White Light Compositions

A flame tanperature of less than 2,000°C will produce a minimum amount of white light by onission from incandescent particles or from excited gaseous sodium atoms. 

Therefore, the initial choice for an oxidizer is one with an exothermic heat of decomposition such as potassium chlorate (KCIO3). However, binary mixtures containing either a chlorate and perchlorate salt with active metal fuels are usually 

The nitrates are considerably endothermic in their decomposition, and therefore deliver less heat per mole than chlorates or perchlorates, but they can be used with somewhat less fear of accidental ignition. However, if fine metal fuel particles are used, static electricity is always a concern regardless of the oxidizer that is used. 

Barium nitrate is often selected for use in white light mixtures. The barium oxide (BaO) product formed upon reaction is a good, broad-range molecular emitter in the vapor phase (the boiling point of BaO is ca. 2,000°C), and condensed particles of BaO found in the cooler parts of the flame are also good emitters of incandescent light. 

For a stoichiometric mixture, 121.5 grams of magnesium and 170 grams of sodium nitrate correspond to the balanced chemical equation (41.6% magnesium and 58.4% 

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A1 (powder) 20 and sulfur 18.9% (Ibid p 191) After WWI, most of the research and development in pyrotechnic compositions for the US Army was carried out at Picatinny Arsenal, where the development of white light compositions proceeded along the following lines 1)... 

The airplane wing-tip flares which were used for signaling during the first World War are good examples23 of aluminum compositions. They were loaded in cylindrical paper cases 4 inches in length and 1% inches in internal diameter. The white light composition consisted of 77 parts of barium nitrate, 13 of flake aluminum, and 5 of sulfur intimately mixed and secured by a binder of shellac, and burned in the cases mentioned, for 1... 

White Light Compositions wiih Sulfate as Oxidizer... 

Triboluminescence is the phenomenon that is observed when coloured light is emitted on grinding, crushing or fracturing certain crystalline compounds, e.g. the bluish white light emitted from sugar. This phenomenon has been known for over 300 years but has remained a curiosity without an obvious application, until very recently when Sage postnlated that this effect could be used to detect flaws in composite materials. ... 

Magnesium metal is the fuel found in most military illuminating compositions, as well as in many fireworks devices. Aluminum and titanium metals, the magnesium /aluminum alloy "magnasium," and antimony sulfide (Sb2S3) are used for white light effects in many... 

The presence of incandescent solid or liquid particles in the flame will adversely affect color quality. The resulting "black body" emission of white light will enhance overall emission intensity, but the color quality will be lessened. A "washed out" color will be perceived by viewers. The use of magnesium or aluminum metal in color compositions will yield high flame temperatures and high overall intensity, but broad emission from incandescent magnesium oxide or aluminum oxide products may lower color purity. 

An improved display exploits scattering in a PLZT of similar composition to that described above but with the grain size increased to about 4.5 /rm. This device has the advantage that it eliminates the need for the polarizer and analyser and the straining arrangement also, white light can be used for both the write and read operations. 

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