Fe_2O_3对β-SiAlON结合刚玉材料性能的影响

Influence of Fe_2O_3 on properties of β-SiAlON bonded corundum refractories

以白刚玉、硅粉、铝粉和α-Al2O3微粉等为原料,在氮化炉中于1460℃原位合成的β-SiAlON-刚玉复合材料,其氮含量(w)为3%,显气孔率为11.8%,体积密度为3.22g.cm-3,耐压强度为106.5MPa。在此基础上,用2%的Fe2O3替代白刚玉,在相同条件下合成的复合材料,其氮含量下降为2.4%,显气孔率和体积密度分别为12.4%和3.21g.cm-3,耐压强度增大为174.5MPa。试样的XRD分析表明,这两个试样的主晶相均为刚玉和z=3的β-SiAlON;未加Fe2O3的试样杂质很少,而加Fe2O3的试样中杂质较多,杂质主要为莫来石,这说明加入的Fe2O3阻碍了材料的氮化。另外,其β-SiAlON相中除了有Si3Al3O3N5外,还有Si4.69Al1.31O1.31N6.69。

By using white corundum, Si powder, AI powder and α-Al2O3 micro-powder as main starting materials, β-SiAION bonded corundum refractories were in-situ synthesized at 1 460 ℃,which had 3% of nitridation rate,11. 8% porosity,3.20 g · cm^-3bulk density,106.5 MPa CCS. Based on the formula,the materials were synthesized at the same condition by using 2% Fe2O3 to substitute white corundum. The specimen had indexes such as content of nitridation rate ：2.4%, porosity： 12.4%, density ：3.22 g · cm^-3., CCS： 174.5 MPa. By XRD analysis,the result showed that the main phasees involved in both specimen were α-Al2O3 and β-SiAION with z =3. The specimen without Fe2O3 contains little impurities, but the one added Fe2O3 contained mullite bearing impurties. Besides Si3Al3O3N5 in the β-SiAION, Si4.69Al1.31 O1.31 N6.69were also found, which means the addition of Fe2O3 interfered the nitridation of the material.