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在刚玉(电熔刚玉、板状刚玉)–高纯镁砂中加入质量分数分别为0、4%、6%、10%的铝粉,在碳管炉1 600℃氮气气氛下制备Al–Mg O–Al_2O_3复合材料。结果表明:烧后试样的主晶相为刚玉和镁铝尖晶石固溶体,基质是由镁铝尖晶石固溶体、氮化铝、Al ON和Mg Al ON等增强相组成的复合结构。随铝粉含量增加,Al N、Al ON和Mg Al ON含量增加且存在未反应的铝粉。铝粉氮化机理为Al反应生成Al N,Al N与Al_2O_3固溶形成Al ON相,氧化镁或新形成的尖晶石与Al ON相固溶形成Mg Al ON相。建立了金属铝粉氮化反应模型,反应模型呈明显的环状结构:内层产物为未反应的铝和反应后形成的微孔;中间层产物为氮化铝和阿隆的复合结构;外层环带状产物为阿隆和镁阿隆的复合结构。电熔刚玉颗粒部分参与反应形成环带状镁铝尖晶石固溶体。
In the corundum (fused corundum, platy corundum) - high purity magnesia by adding mass fraction of 0,4%, 6%, 10% of the aluminum powder in an atmosphere of carbon tube furnace 1 600 ℃ prepared under the atmosphere of Al-Mg O- Al_2O_3 composite material. The results show that the main phase of the burned sample is corundum and magnesium aluminum spinel solid solution, and the matrix is a composite structure composed of magnesium aluminate spinel solid solution, aluminum nitride, Al ON and Mg Al ON reinforcing phases. With the increase of aluminum content, Al N, Al ON and Mg Al ON contents increased and unreacted aluminum powder was present. The mechanism of aluminum powder nitriding is that Al reacts to form Al N, Al N and Al 2 O 3 solid solution to form Al ON phase. Magnesium oxide or newly formed spinel and Al ON form solid solution to form Mg Al ON phase. A model of nitridation of aluminum metal was established. The reaction model showed an obvious ring structure: the inner product was unreacted aluminum and micropores formed after the reaction. The intermediate product was a composite structure of aluminum nitride and Alon; The ring-like ribbon product is a composite structure of Aron and magnesium Aron. Some fused corundum particles participate in the reaction to form ring-shaped Mg-Al spinel solid solution.