低温合成MgO-Al_2O_3-FeO_n复相材料

Novel Process for Synthesis of MgO-Al_2O_3-FeO_n Composite Materials at Low Temperature

高铁镁砂中分别引入质量分数为3%、6%、9%、12%、15%的板状刚玉,经1 420℃烧结制备Mg O-Al2O3-Fe On复相材料。采用X射线衍射和扫描电子显微镜分析试样的物相组成及显微结构。结果表明:在1 420℃,高铁镁砂与板状刚玉反应烧结形成原位合成的镁铁铝尖晶石固溶体,铁氧化物的存在促进了镁铁铝尖晶石固溶体的形成。随着板状刚玉加入量的增加,镁铁铝尖晶石固溶体的含量随之增加。镁铁铝尖晶石固溶体呈现明显的环带结构。最外层环带结构致密,富含铁氧化物;次外层环带结构中铁氧化物的含量有所降低。这些环带结构使得低温制备镁铁铝尖晶石固溶体结合方镁石材料的新工艺得以实现。

The specimens of Mg O-Al2O3-Fe On composite materials were prepared with tabular corundum of 3%(in mass fraction),6%,9%,12% and 15%,respectively,by sintering at 1 420 ℃.The composition and microstructure of the specimens were determined by X-ray diffraction and scanning electron microscopy,respectively.The results show that the in-situ synthesized composite spinel solid solution is formed in the reaction with iron-rich magnesia and tabular corundum at 1 420 ℃,and iron oxide promotes the formation of spinel solid solution.The spinel solid solution content increases with increasing the amount of tabular corundum.The spinel solid solution shows a significant core-shell structure.The outermost zone has a dense structure and is rich in iron oxide.The amount of iron oxide decreases in the second outer layer.The spinel solid solution bonded periclase material can be synthesized due to the core-shell structure.