Effects of Cu(OH)F nanoparticles on the thermal oxidation and ignition characteristics of micron-sized Al powder

In this study, Cu(OH)F nanoparticles are prepared through a simple hydrothermal reaction and their effects on the thermal oxidation and ignition characteristics of micron-sized Al powder (μ-Al) are explored for the first time. Thermal analysis in air atmosphere (50∼1050 °C) shows that compared to raw μ-Al, the normalized weight gain of Al in Al-Cu(OH)F increases by about 36.9%, 64.8%, and 106.3% when the added Cu(OH)F is 1 wt%, 3 wt%, and 5 wt%, respectively. After mixed with NH₄ClO₄, electric ignition and open-air combustion tests show shortened ignition delay time (by 42.6%∼63.8%) and increased maximum light intensity (by 48.9%∼117.8%) for Al-Cu(OH)F. The effects of Cu(OH)F result from its decomposition products, namely, HF and CuO. HF reacts with alumina shell to form AlF₃, which sublimes at high temperature and thus exposes Al core instantly, while CuO can react with Al core to release heat, further facilitating the thermal oxidation and ignition processes.