Pyrotechnical heat-generating composition

Abstract

FIELD: pyrotechnics.SUBSTANCE: used to destroy solid-state information carriers. The heat-generating composition contains components in the following ratios, wt.%: oxidizer – iron oxide 48–53, fuel – aluminum powder 15–20, inert additive – aluminum oxide 25–30, active binder – nitro film 2–7. The composition has a high combustion temperature and heat of combustion.EFFECT: increase of the content of condensed combustion products and ensuring that the shape of the pyrotechnic charge is preserved after it has been detonated.1 cl, 2 dwg, 5 ex

Description

[0001] The invention relates to pyrotechnic heat-generating compositions with an elevated combustion temperature, a minimum amount of gaseous combustion products and preserving the shape of the charge after combustion in the form of a slag residue, namely for the destruction of solid-state information carriers.

[0002] Pyrotechnic heat-generating compositions are widely used in military equipment and the national economy to heat various materials to a temperature sufficient for their intended use, further processing or destruction.

[0003] One application of pyrotechnic heat-generating compounds is the destruction of solid-state storage media. These devices consist of a housing containing a pyrotechnic charge of a heat-generating compound, which fits snugly against the target. They burn at a high temperature, and the combustion products maintain the shape of the charge, maintaining heat transfer, allowing the active layer of the storage media to be destroyed without the possibility of subsequent recovery.

[0004] The main requirements for pyrotechnic heat-generating compositions are: the combustion temperature of the mixture (T г > 2200 K), high calorific value (Q сг > 2500 kJ / kg), the proportion of the condensed phase in the combustion products (z ≥ 95%), the slags during combustion of the composition must retain the shape of the charge.

[0005] The combustion process of a pyrotechnic heat-generating composition involves the interaction of a metal oxide with another, more active metal. Pyrotechnic heat-generating compositions must contain:

[0006] - high-calorific metallic combustibles;

[0007] - metal oxide based oxidizers;

[0008] - refractory oxides (from 15% to 35%).

[0009] When burned, such compositions form products with high thermophysical characteristics, which are necessary for better heat transfer to the heated body, which ensures their efficiency. In addition, the introduction of refractory oxides, which perform the function of a rigid skeleton, allows stabilizing the shape of the charge under high-temperature exposure conditions (Krasov V.N., Evstigneev V.V., Tubalov N.P., Lebedev O.A., Filippov G.Yu. Study of some properties of SHS filter materials / / In the collection: Self-propagating high-temperature synthesis: materials and technologies. - Novosibirsk: Nauka, 2001. - P. 40-43).

[0010] To improve the processability of the pyrotechnic heat-generating composition and enhance the mechanical properties of the charge, nitro film is used. This component also ensures the composition's high sensitivity to thermal impulses and, consequently, low ignition energy.

[0011] A thermite reaction mixture is known according to the patent RU No. 2783434, priority from 12.04.2022, B23K 35 / 24, B23K 23 / 00, containing in a stoichiometric ratio iron oxides in the form of industrial waste, metallic aluminum as a reducing agent and alloying additives, characterized in that as iron oxides it contains scale formed during the rolling of railway rails, as a reducing agent - aluminum and titanium powders, and as alloying additives - carbon-fluorine-containing dust from gas cleaning of aluminum production, in the following ratio, wt.%:

[0012] scale 56.28 - 65

[0013] titanium powder 21.84 - 30.3

[0014] Aluminum powder 4.2 - 5.88

[0015] carbon-fluorine-containing gas cleaning dust

[0016] aluminum production 0.5 - 16.

[0017] The composition of the thermite mixture allows you to obtain a high amount of thermal energy (Q г= 3326±50 kJ / kg), but does not provide a sufficiently high combustion temperature (T) during the combustion process. г = 1980±50 K).

[0018] Also known is a pyrotechnic composition according to patent RU No. 2622127, priority from 31.03.2016, C06B 33 / 00, C06B 45 / 10, F42D 3 / 02, E21C 37 / 16, containing aluminum powder, iron oxide and synthetic rubber as a binder, characterized in that it additionally contains fluoroplast-4 and fluororubber of the SKF-32 brand in the following ratio of components, wt.%

[0019] Aluminum powder 22-32

[0020] Iron oxide 54-60

[0021] fluoroplastic-4 2-3

[0022] fluororubber SKF-32 7-9

[0023] synthetic rubber 5-6.

[0024] The solution ensured the technological effectiveness of the composition in the production of extended charges and increased their functionality when used for their intended purpose.

[0025] However, this pyrotechnic composition has an insufficient content of condensed phase in the combustion products (z = 68%).

[0026] The closest in technical essence is the pyrotechnic composition for charges of thermal destruction of solids according to patent RU No. 2559240, priority from 09 / 08 / 2014, C06 B 33 / 00, E21C 37 / 16, containing a mixture of powders of aluminum-magnesium alloy, iron oxide or iron scale and an organic combustible binder, characterized in that as an organic binder it contains a solution of rosin in spindle oil, with the following ratio of components (wt.%):

[0027] Aluminum-magnesium alloy powder 29-36

[0028] iron scale or iron oxide 62-67

[0029] rosin solution in spindle oil 2-4.

