Worth, Texas, September, 1983.
2C 20 4 ) and cryolite (Na 3 AlF G ) are low in hygroscopicity and they are therefore the color agents used in most commercial yellow flame mixtures. Some representative yellow compositions are given in Table 7.13.
Most sodium compounds tend to be quite hygroscopic, and REFERENCES
therefore simple compounds such as sodium nitrate (NaNO 3 ), sodium chlorate (NaG10 3 ), and sodium perchlorate (NaC10,,) - com-1.
B. E. Douda, "Theory of Colored Flame Production," RDTN
bining the oxidizing anion with the metallic emitter - can not be No. 71, U.S. Naval Ammunition Depot, Crane, Indiana, 1964.
used unless precautions are taken to protect against moisture
166
Chemistry of Pyrotechnics
2.
K. L. Kosanke, "The Physics, Chemistry and Perception of Colored Flames," Pyrotechnica VII, Pyrotechnica Publications, Austin, Texas, 1981.
3.
B. E. Douda, "Spectral Observations in Illuminating Flames,"
Proceedings, First International Pyrotechnics Seminar, Denver Research Institute, Estes Park, Colorado, August, 1968, p. 113 (available from NTIS as AD 679 911).
4.
D. R. Dillehay, "Pyrotechnic Flame Modeling for Sodium D-Line Emissions," Proceedings, Fifth International Pyrotechnics Seminar, Denver Research Institute, Vail, Colorado, July, 1976, p. 123 (available from NTIS as AD A087 513).
5.
A. A. Shidlovskiy, Principles of Pyrotechnics, 3rd Ed. , Moscow, 1964. (Translated by Foreign Technology Division, Wright-Patterson Air Force Base, Ohio, 1974.) 6.
T. Shimizu in R. Lancaster's Fireworks Principles and Practice, Chemical Publishing Co., Inc., New York, 1972.
7.
U.S. Army Material Command, Engineering Design Handbook, Military Pyrotechnic Series, Part One, "Theory and Application," Washington, D.C., 1967 (AMC Pamphlet 706-185).
8.
F. L. McIntyre, "A Compilation of Hazard and Test Data for Pyrotechnic Compositions," Report ARLCD-CR-80047, U.S. Army Armament Research and Development Command, Dover, NJ, 1980.
9.
Pyrotechnica IV, Pyrotechnica Publications, Austin, Texas, 1978.
10.
R. M. Winokur, "The Pyrotechnic Phenomenon of Glitter,"
Pyrotechnica II, Pyrotechnica Publications, Austin, Texas, 1978.
11.
T. Shimizu, Fireworks - The Art, Science and Technique,
pub. by T. Shimizu, distrib. by Maruzen Co., Ltd., Tokyo, 1981.
12.
T. Shimizu, "Studies on Strobe Light Pyrotechnic Composi-A portion of the "finale" of a fireworks display. Several hundred tions," Pyrotechnica VIII, Pyrotechnica Publications, aerial shells are usually launched in a brief period of time to over-Austin, Texas, 1982.
whelm the senses of the audience. A Japanese "chrysanthemum"
13.
T. Shimizu, "Studies on Blue and Purple Flame Composi-shell with its characteristic large, symmetrical burst of color can tions Made With Potassium Perchlorate," Pyrotechnica VI, be seen near the center of the photograph. Several American aerial Pyrotechnica Publications, Austin, Texas, 1980.
shells, with their more-random bursting pattern, can also be seen.
14.
Pyrotechnica I, Pyrotechnica Publications, Austin, Texas, The bright "dots" of light seen in the picture are the bursts of 1977.
"salutes"; these are tubes containing "flash and sound" composition that explode to create a booming noise and a flash of light.
(Zambelli Internationale)
8SMOKE AND SOUND
SMOKE PRODUCTION
Most explosive and pyrotechnic reactions produce significant quantities of smoke, and this visible phenomenon may or may not be desirable. Smoke can obscure colored flames, and therefore attempts are made to keep the production of smoke to a minimum in such mixtures. However, a variety of smoke-producing compositions are purposefully manufactured for use in daytime signalling and troop and equipment obscuration, as well as for amuse-ment and entertainment purposes.
Two basic processes are used to create smoke clouds: the condensation of vaporized material and the dispersion of solid or liquid particles. Materials can either be released slowly via a pyrotechnic reaction or they can instantaneously be scattered using an explosive material. Technically, a dispersion of fine solid particles in air is termed a smoke, while liquid particles in air create a fog. A smoke is created by particles in the 10 -5-10-9 meter range, while larger suspended particles create a dust (1) .
A variety of events that will lead to smoke production can occur in the pyrotechnic flame. Incomplete burning of an organic fuel will produce a black, sooty flame (mainly atomic carbon). A highly-oxidized fuel such as a sugar is not likely to produce carbon. Materials such as naphthalene (C 10H 8) and anthracene ( C 1,,H 10 ) - volatile solids with high carbon content - are good candidates for soot production. Several mixtures that will produce black smokes are listed in Table 8. 1.
The heat from the reaction between an oxidizer and fuel can vaporize a volatile ingredient, with no chemical change occurring 167
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Chemistry of Pyrotechnics
Smoke and Sound
169
phosphorus oxides, creates dense white smoke as the oxides atTABLE 8.1
Black Smoke Compositions
tract moisture to form acids such as phosphoric acid, H 3POa .
% by
Composition
weight
Reference
COLORED SMOKE MIXTURES
I.
Potassium chlorate, KC10 3
55
1
The generation of colored smoke by the volatilization of an or-Anthracene, C 1,,H10