硼铝合金粉制备及其氧化燃烧特性

Boron powder and nano-aluminum powder were used as raw materials to prepare boron-aluminum alloy powder that mainly composes of two phases: Al and AlB₂. Scanning electron microscope, X-ray diffractometer, oxygen bomb calorimeter and synchronous thermal analyzer were used to study the energy release characteristics and thermal oxidation performance. The results show that the AlB₂ content of the boron-aluminum alloy powder increases with the sintering temperature, and the combustion heat value and combustion efficiency of the boron-aluminum alloy powder are higher than those of the amorphous boron. When the mixed molar ratio of boron powder and nano-aluminum powder is 2:1, and sintered at 800 ℃ for 2 h, the measured combustion heat value of the boron-aluminum alloy powder is 33.3 MJ/kg, and the corresponding combustion efficiency is 77.0%. Compared with amorphous boron powder, the measured combustion heat value increases by 139.6%, and the combustion efficiency increases by 53.4%.The mechanism is that a high-melting boron-aluminum composite oxide forms during the combustion of the boron-aluminum alloy powder, which effectively reduces the generation of low-melting liquid B₂O₃ layer, thereby promoting the oxidation and exotherm of the boron-aluminum alloy powder. The thermal oxidation characteristics test shows that the oxidation starting temperature, peak oxidation temperature, and oxidation termination temperature of the boron-aluminum alloy powder are significantly higher than those of the amorphous boron powder, and they increase with the content of AlB₂.