Extending interfacial toughness and thermal cycling lifetime of thermal barrier coatings via interfacial 3D pattern

Weak interface bonding is a critical factor that compromises the long-term durability of the thermal barrier coatings. To mitigate this, we introduce an innovative interface-strengthening approach by integrating four types of 3D patterns at the top coat/bond coat interface using the laser cladding technique. Tensile tests demonstrate a significant enhancement in interfacial bonding strength, increasing by over 139.2% from 21.6 +/- 1.7 MPa for conventional thermal barrier coatings without patterns to 51.67 MPa for the patterned coatings. Moreover, the thermal cycling lifetime has been extended by 41%, from 1026 +/- 25 cycles for the conventional coating to 1936 +/- 164 cycles for the patterned coating. This enhancement in interfacial toughness and thermal cycling lifetime is primarily because of the blocking and deflection effects of 3D patterns on interfacial crack propagation. Besides, the geometric parameters of the patterns play a crucial role in determining the failure behavior of the thermal barrier coatings. This strategy presents a practical solution for the development of durable thermal barrier coatings and provides the valuable insights for the optimization of other heterogeneous interfaces.