Method of safely initiating combustion of a gas generant composition using an autoignition composition

• US 6,221,187 B1
• Filed: 01/21/1999
• Issued: 04/24/2001
• Est. Priority Date: 05/14/1996
• Status: Expired due to Term

• Current Assignee: Nammo Talley, Inc. (Nammo AS)
• Original Assignee: Nammo Talley, Inc. (Nammo AS)
• Inventors: Ludwig, Christopher P., Knowlton, Gregory D.
• Primary Examiner(s): Miller, Edward A.
• Application Number:
  US09/234,884
• Time in Patent Office: 824 Days
• Field of Search: 149/38, 149/37, 149/47, 149/43, 149/77, 149/41, 102/329, 102/205
• US Class Current: 149/38
• CPC Class Codes: B32B 27/10 of paper or cardboard
• CPC Class Codes: C06B 33/00 Compositions containing particulate metal, alloy, boron, silicon, selenium or tellurium with at least one oxygen supplying material which is either a metal oxide or a salt, organic or inorganic, capable of yielding a metal oxide
• CPC Class Codes: C06C 9/00 Chemical contact igniters; Chemical lighters

Abstract

The present invention relates to a low temperature autoignition composition for safely initiating combustion of a main pyrotechnic charge in a gas generator or pyrotechnic device exposed to flame or a high temperature environment. The low temperature autoignition compositions of the invention include a mixture of an oxidizer and a powdered metal, wherein the oxidizer includes a comelt or mixture comprising ammonium nitrate and at least one of an alkali metal nitrate, an alkaline earth metal nitrate, a complex salt nitrate, a dried, hydrated nitrate, an alkali metal chlorate, an alkali metal perchlorate, an alkaline earth metal chlorate, an alkaline earth metal perchlorate, ammonium perchlorate, sodium nitrite, potassium nitrite, silver nitrite, a complex salt nitrite, a solid organic nitrate, a solid organic nitrite, or a solid organic amine, and where the metal fuel and oxidizer are present in amounts sufficient to provide an autoignition composition having an autoignition temperature of no more than about 232° C. The present invention also relates to a method for initiating a gas generating composition or pyrotechnic composition in a gas generator or pyrotechnic device exposed to flame or a high temperature environment. In the method of the invention, the gas generating composition or pyrotechnic composition is placed in thermal contact with a low temperature autoignition composition of the invention.

Claims

1. A method of safely initiating combustion of a gas generating composition or pyrotechnic composition in a gas generator or pyrotechnic device having a housing when the gas generator or pyrotechnic device is exposed to flame or a high temperature environment, the method comprising:

forming a low temperature autoignition composition having an autoignition temperature by mixing an oxidizer composition and a powdered metal fuel, wherein the oxidizer composition comprises a mixture or comelt comprising ammonium nitrate and at least one of an alkali metal nitrate, an alkaline earth metal nitrate, silver nitrate, a complex salt nitrate, a dried, hydrated nitrate, an alkali metal chlorate, an alkali metal perchlorate, an alkaline earth metal chlorate, an alkaline earth metal perchlorate, ammonium perchlorate, sodium nitrite, potassium nitrite, a solid organic nitrate, a solid organic nitrite, or a solid organic amine, wherein the metal fuel and oxidizer are present in amounts sufficient to provide an autoignition composition having an autoignition temperature of no more than about 232°

C.; and

placing the low temperature autoignition composition in thermal contact with the gas generating composition or pyrotechnic composition within the gas generator or pyrotechnic device, such that the low temperature autoignition composition autoignites and initiates combustion of the gas generating composition or pyrotechnic composition when the gas generator or pyrotechnic device is exposed to flame or a high temperature environment.

2. The method of claim 1, further comprising selecting the powdered metal fuel from the group consisting of molybdenum, magnesium, calcium, strontium, barium, titanium, zirconium, vanadium, niobium, tantalum, chromium, tungsten, manganese, iron, cobalt, nickel, copper, zinc, cadmium, tin, antimony, bismuth, aluminum, cerium, and silicon.

3. The method of claim 2, further comprising selecting the powdered metal fuel from the group consisting of molybdenum, magnesium, titanium, zirconium, niobium, nickel, chromium, zinc, aluminum, and cerium.

4. The method of claim 3, further comprising selecting the powdered metal fuel from the group consisting of molybdenum, magnesium, titanium, zirconium, zinc, and cerium.

