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Mechanical properties and simulated thermal conductivity of biomimetic structured PS-PVD(Gd_(0.9)Yb_(0.1))_(2)Zr_(2)O_(7) thermal barrier coatings

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Journal of Materials Science & Technology 2024年第15期182卷 33-40页

作者： Yiqian guo Lei guo Keyi Liu Shiyi Qiu hongbo guo Huibin Xu School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Chinese Aeronautical Establishment Beijing 100012China Tianmushan Laboratory Yuhang DistrictHangzhou 311115China Research Institute for Frontier Science Beihang UniversityBeijing 100191China

Plasma spray physical vapor deposition(PS-PVD)(Gd_(0.9)Yb_(0.1))_(2)Zr_(2)O_(7)(GYbZ)thermal barrier coatings(TBCs)exhibited better silicate-phobicity than coatings produced by electron beam physical vapor *** combination with PS-PVD and ultrafast laser direct writing technology,biomimetic structured GYbZ TBCs,with a triple-scale micro/nano surface microstructure,were *** ablating on the PS-PVD GYbZ coating enhanced the surface roughness,improving its wear resistance without increasing the surface ***,during the laser ablation processing,numerous nanoparticles were deposited in-situ in the gaps between columns of the coating,reducing the coating Young’s *** simulated temperature field and heat flux field demonstrated that the presence of numerous interfaces between small columns of the PS-PVD coatings is beneficial to thermal ***,laser ablation decreased the coating thickness,reducing the thermal insulation by around 20%-30%as compared to its PS-PVD counterpart,suggesting that a moderate increase in the coating thickness should be considered when designing an efficient TBC system.

关键词： Thermal barrier coatings(TBCs) Plasma spray physical vapor deposition (PS-PVD) Laser ablation Biomimetic structure Mechanical properties Thermal insulation

Effects of laser shock processing onθ-Al_(2)O_(3)toα-Al_(2)O_(3)transformation and oxide scale morphology evolution in(γ'+β)two-phase Ni-34Al-0.1Dy alloys

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Journal of Materials Science & Technology 2022年第14期109卷 157-166页

作者： Bangyang Zhou Jian He Qijie Zhou hongbo guo School of Materials Science and Engineering Beihang University(BUAA)Beijing 100191China Research Institute for Frontier Science Beihang University(BUAA)Beijing 100191China Key Laboratory of High-Temperature Structural Materials&Coatings Technology(Ministry of Industry and Information Technology) Beihang University(BUAA)Beijing 100191China

(γ’+β)two-phase Ni-Al is a promising high-temperature protective coating material used on Ni-base superalloys since it has good interfacial compatibility with superalloys due to the low Al content compared to single-phaseβ-NiA *** this paper,we aim to improve the oxidation resistance,whereby Ni-34Al-0.1Dy,a(γ’+β)two-phase Ni-Al alloy,was treated by laser shock processing(LSP)and the oxidation behavior at 1150℃ was *** results showed that after oxidation,Al_(2)O_(3)scale formed on the originalβphase of the untreated alloy with a small grain size(200-800 nm),while for the LSP-treated samples,the scale grown on the originalβphase was dominantly composed of larger Al_(2)O_(3)grains with a size of 2-3μ*** distinction was attributed to the promotion ofθ-Al_(2)O_(3)toα-Al_(2)O_(3)transformation induced by the LSP,because the dislocation density,as well as surface roughness,were increased during LSP treatment which can provide heterogeneous nucleation sites forα-Al_(2)O_(3).In addition,the larger-size Al_(2)O_(3)particles,derived from the direct conversion of needle-likeθ-Al_(2)O_(3)in the initial oxidation stage,could rapidly overspread the wholeβphase surface thus reducing the scale growth rate.

关键词： Intermetallics Laser shock processing Oxidation θ-Al_(2)O_(3)toα-Al_(2)O_(3)transformation Morphology evolution

CMAS-phobic and infiltration-inhibiting protective layer material for thermal barrier coatings

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Journal of Advanced Ceramics 2024年第8期13卷 1254-1267页

作者： Shjun Meng Lei guo hongbo guo Yuanpeng Wang Hongli Liu School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Advanced Joining Technology Key Lab of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin300072China School of Materials Science and Engineering Beihang UniversityBeijing 100191China College of Aeronautical Engineering Civil Aviation University of ChinaTianjin 300300China

