YSZ/MgAl_2O_4复合粉末的合成及其材料的烧成活化能

采用共沉淀法在1100℃制备了70%(体积分数,下同)氧化钇稳定氧化锆xY2O3+(1-x)ZrO2,x=0.02,0.03,0.04,in mole,yttria stabilized zirconia,YSZ]-30%镁铝尖晶石(MgAl2O4)复合粉体,2种原始粉料的配料各为70%和30%,并在1200～1500℃常压烧成制备了陶瓷材料。结果表明:在制得的所有粉末中,未发现单斜相ZrO2;2YSZ(0.02Y2O3+0.98ZrO2,摩尔分数,下同)/MgAl2O4和3YSZ/MgAl2O4这2种粉体中的ZrO2为四方相多晶氧化锆;而4YSZ/MgAl2O4粉末中的ZrO2相为全稳定立方氧化锆。对于1500℃烧结制备的陶瓷材料,2YSZ/MgAl2O4块体中的ZrO2相为部分稳定氧化锆;而3YSZ/MgAl2O4和4YSZ/MgAl2O4块体中的ZrO2相为全稳定氧化锆。(2～4)YSZ/MgAl2O4复相陶瓷的活化能为(623±80)kJ/mol。

SYNTHESIS OF YTTRIA STABILIZED ZIRCONIA/MgAl_2O_4 COMPOSITE POWDERS AND THEIR SINTERING ACTUVATION ENERGY

Yttria stabilized zirconia (YSZ)/MgAl_2O_4 composite powders were prepared by co-precipitation and calcined at 1 100℃, with the composition of 70% (in volume, the same below) xY_2O_3+(l-x)ZrO_2 (x=0.02, 0.03 and 0.04, in mole, named 2YSZ, 3YSZ and 4YSZ, respectively) and 30% MgAl_2O_4. The corresponding samples were sintered at 1 200-1 500℃ in air atmosphere. The results show that no monoclinic-zirconia phase was formed in any of the as-prepared powders. The zirconia in 2YSZ/MgAl_2O_4 and 3YSZ/MgAl_2O_4 powders is tetragonal-zirconia polycrystalline. The zirconia in the 4YSZ/MgAl_2O_4 powder is fully-stabilized zirconia (FSZ). For the ceramic samples sintered at 1 500℃, the zirconia in the 2YSZ/MgAl_2O_4 ceramic is partially-stabilized zirconia, while the zirconia in the 3YSZ/MgAl_2O_4 and 4YSZ/MgAl_2O_4 ceramics is FSZ. The activation energy of (2-4)YSZ/MgAl_2O_4 composite ceramics is in the range of (623±80) kJ/mol.