Tatb-based Pbx Nanoporous Aging Evolution Of The Positron Annihilation Lifetime Spectroscopy

A positron lifetime study of the nano-void in TATB-based PBX and its evolution during accelerated aging is presented. First, adjustment of the positron annihilation lifetime spectra equipment is made, and the influence of parameter setting on the result of the fit program is analyzed by computer simulation. Then several groups of TATB-based PBX specimen with same components but different densities are prepared by different press intensities, and their positron lifetime spectra are measured. The spectra show that the positronium formation is negligible in TATB-based PBX, therefore the 2-component fit is applicable. The result shows an increasing dimension but decreasing concentration of nano-void during PBX pressing, which means the nano-void in TATB crystalline increased due to the damage and crack under pressure, however the intergranular nano-void is decreasing or even closed. Finally, accelerated aging of several specimen is taken, including TATB-based PBX and its two components (TATB, fluoro rubber binder). The positron lifetime spectrum of the specimen are measured periodically, thus the nano-void evolution during aging process is obtained. The evolution curve of PBX has a similar shape with TATB, but with more uncertainty. This reveals the intimate relationship between PBX and TATB. The evolution of nano-void in PBX is almost due to TATB, with some uncertain influence from the fluoro rubber binder which is still uncharacterized.