Optimizing YSZ top‐coat thickness for enhanced erosion, adhesion, and hot‐corrosion resistance in plasma‐sprayed thermal barrier coatings: finite element predictions and experimental validation

Finite element modeling combined with experimental validation was employed to evaluate the effect of YSZ top‐coat thickness on the performance of thermal barrier coatings (TBCs) for locomotive turbochargers. Two coating configurations, with 100 μm (Sample A) and 200 μm (Sample B) top coats over a CoNiCrAlY bond coat, were analyzed. Computational results predicted a 31% reduction in peak von Mises stress and a 40 °C lower substrate temperature for the thicker coating. Experimental investigations—including SEM/EDS, XRD phase analysis, pull‐off adhesion, solid particle erosion (ASTM G76), and Na 2 SO 4 ‐induced hot corrosion (ISO 17245:2015)—confirmed these predictions. Sample B exhibited 19.3% lower erosion weight loss, a slight increase in adhesion strength (25 ± 2 MPa vs. 23 ± 2 MPa), and 27% reduced hot corrosion degradation compared to Sample A. Microstructural examination revealed better porosity control, preserved tetragonal ZrO 2 stability, and slower TGO growth in the thicker coating. The strong correlation between modeling and experimental results validates a stress‐based optimization approach for TBC thickness selection. These findings demonstrate that strategic top‐coat thickness enhancement significantly improves thermal, mechanical, and environmental resistance, providing critical guidance for TBC design in high‐temperature, corrosive turbocharger applications.