【摘要】 镁锆砖具有优异的高温性能和抗渣性能,但生产中会出现表面龟裂等外观缺陷,为解决MgO-ZrO2耐火材料在烧结时相变导致的龟裂,研究了CaO添加剂和烧结助剂Y2O3对MgO-ZrO2材料性能的影响。结果表明,在镁锆砖中添加的CaO首先和ZrO2发生反应,而不和MgO发生反应或固溶,添加的CaO没有起到强化镁锆砖的作用,反而由于存在高温时的扩散过程和化学反应之间的定态耦合,致使CaO和Y2O3会发生逆向扩散,在晶界处富集偏析,出现非化学热力学平衡态的稳定结构,使得镁锆砖的高温韧性变差,耐热震性能变差。更多还原

【Abstract】 Magnesia-zirconia brick have excellent high temperature properties and perfect slag attacking resistance performance,but producing magnesia-zirconia brick may often occur surface craze defect due to phase transition.Additive CaO and sintering aid Y2 O3 are added to MgO-ZrO2 composite in order to resolve MgO-ZrO2 material craze.It indicates that CaO reacts to ZrO2 firstly rather than reacts to MgO or dissolves in MgO.CaO and Y2 O3 are counter diffused to the crystal boundary of the periclase and zirconia,resulting in enrichment and segregation at the boundary because of steady state coupling between CaO diffusion and CaO and ZrO2 reaction at high temperature.The existence of the state coupling leads to form nonequilibrium thermodynamics stable structure in the system of MgO-ZrO2-CaO.So,additive CaO does not reinforce the strength of MgO-ZrO2 refractory but impairs the high temperature toughness and decreases the thermal shock resistance of MgO-ZrO2 composite owing to ZrO2 consuming and its transformation toughening diminished.更多还原