论文部分内容阅读
用化学共沉淀法制备4.5%Y_2O_3-ZrO_2(YSZ)和0.6%La_2O_3-YSZ、0.8%La_2O_3-YSZ、1.2%La_2O_3-YSZ(0.6La、0.8La、1.2La)(摩尔分数)纳米复合陶瓷粉末,研究了四组粉末的高温相稳定性。结果表明:采用正向滴淀方法制备的0.6La粉末(粒径～50 nm)团聚严重,而用反向滴淀方法制备的0.6La粉末(粒径～20 nm),粉末团聚少;各组前躯体粉末在600℃煅烧2 h后都呈单一四方相结构;在1200℃烧结100 h后0.6La、0.8La坯体呈单一四方相结构,无相变,YSZ和1.2La坯体都有立方相且1.2La坯体有锆酸镧相生成;在1300℃烧结100 h后0.6La,0.8La,1.2La坯体呈四方相和立方相结构,其中1.2La坯体有锆酸镧相生成,在相同条件下烧结的YSZ坯体有少量(～1.5%)单斜相产生;在1400℃烧结100 h后各组份中四方相已不能保持稳定,转化为单斜相和立方相,0.6La、0.8La、1.2La、YSZ坯体单斜相含量分别为30.5%,32%,35%,46.0%。在YSZ中添加少量La_2O_3在1300℃烧结能有效改善其高温相的稳定性。
The nanocomposite ceramic powders of 4.5% Y_2O_3-ZrO_2 (YSZ), 0.6% La_2O_3-YSZ, 0.8% La_2O_3-YSZ and 1.2% La_2O_3-YSZ (0.6La, 0.8La, 1.2La) , The stability of high temperature phase of the four groups of powders was studied. The results show that 0.6La powder (particle size ~ 50 nm) prepared by the forward drop method has a serious agglomeration, while 0.6La powder (particle size ~ 20 nm) prepared by the reverse titration method has less powder agglomeration. After calcination at 600 ℃ for 2 h, the precursor powders had a single tetragonal phase structure. After sintering at 1200 ℃ for 100 h, the 0.6La and 0.8La bodies showed a single tetragonal phase structure with no phase transformation. The YSZ and 1.2La bodies had cubic Phase and the phase of 1.2La body is lanthanum zirconate phase. After sintered at 1300 ℃ for 100 h, the bodies of 0.6La, 0.8La and 1.2La have tetragonal phase and cubic phase structure, of which 1.2La body is formed with lanthanum zirconate phase, The YSZ green body sintered under the same conditions has a small amount of (~ 1.5%) monoclinic phase. After sintering at 1400 ℃ for 100 h, the tetragonal phase can not be stable and transformed into monoclinic phase and cubic phase, 0.6La The monoclinic phase contents of 0.8La, 1.2La and YSZ were 30.5%, 32%, 35% and 46.0% respectively. The addition of a small amount of La 2 O 3 in YSZ at 1300 ℃ can effectively improve the stability of the high temperature phase.