Bismuth Chromate in Delay Compositions

Abstract

Barium chromate is used as a secondary oxidiser in delay compositions which slows down the rate of the reaction. The composition containing barium chromate potassium perchlorate and sulphur along with the binder, gives inverse burning rates up to 4.5 s/cm. If barium chromate is substituted by bismuth chromate hydrate, the rate of reaction is slowed down further to 11.8 s/cm. Various compositions were prepared by changing the percentage of barium chromate and bismuth chromate. The energy of activation was determined to be 14.5 kcal/mole for the composition with 40 per cent bismuth chromate. The explosion temperature for a delay of 5 s was observed as 480 degree centigrade. These compositions were subjected to impact and friction sensitivity tests to determine the safety aspects. This paper presents the results of burning rate calorimetry, explosion temperature and the sensitivity data of some delay compositions containing bismuth chromate.