Thermal shock and oxidation behavior of multiscale silicon carbide reinforced yttria-partially stabilized zirconia thermal barrier coatings

Multiscale silicon carbide (SiC) reinforcement of yttria-stabilized zirconia (YSZ) is a promising strategy for enhancing thermal shock resistance and high-temperature oxidation resistance of thermal barrier coatings (TBCs). Herein, the use of multiscale SiC reinforced YSZ coatings as an intermediate layer in dual-layer TBCs is reported. Their thermal shock resistance, oxidation behavior, and underlying mechanisms were systematically investigated. Multiscale SiC promotes the formation of a dense protective layer during high-temperature oxidation, suppressing excessive thermally grown oxide (TGO) and the associated stress accumulation. During thermal shock, thermal mismatch and TGO-induced stresses drive crack initiation and propagation. Multiscale SiC improves the thermal shock resistance by suppressing crack growth and promoting the formation of a protective oxide layer. A higher SiC nanowire content significantly extends the coating lifetime, while agglomeration might induce localized stress concentrations and microcrack formation. Thus, multiscale SiC has the potential to regulate TGO and enhance structural stability, providing valuable guidance for designing of highly reliable TBCs, with its long-term stability requiring further evaluation.