Interfacial Evolution Behavior of ZrO2(ZrB2) Active Diffusion Barrier

Abstract Two sample groups, N5/(ZrB 2 +ZrO 2 )/NiCrAl and N5/ZrO 2 /NiCrAl, were prepared on Ni-based single crystal alloy (Rene N5) substrate by electron beam physical vapor deposition (EB-PVD). Both sample groups were exposed to isothermal oxidation at 900 °C for 5 h and at 1000 °C, for 250 h, 300 h or 350 h. The microstructural evolution and deterioration failure behavior was investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results suggest that the introduction of ZrB 2 decelerates the interfacial reaction rate of the active diffusion barrier of Al 2 O 3 but does not affect the final formation of the Al 2 O 3 diffusion barrier with anti-diffusion properties. Moreover, the introduction of ZrB 2 prolongs the service life of active diffusion barrier structure and changes its failure mode.