The effect of the grain structure of Al2O3 substrate on the solid state reaction with a layer of NiO: A comparative backscattering spectrometry study 1

Abstract

AbstractThe solid state reaction of Al2O3NiO reaction couples was investigated by means of Rutherford backscattering spectrometry. NiO films on the alumina substrates were obtained by vapour–deposition of Ni and subsequent oxidation at 800°C in air. Substrates of about the same surface roughness, thus providing equal contact areas for the reaction couples, were used. The materials were characterized by scanning electron microscopy. In spite of the different structure and a grain size that varied within a factor of 10, of the Al2O3 materials, no obvious difference in the spectra based on the used reaction couples could be detected. Suggested substantial contribution to the reaction from surface diffusion and grain boundary diffusion along the substrate grain boundaries could therefore be rejected.