Research On Microstructure And Properties Of Tbc Produced By Electrophoretic Deposition

In this paper, YSZ thermal barrier coatings were synthesized on the substrate of Inconel 600 superalloy by electrophoretic deposition technology. Effect of YSZ Gd2O3 doped with various quantities metal powder Ni, Al on high temperature oxidation resistance and bond strength of composite coating were studied. Diffusion law of each element and performance analysis in the YSZ/(Ni,Al) composite coatings after plastic deformation of the superalloy substrate were also investigated.The results showed that, after Y2O3 stabilized Zr O2 doped with the concentration in mol% varied from 2-4 mol%, Gd2O3-Y2O3-Zr O2 composite coatings were mainly composed of tetragonal Zr O2 phase, monoclinic Zr O2 phase, and Gd2Zr2O7 phase sintered at 1100 ℃ for 2 h under vacuum(<10-3 Pa), corresponding composite coatings were mainly composed of tetragonal Zr O2 phase, monoclinic Zr O2 phase and cubic phase, while Gd2Zr2O7 phase disappeared, after isothermally annealed at 1100 ℃ in air for 100 h. The amount of monoclinic phase increased with increasing Gd2O3 concentration. The rare earth gadolinia addition to YSZ coating could significantly suppress the grain growth at 1100 ℃in air.YSZ/(Ni,Al) composite coatings were prepared by electrophoretic deposition technique. The addition of Al and Ni to the green YSZ coating formed composite coatings after vacuum sintering at 1100 ℃ for 2 h. YSZ/(Ni,Al) composite coatings were mainly composed of tetragonal/cubic Zr O2, Al Ni3, Al2O3 and Ni Al2O4 phases sintered at 1100 ℃for 2 h under vacuum(<10-3 Pa). Al2O3 phase helps to improve the oxidation resistance of superalloys. It can be also observed that Cr outward diffusion from the substrate and the Al inward diffusion from the surface to the nickel substrate. In comparison with the bond strength of 3.5 N for YSZ coating, the bond strength for YSZ/(Ni,Al) composite coating increased to 4.4 N. YSZ/(Ni,Al) composition coatings show also superior oxidation resistance than that of YSZ coating.Compared with non-plastic deformation of the substrate, The mass fraction composite coating of Al Ni3 phase reduced from 5.42 % to 2.39 % after the plastic deformation of thesubstrate, vacuum sintering at 1100 ℃ for 2 h. Compared with non-plastic deformation of the substrate, improving the oxidation resistance and bonding strength of the composite coating were improved after plastic deformation of the substrate.