High-temperature electrical insulation degradation mechanism in TiN/Ti(C, N)/Al2O3 composite ceramic films

Understanding the mechanisms behind insulation degradation is essential for effectively enhancing the electrical insulation properties of insulating layers. This study provides a comprehensive analysis of the high-temperature degradation of electrical insulation in titanium nitride/titanium carbonitride/alumina (TiN/Ti(C, N)/Al 2 O 3 ) composite ceramic films, utilizing band theory, oxidation kinetics, and microstructural characterization. The results show that the resistance decay of these composite films at elevated temperatures follows an exponential function, consistent with band theory and statistical physics principles. At high temperatures, oxygen reacts spontaneously with TiN/Ti(C, N), leading to the formation of highly conductive titania (TiO 2 ). Due to surface compressive stress and concentration gradients , the newly formed TiO 2 diffuses through potential migration pathways to the surface of the Al 2 O 3 insulation layer , causing short circuits and ultimately resulting in the failure of the insulating film. Furthermore, thermal cycling stress, combined with differences in the coefficients of thermal expansion between the substrate, the composite films, and between Al 2 O 3 and TiO 2 , causes the majority of the composite films to detach from the substrate surface . The findings of this study enhance the understanding of the high-temperature electrical insulation failure mechanisms in multilayered TiN/Ti(C, N)/Al 2 O 3 coatings, offering valuable insights for improving their high-temperature electrical insulation performance.