Gd2Zr207 has been considered as a promising thermal barrier coating candidate, but its toughness and thermal expansion coefficient （TEC） need to be improved. In this study, Gd2-xZr2 ＋xO7 ＋χ/2 （χ = 0, 0.1, 0.3, ...Gd2Zr207 has been considered as a promising thermal barrier coating candidate, but its toughness and thermal expansion coefficient （TEC） need to be improved. In this study, Gd2-xZr2 ＋xO7 ＋χ/2 （χ = 0, 0.1, 0.3, 0.5, 0.7） compounds were produced to improve the toughness and enlarge the TEC. Gd2Zr207 and Gd1.9Zr2.1O7.05 exhibited pyrochlore structure, while Gd2-xZr2 ＋xO7 ＋χ/2 （χ = 0.3, 0.5, 0.7） consisted of pyrochlore and t＇-ZrO2 phases. With increasing ZrO2 content, the pyrochlore in the compounds had decreased lattice parameter, and its ordering degree decreased when χ 〈 0.3, then it almost kept unchanged with higher ZrO2 content. Among the Gd2-xZr2 ＋xO7 ＋χ/2 ceramics investigated, the toughness of the compounds in- creased with increasing ZrO2 content, while Gd1.7Zr23O7.15 exhibited the largest TEC. The related mechanisms were discussed in detail.展开更多
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
Y2O3 stabilized ZrO2(YSZ)thermal barrier coatings(TBCs)are prone to hot corrosion by molten salts.In this study,the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to impro...Y2O3 stabilized ZrO2(YSZ)thermal barrier coatings(TBCs)are prone to hot corrosion by molten salts.In this study,the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance.By optimizing the laser parameters,a^18μm smooth glazed layer with some vertical cracks was produced on the coating surfaces.The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000℃for 4 h in V2O5 molten salt,and the results revealed that the modified one had improved corrosion resistance.After hot corrosion,the glazed layer kept structural integrity,with little evidence of dissolution.However,the vertical cracks in the glazed layer acted as the paths for molten salt penetration,accelerating the corrosion of the non-modified coating.Further optimization of the glazed layer is needed in the future work.展开更多
基金sponsored 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Gd2Zr207 has been considered as a promising thermal barrier coating candidate, but its toughness and thermal expansion coefficient （TEC） need to be improved. In this study, Gd2-xZr2 ＋xO7 ＋χ/2 （χ = 0, 0.1, 0.3, 0.5, 0.7） compounds were produced to improve the toughness and enlarge the TEC. Gd2Zr207 and Gd1.9Zr2.1O7.05 exhibited pyrochlore structure, while Gd2-xZr2 ＋xO7 ＋χ/2 （χ = 0.3, 0.5, 0.7） consisted of pyrochlore and t＇-ZrO2 phases. With increasing ZrO2 content, the pyrochlore in the compounds had decreased lattice parameter, and its ordering degree decreased when χ 〈 0.3, then it almost kept unchanged with higher ZrO2 content. Among the Gd2-xZr2 ＋xO7 ＋χ/2 ceramics investigated, the toughness of the compounds in- creased with increasing ZrO2 content, while Gd1.7Zr23O7.15 exhibited the largest TEC. The related mechanisms were discussed in detail.
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This research is sponsored by the National Natural Science Foundation of China(Grant No.51971156).
文摘Y2O3 stabilized ZrO2(YSZ)thermal barrier coatings(TBCs)are prone to hot corrosion by molten salts.In this study,the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance.By optimizing the laser parameters,a^18μm smooth glazed layer with some vertical cracks was produced on the coating surfaces.The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000℃for 4 h in V2O5 molten salt,and the results revealed that the modified one had improved corrosion resistance.After hot corrosion,the glazed layer kept structural integrity,with little evidence of dissolution.However,the vertical cracks in the glazed layer acted as the paths for molten salt penetration,accelerating the corrosion of the non-modified coating.Further optimization of the glazed layer is needed in the future work.
