Flitter vs Glitter

Flitter compositions based on potassium nitrate are not a principal topic of this paper. However, since flitter effects often intrude in discussions of glitter and since the flitter effect is often seen in experimental mixtures, a short discussion is necessary. The basic difference between glitter and flitter effects is that glitter effects burn the metal fuels in a sudden flash reaction, while flitter effects burn the metal fuels more gradually, thus the flash and associated sound are not found in flitter effects. 

In most formulas for potassium nitrate-based flitter effects, the sulfur content of the stars will be found to be below the stoichiometric requirements for the formation of sulfide from all of the potassium nitrate. In most of the formulas of this type there is insufficient carbon to perform the total reduction of the potassium nitrate to form sulfides. Potassium nitrate can react with sulfur to produce sulfate directly and this is common in flitter effects. In all cases flitter effects will be found to have insufficient molten sulfide melts to protect the aluminum from direct reaction with oxygen from air. A thin layer of potassium sulfide at the melting point is quickly oxidized and thus there is rapid loss of the sulfur content. A thin layer of potassium sulfide on aluminum is insufficient to cause delay. The oxidation of the aluminum takes place first through a rate moderating oxygen transport system liquid layer covering the aluminum and then must later take place within the solid jacket of potassium aluminate that forms over the aluminum. This explains the observation that most flitter sparks lose incandescence in a smooth decent of temperatures at the end of their burn. This can also explain why some formulas appear to produce sparks at more than one temperature. Adjustment of flitter effects is easily made with an understanding of the phenomenon involved. 

All of the sparks from formulas producing flitter effects from potassium nitrate mixtures have been found to go through a stage near the end of their burning where the spark has the composition of aluminum coated with alumina and aluminates coated with a very thin film of potassium oxides. 

It can be concluded that flitter effects will be generated by any of the following conditions  

Too much aluminum surface is present for the melt to cover to a depth or thickness sufficient to cause delay reactions. This is why the atomized aluminums are preferred in glitter mixtures and the flake types in flitter mixtures. 

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