(493c) Replacement of Barium Chromate in the Traditional Tungsten Delay

Replacement of Barium Chromate in the
Traditional Tungsten Delay

Barbara
A. Hadrava^a and Lori J. Groven^a

^aSouth Dakota School of Mines and
Technology, Department of Chemical and Biological Engineering, Rapid City, SD,
USA

ABSTRACT

There
is an immediate need to replace Barium Chromate in the current fielded delay due to its hazardous nature. Previous work in this area has
explored various alternate compositions such as metal/metal oxide,
intermetallic, or metalloid/metal oxide systems. However, in many cases these
alternate systems cannot serve as a true replacement due to a lack of
tailorable burn times. In this work, we study the fundamental kinetics of the
tungsten delay system and the role that barium chromate serves towards the
reliability and performance by replacing the barium chromate with barium
molybdate.  Delay
performance was examined at a similar diameter, 6.35 mm, to a common delay
housing.  The measured combustion velocities ranged from 0.94-18.75 mm/s for
6.35 mm pellets, and from 0.82-23.99 mm/s when pressed into 6.35 mm ID Al
housings.  For all W/BaMoO₄/KClO₄
formulations, gas production was measured, and maximum combustion temperatures are
measured as a function of mixture stoichiometry.  Combustion products were
characterized with powder X-ray diffraction and appear benign based upon known
compound information.  Therefore, the W/BaMoO₄/KClO₄ system
seems suitable as a relatively low combustion velocity, low gas producing, low
toxicity delay composition.