Wrinkling of α-alumina films grown by oxidation—II. Oxide separation and failure

Cyclic and Isothermal Oxidation at 1,100 °C of a CVD Aluminised Directionally Solidified Ni Superalloy

“…This leads to a change of kinetics, where the small undulations of the curve can be related to the successive spallation and spontaneous reformation of the oxide scale due to a continuous distribution of Al in the underlying coating. Cooling of the scale produces regions of tensile stress across the interface at the convex areas and corresponding compressive stress in the concave regions [51]. These observations would be consistent with cyclic plastic strains in the coating driven by growth strains in the oxide combined with thermal-expansion mismatch [43].…”

Preparation and Oxidation of Novel Electrodeposited Cu–Ni–Cr Nanocomposites

“…This may be one reason that scale spallation did not occur for this nanocomposite. The other reason may be that the scale stresses were easier released by scale wrinkling (see 8c), 23,24 which is apparently more significant than the oxide wrinkling on S2 (see Fig. 8b).…”

Thermal cycling behavior of EB-PVD TBCs on CVD platinum modified aluminide coatings

“…4d. During cooling from the cyclic temperature, tensile stresses develop at the convex areas normal to the interface and may lead to interface separation and initiate local failure [26]. For this reason, cracking between TGO layer and bond coat interface firstly occurs along grain-boundary ridges on the grit-blasted surface.…”

“…As this layer is formed at high temperature, it is subjected to thickening as well as lengthening growth. The lengthening component may be interpreted as new alumina forming at the grain boundaries of the existing grains [25,26]. The fracture path traverses through the ceramic coating to TGO interface, as well as at the TGO to bond coat interface (Fig.…”