(北京理工大学 材料学院，北京 100081)
摘 要: 以硼粉和纳米铝粉为原料，烧结制备了主要由铝和AlB2两相构成的硼铝合金粉。利用扫描电镜、X射线衍射仪、氧弹量热仪和同步热分析仪，观察了粉体形貌，分析了粉体相组成及其对燃烧热值和热氧化特性的影响。结果表明：硼铝合金粉中的AlB2含量随烧结温度的升高而增大，硼铝合金粉的实测燃烧热值和燃烧效率均高于无定形硼粉。当硼粉、铝粉混合摩尔比为2:1，800 ℃保温烧结2 h时，制得的硼铝合金粉的实测燃烧热值为33.3 MJ/kg，对应的燃烧效率为77.0%。相较于无定形硼粉，其燃烧热值提高了139.6%，燃烧效率提高了53.4%。其机理在于硼铝合金粉燃烧过程中形成了高熔点硼铝复合氧化物，有效减少了低熔点液态B2O3层的产生，从而促进了硼铝合金粉的氧化放热。热氧化特性测试表明硼铝合金粉的氧化起始温度、氧化峰值温度和氧化终止温度均明显高于无定形硼粉，且随着AlB2含量的增大而升高。
关键字: 铝合金；硼化物；烧结；燃烧热
（School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China）
Abstract: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.
Key words: aluminum alloy; borides; sintering; combustion heat
