Enhancing combustion and antioxidant properties of aluminum-lithium alloys with polytetrafluoroethylene and paraffin WAX coatings

Aluminum-lithium alloys (Al-Li alloys) have gained prominence in recent years as promising alternatives to aluminum powders, attributed to their superior thermal and combustion characteristics. However, the high reactivity of Al-Li alloys poses significant challenges to their stability and compatibility with other materials. This study utilized high-energy ball milling to modify Al-Li alloys by incorporating polytetrafluoroethylene (PTFE) and paraffin wax (WAX) as functional coatings. Thermal analysis of Al-Li/PTFE composites revealed a marked reduction in the thermal oxidative exothermic peak temperature with the addition of 10 % and 15 % PTFE, accompanied by enthalpy increases of 1.49 and 2.1 times, respectively. Combustion processes captured using a high-speed camera demonstrated that increasing the PTFE content from 10 % to 30 % intensified the combustion and reduced combustion duration by 50 %. The agglomeration of combustion residues also decreased. Furthermore, incorporating WAX through ball milling facilitated high-temperature phase transformations, producing Al-Li/10PTFE/2WAX composite powders with enhanced antioxidant properties, as evidenced by a contact angle of 131.15°, and improved compatibility. The findings offer a pathway for achieving tunable combustion performance in Al-Li alloys while addressing critical issues related to the storage and processing of these powders for practical applications.