Stabilizing Firework Compositions – I. Minimum Solubility Law to Foresee the Degeneration, II. A New Chemical Method of Magnesium Coating

Dr Takeo Shimizu

ABSTRACT:

These studies concern two important problems at present: one is how to select the component materials of a mixture not to cause degeneration, and another is to find a more effective method of magnesium coating than those at present. A firework mixture generally consists of several solid materials which are closely in contact with each other. The state is not so much natural as artificial. Therefore, the mixture often causes chemical degeneration to remove into a more stable state which is opposite to the purpose. The direction of the change has been unknown without experiences. It has been a great difficulty on selecting materials. I have found a rule to foresee the direction: the component materials in a mixture gradually decompose with each other to create the most water insoluble material. This tendency should be called the “minimum solubility law”. A table was prepared to foresee the direction of the degeneration reactions arranging materials in the order of their solubilities. When a magnesium flake is soaked in a solution of dichromate and sulfate, the flake is gradually coated with a thin black film. It may be CrO₂ and have a high corrosion resistance. The effect was tested with several dichromates and sulfates against mainly ammonium perchlorate using magnesium ribbon and powder. In addition an effect of guanidine nitrate on the coating was observed because it gave a good result of corrosion resistance  when it was used as a blinker (strobes) in the past.

(SH1_063)

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