SE467495B - WANT TO INCREASE THE EFFECTS OF ENERGY-EFFICIENT EXPLOSIVE MIXTURES, AND ACCORDINGLY TO PRODUCING EXPLOSIVE MIXTURES MIXTURES - Google Patents

Description

467 495 the gain thus obtained may, however, be of various kinds. In RSV charges, a significant residual effect can thus be achieved through the copper and aluminum additive, while in aluminum-containing underwater charges, for example, the bubble effect can be increased by 25-50% through a suitably adapted aluminum additive. Aluminum additives are also found in many other mixed explosives.

The Aluminum additive also provides quite large temperature additions to the pure combustion reactions. The high-energy explosive Hexal thus includes, in addition to the secondary explosive hexogen, aluminum powder and it has been calculated that this aluminum powder additive through its oxide and carbide formation in connection with the explosive combustion gives an approximately 25% temperature supplement.

Another alternative to increase the energy yield from explosives and rocket propellants containing secondary explosives and metal additives is described in EP-A-0 323 828. According to this patent specification one can significantly increase the energy yield from such per se known charges containing secondary explosives, perchlorates, aluminum powder and binder if, instead of using molar perchlorate excess as before, the perchlorate proportion is balanced against the oxygen balance of the explosive mixture to a substantially complete formation of carbon dioxide and water.

According to this patent specification, it applies that previously used excess chlorate in the combustion of the charges consumed far too large amounts of energy for its own decomposition for the perchlorate additive to really come into its own. A careful balancing between the perchlorate content and the explosive oxygen balance would, on the other hand, give large amounts of explosive gases which can be easily reduced with the constituent metal powder component, which in turn would give a significant reinforcement of action. There is no reason to doubt this. The main disadvantage of this type of explosive mixture is instead the perchlorate content. In practical use, attempts have always been made for safety reasons to avoid combinations between perchlorates 467,495 and high-energy explosives, since the perchlorates generally give everything for handling-sensitive mixtures. On the other hand, it is common to use perchlorates in pure pyrose batches, which only occur in significantly smaller batches than pure explosive mixtures.

However, the present invention now relates to a new, more general method of markedly increasing the permeability and combustion temperature of energy-rich explosive mixtures and their bubble effect when used in underwater charges. Namely, we have found that there are a number of exothermic reactions, including one or more metal reactants, which can be combined with explosive combustion and which are started by them and which then run more or less parallel to them without the need for energy supplementation but vice versa during energy release. In addition to the choice of the reactants included in the exothermic reactions, it is also required that these are available in finely divided form in intimate contact with each other in the explosive mixture in question.

In order for the reactants to react exothermically with each other, it is required that at least one at some temperature must be soluble in the other.

The exothermic reaction when one of the reactants dissolves in the other is followed in most cases by a second oxide and carbide formation step during which the reactants, i.e. in this case the additive metals, react with available oxygen and possibly with carbon contained in the explosive molecules. This second step is also exothermic, but as a rule not as strongly exothermic as step one.

The oxide, carbide formation step also corresponds in principle to the reaction obtained in other metal-containing explosives, such as the initially mentioned Hexalene, which contains only hexogen and aluminum and which thus completely lacks other metals with which the aluminum can react exothermically.

Exothermic reactions of particular interest in this context are 4-67,495 such intermetallic alloy reactions resulting in borides, aluminides, silicides, alloys including alkaline earth metals and carbides.

Of the alternatives conceivable in this context, we consider that the metals titanium, boron, zirconium, nickel, manganese and aluminum were of particular interest. The same also applies to the so-called alkaline earth metals and hafnium.

In order for the intended exothermic intermetallic reactions to be initiated by the explosive combustion, it is required that the reactants are available distributed in the explosive in intimate contact with each other and in appropriate amounts. Since the reactants consist of two or more of the above-mentioned metals, this is achieved by producing granules of fine particles, which here means that these are in / u-size, of the reactants and distributing these granules in an explosive matrix which may consist of one or more high energy explosives such as HMX, RDX, PETN, TATB, NTO, HNS, guanidine derivatives such as TAGN, NIGU, guanidine nitrate or TNT and binders which may be of the energetic binder type such as polyvinyl nitrate or TNT. (energetic binder = binder which in itself is also an explosive).

Above and below and in industry commonly used abbreviations: RDX = hexogen HMX = octogen HNS = hexanitrile stilbene PETN = pentyl or pentaerythritol tetranitrate TATB = triaminotrinitrobenzene NTO_ = 3-Nitro-1,2,4-Triazole-5-One TNT = Trotyl TAGN = triaminoguanidine nitrate NIGU = nitroguanidine 467 495 As already mentioned, the metal reactants for the intermetallic exothermic reaction must be added to the explosive mixture in the form of granules containing fine particles of all metal reactants, these fine particles of the different metal reactants being as close as possible. These granules can be prepared using small amounts of binder which can be an explosive (energetic binder) or a binder of another type. Granules prepared in other ways than by means of binders are also conceivable.

