(北京理工大學(xué) 材料學(xué)院，北京 100081)
摘 要: 以硼粉和納米鋁粉為原料，燒結(jié)制備了主要由鋁和AlB2兩相構(gòu)成的硼鋁合金粉。利用掃描電鏡、X射線衍射儀、氧彈量熱儀和同步熱分析儀，觀察了粉體形貌，分析了粉體相組成及其對(duì)燃燒熱值和熱氧化特性的影響。結(jié)果表明：硼鋁合金粉中的AlB2含量隨燒結(jié)溫度的升高而增大，硼鋁合金粉的實(shí)測燃燒熱值和燃燒效率均高于無定形硼粉。當(dāng)硼粉、鋁粉混合摩爾比為2:1，800 ℃保溫?zé)Y(jié)2 h時(shí)，制得的硼鋁合金粉的實(shí)測燃燒熱值為33.3 MJ/kg，對(duì)應(yīng)的燃燒效率為77.0%。相較于無定形硼粉，其燃燒熱值提高了139.6%，燃燒效率提高了53.4%。其機(jī)理在于硼鋁合金粉燃燒過程中形成了高熔點(diǎn)硼鋁復(fù)合氧化物，有效減少了低熔點(diǎn)液態(tài)B2O3層的產(chǎn)生，從而促進(jìn)了硼鋁合金粉的氧化放熱。熱氧化特性測試表明硼鋁合金粉的氧化起始溫度、氧化峰值溫度和氧化終止溫度均明顯高于無定形硼粉，且隨著AlB2含量的增大而升高。
關(guān)鍵字: 鋁合金；硼化物；燒結(jié)；燃燒熱
（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
