Irreversible phase transitions in doped metal oxides for use as temperature sensors in explosions

The temperature of post-detonation fireballs produced by advanced energetic formulations is commonly determined using optical methods such as pyrometry and spectral line fitting. These methods are noninvasive and provide an average temperature predominantly from the surface of the fireball. However, for many applications the ability to probe the internal temperature as well as temperature gradients within the fireball is highly desirable. One such method that has shown promise in providing this information is seeding micron to nano-sized temperature sensors into the fireball which can be collected post-detonation and analyzed to determine a temperature profile. In this work, disordered rare-earth-doped metal oxide nanoparticles were synthesized and subjected to various types of heat treatment, including furnace heating, T-Jump (fast pyroprobe), and explosive heating. The heat treatment leads to irreversible phase transitions which are monitored by optically active rare-earth dopants. Eu3+ in particularly ...