Thermal barrier coatings with interface modified by 3D mesh patterns: Failure analysis and design optimization

Surface patterning of the bond coat using a three‐dimensional mesh offers a promising approach to improve the durability of the thermal barrier coatings ( TBC s), in which the geometry parameters of the mesh play a vital role. The objective of this work is to investigate the failure behavior of the air‐plasma sprayed TBC s with mesh, and to identify the optimal mesh design. The study revealed that the failure sequence of the TBC s with mesh patterns consisted of (I) initiation of the interfacial and ridge cracks (around the top of the mesh); ( II ) cracks propagation and buckling of the YSZ layer; ( III ) interfacial cracks deflection and coalescence with ridge cracks, leading to final spallation. The critical parameters governing each step of the failure sequence were discussed and proposed. For a typical TBC s with YSZ thickness about 200 μm, the critical mesh height h and spacing length L is about 110 μm and 7 mm, respectively, when the mesh width w is fixed at about 480 μm.