中文摘要：

为适应精炼钢包用耐火材料轻量化的发展需要,采用两步烧结法向Al2O3-MgO-CaO系复相耐火材料中添加La2O3,并对该耐火材料的抗LF精炼渣侵蚀性能进行了研究。结果表明,添加的La2O3优先固溶入Al2O3-MgO-CaO系复相耐火材料的晶相CaO·6Al2O3中,促使CaO·6Al2O3晶胞产生晶格畸变,有效抑制了CaO·6Al2O3晶粒沿基面的异常长大,进而有效地促进了Al2O3-MgO-CaO系复相耐火材料的烧结致密化。当添加La2O3的质量分数为4%,在1600℃保温2h烧成后,试样的气孔率由占总体积分数的19.2%下降至6.1%,体积密度由2.78g/cm3上升至3.18g/cm3,制得了含MgO·Al2O3、CaO·2Al2O3、CaO·6Al2O3晶相且呈现交织分布、显微结构致密的Al2O3-MgO-CaO系复相耐火材料,其抗LF精炼渣侵蚀性能与同等致密度的Al2O3-MgO质耐火材料相当。

英文摘要：

In order to adapt the demands of refining ladle with the lightweight refractories,La2O3-doped Al2O3-MgO-CaO refractories were prepared by two-stage sintering method,and corrosion resistance of Al2O3-MgO-CaO refractories to LF refining slag was discussed.The results show that La2O3 preferentially dissolves to CaO·6Al2O3phases in Al2O3-MgO-CaO refractory with complex phases,causing the lattice distortion of CaO·6Al2O3crystal cells.Then the abnormal grain growth of CaO·6Al2O3is controlled,and the densification of Al2O3-MgO-CaO refractories is effectively promoted.As a result,the apparent porosity decreases from 19.2vol%to 6.1vol% and the bulk density increases from 2.78g/cm3 to 3.18g/cm3 after heating at 1600℃for 2hby addition of 4mass% La2O3,then a kind of Al2O3-MgO-CaO refractory,which is comprised of MgO·Al2O3,CaO·2Al2O3and CaO·6Al2O3 phases,with crystal intertwined distribution and dense microstructures is produced.Corrosion resistance of La2O3-doped Al2O3-MgO-CaO refractories to the LF refining slag is similar to that of Al2O3-MgO refractories with the same density.