Abstract: This work aims to study the corrosion mechanisms of CaO to MgAl₂O₄ materials and ZrO₂·MgAl₂O₄ materials.MgAl₂O₄ micropowder,desilicated zirconia micropowder,and analytically pure calcium carbonate were used as raw materials.CaO micropowder was obtained by calcining the calcium carbonate and crushing,and then the MgAl₂O₄ material was prepared with the mass ratio of MgAl₂O₄ micropowder to CaO micropowder of 4∶1 and the ZrO₂-MgAl₂O₄ material was prepared with the mass ratio of desilicated zirconium powder,MgAl₂O₄ micropowder and CaO micropowder of 3∶4∶1.Both the materials were heat treated at 1 500,1 600 and 1 700 ℃ for 3 h,respectively.The possible reactions in the system were analyzed using phase diagrams and thermodynamic calculations.The phase composition and microstructure of the fired samples were analyzed by XRD and SEM.The results show that:for the MgAl₂O₄ material,CaO reacts with MgAl₂O₄ to form low-melting-point CaO·Al₂O₃ and 12CaO·7Al₂O₃; for the ZrO₂-MgAl₂O₄ material,a large amount of CaO reacts with ZrO₂ to generate high-melting-point c-ZrO₂ and CaZrO₃,while the remaining small amount of CaO reacts with MgAl₂O₄ to form CaO·Al₂O₃,which reduces the formation of low-melting-point phases.

Key words: MgAl₂O₄, ZrO₂-MgAl₂O₄, CaZrO₃, calcium aluminate

摘要： 为了研究CaO对MgAl₂O₄材料和ZrO₂-MgAl₂O₄材料的侵蚀机制,以MgAl₂O₄微粉、脱硅锆微粉和分析纯碳酸钙为原料,将碳酸钙煅烧、粉碎后得CaO微粉,以MgAl₂O₄粉和CaO粉质量比为4∶1制备了MgAl₂O₄材料,以脱硅锆粉、MgAl₂O₄粉、CaO粉质量比为3∶4∶1制备了ZrO₂-MgAl₂O₄材料,并分别于1 500、1 600、1 700 ℃保温3 h煅烧。利用相图和热力学计算分析了体系中可能发生的反应,利用XRD和SEM分析了烧后试样的物相组成和显微结构。结果表明: 对于MgAl₂O₄材料,CaO与MgAl₂O₄会反应生成低熔点CaO·Al₂O₃和12CaO·7Al₂O₃。对于ZrO₂-MgAl₂O₄材料,大量CaO与ZrO₂反应生成高熔点c-ZrO₂和CaZrO₃,而剩余少量CaO与MgAl₂O₄反应生成CaO·Al₂O₃,减少了低熔点相的生成。

关键词: MgAl₂O₄, ZrO₂-MgAl₂O₄, CaZrO₃, 铝酸钙