Investigating the Relationship between the Atomic Properties of Doped Perovskite and Fuel-Oxidizer Thermite Ignition

摘要

Despite our knowledge of the existence of the violent thermite reaction for over 100 years it is still not yet understood how the properties of a metal oxide oxidizer relate to and influence the ignition temperature. To address this shortcoming we prepared a series of perovskite based oxidizers which enable a systematic investigation of how materials properties of the oxidizer relate to the ignition temperature. In this paper, nine lanthanum based perovskites with different Sr~(2+) doping of the A-site, and different B-site transition metals were synthesized. The perovskite O_2 release and ignition temperatures with aluminum were measured by fast heating (> 105 K/s) temperature-jump/time-of-flight mass spectrometry coupled with high-speed imaging. These results were then correlated with the average bond energy and overall metal-oxygen electronegativity difference. Remarkably we found a linear relationship between average bond energy and electronegativity with ignition temperature. Similar trend was found when the fuel was boron. To our knowledge this is the first demonstration of the connection between metal-oxygen bond energy, electronegativity and ignition temperature.