化学共沉淀法制备Sc_2O_3-Y_2O_3-ZrO_2纳米陶瓷粉末及其高温相稳定性  

Sc_2O_3-Y_2O_3-ZrO_2 ceramic nanopowder fabricated by chemical co-precipitation and its high temperature phase stability

作　　者：何轶伦[1] 龙安平[1] 周伍喜[1,2] 刘怀菲[1] 李玉玺 李松林[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083 [2]自贡长城硬面材料有限公司,自贡643011

出　　处：《粉末冶金材料科学与工程》2014年第1期154-158,共5页Materials Science and Engineering of Powder Metallurgy

基　　金：湖南省自然科学基金重点项目(10JJ2037);中南大学研究生自主探索创新项目(2013zzts190)

摘　　要：以(ZrOCl2·8H2O、Y(NO3)3·6H2O和Sc2O3为原料,聚乙二醇(PEG)为分散剂,采用化学共沉淀法制备YSZ(yttrium stabilized zirconia)(名义成分为4.5%Y2O3-ZrO2)与Sc-YSZ(名义成分为0.6%Sc2O3-YSZ)2种纳米复合陶瓷粉末(Y2O3和Sc2O3的含量均为摩尔分数),经过压制成形后在不同温度下烧结。通过透射电镜、X射线衍射等对粉末进行表征,研究其高温下相的稳定性。结果表明:前躯体粉末在600℃煅烧2 h后都呈单一的非平衡四方相结构。采用正向滴定法制备的0.6%Sc2O3-YSZ粉末粒径约为30 nm,粉末团聚严重,有许多大的团聚体,反向滴定法制备的0.6%Sc2O3-YSZ粉末粒径约20 nm,粉末团聚少。YSZ在1 200℃烧结100 h后,呈平衡四方相,并有立方相产生在1 300℃烧结100 h后,平衡四方相不稳定,产生立方相和少量单斜相;在1 400℃烧结100 h后,四方相全部转变为单斜相和立方相。而Sc-YSZ粉体在1 200、1 300和1 400℃下烧结100 h后都始终保持单一的非平衡四方相结构。因此在YSZ中添加少量Sc2O3可提高其相的稳定性。4.5%Y2O3-ZrO2, 0.6%Sc2O3-YSZ composite ceramic nanopowders were prepared by chemical co-precipitation method in ethanol/water （the volume ratio of alcohol to aqueous is 5：1） using ZrOCl2.8H2O, Y（NO3）3·6H2O, Sc2O3 as raw materials and polyethyleneglycol （PEG） as dispersant. The synthesized powders were characterized by means of TEM and XRD analysis. High temperature stability of composite ceramic nanopowders was also studied. The results show that, after calcined at 600 ℃ for 2 h, the presynthesized powders show the pure noneequilibrium tetragonal structure, the size of 0.6%Sc2O3-YSZ particles prepared by reverse titration method is～20 nm compared with～30 nm prepared by the straight titration method. After sintered at 1 200 ℃ for 100 h, YSZ shows equilibrium tetragonal structure together with cubic phase;after sintered at 1 300℃for 100 h, the equilibrium tetragonal structure partly transforms to cubic phase and a small amount of monoclinic phase;after sintered at 1 400℃for 100 h, the tetragonal structure transforms to cubic and monoclinic phase entirely. Whereas, 0.6%Sc2O3-YSZ keeps the pure noneequilibrium tetragonal structure after sintered at 1 200, 1 300 or 1 400℃for 100 h. Therefore, the high temperature phase stability of YSZ can be modified by addition small fraction of Sc2O3.

关 键 词：纳米陶瓷粉末 稀土共掺杂二氧化锆 共沉淀 相稳定性 热障涂层 

分 类 号：TG174[金属学及工艺—金属表面处理]