TiO_2微粉对Al_2O_3-MgO-Cr_2O_3浇注料性能的影响

Effect of TiO_2 micro powder on properties of Al_2O_3-MgO-Cr_2O_3 castables

以板状刚玉为骨料,配以电熔白刚玉、α-Al2O3、MgO和Cr2O3细粉以及secar71水泥结合剂制得Al2O3-MgO-Cr2O3浇注料,研究添加TiO2微粉对浇注料性能的影响。结果表明,在Al2O3-MgO-Cr2O3浇注料中加入TiO2微粉后,材料致密化程度增加、体积密度和冷态强度增大,且材料经高温烧成后由于生成钛酸铝而使材料抗热震性显著提高。但材料在高温下形成少量低熔相,且钛酸铝在750～1280℃下易分解为Al2O3和TiO2,使得材料的高温抗折强度降低。

A12O3-MgO-Cr2O3 castables were prepared by using tabular alundum as aggregate, white fused corundum,α-Al2O3, MgO and Cr2O3 micro powder as matrixes, and calcium aluminate cement as binder. Influence of the addition of TiO2 micro powder on properties of the castables was studied. The results show that the addition of TiO2 micro powder can promote the sintering, increase the densification extent, and raise the bulk density and cold strength of castables. After sintering at high temperature, the thermal shock resistance of materials is significantly improved due to the formation of Al2TiO5. However, the hot rupture strength of materials is reduced because a little of low-melting phase is generated at high temperature and Al2TiO5 is resolved into Al2O3 and TiO2 at 750～1280 ℃.