Thermal reaction or sensitivity of Bi2O3 and metal powder

The thermal reactivity and sensitivity of mixtures of five metallic substances with bismuth oxide (Bi2O3)were observed in an investigation of lead-free, environmentally-friendly ignition charge. The metallic substances used were aluminum (Al), magnalium(MgAl), boron (B), ferrosilicon (Fe Si), and silicon (Si). A thermal analysis, ignition temperature test, and burning test were carried out to examine the thermal reactivity of these mixed systems. And their sensitivity was examined with electrostatic sensitivity and friction sensitivity tests. Exothermic reactions caused by thermite reactions were seen in mixed systems of Bi2O3 and each of the metallic substances. The ignition temperature test revealed that the thermal conductivity of each metallic substance was related to its ignition energy and minimum ignition temperature. Thermal reactivity did not differ with changes in mixing ratio of the Bi2O3 and metals mixture. The mixed systems of Bi2O3 with Al, Mg Al and B burned vigorously in the burning tests, but the FeSi-Bi2O3 and Si-Bi2O3 mixed systems showed relatively gentle combustion. Based on the standards of the Japan Explosives Society, the electrostatic sensitivity test indicated a safety level of Class3 to Class5. Based on the standards of the JIS, the friction sensitivity test indicated a safety level of Class4 to Class7.