Surface Contamination and Corrosion in Pyrotechnic Actuators

Abstract

Accelerated aging studies of pyrotechnic actuators containing a mixture of titanium metal and potassium Perchlorate powders have revealed that extensive corrosion of the metal pins and bridgewires used to ignite the device occurs in relatively short times. Analyses suggest that the corrosive process is associated with chlorine and organic contaminants. These can trigger corrosion by attacking the passivating oxide layer on the surface of metal alloys, thereby promoting reaction between the pyrotechnic and the metal. The contaminants may also react directly with the pyrotechnic to cause decomposition to corrosive species. Residual moisture in the pyrotechnic powder tends to enhance corrosion rates when contaminants are present. Tests run on several metal alloys have verified the corrosive action of certain organic solvent mixtures. Specifically, Tophet A®, Tophet C®, and Alloy 52 were corroded when exposed to combinations of alcohols and chlorinated organic liquids.

This work was supported by the U. S. Department of Energy.