第十三届全国表面工程大会暨第十二届全国青年表面工程论坛

290 / 2020-10-10 15:43:50

Hot corrosion resistance of Al-modified 7YSZ TBCs for marine environment

marine environment; plasma spray-physical vapor deposition; Al-modification; hot-corrosion.

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With more and more marine activities, more frequent running of the gas turbine engine is taking place in the marine environment. Therefore, the TBCs on the surface of turbine blade will face more severe test. In the manuscript, feather-like columnar structure coatings with high thermal insulation and high stress tolerance were obtained by plasma spray-physical vapor deposition (PS-PVD). In order to improve the corrosion resistance of the coating, Al-modification was carried out. Then, hot corrosion of coatings in marine environment was tested by thermal exposure of NaCl and gas-salt spray. The results show that the Al-modified TBCs have better hot corrosion resistance compared to the as-sprayed TBCs because of the protective overlay. In the thermal exposure of NaCl, NaCl mainly acts on the thermally grown oxides (TGO), which accelerates the thickening of TGO through the electrochemical corrosion mechanism. After gas-salt spray corrosion, the YSZ coatings sintered and the evolution of mechanical properties were analyzed. The hardness of the initial YSZ coating, the corroded YSZ coating and the corroded Al-modified YSZ coating on the middle part of the cross-section were 7910.4 MPa, 13046.1 MPa and 11467 MPa respectively, and the elastic modulus was 89.6 Gpa, 133 Gpa and 129.6 Gpa, respectively