It is previously known that some intermetallic reactions are exothermic. Other exothermic reactions are also known. What is new with the present invention is therefore the combination with explosive where the explosive combustion is used for the initial energy supplement required to start up the exothermic intermetallic reaction which then contributes with a not insignificant energy supplement to the energy development obtained from the explosive combustion. A particular problem in the context of the invention is to select the exothermic reactions which can be used in the context of explosives and which give the greatest energy yield.

In addition, it is important to choose metal reactants that can be practically handled together with explosives and that are economically acceptable given the energy supplement they provide. Since the exothermic alloy formations are relatively slow reactions compared to the explosive combustion, the metal mixtures in question here and the consequent alloy reactions mean a certain reduction in the detonation rate of the explosive mixture compared to the pure explosive but at the same time the exothermic metal reaction residual effect in the form of an elevated temperature in combination with the formation of liquid / solid particles, which is very favorable when it comes to achieving a strong impact effect, for example through steel plates and when the charge detonates underwater and thereby gives rise to an enhanced bubble effect. - the water charge receives an extra energy supplement from formed by-products which in turn react with the water, which thereby acts as an oxidizing agent. 467 495 Charges of the type characteristic of the invention are therefore particularly well suited for underwater use, i.e. mines and torpedoes. primarily in the Charges according to the invention can be produced as castable PBX (plastic bond explosives) based on metal granules and crystalline explosives and a relatively high binder content.

A requirement that must be placed on the charges according to the invention is that these must have good cohesion. In cases where the charges according to the invention are composed of fine-grained with 1-2% by weight of binder granulated crystalline explosive and granules of the metal reactants of the type indicated above and main binder, explosive contents can be calculated in the finished charge if 30-90% by weight, as well as alloy metals in the amounts of 10-70% by weight and 1-40% by weight of binder. The latter may be a thermoset, a thermoplastic or a thermoplastic such as an acrylate, a polyurethane, a polyester or a thermoplastic rubber. The lowest binder contents can be obtained if you use energetic binders, such as TNT or polyvinyl nitrate, which are both binders and explosives. For example, in our experience, the metal and explosive granules should have a particle size of 100-200 pm.

An example of an exothermic alloy system Ti + B2 in connection with the present invention which can provide an energy supplement corresponding to about -71.6 kcal / mol and 4000 ° K. a reaction temperature approx. Another exothermic system is Al + Mn.

On the other hand, a reaction with pure Al to alumina or possibly aluminum carbide, which has already been mentioned, does not increase energy to the same degree.

Additional energy-enhancing systems are Zr + Ni -a 467 495 Metal combinations which provide exothermic alloy systems and therefore may be relevant in connection with the present invention Alkaline fi type metals Barium plus either, bismuth or tin.

Magnesium plus tin Calcium plus aluminum Strontium plus aluminum Beryllium plus aluminum Borides Boron plus magnesium, silicon, titanium, zirconium, chromium, molybdenum, tungsten or manganese.

Aluminides Aluminum plus copper, calcium, boron, titanium or zirconium, chromium, manganese, iron, cobalt, nickel, palladium and platinum.

Silicides Silicon plus calcium, titanium, zirconium, hafnium, chromium, molybdenum and nickel.

Furthermore, small additions of substances or alloys from the lanthanide group and / or the metal hafnium can be added to catalyze the alloying reaction according to the invention.

Manufacturing: The exothermic alloy kit according to the invention is suitably manufactured by homogeneous mixing of actual components in a suitable particle size together with a few percent binder of which granules of a suitable size are produced. We have found that suitable binders for this can be acrylates (solvent-based or water-dispersible). Granules obtained thereby containing the reactants exothermically reacting in the explosive combustion are then added to the explosive in question, which may be RDX, HMX, HNS, PETN, or other previously mentioned explosive to approx. 10 - 70% mixture.

The metal additives designed in accordance with the invention can also be used to advantage for castable explosives, for example trotyl or castable PBX.

A special advantage of the additives characteristic of the invention is that they do not give any appreciable increase in the handling sensitivity of the finished explosive mixtures. This is a very important property which is not obtained when reinforcing explosive mixtures with pyrotechnic batches where, due to these chlorate, perchlorate and / or peroxide contents, a significant increase in the handling sensitivity of the mixtures must be expected.

The invention which has been defined in the appended claims will now be further illustrated with some general examples and some more detailed ones.

EXAMPLE I Detonating charges a) A first explosive mixture consisting of; 60% RDX (Hexogen) 23% Titanium 14% Boron 3% Binder increases the impact effect by approx; 20% against pure RDX rate. b) A second explosive mixture consisting of 68% RDX (Hexogen) 21% Zirconium 9% Nickel 2% Binder increases the impact effect by more than 50% against pure RDX batch. 467 495 c) A third explosive charge consisting of 50% RDX (Hexogen) 22% Manganese 14% Aluminum 3% Binder gives an effect equivalent to RDX in terms of volume but the charge density is increased from 1.7 grams / cm3 to 2.4 grams / cm3 which gives an increase in power per unit volume.