Calcium-magnesium-alumina-silicate(CMAS)corrosion has attracted special attention in the thermal barrier coating(TBC)*** high temperatures,when CMAS melts,it adheres to the coating surface and penetrates the interior,severely destroying the *** this study,a promising CMAS-phobic and infiltration-inhibiting material,GdPO4,on which molten CMAs is difficult to wet and penetrate,was *** desirable attributes are explained by analyzing the material characteristics of GdPO_(4) and its interfacial reaction with ***4 is demonstrated to have low surface energy,making it difficult for molten CMAS to wet and adhere to the *** in contact with molten CMAS,a double-layer structured reaction layer consisting of an acicular upper sublayer and a compact lower sublayer is formed on the GdPO4 surface,which can effectively impede molten CMAS spreading and ***-principles calculation results revealed that the reaction layer has low surface energy and low adhesion to CMAS,which are favorable for molten CMAS ***,the formation of the reaction layer increases the viscosity of the molten CMAS,which can increase melt wetting and ***,GdPO4,which exhibits excellent CMAS-phobicity and infiltration-inhibiting ability,is a promising protective layer material for TBCs against CMAS adhesion and attack.

关键词： thermal barrier coatings(TBCs) calcium-magnesium-alumina-silicate(CMAS)-phobicity GdPO_(4) interface reaction layer first-principles calculation

Effect of Sintering on Thermal Conductivity and Thermal Barrier Effects of Thermal Barrier Coatings

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Chinese Journal of Aeronautics 2012年第5期25卷 811-816页

作者： WANG Kai PENG Hui guo hongbo GONG Shengkai School of Materials Science and Engineering Beihang UniversityBeijing 100191China

Thermal barrier coatings （TBCs） are mostly applied to hot components of advanced turbine engines to insulate the compo- nents from hot gas. The effect of sintering on thermal conductivity and thermal barrier effects of conventional plasma sprayed and nanostructured yttria stabilized zirconia （YSZ） thermal barrier coatings （TBCs） are investigated. Remarkable increase in thermal conductivity occurs to both typical coatings after heat treatment, The change of porosity is just the opposite. The grain size of the nanostructured zirconia coating increases more drastically with annealing time compared to that of the conventional plasma sprayed coating, which indicates that coating sintering makes more contributions to the thermal conductivity of the nanostructured coating than that of the conventional coating. Thermal barrier effect tests using temperature difference technique are performed on both coatings. The thermal barrier effects decrease with the increase of thermal conductivity after heat treat- ment and the decline seems more drastic in low thermal conductivity range. The decline in thermal barrier effects is about 80℃ for nanostructured coating after 100 h heat treatment, while the conventional coating reduces by less than 60 ℃ compared to the as-sprayed coating.

关键词： thermal barrier coatings (TBCs) sintering thermal conductivity thermal insulation laser flash method

Cyclic Oxidation Behavior of an EB-PVD CoCrAlY Coating Influenced by Substrate/coating Interdiffusion

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Chinese Journal of Aeronautics 2012年第5期25卷 796-803页

作者： LIANG Tianquan guo hongbo PENG Hui GONG Shengkai School of Materials Science and Engineering Beihang University Beijing 100191 China School of Materials Science and Engineering Guangxi University Nanning 530004 China

To reveal the influence of substrate/coating interdiffusion on the cyclic oxidation property of a metallic coating, cyclic oxida- tion behavior of an EB-PVD CoCrAIY coating on directionally solidified Ni-based superalloy DZ125 at 1 050℃ is investigated. The 40 μm thick CoCrA1Y coating has a cyclic oxidation life of around 160 h, and the oxidation constant is 1.915× 10^-7 ***^-8.s-1. However, severe spallation of the oxides containing Co, Cr, Ni, Ta and Ti occurs with longer cyclic oxidation. The degradation in oxidation resistance for the coating is related to the depletion of A1 due to the oxide spallation and interdiffu- sion. Severe interdiffusion between the coating and underlying substrate occurs at 1 050 ℃. The composition of the substrate has an important effect on the thermal cycling lifetime of the coating. The influencing mechanism is discussed.

