添加纳米TiO2对刚玉浇注料性能的影响

Effects of nano-TiO2 addition on properties of corundum castables

以板状刚玉、活性氧化铝微粉BL - 2、铝酸钙水泥Secar 71为主要原料,加入不同含量的纳米TiO2 (加入质量分数为0、0.5%和1%),比较了纳米TiO2 加入量对于刚玉浇注料物相组成、显微结构和物理性能的影响。结果表明,纳米TiO2 的加入加速了CA6的生成,提高了1 250 ℃烧后试样的强度,有利于浇注料中温强度的提升;当加入量较大时,CA6的片状厚度增加,难以形成相互交叉堆叠结构,导致试样的强度降低;当纳米TiO2 加入量( w )为0.5%时,试样高温下强度降低较少,但中温强度明显提升,高温烧后呈现微膨胀,为最佳加入量。

Tabular corundum,active alumina micropowder BL-2,and calcium aluminate cement Secar 71 were used as starting materials,added with different amounts of nano-TiO2 (0,0.5%,and 1%,by mass) to prepare corundum castables.The effects of nano-TiO2 addition on the phase composition,microstructure and physical properties of corundum castables were compared.The results indicate that (1)the addition of nano-TiO2 enhances the formation of CA 6,improves the strength of the specimens calcined at 1 250 ℃,and is beneficial to improving the medium temperature strength;(2)the thickness of platelet CA 6 increases when TiO2 addition rises to 1%,which makes it difficult to form interlock and stack structure,therefore,the strength of castables decreases;(3)with 0.5% TiO2 ,the high temperature strength decreases slightly but the medium temperature strength increases obviously;after high temperature firing,the specimen mildly expands,thus the optimal nano-TiO2 addition is 0.5%.