The burning and explosion of single crystals

Abstract

A study has been made of the combustion and explosion of single crystals of a number of compounds. These include the styphnates, fulminates and azides. A high-speed ciné microscope developed by Courtney-Pratt has been used. This enables magnified pictures of events lasting several milliseconds to be recorded. Crystals which have faults break up during combustion, and particles fly off at high speed. When the crystals are relatively free from faults the combustion may be followed along the length of the crystal and burning speeds may be measured. A variation in speed with crystal size and initial temperature has been observed, and this is discussed in relation to thermal losses during burning. The combustion of cyanuric triazide under water has also been recorded. The behaviour of the compounds such as silver and thallous azide which can melt is different from that of crystals which explode without melting. The effect of crystal size on the development of combustion and explosion is discussed with particular reference to silver azide.