A RUTHERFORD BACKSCATTERING STUDY OF INTERFACIAL REACTIONS OF NICKEL AND COBALT OXIDES WITH ALUMINUM-OXIDE

In view of the importance for heterogeneous catalysis, the high-temperature behaviour of Ni and Co layers on Al2O3 has been investigated. The samples were oxidized at moderate temperatures and annealed at high temperatures (up to 1000-degrees-C) in N2/02 or N2/02/30%H2O. Subsequently, the formation of NiAl2O4 and CoAl2O4 WaS assessed using Rutherford backscattering spectrometry and X-ray diffraction. Reaction to CoAl2O4 appeared to proceed considerably faster than NiAl2O4 formation, and gamma-Al2O3 showed a much higher reactivity towards CoO than alpha-Al2O3. The main influence of steam was bringing about a loss of Ni or Co atoms by volatilization.