Two thermal barrier coating(TBC)systems comprising NiCoCrAlY bond coat onto a second-generation Ni-based single crystal superalloy and nano structured4 mol%Y_(2)O_(3)-stabilized ZrO_(2)(4YSZ)and conventional yttria-st...Two thermal barrier coating(TBC)systems comprising NiCoCrAlY bond coat onto a second-generation Ni-based single crystal superalloy and nano structured4 mol%Y_(2)O_(3)-stabilized ZrO_(2)(4YSZ)and conventional yttria-stabilized zirconia(YSZ)top coats upwardly were deposited by approaches of arc ion plating(AIP)and air plasma spray(APS).As indicted by the experimental results,the 4YSZ TBCs exhibited superior thermal cycling resistance compared with conventional YSZ TBCs at 1100℃.The 4YSZ top coat exhibited higher toughness due to its intrinsic property of nanocrystalline structure,homogeneously distributed and diverse directions of pores and preexisted cracks.The cracks and spallation in 4YSZ TBCs occurred at the interface of top coat and thermally grown oxide(TGO)layer.Instead,the crack initiation and propagation started along the lamellar interface in the top coat of conventional YSZ TBCs,leading to the rapid crack bridging and subsequent spalling of top coat.Additionally,before and after oxidation,the 4YSZ top coat showed higher hardness compared to conventional YSZ top coat.Degradation mechanism and distribution of residual stress in TGO for the 4YSZ TBCs were investigated in the current study.展开更多
Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat....Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat.However,the continuous pursuit of a higher operating temperature leads to degradation,delamination,and premature failure of the top coat.Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems.In this paper,the latest progress of some new ceramic materials is first reviewed.Then,a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth,ceramic sintering,erosion,and calcium–magnesium–aluminium–silicate(CMAS)molten salt corrosion.Finally,new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar,columnar,and nanostructure inclusions.The latest developments of ceramic top coat will be presented in terms of material selection,structural design,and failure mechanism,and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance,better thermal insulation,and longer lifetime.展开更多
To refrain the interdiffusion of elements while holding good oxidation resistance,a(Ni,Pt)Al/Ni composite coating was prepared by sequential treatments of electroplating Ni and Pt and successive gaseous aluminization....To refrain the interdiffusion of elements while holding good oxidation resistance,a(Ni,Pt)Al/Ni composite coating was prepared by sequential treatments of electroplating Ni and Pt and successive gaseous aluminization.In comparison with normal(Ni,Pt)Al coating,high-temperature performance of the composite coating was evaluated in isothermal oxidation test at 1100℃.Both the two coatings exhibited good resistance against high-temperature oxidation,but the interdiffusion of elements between composite coating and single-crystal(SC)superalloy substrate was greatly relieved,in which the thickness of secondary reaction zone(SRZ)and the amount of precipitated topologically close-packed phase in the SC alloy matrix were significantly decreased.Mechanisms responsible for delaying rate of coating degradation and SRZ growth/propagation are discussed.展开更多
The overarching goal of present study is to investigate the effects of Ir and Pd additions on the oxidation behaviour of PtAl coatings. Prior to depositing standard PtAl coating, Ir layer was electroplated by IrBr 3 a...The overarching goal of present study is to investigate the effects of Ir and Pd additions on the oxidation behaviour of PtAl coatings. Prior to depositing standard PtAl coating, Ir layer was electroplated by IrBr 3 aqueous solution while Pd layer was prepared using electroless deposition. Comparing with normal PtAl coating, cyclic oxidation tests were carried out on both the Ir-and Pd-modified aluminide coatings. The results showed that Ir-modified PtAl coating exhibited better oxidation resistance than both Pd-modified and normal PtAl coatings because Ir partly served as diffusion barrier to reserve Al while Pd did not.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51671202 and51301184)the Defense Industrial Technology Development Program (No.JCKY2016404C001)the“Liaoning Baiqianwan Talents Program.”。
文摘Two thermal barrier coating(TBC)systems comprising NiCoCrAlY bond coat onto a second-generation Ni-based single crystal superalloy and nano structured4 mol%Y_(2)O_(3)-stabilized ZrO_(2)(4YSZ)and conventional yttria-stabilized zirconia(YSZ)top coats upwardly were deposited by approaches of arc ion plating(AIP)and air plasma spray(APS).As indicted by the experimental results,the 4YSZ TBCs exhibited superior thermal cycling resistance compared with conventional YSZ TBCs at 1100℃.The 4YSZ top coat exhibited higher toughness due to its intrinsic property of nanocrystalline structure,homogeneously distributed and diverse directions of pores and preexisted cracks.The cracks and spallation in 4YSZ TBCs occurred at the interface of top coat and thermally grown oxide(TGO)layer.Instead,the crack initiation and propagation started along the lamellar interface in the top coat of conventional YSZ TBCs,leading to the rapid crack bridging and subsequent spalling of top coat.Additionally,before and after oxidation,the 4YSZ top coat showed higher hardness compared to conventional YSZ top coat.Degradation mechanism and distribution of residual stress in TGO for the 4YSZ TBCs were investigated in the current study.
文摘Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat.However,the continuous pursuit of a higher operating temperature leads to degradation,delamination,and premature failure of the top coat.Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems.In this paper,the latest progress of some new ceramic materials is first reviewed.Then,a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth,ceramic sintering,erosion,and calcium–magnesium–aluminium–silicate(CMAS)molten salt corrosion.Finally,new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar,columnar,and nanostructure inclusions.The latest developments of ceramic top coat will be presented in terms of material selection,structural design,and failure mechanism,and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance,better thermal insulation,and longer lifetime.
基金financially supported by the National Natural Science Foundation of China (Nos.51671202 and 51301184)the "Liaoning BaiQianWan Talents" Program
文摘To refrain the interdiffusion of elements while holding good oxidation resistance,a(Ni,Pt)Al/Ni composite coating was prepared by sequential treatments of electroplating Ni and Pt and successive gaseous aluminization.In comparison with normal(Ni,Pt)Al coating,high-temperature performance of the composite coating was evaluated in isothermal oxidation test at 1100℃.Both the two coatings exhibited good resistance against high-temperature oxidation,but the interdiffusion of elements between composite coating and single-crystal(SC)superalloy substrate was greatly relieved,in which the thickness of secondary reaction zone(SRZ)and the amount of precipitated topologically close-packed phase in the SC alloy matrix were significantly decreased.Mechanisms responsible for delaying rate of coating degradation and SRZ growth/propagation are discussed.
基金sponsored by the‘Liaoning BaiQian Wan Talents’Programpartly supported by the R&D Program in Key Fields of Guangdong Province(No.2019B010936001)。
文摘The overarching goal of present study is to investigate the effects of Ir and Pd additions on the oxidation behaviour of PtAl coatings. Prior to depositing standard PtAl coating, Ir layer was electroplated by IrBr 3 aqueous solution while Pd layer was prepared using electroless deposition. Comparing with normal PtAl coating, cyclic oxidation tests were carried out on both the Ir-and Pd-modified aluminide coatings. The results showed that Ir-modified PtAl coating exhibited better oxidation resistance than both Pd-modified and normal PtAl coatings because Ir partly served as diffusion barrier to reserve Al while Pd did not.