5. The method of claim 4, further comprising selecting molybdenum as the powdered metal fuel.

6. The method of claim 5, further comprising mixing the molybdenum fuel with the oxidizer in an amount that is greater than the stoichiometric amount of molybdenum to decrease the autoignition temperature.

7. The method of claim 5, further comprising forming a comelt comprising ammonium nitrate as the oxidizer, and grinding the comelt to a particle size of about 10 to about 30 microns, and grinding the molybdenum powdered metal fuel to a particle size of less than about 6 microns.

8. The method of claim 1, further comprising selecting an oxidizer of a comelt or mixture comprising ammonium nitrate and at least one of guanidine nitrate, nitroguanidine, tetramethyl ammonium nitrate, 5-aminotetrazole, and barbituric acid.

9. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with guanidine nitrate.

10. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with nitroguanidine.

11. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with tetramethyl ammonium nitrate.

12. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with tetramethyl ammonium nitrate and guanidine nitrate.

13. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with 5-aminotetrazole.

14. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with 5-aminotetrazole and potassium chlorate.

15. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with 5-aminotetrazole and potassium perchlorate.

16. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with barbituric acid.

17. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with barbituric acid and potassium chlorate.

18. The method of claim 8, further comprising forming the oxidizer by mixing ammonium nitrate with barbituric acid and potassium perchlorate.

19. The method of claim 1, further comprising mixing the low temperature autoignition composition with an output augmenting composition, the output augmenting composition comprising an energetic oxidizer of ammonium perchlorate, alkali metal chlorate, alkali metal perchlorate or alkali metal nitrate, in combination with a metal or boron, such that the low temperature autoignition composition autoignites and initiates combustion of the output augmenting composition, which initiates combustion of the gas generating composition or pyrotechnic composition when the gas generator or pyrotechnic device is exposed to flame or a high temperature environment.

20. The method of claim 19, further comprising selecting the metal for the output augmenting composition from the group consisting of Mg, Ti, and Zr.

21. The method of claim 1, further comprising mixing the low temperature autoignition composition with an output augmenting composition, which comprises an energetic oxidizer of ammonium perchlorate, alkali metal perchlorate or alkali metal nitrate, in combination with boron.

22. The method of claim 1, further comprising adding a metal oxide catalyst to the low temperature autoignition composition.

23. The method of claim 22, further comprising selecting the metal oxide catalyst from the group consisting of Al₂O₃, SiO₂, CeO₂, V₂O₅, CrO₃, Cr₂O₃, MnO₂, Fe₂O₃, Co₃O₄, NiO, CuO, ZnO, ZrO₂, Nb₂O₅, MoO₃, and Ag₂O.

24. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 10 to about 70 percent by weight Guanidine Nitrate, from about 10 to about 70 percent by weight Ammonium Nitrate, and from about 10 to about 45 percent by weight Mo.

25. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 5 to about 65 percent by weight Guanidine Nitrate, from about 5 to about 65 percent by weight Nitroguanidine, from about 10 to about 70 percent by weight Ammonium Nitrate, and from about 5 to about 45 percent by weight Mo.

26. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 10 to about 50 percent by weight Guanidine Nitrate, from about 3 to about 15 percent by weight Tetramethyl Ammonium Nitrate, from about 10 to about 65 percent by weight Ammonium Nitrate, and from about 5 to about 45 percent by weight Mo.

27. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 5 to about 70 percent by weight Tetramethyl Ammonium Nitrate, from about 35 to about 80 percent by weight Ammonium Nitrate, and from about 5 to about 45 percent by weight Mo.

28. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 5 to about 45 percent by weight 5-ATZ, from about 5 to about 60 percent by weight KClO₃, from about 5 to about 70 percent by weight Ammonium Nitrate, and from about 5 to about 45 percent by weight Mo.

29. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 5 to about 50 percent by weight 5-ATZ, from about 5 to about 60 percent by weight KClO₄, from about 5 to about 70 percent by weight Ammonium Nitrate, and from about 5 to about 45 percent by weight Mo.

30. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 5 to about 35 percent by weight Barbituric Acid, from about 5 to about 70 percent by weight KClO₃, from about 5 to about 75 percent by weight Ammonium Nitrate, and from about 5 to about 45 percent by weight Mo.

31. The method of claim 1, further comprising forming the low temperature autoignition composition by forming a composition comprising from about 5 to about 40 percent by weight Barbituric Acid, from about 5 to about 65 percent by weight KClO₄, from about 5 to about 75 percent by weight Ammonium Nitrate, and from about 5 to about 45 percent by weight Mo.