guided missiles, the metal carbonyls used as outer shells can be formed as segmented bodies, which can be separately mounted and before use will only have to be assembled. Alternatively, when using iron pentacarbonyl as a metal carbonyl component, there exists the possibility of using of suitable pumping systems to fill up the already prepared containers only shortly before use of the release munitions. 
     In addition to the use of metal carbonyl in an undirected blast, multi-shell structured blast effect charges in appropriately configured munitions with at least a partially directed blast effect or in shaped charges are conceivable. 
     Through the use of established explosive formulations as used in other shaped charges, for example, through a conical molded container, which is then filled with a metal carbonyl, a partially directed blast enhancing effect or a performance-increasing shaped charge can be generated (compare performance-increasing shaped charges by lining the same with reactive materials such as coruscatives). Therefore, in particular, chromium hexacarbonyl should itself be suitable, which with fast heating up over 200° C. disintegrates explosively. 
     Furthermore it is conceivable, that from the conically molded container material in combination with, if necessary the spontaneous conversion and finely distributed metal, a spiked shaped-charge or projectile can be formed with enhanced properties compared with the pure container (higher density, greater hardness). For such designed shaped charges, the metal carbonyls of other heavy metals, preferably those of the molybdenum or tungsten, are particularly suitable. 
     In the above-described manner shaped charges should if necessary also work if between the metal deposit and the explosive material there is inserted a layer of thermite composition, which releases the suitable heavy metals. Compared with shaped charges constructed in this manner, the herein proposed shaped charges with metal carbonyl integrated in the container have the advantage that the release of the respective elementary heavy metals faster and in a comparatively more finely distributed form takes place, so that a spiked shaped or a projectile of higher quality is built. 
     In the herein proposed shaped-charge-like structured explosive charges in the form of closed containers with integrated metal carbonyls, there can also be present depending on their chemical physical properties in an appropriately formed container compressed bulk powder or a bulk powder in an suitable container in molten solid state (e.g. when using chromium hexacarbonyl). Furthermore, depending on the chemical physical properties of each of the metal carbonyls under consideration, use of a mechanically compressible or pressable metal carbonyl granulate, consisting of a metal carbonyl and a suitable bonding agent in quantities up to a maximum of 10 percent by weight, is not excluded. 
     The containers, into which the metal carbonyls for the herein proposed shaped-charge-like explosive charges must be integrated, can be formed pointed or frusto-conical. Furthermore expressly no constraints regarding the shaping of the metal carbonyl-filled containers to obtain defined effects are made. This includes also inset containers, which are formed with areas of different wall thicknesses for performance-enhancing effect. Beside copper as the container material, the use of other suitable container materials is not excluded. 
     The amount of the correspondingly formed inset container to build metal carbonyls can lie between 5 percent by weight and 95 percent by weight of the total mass of the container and integrated metal carbonyl. 
     For, the herein proposed shaped-charge-like explosive charges with respect to the explosive formulations to be used no constraints regarding the contained explosive or explosive mixtures, any binder matrices, such as stabilizers, catalysts or auxiliary materials are made. Furthermore, the explosive formulations can contain additions of inorganic fuel and/or inorganic oxidizing agents up to 70 percent by weight, relative to the respective explosive formulation, themselves.