Effect of Si alloying on the self-healing kinetics of Cr2AlC and phase formation of Nb2AlC thin films

IIn this thesis, the effect of Si alloying on the phase stability and self-healing kinetics of Cr₂AlC films as well as the phase formation of Nb₂AlC thin films were investigated by theory and experiments. It was found that Si changes affects the microstructure microstructural evolution and during oxidation kinetics of Cr₂AlC. Alloying Cr₂AlC with up to 0.7 at% Si leads to 40% causes an increase of thein self-healing rate of up to 40 ± 17% under the deposition conditions studied. Electron microscopy and atom probe tomography data support the notion that the here reported Si concentration induced 40% increase in self-healing rate is enabled by the Si concentration induced, and hence concomitant, increase in nucleation density of the healing agent. The lowest formation temperature for Nb₂AlC is between 710 and 750 °C under the deposition conditions studied and a predominantly single phase Nb₂AlC region where 99% of the X-ray diffraction intensity originates from Nb₂AlC was identified from the Nb-Al-C thin film deposited at 870 °C. The study of the effect of Si alloying on the self-healing kinetics of Cr₂AlC films contributes to the identification and understanding of the basic design principles for crack and erosion damage healing materials.