关键词： CoCrA1Y coating cyclic oxidation degradation interdiffusion substrate composition

Hot Corrosion Behavior of Double-ceramic-layer LaTi_2 Al_(9)O_(19)/YSZ Thermal Barrier Coatings

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Chinese Journal of Aeronautics 2012年第1期25卷 137-142页

作者： XIE Xiaoyun guo hongbo GONG Shengkai XU Huibin School of Materials Science and Engineering Key Laboratory of Aerospace Materials&Performance(Ministry of Education)Beihang UniversityBeijing 100191China

LaTi2Al9O19 （LTA） exhibits promising potential as a new kind of thermal barrier coating （TBC） material, due to its excellent high-temperature capability and low thermal conductivity. In this paper, LTA/yttria stabilized zirconia （YSZ） TBCs are produced by atmospheric plasma spraying. Hot corrosion behavior and the related failure mechanism of the coating are investigated. Decomposition of LTA does not occur even after 1 458 hot corrosion cycles at 1 373 K, revealing good chemical stability in molten salt of Na=SO4 and NaCl. However, the molten salt infiltrates to the bond coat, causing dissolving of the thermally grown oxide （TGO） in the molten salt and hot corrosion of the bond coat. As a result, cracking of the TBC occurs within the oxide layer. In conclusion, the ceramic materials LTA and YSZ reveal good chemical stability in molten salts of Na2SO4 and NaCl, and the bond coat plays a significant role in providing protection for the component against hot corrosion in the LTA/YSZ TBCs. LTA exhibits very promising potential as a novel TBC material.

关键词： thermal barrier coatings LaTi2Al9O19 hot corrosion plasma spraying failure

Impermeability of Y_3Al_5O_(12) ceramic against molten glassy calcium-magnesium-alumina-silicate

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Chinese Journal of Aeronautics 2018年第12期31卷 2306-2311页

作者： Zhaolu XUE Yue MA Shengkai GONG hongbo guo School of Materials Science and Engineering Beihang UniversityBeijing 100083China Key Laboratory of High-Temperature Structure Materials and Coatings Technology (Ministry of Industry and Information Technology) Beihang UniversityBeijing 100083China

Degradation of thermal barrier coatings(TBCs) caused by calcium-magnesium-aluminasilica(CMAS) glassy penetration is becoming an urgent issue for TBCs industrial applications. In this work, yttrium aluminum garnet(YAlO, YAG) nano-powders were synthesized through a chemical co-precipitation route. The resistance of YAG ceramic to glassy CMAS infiltration at1250 °C was evaluated. YAG ceramic bulk sintered at 1700 °C for 10 h was comprised of a single garnet-type YAlOphase. The molten CMAS glass was suppressed on the surface of the YAG ceramic at 1250 °C. A chemical reaction between YAG and the molten CMAS glass did not occur at 1250 °C for 24 h, suggesting that YAG could act as an impermeable material against glassy CMAS deposits in the TBC field.

关键词： Calcium-magnesium-alu mina-silicate(CMAS) Ceramics Thermal barrier coating Yttrium aluminum garnet Zirconia

Effects of Pressure during Preparation on the Grain Orientation of Ruddlesden-Popper Structured BaLa_2Ti_3O_(10) Ceramic

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Journal of Materials Science & Technology 2014年第5期30卷 455-458页

作者： Xizhong Wang Lei guo hongbo guo guohui Ma Shengkai Gong School of Materials Science and Engineering Beihang University Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology Beihang University

As potential thermal barrier coating （TBC） materials, Ruddlesden-Popper structured BaLn2Ti3010 （Ln = rare earth） compounds possess excellent phase stability and desirable thermo-physical properties as well as interesting anisotropic structure. In this paper, the effects of pressure during BaLa2Ti3010 （BLT） bulk preparation on the grain orientation were investigated. BLT grains exhibited lamellar structure, but the grain orientation depended strongly on the existence of pressure during bulk preparation. When pressure was applied, BLT grains preferentially grew along pressing direction, leading to formation of the texture parallel to pressing direction, but BLT grain orientation became relatively random when pressure was absent. However, in the small scale area, BLT grains grew preferentially along c-axis with independence on pressure during preparation. Pressure affected BLT grain orientation at the rapid growth stage according to the grain growth model of BLT.

关键词： Thermal barrier coating (TBC) Ceramics Pressure Grain growth

Influence of Gd_2O_3 and Yb_2O_3 Co-doping on Phase Stability,Thermo-physical Properties and Sintering of 8YSZ

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Chinese Journal of Aeronautics 2012年第6期25卷 948-953页

作者： ZHANG Yanli guo Lei YANG Yongping guo hongbo ZHANG Hongju GONG Shengkai School of Materials Science and Engineering Beihang University Beijing 100191 China Guizhou LiyangAviation Power Co. Ltd. Anshun 561102 China

The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings （TBCs） materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 （GYb-YSZ） powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.

关键词： thermal barrier coatings (TBCs) Gd2O3 and Yb2O3 co-doped 8YSZ (GYb-YSZ) phase stability sintering ther-mo-physical properties