Pyrotechnic ignition materials are used for ignition in rocket motors. One example ignition material is boron potassium nitrate. Boron potassium nitrate has attractive handling characteristics; however, as an ignition material it has relatively low energy and ignition rate. While there are ignition materials that have higher energy and ignition rates, such materials fall short of the desired handling characteristics and thus cannot be used in substitute of boron potassium nitrate.
An ignition system according to an example of the present disclosure includes a wire having an outer jacket encasing an inner core. The outer jacket includes palladium and ruthenium, and the inner core includes aluminum, and a fluorine-containing polymer coating on the wire.
In a further embodiment of any of the foregoing embodiments, the fluorine-containing polymer coating includes a fluorocarbon polymer with carbon-fluorine bonds.
In a further embodiment of any of the foregoing embodiments, the fluorine-containing polymer coating is selected from a group consisting of polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyvinylidene fluoride (PVF), hexafluoropropylene (HFP), polyvinylfluoride (PVD), polyethylenetetrafluoroethylene (ETFE), and combinations thereof.
In a further embodiment of any of the foregoing embodiments, the outer jacket has, by weight, approximately 95% of palladium and approximately 5% of ruthenium.
In a further embodiment of any of the foregoing embodiments, the inner core has, by weight, approximately 95% of aluminum.
An ignition system according to an example of the present disclosure includes a multi-metallic ignition body including at least two metallic elements in contact with each other. The at least two metallic elements define an ignition initiation temperature above which there is a self-sustaining alloying reaction of the at least two metallic elements. A fluorine-containing body is in contact with the multi-metallic ignition body.
In a further embodiment of any of the foregoing embodiments, the at least two metallic elements include aluminum and palladium.
In a further embodiment of any of the foregoing embodiments, the at least two metallic elements further include ruthenium.
In a further embodiment of any of the foregoing embodiments, the at least two metallic elements includes a first metallic element and a second metallic element in one or more filaments, and each of the one or more filaments includes an outer jacket of the first metallic element that circumscribes an inner core of the second metallic element.
In a further embodiment of any of the foregoing embodiments, the multi-metallic ignition body includes a plurality of the filaments.
A method of fabricating an ignition system according to an example of the present disclosure includes providing a multi-metallic ignition body that includes at least two metallic elements in contact with each other and bringing a fluorine-containing body into contact with the multi-metallic ignition body. The at least two metallic elements define an ignition initiation temperature above which there is a self-sustaining alloying reaction of the at least two metallic elements.
In a further embodiment of any of the foregoing embodiments, the fluorine-containing body is a tube, and the bringing of the fluorine-containing body into contact with the multi-metallic ignition body includes shrink-wrapping the tube onto the multi-metallic ignition body.
In a further embodiment of any of the foregoing embodiments, the fluorine-containing body is initially a liquid, and the bringing of the fluorine-containing body into contact with the multi-metallic ignition body includes depositing the liquid onto the multi-metallic ignition body followed by solidifying the liquid to form the fluorine-containing body.
The various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
In the illustrated example, the metallic elements 24/26 of the multi-metallic ignition body 22 and the fluorine-containing body 30 are each provided as layers. Such layers are generally of uniform thickness and can be flat or curved, for example. As will be appreciated given this disclosure, the metallic elements 24/26 of the multi-metallic ignition body 22 and/or the fluorine-containing body 30 may alternatively be provided in geometries other than layers.
The metallic elements 24/26, as well as additional metallic elements if present, are reactive with each other, in the absence of oxygen, above an ignition initiation temperature. When heated above the ignition temperature by electric current or other energy source the metallic elements react in an exothermic self-sustaining alloying reaction to generate heat. The self-sustaining alloying reaction proceeds until the alloying is complete. For instance, the alloying reaction is rapid and results in deflagration without the support of oxygen.
