Microstructure and mechanical properties of multilayer-lined composite pipes prepared by SHS centrifugal-thermite process

Using a self-propagating high-temperature synthesis centrifugal-thermite process, pipes were lined with a multiphase ceramic layer. The ceramic layer was metallurgically joined with an intermediate intermetallic layer, situated between the base metal and the ceramic layer. The microstructures of the intermetallic layer, the multiphase ceramic layer, and the interfaces between them were investigated. The results showed that ceramic layer was composed of Al2O3, TiO2, and TiC while the intermediate layer contained AlFe, AlCrFe, and NiFe. Under the action of the centrifugal force, the phase TiC settled in the interface between the intermetallic and ceramic layers. The good wettability of TiC by ferrous metals and by Al2O3, the intermetallic layer and ceramic layer resulted in a good bond with improved bonding strength. Mechanical characterization of the pipes showed a significant improvement over conventional thermite self-propagating high-temperature synthesis (SHS) methods.