[0030] This pyrotechnic composition allows for effective localized destruction of solids due to its high combustion temperature (T г= 2262±50 K) and the amount of generated thermal energy (Q г = 3737±50 kJ / kg), but the absence of refractory oxides in the composition does not allow the slags to be preserved in the form of the initial charge from this composition.

[0031] The technical result of the claimed invention is the development of a pyrotechnic heat-generating composition that has a high heat-generating capacity due to the provision of a maximum content of condensed combustion products, high values ​​of combustion temperature and heat of combustion, which ensures its reliable and efficient operation.

[0032] The technical problem is solved by using a pyrotechnic heat-generating composition for various heat-generating devices, containing iron oxide, a fuel, an inert additive, and an active binder. Aluminum powder serves as the fuel, aluminum oxide as the inert additive, and nitro film as the active binder, with the following component ratios (wt.%):

[0033] aluminum powder 15-20 iron oxide 48-53 aluminum oxide 25-30 nitro film 2-7

[0034] The use of aluminum powder and iron oxide allows for the production of a large amount of thermal energy and condensed products during combustion and ensures the transfer of reaction energy from hot combustion products through the conductive mechanism.

[0035] The use of aluminum oxide ensures that the charge maintains its shape after it is fired due to the formation of a solid-phase framework that is stable in the temperature range of the composition’s combustion, and also prevents the spread of combustion products.

[0036] To improve the processability of the pyrotechnic heat-generating composition and enhance the mechanical properties of the charge, nitro film is used. This component also ensures the composition's high sensitivity to thermal impulses and, consequently, low ignition energy.

[0037] Typical formulations of variants of the pyrotechnic heat-generating composition for heat-generating devices and the prototype composition are shown in Table 1 (Fig. 1). Achievement of the required technical result is illustrated by calculated data on the values ​​of combustion temperature, heat of combustion and content of condensed combustion products, as well as the quality and form of slags after combustion - the prototype and the pyrotechnic thermite composition for heat-generating devices, which are presented in Table 2 (Fig. 2).

[0038] From Table 2 it follows that the proposed technical solution ensured that the characteristics of the presented pyrotechnic heat-generating composition comply with the set of energy and thermodynamic requirements.

[0039] The nominal formulation of the pyrotechnic heat-generating composition (option No. 3) has higher combustion temperature values ​​(ΔT) compared to the prototype г= 65 K) and the amount of condensed phase (Δ z = 13.8%). The composition of the nominal recipe releases the required amount of heat of combustion (Q cг , = 2954 kJ / kg), which meets the technical requirements (Q Cг > 2500 kJ / kg). The slags of the nominal formulation remain solid during combustion, unlike the prototype.

[0040] Reducing the aluminum powder content to C value m <15 wt.%, due to the increased oxidizer content, impairs the physicochemical transformation process during the combustion reaction due to the insufficient content of combustible elements in the composition. This leads to a decrease in the thermal effect. However, the amount of condensed phase in the combustion products increases due to partial and incomplete reduction of the oxidizer.

[0041] Reducing the oxidizer content in the composition to a value of C m< 48 wt.% due to the increase in the fuel content leads to a decrease in the proportion of the condensed phase in the combustion products due to a more complete reaction of the oxidizer reduction during the combustion of the composition and an increase in the heat of combustion.

[0042] Using aluminum oxide in the amount of C m = 25 - 30 wt.% ensures the preservation of the charge shape after combustion, due to the formation of a solid-phase framework.

[0043] Used in the composition of nitro film in the amount of C m A nitro film content of 2-7 wt.% ensures high initiation reliability from a thermal pulse source. Increasing or decreasing the nitro film content from the formula's stated value reduces the processability of the pyrotechnic heat-generating composition and, consequently, the charge's strength.

[0044] Thus, variants No. 2, 3, and 4 of the pyrotechnic heat-generating composition, containing the above-mentioned components in their optimal ratios, ensured the desired technical result. These variants are characterized by high combustion temperatures, heat of combustion, and condensed phase content in the combustion products.

[0045] To confirm the thermodynamic characteristics of the pyrotechnic heat-generating composition, standard and typical calculation and experimental methods were used. The results of determining the quantitative content of the formulation components and the performance of pyroelements made from the proposed pyrotechnic heat-generating composition were confirmed during testing, as well as in a heat-generating device under bench-scale installation conditions.

[0046] A comparative analysis of the proposed technical solution with identified prior art analogs, from which the invention does not clearly follow for a specialist in the field of pyrotechnics, showed that it is unknown, and taking into account the practical possibility of serial production of a pyrotechnic heat-generating composition for various heat-generating devices, including devices for destroying solid-state storage media, it can be concluded that it meets the criteria of patentability.

Claims

A pyrotechnic heat-generating composition containing iron oxide as an oxidizer, characterized in that the composition contains aluminum powder as a fuel, aluminum oxide as an inert additive, and nitro film as an active binder, wt.%: aluminum powder 15-20 iron oxide 48-53 aluminum oxide 25-30 nitro film 2-7

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