Solid state synthesis and spectroscopic analysis of CuAlO2 and spinel CuAl2O4

The multitude of effected works about oxides obtained from the system Cu/Al2O3 proves the increasing interest for these oxides in synthesis and technological applications, due to their physical and chemical properties. In this work, CuAlO2 and spinel CuAl2O4 were prepared by conventional technique of brazing in oxidizing atmosphere starting from the Cu/Al2O3 assembly. Thermal treatment was performed at 1150°C, with a sufficiently long time in order to obtain a large interaction zone. The structure of the Cu/Al2O3 interface was characterized using XRD microanalysis and Raman spectroscopy. The obtained results show an interaction zone with a complex structure, where CuAlO2 and spinel CuAl2O4 coexist, at Cu/Al2O3 junction, with a dendritic structure of Cu2O and silicon in solution. Otherwise, we showed that the presence of both the silicon inclusion and the multiple crystalline phases, mixed the ones with the others, led to the photonic modes activation not predicted by the groups theory.