Research on the Influence of Titanium Powder Particle Size on the Performance of the CO<sub>2</sub> Phase-Change Excitation Agent under Zero Oxygen Balance.

Abstract

To study the influence of titanium powder particle size on the performance of the CO₂ phase-change excitation agent, the ignition reliability, pressure performance, thermal decomposition characteristics, safety performance, and temperature-resistance performance are studied by ignition tests, pressure tests, thermogravimetry, temperature-resistance performance tests, and theoretical calculations. The results indicate that after adding titanium powder with particle sizes of 100, 200, 300, 400, 500, and 600 mesh, the excitation agent poses no risk of combustion or explosion when encountering thermal action at room temperature and is successfully ignited inside the tube. The peak pressure is negatively correlated with the particle size of titanium powder. Within the particle size range selected in this study, the peak pressure increased by 5.87%, 11.29%, 14.21%, 15.89%, 17.25%, and 19.22% compared to the original formula. As the particle size of titanium powder decreases, the thermal stability of the excitation agent first increases and then decreases. When the particle size of the added titanium powder is 500 and 600 mesh, the apparent activation energy is increased by 6.80 kJ·mol^-1 and decreased by 7.50 kJ·mol^-1, respectively, compared to the original formula. After adding titanium powder with different particle sizes, there is no reaction between the components of the optimized formula at room temperature, and the safety performance is favorable. The temperature indexes <i>T</i> _S obtained through theoretical calculations are all above 90 °C.