EXAMPLE II Manufacturing; Lab Scale Rate IMR-comp 05; Manganese powder, grain size approx; 10 u is mixed with aluminum powder (MIL 512), grain size 2.5 - 5 u. The mixture is carried out as a dry mixture in, for example, a rotokub. The composition shall be 30% manganese and 70% aluminum. The metal composition is mixed with acrylate binder dissolved in trichlorethylene, binder content approx; 1%.

The mixture is dried to about; 5-7% dry matter and granulated on a 50 mesh screen. The granules are mixed with 50% RDX, grain size 15 p, before the final drying in a mixer. The explosive composition is finally dried at 60-70 ° C for 12 hours, to a moisture content <0.1%.

The batch can then be easily pressed into compacts with a density of 2.35 - 2.40 g / cm3.

In our experiments, the composition has given an increased impact in sheet steel, compared with, for example, hexal 70/30.

The test has been carried out by placing compacts with a size of 0 22x20 mm standing on a steel plate 8 mm thick and with a porous wood base.

The pellets have been initiated with a detonator No. 8.

During the test, good breakthroughs were obtained in all cases, i.e. holes 0 4-5 mm were formed in the plate. The corresponding sample with hexal 70/30, on the other hand, is only able to give crack formation in the plate. 467 495 10 Other mixtures of the various groups which have given good results and which have been prepared in principle in accordance with the procedure described above.

Borides a) Boron and zirconium powder 0.5-5 p were mixed in a ratio of 80% zirconium and 20% boron, the mixture was granulated with approx; 1-2% binder through 50 mesh.

The metal mixture was mixed into RDX to a percentage of 50. b) Boron and titanium of the same particle size were mixed and granulated accordingly of 14% boron and 23% titanium with the addition of 3% binder. Then a mixture of 60% RDX was made.

The two batch recipes described above have in common that they are reacted at a temperature between 3500 ° K - 4200 OK at fully developed pressure. in!

Claims (10)

11 4e7 495 PATENT CLAIMS 1. In high-energy explosive mixtures whose matrix consists of one or more secondary explosives of the type HMX, RDX, PETN, TATB, NTO, HNS, guanidine derivatives such as TAGN, NIGU, guanidine nitrate or TNT increase the energy yield in the form of permeability temperature, combustion temperature and in the case of underwater charges in the form of the bubble effect from the detonating explosive mixture, characterized in that the explosive combustion (detonation) is used to start an exothermic intermetallic alloy reaction between reactants contained in the explosive mixture in the form of two or more finely divided explosives. and in intimate contact with each other involved metals which as a final product are given a boride, an aluminide, a silicide, a zirconium-nickel alloy or an alloy containing at least one alkaline earth metal after which said intermetallic alloy reaction runs more or less parallel to the explosive combustion without energy addition from this but during the release of energy. 2. A method according to claim 1, characterized in that the metal reactants necessary for the exothermic intermetallic reaction are mixed into the high-energy explosive mixture in the form of particles or granules of the order of 100-200 .mu.m, each comprising all the constituent metal reactants in the form of particles of size. connected to each other. 3. A method according to either claim 1 or 2, characterized in that the combustion of the explosive is combined with an exothermic metal reaction in the form of an intermetallic alloy reaction between two or more metals titanium, boron, zirconium, nickel, manganese and aluminum. 4. A method according to either of claims 1-3, wherein the mixing ratio between the constituents 467 4-95 1? the components are selected within the following range 10-70% by weight of alloy metal 30-90 "explosive and 1-40" binder P 5. A method according to any one of claims 1-4 characterized in that the alloy metals are distributed in an explosive binder matrix in the form of granules with a particle size of 100-200 .mu.m. High energy explosive mixture prepared according to the method according to either of Claims 1 to 5, characterized in that it contains, in addition to a possible binder which may be energetic and its main constituent in the form of one or more secondary explosives of the type RDX, HMX, HNS, PETN , TATB, NTO, HNS, guanidine derivatives such as TAGN, NIGU, guanidine nitrate or trotyl also a metal additive in the form of two or more metals which in finely divided form and in intimate contact with each other are distributed in the base mass consisting of the secondary explosive and which in the secondary explosive combustion gives rise to an exothermic intermetallic alloy reaction and said metal additive includes at least two metals which in the intermetallic alloy reaction between them give a boride, an aluminide, a silicide, a zirconium nickel alloy or an alloy containing at least one alkaline earth metal. High-energy explosive mixture according to Claim 6, characterized in that the metal additive comprises at least two of the metals titanium, boron, zirconium, nickel, manganese or aluminum. High-energy explosive mixture according to either of Claims 6 to 7 *, characterized in that the metal additive comprises W in the form of granules or particles consisting of all constituent * metals in the form of particles of U-size bonded with a binder which can be energetic and wherein the granules have a size of 100-200 .mu.m and are distributed in the explosive matrix which may also contain binders of the same or different C High-energy explosive mixture according to one or more of Claims 7 to 11, characterized in that it comprises 30-90% by weight of explosive. 10. -70 "alloy-forming metal and 1-40 binders.