While the reaction between the metallic elements 24/26 alone releases heat, at least the fluorine in the fluorine-containing body 30 also reacts to augment thermal release beyond that of the metals alone. For example, the fluorine serves as an oxidant to react with the metallic elements, the reaction products of the metallic elements, or both in a pyrotechnic chemical reaction. The exothermic reactions between the metallic elements, the metallic elements with the fluorine, and/or the byproducts of the metallic elements and fluorine releases heat and generates hot gases. The hot gases may contain the metallic elements, metal fluorides, fluorine, and/or metal carbides of the metallic elements. The hot gases may be utilized to rapidly pressurize and ignite a grain material, such as a solid propellant grain material in a rocket motor.
In one example, the metallic elements 24/26 of the multi-metallic ignition body 22 are based upon at least palladium and aluminum. For example the metallic element 24 is aluminum or an aluminum-based alloy and the metallic element 26 is palladium or a palladium-based alloy. Although not limited, one example of a useful aluminum alloy is aluminum alloy 5056, which has, by weight, approximately 5% magnesium, approximately 0.12% manganese, approximately 0.12% chromium, and a remainder of aluminum and any impurities.
In a further example, the multi-metallic ignition body 22 includes ruthenium as an additional, reactive metallic element. The ruthenium may be provided as an alloy with the palladium. In one example the palladium-ruthenium alloy includes, by weight, approximately 95% palladium and approximately 5% ruthenium.
In additional examples, the fluorine-containing body 30 is a fluorine-containing polymer. One example of a fluorine-containing polymer is a fluorocarbon polymer. As used herein, a fluorocarbon polymer is a polymer that has carbon-fluorine bonds. Non-limiting examples of fluorine-containing polymers include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyvinylidene fluoride (PVF), hexafluoropropylene (HFP), polyvinylfluoride (PVD), polyethylenetetrafluoroethylene (ETFE), and combinations thereof.
The ignition system 120 further includes a fluorine-containing body 130 in the form of a fluorine-containing polymer coating 130a that is in contact at interface 132 with the multi-metallic ignition body 122. The fluorine-containing polymer coating 130a may include the fluorine-containing polymer as described above.
By encasing the multi-metallic ignition body 122, the fluorine-containing polymer coating 130a protects the multi-metallic ignition body 122 from moisture infiltration, foreign substance exposure, mechanical damage, and the like. The ignition system 120 thus provides enhanced handling characteristics in combination with high energy release and good ignition rate from the reaction between the metals and also the fluorine oxidizer.
In the example shown, the wire or filament is substantially circular in cross-section.
The deposition technique may include initially providing the fluorine-containing polymer as a liquid. The liquid is deposited onto the multi-metallic ignition body 22/122 and then solidified to form the fluorine-containing body 30/130. The manner of deposition may be varied depending on the selected geometry of the ignition systems 20/120/220. Non-limiting examples may include dipping and spraying. The manner of solidification may depend on the type of polymer selected. As examples, the solidification may include curing the polymer or cooling the polymer.
Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.
This application claims priority to U.S. Provisional Application No. 62/156,247, filed on May 2, 2015.
Filing Document | Filing Date | Country | Kind |
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PCT/US2016/021985 | 3/11/2016 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2016/178744 | 11/10/2016 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3729935 | Fletcher et al. | May 1973 | A |
3734019 | Rentz et al. | May 1973 | A |
3776958 | Hill et al. | Dec 1973 | A |
4152988 | Haas | May 1979 | A |
4208967 | Betts | Jun 1980 | A |
5042386 | Kruse et al. | Aug 1991 | A |
6087591 | Nguyen | Jul 2000 | A |
6359230 | Hildreth | Mar 2002 | B1 |
20080241534 | Ohtani | Oct 2008 | A1 |
20120055594 | Kellett et al. | Mar 2012 | A1 |
20140209347 | Buck | Jul 2014 | A1 |
Entry |
---|
Anonymous. Sigmund Cohn—Pyrofuze. Retrieved May 27, 2016 from: https:/iweb.archive.orglwebl20150224220550/http:/isigmundcohn.com/internal.asp?pagel D=11. |
International Search Report for International Patent Application No. PCT/2016/021985 completed May 27, 2016. |
International Preliminary Report on Patentability for PCT/US2016/021985 dated Nov. 16, 2017. |
Number | Date | Country | |
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20180086676 A1 | Mar 2018 | US |
Number | Date | Country | |
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62156247 | May 2015 | US |