Research On High Temperature Resistance Of Multilayer Thermal Barrier Coatings

With the development of aeronautics and astronautics industry,it is more likely that thermal barrier coatings(TBCs)on engine turbine blade would work in more complex environment.In high temperature,the thermal stress caused by the mismatch of materials'thermal expansion coefficient and the thermal growth oxide(TGO)in the coatings are the main reasons leading to the peeling failure.People have paid more attention to improve the thermal matching and anti-oxidation ability of the coatings.In this paper,a new kind of thermal barrier coatings was prepared.For this new kind of coatings,In order to overcome the mismatch of thermal expansion coefficient as well as reduce the rate of the external O diffusing into the surface of adhesive layer,a transition layer was prepared in the middle of bond coat and ceramic coat,So that the thermal shock resistance and high temperature oxidation resistance of the coatings were improved.Traditional TBCs and Multilayer TBCs were prepared on the superalloy substrate by electron beam physical vapor deposition(EB-PVD).And their thermal shock resistance and high temperature resistance were tested at 1100?.Then the oxidation kinetics curves of two kinds TBCs were obtained by weighing samples which were kept in 1100? for different holding time.The surface and cross-section structure and composition of the samples were analyzed by scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and X-ray analysis(XRD).Then the internal stress of ceramic layer were calculated.It was found that the growth rate of TGO layer of the TBCs on the multilayer coatings was grown slower than that of the traditional TBCs at 1100?.Multilayer TBCs showed a better high temperature oxidation resistance.During the thermal shock test,the TGO layer of the traditional thermal barrier coatings become thick faster,and a large area of peeling occurred after 175 cycles of thermal cycling,and the delamination occurred near the interface between the adhesive layer and the TGO.In contrast,the multilayer TBCs' peeling area was only 18.2%,and the peeling position was inside the mixed layer,which showed good thermal shock resistance.