Numerical modelling of CMAS infiltration and dimensionless numbers of anti-infiltration designs of thermal barrier coatings

• The proposed multiphase flow model demonstrated excellent capability in predicting calcium–magnesium–alumina–silicate (CMAS) infiltration in thermal barrier coatings. • CMAS infiltration depth follows a power-law relation of H * = 0.377 · ( K · T ) 0 . 568 . • Thermal barrier coatings with K < 2 indicate excellent resistance to CMAS infiltration. • Thermal barrier coatings with S-shaped gaps and spherical pores can slow CMAS infiltration. Resistance to calcium–magnesium–alumina–silicate (CMAS) infiltration and corrosion is a crucial problem for safely applying thermal barrier coatings (TBCs) in advanced aero engines. This work proposes a CMAS infiltration model based on the phase-field method to simulate the CMAS infiltration process in TBCs and analyse the influence factor. Further, a key dimensionless number called relative driving force K = r σ cos ( θ c ) t s μ ϛ 2 h TC 2 was found to determine the CMAS infiltration depth using dimensional analysis. A criterion of K <2 was derived and was considered to be the evaluation standard of TBCs with excellent CMAS infiltration resistance. Based on K minimization, novelty TBCs with microstructure of S-shaped intercolumnar gaps and spherical pores are expected to significantly improve the resistance to CMAS infiltration and corrosion.