Study on carbon contamination and carboxylate group formation in Y_2O_3-MgO nanocomposites fabricated by spark plasma sintering

摘要

For Y_2O_3-MgO nanocomposites fabricated by spark plasma sintering (SPS), the strong absorption peaks, which are assigned to the stretching vibrations of carboxylate group (O-C=0), are commonly observed in IR spectra. These absorption peaks can negatively affect military applications such as IR windows or domes. In order to suppress the formation of these absorption peaks, therefore, it is important to understand how the carboxylate group in the SPSed Y_2O_3-MgO nanocomposite originated. In this study, it is demonstrated that the formation of the carboxylate group is related to the carbon contamination during SPS processing. The carbon phase transforms into CO_2 gas by annealing and this leads to a reaction with metal oxide phases, resulting in the formation of carbonate phase. This carbonate phase contributes to the absorption peaks of the carboxylate group.