Igniter pellet and related composition for decoy countermeasure assembly

Abstract

The present technology is directed to igniter pellets for use with an expendable countermeasure flare assembly with an igniter assembly with a pellet receptacle. An igniter pellet of one or more embodiments has a moisture insensitive first layer formed by a first composition comprising a mixture of a fuel material that includes Boron, an oxidizer material that includes Bismuth Oxide and/or Potassium Perchlorate, and a granular matrix binder holding the fuel material and the oxidizer material together. A second layer is formed by a second composition that has a fuel material that includes Magnesium, an oxidizer that includes Polytetrafluoroethylene, and a binder material that includes a fluoropolymer elastomer. The second layer is contained in the pellet receptacle and covered by the first layer, so that the second layer is isolated and protected from ambient moisture by the moisture insensitive first layer.

I claim: 
     
         1 . An igniter pellet for use with an expendable countermeasure flare assembly having an igniter assembly with a pellet receptacle therein, the igniter pellet comprising:
 a first layer formed by a first composition comprising a mixture of a first fuel material that includes Boron, a first oxidizer material that includes Bismuth Oxide and/or Potassium Perchlorate, a granular matrix binder holding the fuel material and the oxidizer material together, wherein the first composition is insensitive to ambient moisture;   a second layer formed by a second composition different than the first composition, the second composition comprising a second fuel material that includes Magnesium, a second oxidizer that includes Polytetrafluoroethylene, and a binder material that includes a fluoropolymer elastomer;   wherein the second layer is configured to be contained in the pellet receptacle and covered by the first layer so that the second layer is isolated and protected from ambient moisture by the moisture insensitive first layer.   
     
     
         2 . The igniter pellet of  claim 1  wherein the first layer is positioned onto the second layer with an interface area there between configured to propagate ignition from the first layer to the second layer. 
     
     
         3 . The igniter pellet of  claim 1  wherein the first and second layers are arranged with an interface area between the layers in which a portion of the first composition mixes with a portion of the second composition to form an ignition pathway from the first composition to the second composition. 
     
     
         4 . The igniter pellet of  claim 1  wherein the first layer is pressed into fixed engagement with the second layer with an interface area there between configured to propagate ignition from the first layer to the second layer. 
     
     
         5 . The igniter pellet of  claim 1  wherein the first layer is applied to the second layer in a slurry format. 
     
     
         6 . A method of forming an igniter pellet for use with a countermeasure assembly having an impulse cartridge with a pellet receptacle therein, the method comprising:
 Forming a moisture-insensitive first ignition composition for a first layer of the igniter pellet by:
 dissolving a first rubber-based binder in a polar solvent to form a binder solution; 
 mixing the binder solution with a first fuel material that includes Boron, and a first oxidizer material that includes Bismuth Oxide and/or Potassium Perchlorate to form a first mixture; 
 adding a low boiling point non-polar solvent to the mixture and precipitating the binder from the mixture to form a coagulation composition; 
 converting the coagulation composition to a first moldable granular composition; 
   Providing a second ignition composition that comprises a mixture of Magnesium, Polytetrafluoroethylene and a fluoropolymer elastomer binder;   Positioning the first and second ignition compositions into the pellet receptacle of the impulse cartridge wherein the first composition forms a first layer, and the second composition forms a second layer that is covered and isolated from ambient moisture by the first layer.   
     
     
         7 . The method of  claim 6  wherein the polar solvent is a ketones or ketone mixture. 
     
     
         8 . The method of  claim 6  wherein the non-polar solvent is a saturated hydrocarbon material. 
     
     
         9 . The method of  claim 6  wherein the ketones or ketone mixtures. 
     
     
         10 . The method of  claim 6  wherein the second composition is a mixture of Magnesium, Teflon, and Viton®. 
     
     
         11 . The method of  claim 6  wherein positioning the first and second ignition compositions into the pellet receptacle comprises pressing the second ignition composition into the pellet receptacle, and then pressing a layer of the first ignition composition over the second ignition composition in the pellet receptacle, wherein the layer of first ignition composition and the pellet receptacle substantially fully isolate the second composition from ambient moisture. 
     
     
         12 . The method of  claim 6  wherein positioning the first and second ignition compositions into the pellet receptacle comprises pressing the first and second compositions together to form a layered arrangement with an interface area between the first and second compositions where the portions of the first composition mixes with the second composition to form an ignition pathway from the first composition to the second composition. 
     
     
         13 . The method of  claim 6  wherein positioning the first and second ignition compositions into the pellet receptacle comprises applying the first composition over the second composition in a slurry format. 
     
     
         14 . A deployable infrared countermeasure assembly, comprising:
 An outer case suitable for installation into countermeasure dispensing systems and containing;   A port for installation of an impulse cartridge to eject the countermeasure payload;   An Igniter Assembly to transfer the ignition train from the impulse cartridge to the countermeasure flare payload, the igniter assembly having an igniter pellet therein;   A deployable, ignitable payload to provide the Infrared Signature;   An impulse cartridge coupled to the base portion or port of the outer flare case, wherein the impulse cartridge comprises an electrical activator adjacent to an ignition and output charge, wherein the output charge expels the payload including the igniter assembly containing the hybrid ignition pellet   Wherein the ignition pellet comprises:
 a first layer formed by a first composition comprising a mixture of a first fuel material that includes Boron, a first oxidizer material that includes Bismuth Oxide and/or Potassium Perchlorate, a granular matrix binder holding the fuel material and the oxidizer material together, wherein the first composition is insensitive to ambient moisture; 
 a second layer formed by a second composition different than the first composition, the second composition comprising a second fuel material that includes Magnesium, a second oxidizer that includes Polytetrafluoroethylene, and a binder material that includes a fluoropolymer elastomer; 
 wherein the second layer is configured to be fully contained in the igniter assembly and covered by the first layer so that the first layer is adjacent to the output of the impulse cartridge and the second layer is isolated and protected from ambient moisture by the moisture insensitive first layer. 
   
     
     
         15 . The igniter pellet of  claim 14  wherein the first layer is positioned onto the second layer with an interface area therebetween configured to propagate ignition from the first layer to the second layer. 
     
     
         16 . The igniter pellet of  claim 14  wherein the first and second layers are arranged with an interface area between the layers in which a portion of the first composition mixes with a portion of the second composition to form an ignition pathway from the first composition to the second composition. 
     
     
         17 . The igniter pellet of  claim 14  wherein the first layer is pressed into fixed engagement with the second layer with an interface area therebetween configured to propagate ignition from the first layer to the second layer. 
     
     
         18 . The igniter pellet of  claim 14  wherein the first layer is applied to the second layer in a slurry format. 
     
     
         19 . A method of forming an igniter pellet for use with a countermeasure assembly having an igniter assembly with a pellet receptacle therein, the method comprising:
 Forming a moisture-insensitive ignition composition by:
 dissolving a first rubber-based binder in a polar solvent to form a binder solution; 
 mixing the binder solution with a first fuel material that includes Boron, a first oxidizer material that includes Bismuth Oxide and/or Potassium Perchlorate, and a second oxidizer material and burn rate enhancer that includes finely divided Potassium Perchlorate powder to form a mixture; 
 adding a low boiling point non-polar solvent to the mixture and precipitating the binder from the mixture to form a coagulation composition; 
 converting the coagulation composition to a first moldable granular composition; 
   Positioning the moisture insensitive ignition composition into the pellet receptacle of the igniter assembly to form an igniter pellet adjacent to the output of the impulse cartridge.