【摘要】 采用XRD、SEM手段研究了NaF添加量和烧结温度对高铝粉煤灰合成刚玉-莫来石材料的性能、晶体结构和显微形态的影响。实验结果表明,NaF可以有效降低合成刚玉-莫来石材料的烧结温度,在1200℃、NaF添加量为2%时,生成的莫来石颗粒较细小,且均匀分布在玻璃相中,材料的综合性能良好,体积密度为3.08g/cm3,抗折强度为62.11 MPa,莫来石与刚玉的含量比约为2∶1;当NaF添加至4%时,莫来石发育为长柱状,长径比约6~10,并且相互交错成网状,但其含量减少,材料强度降低;NaF添加至8%时,莫来石相消失,材料主晶相为刚玉,同时生成较多的玉米状呈十字交叉形的钠长石晶簇。更多还原

【Abstract】 In this paper, the effects of temperature and NaF on the properties, crystal structure, and morphology of corundum-mullite materials prepared from fly ash and bauxite were studied in detail by XRD and SEM. The results indicate that the relatively low sintering temperature of 1200℃ can be obtained by adding 2% NaF, which helps effectively to promote sintering during the solid reaction, and that the obtained materials have excellent properties: bulk density 3.08 g/cm3, flexural strength 62.11 MPa, and the content ratio of mullite/corundum 2∶1. When NaF content rises to 4%, mullite assumes the long columnar form in network structure, with the single crystal aspect ratio ranging from 6 to 10; nevertheless, the lower mullite content in this sample results in relatively low mechanical strength. When NaF content rises to 8%, mullite phase disappears, and the main phase of the material is corundum, with the appearance of a large amount of albite, which mostly develops into crossed corn-like crystal clusters under the SEM.更多还原