Modeling and characterisation of depletion of aluminium in bond coat and growth of mixed oxides in thermal barrier coatings

摘要: Most existing thermal barrier coating (TBC) studies do not account for the depletion of Al in BC and growth mixed oxides (MOs). In this complementary study, we modify extend our earlier (Lim Meguid Mater Des, 2019. https://doi.org/10.1016/j.matdes.2018.107543 ) coupled finite volume (FV)–finite element (FE) formulations to incorporate diffusion reactions Cr BC. The modified/expanded FV–FE are supported by introduction appropriate diffusion–reaction equations high temperature oxidation model. Three aspects work were accordingly examined. Firstly, FV model is used describe reaction O2 formation α-Al2O3. β-phase rate predicted agrees well with experimental findings. Secondly, through TGO that leads an external layer MOs simulated using Our simulations reveal form early stage exposure, although there sufficient sustain α-Al2O3 phase. We reasoned internal cell Lastly, studied effect roughness on (α-Al2O3 + MOs). show peak undulation depletes faster interface between β + γ phase γ straightens over time. Furthermore, results tend valley due shorter path.