Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by spray-drying.The single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic...Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by spray-drying.The single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic-layer(DCL)Gd_(2)Zr_(2)O_(7)/YSZ TBCs with quasicolumnar structure were successfully fabricated by plasma spray-physical vapor deposition(PS-PVD).Tensile and water-quenching tests were applied to evaluate TBCs performances.The results show that adhesion strength of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs is36.5 MPa and 15.4 MPa,respectively.The delamination of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs in the tensile test takes place at the middle and bottom of Gd_(2)Zr_(2)O_(7)layer,respectively,due to relatively lower fracture toughness of Gd_(2)Zr_(2)O_(7)layer.After 40 cycles of water-quenching test,DCL Gd_(2)Zr_(2)O_(7)/YSZ TBC surface keeps relatively intact,while SCL Gd_(2)Zr_(2)O_(7)TBC surface shows 20%visible destroyed regions,which demonstrates that DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs have a better thermal shock resistance than SCL Gd_(2)Zr_(2)O_(7)TBCs.The cracks in the SCL system propagate near thermally grown oxide(TGO)due to thermal mismatch and TGO growing stress,while cracks in the DCL system propagate in the Gd_(2)Zr_(2)O_(7)layer due to its relatively lower fracture toughness.展开更多
7 YSZ coating was prepared by plasma sprayphysical vapor deposition(PS-PVD) technique based on a specific experimental design.The microstructure and deposition properties of 7 YSZ coating along the radius of plasma je...7 YSZ coating was prepared by plasma sprayphysical vapor deposition(PS-PVD) technique based on a specific experimental design.The microstructure and deposition properties of 7 YSZ coating along the radius of plasma jet were investigated in detail.Results show that the coating presents regional characteristic in the radial direction,which could be divided into three typical zones:In Zone Ⅰ,the coating is all composed of columnar structures with cauliflower structure,and the coating properties including the surface roughness and deposition efficiency(DE) are almost stable;in Zone Ⅲ,the coating is made up of solid particles,droplet and gas phase mixed without columnar structures;Zone Ⅱ is between Zone Ⅰ and ZoneⅢ, in which there are columns with domed top and small particles.Based on experiment results,a model on the state and distribution of particles in plasma jet was proposed to clarify the regional characteristic.This study is helpful to comprehend and control coatings deposition by PS-PVD technique.展开更多
基金Project(2017YFB0306100) supported by the National Key Research&Development Plan of ChinaProjects(51801034,51771059) supported by the National Natural Science Foundation of China+3 种基金Projects(2018GDASCX-0949,2018GDASCX-0950,2017GDASCX-0111) supported by the Guangdong Academy of Sciences,ChinaProjects(2017B090916002,2017A070701027) supported by the Guangdong Technical Research Program,ChinaProjects(2016A030312015,2017A030310315) supported by the Natural Science Foundation of Guangdong Province,ChinaProjects(201605131008557,201707010385) supported by the Technical Research Program of Guangzhou City,China
基金financially supported by the National Key Research and Development Program of China(No.2017YFB0306100)the National Natural Science Foundation of China(No.51771059)+2 种基金the Natural Science Foundation of Hunan Province(No.2018JJ2524)the International Scientific Technological Cooperation Projects of China(Nos.2015DFR50580 and 2013DFA31440)the Science and Technology Planning Project of Guangdong Province(No.2017A070701027)。
文摘Spherical Gd_(2)Zr_(2)O_(7)hollow powders with a mean size of 8.8μm were fabricated as feedstock for thermal barrier coatings(TBCs)by spray-drying.The single-ceramic-layer(SCL)Gd_(2)Zr_(2)O_(7)TBCs and double-ceramic-layer(DCL)Gd_(2)Zr_(2)O_(7)/YSZ TBCs with quasicolumnar structure were successfully fabricated by plasma spray-physical vapor deposition(PS-PVD).Tensile and water-quenching tests were applied to evaluate TBCs performances.The results show that adhesion strength of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs is36.5 MPa and 15.4 MPa,respectively.The delamination of SCL Gd_(2)Zr_(2)O_(7)TBCs and DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs in the tensile test takes place at the middle and bottom of Gd_(2)Zr_(2)O_(7)layer,respectively,due to relatively lower fracture toughness of Gd_(2)Zr_(2)O_(7)layer.After 40 cycles of water-quenching test,DCL Gd_(2)Zr_(2)O_(7)/YSZ TBC surface keeps relatively intact,while SCL Gd_(2)Zr_(2)O_(7)TBC surface shows 20%visible destroyed regions,which demonstrates that DCL Gd_(2)Zr_(2)O_(7)/YSZ TBCs have a better thermal shock resistance than SCL Gd_(2)Zr_(2)O_(7)TBCs.The cracks in the SCL system propagate near thermally grown oxide(TGO)due to thermal mismatch and TGO growing stress,while cracks in the DCL system propagate in the Gd_(2)Zr_(2)O_(7)layer due to its relatively lower fracture toughness.
基金financially supported by Guangdong Natural Science Foundation (No.2016A030312015)the Science and Technology Cooperation Project of Guangdong Province (No.2013B050800027)the Science and Technology Cooperation Project of Guangzhou (No.201508030001)。
文摘7 YSZ coating was prepared by plasma sprayphysical vapor deposition(PS-PVD) technique based on a specific experimental design.The microstructure and deposition properties of 7 YSZ coating along the radius of plasma jet were investigated in detail.Results show that the coating presents regional characteristic in the radial direction,which could be divided into three typical zones:In Zone Ⅰ,the coating is all composed of columnar structures with cauliflower structure,and the coating properties including the surface roughness and deposition efficiency(DE) are almost stable;in Zone Ⅲ,the coating is made up of solid particles,droplet and gas phase mixed without columnar structures;Zone Ⅱ is between Zone Ⅰ and ZoneⅢ, in which there are columns with domed top and small particles.Based on experiment results,a model on the state and distribution of particles in plasma jet was proposed to clarify the regional characteristic.This study is helpful to comprehend and control coatings deposition by PS-PVD technique.
