Nd2Zr2O7 is being explored as an alternate thermal barrier coating （TBC） material for operating above 1300 ℃, and great effort has been made to enlarge its thermal expansion coefficient （TEC） and improve its toug...Nd2Zr2O7 is being explored as an alternate thermal barrier coating （TBC） material for operating above 1300 ℃, and great effort has been made to enlarge its thermal expansion coefficient （TEC） and improve its toughness. In this study, Sc203 vvas doped to Nd2Zr2O7. The phase structure, TECs and toughness of （Nd1-xScx）2Zr2O7 （x = 0, 0.025, 0.05, 0.075, 0.1 ） compounds were investigated. （Nd1-xScx）2Zr2O7 （x = 0, 0.025, 0.05, 0,075） exhibited pyrochlore structure, while （Nd0.9Sc0.1）2Zr2O7 consisted of pyrochlore and fluorite phases. With the increase of the Sc203 content, the ordering degree of the pyrochlore in the compounds decreased. In （Nd1-xScx）2Zr2O7 series, （Nd0.925Sc0.075）2Zr2O7 exhibited the largest TEC, while the toughness of the compounds increased with increasing the Sc2O3 content. The related mechanisms were discussed based on the crystal structure analysis. Considering the TEC and toughness, 10 mol% Sc2O3 was sug- gested as the optimal doping content for Nd2Zr2O7 ceramic.展开更多
Fine grains and slow grain growth rate are beneficial to preventing the thermal stress-induced cracking and thermal conductivity increase of thermal barrier coatings.Inspired by the sluggish diffusion effect of high-e...Fine grains and slow grain growth rate are beneficial to preventing the thermal stress-induced cracking and thermal conductivity increase of thermal barrier coatings.Inspired by the sluggish diffusion effect of high-entropy materials,a novel high-entropy(HE)rare-earth zirconate solid solution(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 was designed and successfully synthesized in this work.The as-synthesized(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 is phase-pure with homogeneous rare-earth element distribution.The thermal conductivity of as-synthesized(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 at room temperature is as low as 0.76 W m^-1 K^-1.Moreover,after being heated at 1500℃for 1-18 h,the average grain size of(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 only increases from 1.69μm to 3.92μm,while the average grain size of La2Zr2O7 increases from 1.96μm to 8.89μm.Low thermal conductivity and sluggish grain growth rate indicate that high-entropy(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7 is suitable for application as a thermal barrier coating material and it may possess good thermal stress-induced cracking resistance.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51501127 and 51375332)the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120032110031)
文摘Nd2Zr2O7 is being explored as an alternate thermal barrier coating （TBC） material for operating above 1300 ℃, and great effort has been made to enlarge its thermal expansion coefficient （TEC） and improve its toughness. In this study, Sc203 vvas doped to Nd2Zr2O7. The phase structure, TECs and toughness of （Nd1-xScx）2Zr2O7 （x = 0, 0.025, 0.05, 0.075, 0.1 ） compounds were investigated. （Nd1-xScx）2Zr2O7 （x = 0, 0.025, 0.05, 0,075） exhibited pyrochlore structure, while （Nd0.9Sc0.1）2Zr2O7 consisted of pyrochlore and fluorite phases. With the increase of the Sc203 content, the ordering degree of the pyrochlore in the compounds decreased. In （Nd1-xScx）2Zr2O7 series, （Nd0.925Sc0.075）2Zr2O7 exhibited the largest TEC, while the toughness of the compounds increased with increasing the Sc2O3 content. The related mechanisms were discussed based on the crystal structure analysis. Considering the TEC and toughness, 10 mol% Sc2O3 was sug- gested as the optimal doping content for Nd2Zr2O7 ceramic.
基金financially supported by the National Natural Science Foundation of China (Nos.51672064 and U1435206)
文摘Fine grains and slow grain growth rate are beneficial to preventing the thermal stress-induced cracking and thermal conductivity increase of thermal barrier coatings.Inspired by the sluggish diffusion effect of high-entropy materials,a novel high-entropy(HE)rare-earth zirconate solid solution(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 was designed and successfully synthesized in this work.The as-synthesized(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 is phase-pure with homogeneous rare-earth element distribution.The thermal conductivity of as-synthesized(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 at room temperature is as low as 0.76 W m^-1 K^-1.Moreover,after being heated at 1500℃for 1-18 h,the average grain size of(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2 Zr2 O7 only increases from 1.69μm to 3.92μm,while the average grain size of La2Zr2O7 increases from 1.96μm to 8.89μm.Low thermal conductivity and sluggish grain growth rate indicate that high-entropy(La0.2Ce0.2Nd0.2Sm0.2Eu0.2)2Zr2O7 is suitable for application as a thermal barrier coating material and it may possess good thermal stress-induced cracking resistance.
