利用铝灰和粉煤灰铝热还原氮化制备镁铝尖晶石-刚玉-Sialon复相材料

以铝灰和粉煤灰为原料,以铝灰中的金属铝为还原剂在1550 ℃,3 h下进行原位铝热还原氮化制备镁铝尖晶石-刚玉-Sialon复合材料.采用XRD分析了不同原料配比对合成产物物相的影响,并对制备的镁铝尖晶石-刚玉-Sialon复相材料进行了显微形貌和性能表征.结果表明,当铝灰过量50%时,制备得到了镁铝尖晶石-刚玉-Sialon复合耐高温材料,其中,尖晶石为富铝尖晶石,含量为45%;刚玉含量为25%,呈板片状;Sialon的含量为26%,其Z值为4,呈柱状形貌.此时其抗折强度最大,为183 MPa,显气孔率最小,为5.3%,体积密度为2.6 g/cm~3,洛氏硬度HRB的值为123.

Preparation of Spinel-Corundum-Sialon Composite Materials from Aluminum Dross and Fly Ash by Aluminothermic Reduction-Nitradation

The spinel-corundum-sialon composite materials were prepared from fly ash and aluminum dross by in-situ aluminothermic reduction-nitration. The phase composition, content and microstructure of composites were investigated by XRD and SEM with EDS. The properties of composites were also characterized. The results showed that when aluminum dross exceeded 50%, the spinel-corundum-Sialon composite materials were prepared successfully at 1550 ℃ for 3 h, in which the content of phases were 45% of allitic spinel, 25% of corundum and 26% of Sialon with Z=4. The patterns of phases were octahedral structure of allitic spinel, platy corundum, columnar crystals of sialon. When aluminum dross exceeded 50%, the bending strength of the prepared spinel-corundum-Sialon composites reached the maximum of 183 MPa, the apparent porosity was the minimum of 5.3%, the bulk density was 2.6 g/cm~3 and HRB hardness was 123.