摘要
目的 通过关注纳米8YSZ粉末在不同温度下烧结过程中的晶粒长大行为及相结构组成变化,获得纳米8YSZ粉末的高温稳定性,防止高温烧结导致纳米8YSZ涂层性能明显衰减,致使涂层在正常服役过程中过早失效。方法 采用共沉淀工艺合成低杂质含量的8YSZ纳米粉末,经过低温煅烧预处理后,在900～1200℃温度区间进行3～12 h的烧结。通过X射线衍射仪和扫描电子显微镜对纳米颗粒进行物相结构和形貌分析,根据Scherrer公式计算热处理后的颗粒平均晶粒尺寸,采用Arrhenius公式得到晶粒生长活化能,进而确定晶粒的生长机制。结果 经过低温煅烧预处理后,粉末绝大多数仍然保持非晶态结构,经过高温热处理后,粉末均完成了晶态转化,相结构基本为单一四方相。温度为900～1100℃时,晶粒生长的活化能为42.638 k J/mol;温度为1100～1200℃时,晶粒生长的活化能为3.849 k J/mol。结论 高温热处理后,纳米8YSZ粉末物相结构为单一四方相,可以保持高温稳定性,防止涂层性能明显衰减。温度为900～1200℃时,晶粒生长机制以表面扩散为主的聚合生长。
Objective To obtain the temperature stability of nanocrystalline 8% yttria stabilized zirconia （8YSZ） and prevent the apparent decline of properties of the 8YSZ coating owing to the sintering behavior by investigating the changes of the grain size and the phase composition of the nanocrystalline 8YSZ powders. Methods The nanocrystalline 8YSZ powders with low impurity were prepared by co-precipitation method. Then they were sintered for 3-12 h at 900-1200℃ after low temperature calcination. Phase composition and morphology were analyzed by XRD and SEM. The average particle size after heat treatment was calculated by Scherrer formula. Grain growth activation energy was obtained by Arrhenius formula and then the grain growth mechanism was determined. Results Most powders kept amorphous after low temperature calcination pretreatment. After high temperature heat treatment, crystalline state was transformed and the phase of the powders changed to tetragonal. The activation energy was 42.638 kJ/mol at 900-1100℃, and 3.849 kJ/mol at 1100-1200℃. Conclusion It is primary tetragonal phase after high temperature heat treatment among the nanocrystalline 8YSZ powders which could retain the temperature stability and prevent apparent decline of coating property while the grain growth is controlled by surface diffusion at 900-1200℃.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2016年第9期118-125,共8页
Surface Technology
关键词
纳米8YSZ粉末
高温热处理
晶粒尺寸
相转变
晶粒生长
生长活化能
nanocrystalline 8% yttria stabilized zirconia powders
high temperature heat treatment
particle size
phase transition
grain growth
activation energy
