30
Aluminum
40
7
Steel filings
30
chlorate, KC10,,
Dextrine
10
Barium nitrate,
30
Aluminum powder
8
Ba(N03)2
Fine charcoal
0.5
IV.
Barium nitrate,
54.5
Magnalium
45.5
8
Boric acid
1.5
Ba(NO 3 ) 2
Aluminum
4
III.
Potassium perchlorate,
42.1
White sparks
9
KC1O,,
Titanium
42.1
De xt rine
15.8
(Make a paste from dextrine
reaction temperature; they are the brilliant sparks seen in the and water, then mix in ox-popular "gold sparkler" ignited by millions of people on the 4th idizer and fuel)
of July.
IV.
Potassium perchlorate,
50
White sparks "water-
6
Magnesium metal does not produce a good spark effect. The KClO,,
falls" effect
metal has a low boiling point (1107°C), and therefore tends to
"Bright" aluminum
25
vaporize and completely react in the pyrotechnic flame [6]. "Mag-powder
nalium" can produce good sparks that burn in air with a novel,
"Flitter" aluminum ,
12.5
crackling sound. Several spark-producing formulas are given in 30-80 mesh
Table 7.4.
Remember, the particle size of the fuel is very impor-
"Flitter" aluminum,
12.5
tant in producing sparks - experimentation is needed to find the 5-30 mesh
ideal size.
For a good spark effect, the fuel must contain particles large enough to escape from the flame prior to complete combustion.
Note:
Particle size of the fuel is very important in determining Also, the oxidizer must not be too effective, or complete reac-the size of the sparks.
tion will occur in the flame. Charcoal sparks are difficult to achieve with the hotter oxidizers; potassium nitrate (KNO 3 ) -
with its low flame temperatures - works best. Some gas production is required to achieve a good spark effect by assisting in FLITTER AND GLITTER
the ejection of particles from the flame. Charcoal, other organic fuels and binders, and the nitrate ion can provide gas for this Several interesting visual effects can be achieved by careful se-purpose.
lection of the fuel and oxidizer for a spark-producing composition.
15 0
Chemistry of Pyrotechnics
Color and Light Production
151
A thorough review article discussing this topic in detail -- with TABLE 7.5 Glitter Formulasa
numerous formulas - has been published [101.
"Flitter" refers to the large white sparks obtained from the burning of large aluminum flakes. These flakes burn continuously upon ejection from the flame, creating a beautiful white effect, and they are used in a variety of fireworks items.
I.
Potassium nitrate, KNO 3
55
Good white Used in aerial
"Glitter" is the term given to the effect produced by molten
"Bright" aluminum powder 5
glitter
stars
droplets which, upon ejection from the flame, ignite in air to Dextrine
4
produce a brilliant flash of light. A nitrate salt (KNO
Antimony sulfide, Sb
3 is best)
2S3
16
and sulfur or a sulfide compound appear to be essential for the Sulfur
10
glitter phenomenon to be achieved. It is likely that the low melt-Charcoal
10
ing point (334°C) of potassium nitrate produces a liquid phase II. Potassium nitrate, KNO
that is responsible, at least in part, for this effect. Several B
55
Gold glitter Used in aerial
"Bright" aluminum powder 5
stars
"glitter" formulas are given in Table 7.5. The ability of certain Dextrine
4
compositions containing magnesium or magnalium alloy to burn in Antimony sulfide, Sb2S3
14
a pulsing, "strobe light" manner is a novel phenomenon believed Charcoal
8
to involve two distinct reactions. A slow, "dark" process occurs Sulfur
8
until sufficient heat is generated to initiate a fast, light-emitting reaction. Dark and light reactions continue in an alternate man-III. Potassium nitrate, KNO 3
55 Good white Used in foun-
ner, generating the strobe effect [11, 12].
Sulfur
10
glitter
tains
Charcoal
10
Atomized aluminum
10
Iron oxide, Fe
COLOR
203
5
Barium carbonate, BaCO 3 5
I ntroduction
Barium nitrate, Ba(N0 3) 2 5
Certain elements and compounds, when heated to high temperature, have the unique property of emitting lines or narrow bands of light in the visible region (380-780 nanometers) of the electro-a Reference 10.
magnetic spectrum. This emission is perceived as color by an observer, and the production of colored light is one of the most important goals sought by the pyrotechnic chemist. Table 7.6 lists the colors associated with the various regions of the visible spec-blue and red light in the proper proportions will produce a purple trum. The complementary colors - perceived if white light minus effect. Color theory is a complex topic, but it is one that should a particular portion of the visible spectrum is viewed -- are also be studied by anyone desiring to produce colored flames [2].
given in Table 7.6.
The production of a vividly-colored flame is a much more chal-To produce color, heat (from the reaction between an oxidizer lenging problem than creating white light. A delicate balance of and a fuel) and a color-emitting species are required. Sodium factors is required to obtain a satisfactory effect compounds added to a heat mixture will impart a yellow color to the flame. Strontium salts will yield red, barium and copper compounds can give green, and certain copper-containing mixtures 1. An atomic or molecular species that will emit the desired will produce blue. Color can be produced by emission of a narrow wavelength, or blend of wavelengths, must be present in band of light (e.g. , light in the range 435-480 nanometers is per-the pyrotechnic flame.