Photoflash formulations

Photoflash compns containing Hf and K perchlorate possess greater luminous efficiency on a volume basis than do other formulations (Ref 128). Zr, for example, when burned in oxygen has an average color temp of 4883°K compared with 5235°K for Hf when measured at peak intensity (Ref 65). In pyrotechnic flash units, substitution of Al with Hf and Ti produced comparable peak output, but inferior output... 

In a nutshell, Mg and Al are the most commonly used pyrotechnic fuels to create heat and light. Both have been used in the development of radiation effect. While Mg is the fuel of choice for most illuminating and tracer formulations, Al is still the main ingredient of photoflash and thermite formulations. The pyrotechnic behavior of Mg is due to its low melting and boiling points in comparison to most... 

Some pyrotechnic formulations are used for photographic purposes and the main requirement of such formulations is that they should produce a very powerful illumination for a short duration. Such pyrotechnic formulations are known as photoflash formulations and are used in photoflash cartridges, photoflash bombs and dust bombs. 

Aluminum powder is used in photoflash formulations with barium nitrate or potassium perchlorate as oxidizers. Further, it is never used with sodium nitrate because of their chemical incompatibility in the presence of moisture. However, potassium and calcium nitrates have been used for this purpose. 

The main reactions involved in the photoflash formulations are as follows (Equations 5.4—5.6) ... 

Edelman, Kaye and Jackson (Ref 10) found that a photoflash formulation containing Hf as a replacement for Al exhibited a greater luminous efficiency on a volumetric basis than did the standard 60/40 K perchlorate/Al mixt, and that Hf could also be used as an alternative to Al in a formulation of the PI type (Ba nitrate 30%,... 

Zinc-carbon batteries are made in a number of different sizes with different formulations to meet a variety of applications. The single-cell and multicell batteries are classified by electrochemical system, either Leclanche or zinc chloride, and by grade general purpose, heavy duty, extra heavy duty, photoflash, and so on. These grades are assigned accortUng to their output performance under specific discharge conditions. 

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