Ignition material for an igniter

Abstract

An electrically actuatable igniter ( 24 ) comprises a pair of electrodes ( 40 ) and ( 42 ). A heating element ( 44 ) is electrically connected between said electrodes ( 40 ) and ( 42 ). An ignition material ( 48 ) is in contact with the heating element ( 44 ). The ignition material ( 48 ) comprises a metal powder and an oxidizer that exothermically reacts with the metal powder. The metal powder includes macro-agglomerates of metal particles. The metal particles have an average diameter less than about 0.1 μm and have an oxide layer that prevents contact of the particles with the oxidizer. The ignition material ( 48 ) deflagrates when the heating element is heated to a temperature of at least about 250° C.

1 . An electrically actuatable igniter comprising: 
 a pair of electrodes;    a heating element electrically connected between said electrodes; and    an ignition material in contact with said heating element, said ignition material comprising a metal powder and an oxidizer that exothermically reacts with said metal powder, said metal powder including macro-agglomerates of metal particles, said metal particles having an average diameter less than about 0.1 μm and having an oxide layer that prevents contact of said particles with said oxidizer, wherein said ignition material deflagrates when the heating element is heated to a temperature of at least about 250° C.    
   
   
       2 . The electrically actuatable igniter of  claim 1  wherein the macro-agglomerates have an average diameter of about 1 μm to about 2 μm.  
   
   
       3 . The electrically actuatable igniter of  claim 1  wherein said oxidizer is selected from the group consisting of alkali metal nitrates, alkaline earth metal nitrates, alkali metal perchlorates, alkaline earth metal perchlorates, alkali metal chlorates, alkaline earth metal chlorates, ammonium perchlorates, ammonium nitrate, and mixtures thereof.  
   
   
       4 . The electrically actuatable igniter of  claim 3  wherein the oxidizer has an average particle size of about 1 μm to about 30 μm.  
   
   
       5 . The electrically actuatable igniter of  claim 1  wherein the metal powder is selected from the group consisting of electro-exploded aluminum powder, electro-exploded titanium powder, electro-exploded copper powder, electro-exploded zinc powder, and electro-exploded yttrium powder.  
   
   
       6 . The electrically actuatable igniter of  claim 5  wherein the electro-exploded metal powder is electro-exploded aluminum.  
   
   
       7 . The electrically actuatable igniter of  claim 1  wherein the electro-exploded metal powder is about 15% to about 75% by weight of the ignition material.  
   
   
       8 . The electrically actuatable igniter of  claim 1  wherein the amount of oxidizer is about 25% to about 85% by weight of the ignition material.  
   
   
       9 . The electrically actuatable igniter of  claim 1  wherein the ignition material upon ignition deflagration produces an ignition product with a temperature of about 3000° C. to about 6000° C.  
   
   
       10 . The electrically actuatable igniter of  claim 1  wherein the ignition material does not thermally decompose at temperatures up to about 120° C.  
   
   
       11 . An electrically actuatable igniter comprising: 
 a pair of electrodes;    a heating element electrically connected between said electrodes; and    an ignition material in contact with said heating element, said ignition material comprising an electro-exploded metal powder and a particulate oxidizer, wherein said ignition material deflagrates when the heating element is heated to a temperature of at least about 250° C.    
   
   
       12 . The electrically actuatable igniter of  claim 11  wherein said oxidizer is selected from the group consisting of alkali metal nitrates, alkaline earth metal nitrates, alkali metal perchlorates, alkaline earth metal perchlorates, alkali metal chlorates, alkaline earth metal chlorates, ammonium perchlorate, ammonium nitrate, and mixtures thereof.  
   
   
       13 . The electrically actuatable igniter of  claim 12  wherein the oxidizer has an average particle size of about 1 μm to about 30 μm.  
   
   
       14 . An electrically actuatable igniter comprising: 
 a pair of electrodes;    a heating element electrically connected between said electrodes; and    an ignition material in contact with said heating element, said ignition material comprising a uniformly dispersed mixture of a metal powder and a particulate inorganic salt oxidizer that exothermically reacts with said metal powder, said oxidizer having an average particle size of about  1  μm to about 30 μm, said metal powder being selected from the group consisting of electro-exploded aluminum powder, electro-exploded titanium powder, electro-exploded copper powder, electro-exploded zinc powder, and electro-exploded yttrium powder, wherein said ignition material does not thermally decompose at temperatures up to about 120° C. and deflagrates when the heating element is heated to a temperature of at least about 250° C., wherein said ignition material is free of a binder and the mixture of metal powder and particulate oxidizer being formed without the use of a solvent.    
   
   
       15 . The electrically actuatable igniter of claim  33  wherein the oxidizer is selected from the group consisting of alkali metal nitrates, alkaline earth metal nitrates, alkali metal perchlorates, alkaline earth metal perchlorates, alkali metal chlorates, alkaline earth metal chlorates, ammonium perchlorates, ammonium nitrate, and mixtures thereof.  
   
   
       16 . The electrically actuatable igniter of claim  33  wherein the electro-exploded metal powder is electro-exploded aluminum.  
   
   
       17 . The electrically actuatable igniter of claim  33  wherein the electro-exploded metal powder is about 15% to about 75% by weight of the ignition material.  
   
   
       18 . The electrically actuatable igniter of claim  33  wherein the amount of oxidizer is about 25% to about 85% by weight of the ignition material.  
   
   
       19 . The electrically actuatable igniter of claim  33  wherein the ignition material upon ignition produces an ignition product with a temperature of about 3000° C. to about 6000° C.  
   
   
       20 . The electrically actuatable igniter of claim  33  wherein said metal powder has a surface area of about 15 square meters per gram.  
   
   
       21 . An electrically actuatable igniter comprising: 
 a pair of electrodes;    a heating element electrically connected between said electrodes; and    an ignition material in contact with said heating element, said ignition material consisting essentially of a uniformly dispersed mixture of a metal powder and a particulate inorganic salt oxidizer, the metal power being present in the ignition material in an amount of about 25% to about 50%, by weight of the ignition material, said particulate oxidizer reacting exothermically with said metal powder, said particulate oxidizer having an average particle size of about 1 μm to about 30 μm, wherein said metal powder consists of electro-exploded aluminum powder and said ignition material deflagrates when the heating element is heated to a temperature of at least about 250° C., the mixture of metal powder and particulate oxidizer being formed without the use of a solvent.    
   
   
       22 . The electrically actuatable igniter of claim  42  wherein said oxidizer is selected from the group consisting of alkali metal nitrates, alkaline earth metal nitrates, alkali metal perchlorates, alkaline earth metal perchlorates, alkali metal chlorates, alkaline earth metal chlorates, ammonium perchlorate, ammonium nitrate, and mixtures thereof.  
   
   
       23 . The electrically actuatable igniter of claim  42  wherein said ignition material upon deflagration produces an ignition product with a temperature of about 3000° C. to about 6000° C.