Ignition enhancing propellant coatings
AssigneeTeledyne McCormick Selph, an operating division of Teledyne Industries, Inc.
InventorsTerrence P. Goddard, Donald N. Thatcher, Charles G. Garrison
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Abstract
This invention teaches preparation of individual and uncoated propellant grains by incorporating a coating or integral layer of ignition compound, specifically simple salts of decahydrodecaboric acid and coprecipitates of these salts with an oxidizer. The resulting propellant grains so prepared exhibit substantially improved ignition capability, virtually independent of ambient conditioning temperature conditions at the time of use.
Claims23
A process for incorporating an ignition compound comprised of certain dechydrodecaborate compounds directly upon exterior surfaces of uncoated nitrocellulose-based propellant grains, through the steps of:
- (A) wetting uncoated, loose propellant grains on their exterior surfaces with a coating fluid having a solvating effect on said grains, the coating fluid being in the range of approximately 0.010 to 0.100 milliliters of fluid per gram of propellant,
- (B) introducing a layer of decahydrodecaborate compound onto the exterior surfaces of said grains as the result of the wetting effect of said coating fluid, wherein said compound is in the range of approximately 0.1 to 4.0% of the total propellant weight, wherein said compound further includes a salt selected from the class of salts having the common anion B.sub.10 H.sub.10.sup.-2, and a cation selected from the group consisting of:
- (i) ammonium, wherein the salt has the formula (NH.sub.4).sub.2 B.sub.10 H.sub.10 ;
- (ii) hydrazinium, wherein the salt has the general formula (NH.sub.2 NH.sub.3)B.sub.10 H.sub.10 ;
- (iii) metal ions derived from the elements in Groups 1, 2, 8, 3b, 4b, 5b, 6b, 7b, and the elements of Groups 3a, 4a, 5a, and 6a which have atomic numbers respectively greater than 5, 14, 33 and 52;
- and,
- (C) drying the thusly coated propellant grains until the exterior surface of each grain presents a dry appearance.
A process for incorporating an ignition compound comprised of certain dechydrodecaborate compounds directly upon exterior surfaces of uncoated nitrocellulose-based propellant grains, through the steps of:
- (A) wetting uncoated, loose propellant grains on their exterior surfaces with a coating fluid having a solvating effect on said grains, the coating fluid being in the range of approximately 0.010 to 0.100 milliliters of fluid per gram of propellant, and
- (B) introducing a layer of decahydrodecaborate compound onto the exterior surfaces of said grains as the result of the wetting effect of said coating fluid, wherein said compound is in the range of approximately 0.1 to 4.0% of the total propellant weight, wherein said compound further includes a salt selected from the class of salts having the common anion B.sub.10 H.sub.10.sup.-2, and a cation selected from the group consisting of:
- (i) substituted ammonium cations, wherein the salt has the general formula (R.sub.3 NH).sub.2 B.sub.10 H.sub.10, wherein further R is selected from the group consisting of hydrogen and alkyl radicals containing less than six carbon atoms;
- (ii) substituted hydrazinium cations, wherein the salt has the general formula (R.sub.2 NHR.sub.2 H).sub.2 B.sub.10 H.sub.10 wherein further R is selected from the group consisting of hydrogen and alkyl radicals contain less than six atoms;
- (iii) tetramethylammonium, (CH.sub.3).sub.4 N+, tetraethylammonium, (CH.sub.3 CH.sub.2).sub.4 N+, and quanternary ammonium cations having the general formula R.sub.4 N+ where R is an alkyl radical;
- (iv) pyrididinium, bipyridinium aryl-diazonium, aryl containing cations and substituted aryl containing cations.
- (v) the guanidinium cation, C(NH.sub.2).sub.3 +;
- and
- (D) drying the thusly coated propellant grains until the exterior surface of each grain presents a dry appearance.
Dependencies are inferred from the claim text.