Mechanism of Pyrolysis Reaction of Al-Rich Al/PTFE/TiH₂ Active Material

Abstract

In order to obtain the chemical reaction mechanism of Al-rich Al/PTFE/TiH2 composites in argon and oxygen atmosphere, Al/PTFE, PTFE/TiH2, Al/TiH2 and Al-rich Al/PTFE/TiH2 with different contents of TiH2 composites were prepared by using the wet mixing method. The pyrolysis behavior of the above composites was investigated by thermogravimetric differential scanning calorimeter (TG-DSC). In addition, the calorific value of the above composite was measured by an oxygen bomb calorimeter. The compositions of TG-DSC residues at different peak temperatures and 1000 °C and the residues of oxygen bomb experiment were analyzed by X-ray diffraction (XRD), The results show that the pyrolytic products of Al-rich Al/PTFE/TiH2 materials under argon atmosphere can be divided into four stages. In the first stage (328.6–378.6 °C), the products are TiH1.924, (C2F4)n, (CF2)n, H2(g), Al and TiH2; in the second stage (510.8–534.3 °C), the products are Al, TiH1.924, (C2F4)n, (CF2)n, Ti, AlF3, TiF3, TiF4(g), C and H2(g). In the third stage (540.8–618.1 °C), the products are Al, C, Ti, (C2F4)n, (CF2)n, AlF3, TiF3, TiF4, CF4(g), C3F6(g), C4F8(g), C2F6(g), Al5Ti2 and H2(g); in the fourth stage (918.5–1000 °C), the products are AlCTi2, Al2Ti, AlTi, TiC, AlF3, Al, TiF3, TiC0.957, TiC0.981 and TiC0.95. The calorific value of the combustion of Al-rich Al/PTFE/TiH2 composite with 10% the content of TiH2 is the highest and is 19,899 J/g, which is 3.776% higher than that of Al-rich Al/PTFE composite. When TiH2 content is greater than zero and not more than 10%, the chemical reaction mechanism of Al-rich Al/PTFE/TiH2 is almost the same under oxygen atmosphere. When the content of TiH2 is higher than 10%, the mechanism of this material is different.

Keywords

• Al-rich Al/PTFE/TiH₂ composite
• wet mixing
• thermogravimetry differential scanning calorimetry
• X-ray diffractometer
• oxygen bomb calorimeter
• component analysis