Patent Publication Number: US-3876478-A

Title: Light sensitive explosive mixture

Description:
O United States Patent 1 1 1111 3,876,478 Menichelli Apr. 8, 1975 LIGHT SENSITIVE EXPLOSIVE MIXTURE 3,055,780 9/1962 Finnegan et al. 149/24 x 3.420,l37 1/1969 Staba [75] Inventor: Vlncent J. Menlchelh, Glendale, 3 6|7 405 H971 Sevenson n Callf- 3,725,5l6 4/1973 Kaufman 149/42 x (73] Assignee: The United States of America as represented by the Secretary of the Imar E.\ 1n1n1erBen am1n R. Padgett Navy wdshmgton Assistant Examiner-P. A. Nelson [22] Filed: Dec. 18, 1972 Attorney, Agent, or FirmRichard S. Sciascia; Joseph 21 Appl. 190.; 321,484 wand [52] US. Cl. 149/24; 149/39; 149/40;  
  149/42; 149/76; 149/111 [57] ABSTRACT [5i] Int. Cl C06b 1/04 An ex I ploslve mlxture wh1ch can be InItIated by a [58] Field of Search 149/24 1232 strong light source, the mixture consisting of a composition of ammonium perchlorate, lead styphnate, and [56] References Cited Zlrcomum&#39; UNITED STATES PATENTS 2 Claims N0 Drawings 2.951.752 9/l960 Stevenson 149/42 LIGHT SENSITIVE EXPLOSIVE MIXTURE BACKGROUND OF THE INVENTION The present invention relates to explosive Compositions and more particularly to a primer composition which is adapted to be initiated by a strong light source.  
  Prior methods for initiation of explosive devices have involved compositions requiring either electrical pulse or bridge wire. or mechanical percussion or friction means for ignition or detonation. However, none of the prior known explosive compounds are initiated from a strong light source.  
  The advantage of a light initiated device is in its response to a unique form of energy, i.e., a light pulse of a given spectrum and intensity.  
  Increased safety in handling light initiated devices can be realized because many problems associated with electromagnetic pick-up in electrical initiated devices is eliminated. Increased reliability will be observed due to the simplicity of the workings of such a device.  
 OBJECTS OF THE INVENTION An object of the invention is to provide an explosive mixture which is initiated by a strong light source.  
  Another object is to provide an explosive for fuzing or ordnance applications where initiation of the explosive is from high-intensity light sources whose wavelength is of a select bandwidth.  
  Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention.  
 SUMMARY OF THE INVENTION The present invention consists of mixtures of ammonium perchlorate (NH ClO4), lead styphnate (PbC H -,N O). and Zirconium (Zr) which. when properly mixed to achieve homogeneity, can be initiated by a high-intensity light source.  
 DESCRIPTION OF PREFERRED EMBODIMENTS A preferred embodiment of the invention consists of a mixture. in equal proportions by weight, of ammonium perchlorate (NH CIO lead styphnate (PbC H N O and zirconium (Zr). Very fine control must be maintained over purity, particle size and particle size distribution. The ingredients should be 99 percent pure or better. the particles should average microns in size, and the particle size distribution should range from 100 to 7 microns in size. The ingredients are dried mixed in a rotary type blender to give a homogeneous composition. In the process, it is important to achieve homogeneity.  
  The advantage of this new mixture is its selective sensitivity to a pulse of light energy. Several characteristics of the mixture are its sensitivity to Xenon flash lamp and its impact sensitivity. The mixture will initiate from the light output ofa 3-inch long Xenon lamp when fired from a capacitor bank (400 micro farads) charged to approximately 900 volts. Sensitivity to impact using a 2-kilogram weight gave a mean height of 3225 centimeters. PETN on the same machine measured 28.0 centimeters. The explosive mixtures disclosed herein are sensitive to a wavelength spectrum range of from 2.500 A to 10.000A, which includes the ruby frequencies and neodynium laser frequencies, and can be initiated with less than a joule of energy. A lensing system, such as disclosed in copending US. Pat. application, Ser. No. 765,749 filed Oct. 3, 1968, for OPTICAL SEMI-ACTIVE BOMBLET FUZE&#34; can be advantageous to focus high-intensity light energy onto the ex plosive mixture.  
  Other combinations can be concocted but would not be optimum. Zirconium, because of its color, is a good absorber oflight energy and, because of its high chemical reactivity, acts as the fuel for the system. Ammonium perchlorate is an ideal oxidizing agent to chemically react with the zirconium supplying heat and gas to the system. Lead styphnate accelerates the reaction to a very high velocity (close to detonation) and insures the reliable transfer of initiation to the next increment in an explosive train.  
 Other operable mixtures are listed below:  
 25 percent lead styphnate 25 percent ammonium perchlorate 50 percent zirconium 50 percent lead styphnate 25 percent ammonium perchlorate 25 percent zirconium 25 percent lead styphnate 50 percent ammonium perchlorate 25 percent zirconium 15 percent lead styphnate 15 percent ammonium perchlorate percent zirconium 50 percent ammonium perchlorate 50 percent zirconium 50 percent lead styphnate 50 percent zirconium 50 percent potassium perchlorate 50 percent zirconium  Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.  
 I claim:  
 1. An explosive composition for initiation from highintensity light sources, comprising:  
 a. a homogeneous mixture of ingredients consisting in proportion by weight of 25 to 70 percent zirconium, 15 to 50 percent ammonium perchlorate. and l5 to 50 percent lead styphnate;  
 b. said ingredients being 99 percent pure and having particle size averaging 40 microns with particle size distribution ranging from 100 to 7 microns in size;  
 0. said homogeneous mixture being sensitive to a wavelength spectrum range of from 2,500 A to 10,000 A, which includes the ruby frequencies and neodynium laser frequencies, and can be initiated with less than a joule of energy.  
 2. An explosive composition as in claim 1 wherein the mixture of ingredients is in equal proportions by