Structures of Nb/Al2O3 Interfaces Produced by Different Experimental Routes

Abstract

AbstractNb/Al2O3 interfaces were produced by (i) diffusion bonding of single crystalline Nb and Al2O3 at 1973 K, (ii) internal oxidation of a Nb-3at.% Al alloy at 1773 K, and (iii) molecular beam epitaxy (MBE) growth of 500 nm thick Nb overlayers on sapphire substrates at 1123 K. Cross-sectional specimens were prepared and studied by conventional (CTEM) and high resolution transmission electron microscopy (HREM). The orientation relationships between Nb and Al2O3 were identified by diffraction studies. HREM investigations revealed the structures of the different interfaces including the presence of misfit dislocations at or near the interface. The results for the different interfaces are compared.