La^(3+)掺杂对堇青石陶瓷的相组成和性能的影响

Effects of La^(3+)-doping on the phase components and properties of cordierite ceramics

为了获得堇青石含量高且具有一定孔隙率的堇青石质耐火材料,用X射线衍射仪,差热分析仪等手段研究了由溶胶-凝胶法(Mg盐、Al盐和正硅酸乙酯按堇青石化学计量比配制)制备堇青石陶瓷时,添加La3+对堇青石陶瓷相组成和性能的影响,分析了La3+在烧结过程中的作用机理。试验表明,随着烧结温度的提高,La3+含量的增加,该陶瓷的致密度、弯曲强度逐渐提高,而气孔率逐渐下降。适量添加La3+(质量分数为4%~6%),显著降低中间相(尖晶石、方石英等)的含量。La3+的作用主要是作为烧结助剂,降低烧结温度,提高致密度。

La^3＋ was used as an additive in the sintering of cordierite ceramic to obtain ceramics with highly amounts of cordierite and to decrease the sintering temperature. In the present work, the cordierite ceramics were prepared by the sol-gel method. The effects of La^3＋ on the phase components and properties were studied using X-ray diffraction （XRD） and differential thermal analysis （DTA）. The mechanism of La^3＋ in sintering was also discussed. The density, bending strength increase with increasing La^3＋ content. The 4wt%～6wt% La^3＋ -dipedceramics was suitable for fabricating porous assembiles, such as filters for high temperature streams and catalytic supports for purifying vehicle exhaust. The action of La^3＋ was accociated with the modification of cation diffusion in the sintering process.